Abstract
Brain stimulation has become one of the most acceptable therapeutic approaches in recent years and a powerful tool in the remedy against neurological diseases. Brain stimulation is achieved through the application of electric currents using non‐invasive as well as invasive techniques. Recent technological advancements have evolved into the development of precise devices with capacity to produce well‐controlled and effective brain stimulation. Currently, most used non‐invasive techniques are repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), whereas the most common invasive technique is deep brain stimulation (DBS). In last decade, application of these brain stimulation techniques has not only exploded but also expanded to wide variety of neurological disorders. Therefore, in the current review, we will provide an overview of the potential of both non‐invasive (rTMS and tDCS) and invasive (DBS) brain stimulation techniques in the treatment of such brain diseases.
Keywords: deep brain stimulation, invasive brain stimulation, non‐invasive brain stimulation, repetitive transcranial magnetic stimulation, transcranial direct current stimulation, transcranial magnetic stimulation
Diagrams of representative non‐invasive and invasive brain stimulation techniques. (A) represents the standard figure‐eight transcranial magnetic stimulation (TMS) coil, which is connected to intensity and pulse regulator. (B) exhibits bipolar transcranial direct current stimulation (tDCS) electrodes and current regulator. (C) shows deep brain stimulation (DBS) microelectrodes inserted in brain and connected to a stimulator implanted elsewhere.
1. INTRODUCTION
There are two modalities of brain stimulation: non‐invasive and invasive, and along the time, several techniques have been developed within both categories (Box 1). The non‐invasive stimulation is done by two techniques: transcranial magnetic stimulation (TMS), which was introduced in 1985, 1 and transcranial electrical stimulation (tES). The transcranial direct current stimulation (tDCS) is the most modern and most used form of tES. These non‐invasive techniques are applied directly through electrodes or magnetic fields on the scalp of the patient to produce electrical currents for the stimulation of brain cells. However, invasive stimulation, such as deep brain stimulation (DBS), involves passing electric current into the subcortical area through surgically implanted electrodes deeper in the brain. Unlike invasive, non‐invasive methods do not require anesthesia and surgical operation, and therefore, these are preferred over invasive methods. Both non‐invasive techniques, rTMS and tDCS, have been used in clinical settings, are already regulated for clinical use in many countries and, currently, are approved by the Food and Drug Administration (FDA). On the other hand, invasive technique, DBS, is also an FDA‐approved treatment and, in the late 1980s, it began to emerge as a life‐changing therapy for patients with involuntary movement disorders.
BOX 1. Various types of brain stimulation techniques.
1. Non‐invasive brain stimulation techniques modulate brain excitability by the application of either magnetic fields over the head or electrical currents directly through electrodes placed on the scalp. There are several modalities of use in both the techniques.
1.1. Transcranial magnetic stimulation (TMS)
In TMS, short electromagnetic pulses are administered through a magnetic coil. In repetitive TMS (rTMS), a figure‐of‐eight coil is used to stimulate precise but relatively superficial locations on the cortex, whereas in deep TMS (dTMS) a H‐coil targets broader but deeper brain areas.
Magnetic seizure therapy (MST) involves the induction of a seizure by applying high‐intensity magnetic field pulses through a magnetic coil placed on the head. The stimulation is limited to a focused area in the brain, and therefore, it produces minimal effect in surrounding tissues.
1.2. Transcranial electrical stimulation (tES)
The most modern and used version of tES is transcranial direct current stimulation (tDCS). In tDCS, continuous but low‐intensity current is applied through electrodes (anode and cathode) placed on the scalp. High‐definition tDCS (HD‐tDCS) is a variant of this technique and in contrast to tDCS where distribution of electrical current in a target area is relatively diffused; HD‐tDCS devices are used for increased focal stimulation of a target area.
Cranial electrotherapy stimulation (CES) is a form of neurostimulation that applies pulsed, low‐intensity current through electrodes placed on anatomical positions around the head, such as earlobes and temples.
Transcranial random noise stimulation (tRNS) is achieved by applying an alternating current which varies in frequency and amplitude (within a certain range) throughout the stimulation period. However, transcranial alternating current stimulation (tACS) is frequency specific stimulation, and therefore, current is applied at a fixed frequency rather than randomly acquired range of frequencies as in case of tRNS.
Electroconvulsive therapy (ECT) involves a brief electrical stimulation of the brain while the patient is under anesthesia. Electrodes are placed at specific sites on the scalp and electrical currents are passed through the brain to produce a brief seizure.
2. Invasive brain stimulation techniques generally involve surgery to implant an electrode deep in the brain to deliver electrical pulses at a high frequency. The intensity and frequency of electrical currents are controlled by a generator implanted under the skin of chest.
Deep brain stimulation (DBS) involves application of continuous stimulation through a pair of electrodes implanted in a specific area of brain. However, vagus nerve stimulation (VNS) implicates the delivery of electrical pulses to the left vagus nerve through a device implanted under the skin.
2. NON‐INVASIVE BRAIN STIMULATION
2.1. Transcranial magnetic stimulation
TMS is a neuromodulation technique that uses large transient magnetic fields to induce focal electrical fields in a specific brain area, and the availability of sophisticated equipment has made it possible to employ repetitive TMS (rTMS). The effects of rTMS vary depending on the shape of the coil (figure of eight, H coil, double cone coil), 2 pacing pattern (high frequency, low frequency, theta‐burst), and stimulation site. In fact, TMS is considered as a tool with great therapeutic potential because it is safe and the risk of severe negative side effects upon application is very low.
2.1.1. Mechanism of action
TMS induces short pulses of intracranial electrical current and is applied in several ways: as single pulse, as paired pulse to the same or different brain areas, or as rTMS. Single‐pulse stimulus depolarizes neurons 3 ; however, rTMS can induce changes in excitability of the cerebral cortex, locally as well as in neurons at areas far from the stimulation site, along functional anatomical connections. 3 , 4 Although underlying mechanisms of the therapeutic outcomes of rTMS application have not been fully elucidated, rTMS can induce changes in cerebral blood flow, 5 oxygen consumption, cortical activity, 6 and release of neurotransmitters. 7 , 8 Therefore, it has been argued that these functional changes might be associated with positive clinical results.
2.1.2. TMS application to alleviate the symptoms of neurological disorders
For effective rTMS application, adjustments in both spatial and temporal parameters are essential. In literature, for the determination of spatial location of a target in brain, 52% of the studies have used magnetic resonance imaging, 27% scalp measurement, 15% functional magnetic resonance imaging, and 6% hotspot targeting. 9 Similarly, temporal parameters, which include stimulation frequency, number of pulses per trial, and interval duration between each stimulus, are also diverse. For stimulation frequency, few studies have used low‐frequency stimulation of 1 Hz and most studies have applied a high‐frequency stimulation ranging from 5 Hz (in 14%), 10–19 Hz (in 67%), to more than 20 Hz (in 20%). The stimulus interval time varied from 300 ms to 37,400 ms, and the number of pulses administered in each trial was <10; however, some studies applied more than 20 pulses. Additionally, combining rTMS with concurrent behavioral interventions in some neurological disorders has turned out to be more effective. 10 Therapeutic benefits of rTMS are summarized in Table 1.
TABLE 1.
Disorder | Participant size | Stimulation site | Stimulus frequency | Outcome of treatment |
Effect size or SMD and p‐value |
References and comment |
---|---|---|---|---|---|---|
Parkinson´s disease | 646 | M1 | High frequency (10–50 Hz) | Long‐term motor function improvement |
0.97 (p < 0.01) |
Yang et al., 2018 14 (Meta‐analysis of 23 studies) |
Alzheimer´s disease | 293 | DLPFC | Low frequency (1 Hz) | Improvement in memory functions | 1.53 (p < 0.005) | Chou et al., 2019 25 (Meta‐analysis of 13 studies) |
High frequency (5–20 Hz) | 0.77 (p < 0.005) | |||||
94 | DLPFC | High frequency (>1 Hz) | Improvement in cognitive functions | 1.00 (p = 0.0008) | Liao et al., 2015 26 (Meta‐analysis of 7 studies) | |
Attention deficit hyperactivity disorder | 43 | PFC | High frequency (18 Hz) | Improvement in ADHD symptoms | 0.96 (p = 0.0009) | Alyagon et al., 2020 33 (Clinical trial) |
7 | PFC | High frequency (10 Hz) | Improvement in ADHD symptoms | 0.48 (p < 0.05) | Weaver et al., 2012 32 (Pilot study) | |
Dyslexia | 10 | IPL and STG | High frequency (5 Hz) | Improvement in reading performance | 0.54 (p < 0.001) |
Costanzo et al., 2013 35 (Pilot study) |
Autism spectrum disorder | 317 |
DLPFC (16 studies) PFC (3 studies) SMA (3 studies) PMC (1 study) Multiple sites (1 study) |
Low to high frequency (0.5–50 Hz) | Significant improvement in repetitive behavior, sociability, and cognitive and executive functions | ND | Khaleghi et al., 2020 42 (Review of 24 studies) |
339 |
DLPFC (15 studies) PFC (3 studies) PMC (3 studies) Multiple sites (2 study) |
Low to high frequency (>0.5) | Improvement in repetitive and stereotyped behaviors, social behavior, and executive functions |
0.29–0.53 (p < 0.008) |
Barahona‐Correa et al., 2018 41 (Meta‐analysis of 23 studies) | |
Chronic pain | 682 |
M1 |
High frequency (5–20 Hz) | Significant reduction in pain intensity (up to 32%) | ND | Gatzinsky et al., 2020 50 (Systematic review of 24 studies) |
250 | M1 | High frequency (5–20 Hz) | Significant pain relief and long‐lasting analgesic effect | ND | Hamid et al., 2019 48 (Systematic review of 7 clinical trials) | |
727 | M1 | High frequency (5–20 Hz) | Significant pain relief (>30%) | ND | Galhardoni et al., 2015 49 (Review of 27 clinical trials) |
Abbreviations: DLPFC, dorsolateral prefrontal cortex; IPL, inferior parietal lobe; M1, primary motor cortex; ND, not determined; PFC, prefrontal cortex; PMC, premotor cortex; SMA, supplementary motor area; SMD, standardized mean difference; STG, superior temporal gyrus.
Parkinson's disease
A progressive degeneration of dopaminergic neurons in the basal ganglia leads to severe impairment in motor functions of patients with Parkinson´s disease (PD). The application of rTMS by several clinical groups found that PD patients improved motor functions upon application of high‐frequency (10 Hz) rTMS in M1 area of motor cortex and most patients showed improvements in bradykinesia. 11 , 12 , 13 , 14 , 15 The motor improvements in PD patients were associated with changes in neuronal activity. 16 Furthermore, a meta‐analysis of 23 studies with total of 646 patients found that the application of rTMS to the motor cortex area of brain produces a significant long‐term improvement in motor functions. 14
Alzheimer's disease
Alzheimer's disease (AD) is a neurodegenerative disease that causes cognitive deficits and is the most common form of dementia. The application of rTMS in AD patients has been shown to improve motor 17 , 18 and cognitive functions. 19 , 20 The cognitive improvement was observed immediately and one month after the treatment but not after 6 months. 21 , 22 Furthermore, the application of high‐frequency (10 Hz) TMS significantly improved cognitive performance in AD patients with mild deterioration, 23 , 24 and similarly, meta‐analysis studies found that rTMS is effective in treating cognitive dysfunctions in AD patients. 25 , 26
Vascular dementia
Vascular dementia is the second most common form of dementia after AD, and it accounts for at least 20% of dementia cases. A study in rats with vascular dementia showed that application of TMS was able to improve spatial learning and memory, 27 protect pyramidal cells from apoptosis, and promote synaptic plasticity in the CA1 area of the hippocampus. 28 , 29 However, the studies in humans are scarce. Nevertheless, a randomized controlled pilot study in 7 patients with vascular disease and mild cognitive deficits without vascular dementia showed that one session of high‐frequency rTMS applied to the left DLPFC improved executive functioning, whereas no effects on any other cognitive functions were observed. 30 Another study in patients with vascular disease and vascular cognitive impairments but without dementia found that the stimulation of left DLPFC and not left M1 area with 4 sessions of rTMS significantly improved the cognitive ability. 31
Attention deficit hyperactivity disorder
Attention deficit hyperactivity disorder (ADHD) is primarily associated with deficits in attention and executive functions. A pilot study in 9 adolescents and young adults with ADHD found significant improvement after the treatment with high‐frequency (10 Hz) rTMS. 32 Another pilot study in 43 adult ADHD patients showed that the application of high‐frequency (18 Hz) rTMS for 3 weeks caused significant improvement in ADHD symptoms. 33 In contrast, a study in adult ADHD patients reported no effect after application of deep TMS (dTMS). 34 The effect of standard rTMS is more focal and reaches a depth of 0.7 cm, while the effect of dTMS is broader and reaches a significant depth of 3.2 cm. Therefore, it seems that a focal treatment with rTMS is more effective in the treatment of ADHD.
Dyslexia
Dyslexia affects at least 5% of school‐aged children and is characterized by difficulty in learning to read and spelling of written texts. Most dyslexics have difficulties in relating alphabet letters to the sounds they symbolize. So far, there is no study with larger number of dyslexia patients. In a study with 10 dyslexics, treatment with high‐frequency (5 Hz) rTMS to areas that are not very active in dyslexics during reading, such as the left superior temporal gyrus and the left inferior parietal lobe, improved both precision and reading speed of the dyslexic adults. 35
Autism spectrum disorder
Autism spectrum disorder (ASD) is a developmental disorder and is characterized by the difficulty in social interaction and emotional recognition, repetitive behaviors, and lack of interest. The prevalence of ASD is estimated at 1 every 110 births with a higher incidence in children. 36 , 37 , 38 In a study, application of low‐frequency (1 Hz) rTMS on DLPFC area of autistic patients caused significant improvements in the process of goal recognition, reduction of motor errors to specific stimuli, and reduction of repetitive and stereotactic behaviors. 39 Another study showed that autistic youths as well as adults improved their executive functions after the application of high‐frequency (20 Hz) rTMS on the DLPFC. 40 In the same line, a review of 24 studies with 317 ASD patients and a meta‐analysis of 23 studies with 339 ASD patients found that the application of rTMS improved the ASD symptoms in patients. 41 , 42
Down syndrome
Down syndrome is a genetic disorder; however, patients with Down syndrome show various neurological symptoms, such as neuromotor abnormalities, reduced learning capacity, cognitive and language alterations, and hampered reading skills. 43 , 44 , 45 The first study with TMS on the motor cortex showed that young people with Down syndrome have normal cortical excitability, but altered cortical synaptic plasticity. 46 So far, there is no study of TMS application to improve the language and cognitive alterations in Down syndrome.
Chronic pain
Chronic pain is a disorder associated with various pathologies and is thought to develop from CNS nerves damage. It has been shown that a single stimulation with high‐frequency TMS produced small (12%) but short‐term reduction in pain intensity, which was not considered as clinically meaningful. 47 However, a systematic review of 12 randomized clinical trials involving 350 patients with focal or generalized chronic pain found that low‐frequency rTMS stimulation produced no effect, whereas high‐frequency stimulation induced long‐lasting analgesic effect and meaningful relief from chronic pain. 48 Similarly, other systematic reviews and meta‐analysis have identified that rTMS 49 , 50 as well as rTMS combined with exercise 51 has beneficial effect on relieving patients from chronic pain.
2.2. Transcranial direct current stimulation
tDCS is the most used form of electrical stimulation. In comparison with rTMS, tDCS is not as powerful and generates weak stimulus; however, it is relatively easy to use and transport, lot less expensive, and it has low incidence of side effects. The effect of tDCS varies according to the type of current (direct, alternating, pulsed, random noise), polarity (anodal or cathodal), current intensity, and stimulation site. 52
2.2.1. Mechanism of action
tDCS modulates neural activity by delivering low‐amplitude electrical current through electrodes and therefore causes a change in the cortical excitability. An anodal tDCS stimulation enhances excitatory synaptic transmission by stimulating glutamate transmission and suppressing gamma‐aminobutyric acid (GABA) transmission and that the change in the balance between glutamate and GABA activities leads to modification in functional connectivity between brain regions. 53 , 54 , 55 , 56 The effect of anodal tDCS stimulation also extends to other brain areas through decrease/increase in axonal release of monoamine transmitters, such as dopamine. 57 In addition, an anodal tDCS stimulation has been shown to cause induction in long‐term potentiation (LTP), 58 increase in cAMP accumulation 59 and mRNA expression, 60 which are kinds of biological activities that facilitate the processing of cognitive functions. 61
2.2.2. tDCS application to alleviate the symptoms of neurological disorders
Therapeutic benefits of tDCS are summarized in Table 2.
TABLE 2.
Disorder | Participant size | Stimulation site | Stimulus current density (mA/cm2) | Outcome of treatment |
Effect size or SMD and p‐value |
References and comment |
---|---|---|---|---|---|---|
Alzheimer´s disease |
146 |
DLPFC (3 studies) Temporal cortex (3 studies) Temporoparietal areas (1 study) |
0.06–0.08 (single session) | Improvement in cognitive performance | 0.84 (p = 0.002) | Cai et al., 2019 65 (Meta‐analysis of 7 studies) |
93 |
DLPFC (3 studies) Temporoparietal areas (1 study) Temporal cortex (1 study) |
0.06–0.08 | Improvement in cognitive functions |
1.35 (p < 0.001) |
Hsu et al., 2015 67 (Meta‐analysis of 5 studies) | |
Parkinson´s disease |
325 |
M1 (9 studies) DLPFC (4 studies) PFC (1 study) Multiple sites (4 studies) |
0.028–0.13 | Improvement in locomotion | 0.36 (p = 0.001) | Lee et al., 2019 69 (Meta‐analysis of 18 studies) |
152 |
M1 (4 studies) PFC (2 studies) Multiple sites (3 studies) |
0.02–0.06 | Improvement in gait | 0.61 (p = 0.005) | Goodwill et al., 2017 70 (Meta‐analysis of 9 studies) | |
Attention deficit hyperactivity disorder |
241 |
DLPFC (10 studies) IFG (1 study) |
0.02–0.08 | Significant improvement in attention, inhibitory control and working memory | ND | Cosmo et al., 2020 88 (Systematic review of 11 studies) |
169 | DLPFC | 0.028–0.08 | Improvement in inhibitory control and working memory | 2.42–2.76 (p < 0 0.015) | Salehinejad et al., 2019 91 (Meta‐analysis of 9 studies | |
Dyslexia | 10 | Temporoparietal areas | 0.04 | Improvement in text accuracy, word recognition speed, perception, and attentional focusing | 2.50 (p = 0.01) |
Lazzaro et al., 2021 84 (Pilot study) |
63 | Temporoparietal areas | 0.04 | Significant improvement in reading ability | ND | Finisguerra et al., 2019 82 (Systematic review of 3 studies) | |
Autism spectrum disorder | 84 |
DLPFC (6 studies) Temporoparietal junction (1 study) Multiple sites (1 study) |
0.02–0.08 | Significant improvement in repetitive behavior, sociability, and cognitive and executive functions | ND | Khaleghi et al., 2020 42 (Systematic review of 8 studies) |
69 | DLPFC | 0.028–0.17 | Reduction in ASD symptoms | ND | Osorio et al., 2019 74 (Systematic review of 5 studies) | |
266 |
DLPFC (10 studies) Temporoparietal junction (3 studies) M1 (2 studies) Multiple sites (4 studies) |
0.028–0.08 | Improvement in socialization, repetitive behavior, and sensory and cognitive awareness | 0.97 (p < 0.001) | García‐González et al., 2021 72 (Meta‐analysis and review of 19 studies) | |
Epilepsy | 328 |
Temporal lobe (2 studies) Parietal lobe (2 studies) M1 (2 studies) Multiple sites (21 studies) |
0.028–0.17 | Significantly reduced seizures frequency | ND | Sudbrack‐Oliveira et al., 2019 100 (Systematic review of 27 studies) |
128 |
Temporal lobe (2 studies) Temporoparietal areas (1) M1 (3 studies) Multiple sites (6 studies) |
0.028–0–083 | Significantly reduced seizures frequency | ND | Regner et al., 2018 98 (Systematic review of 12 studies) | |
Cerebral palsy | 128 |
M1 |
0.028–0.04 | Significant improvement in gait, mobility, and balance | ND | Fleming et al., 2018 105 (Review of 10 studies) |
373 | M1 | 0.028–0.04 | Improvement in velocity, stride length, and cadence | 3.75–4.48 (p < 0.0005) | Saleem et al, 2019 107 (Review and meta‐analysis of 17 studies) | |
178 |
M1 (8 studies) Cerebellum (1 study) |
0.028–0.04 | Improvement in gait velocity and step length | 0.23 (p < 0.01) | Hamilton et al., 2019 106 (Review and meta‐analysis of 9 studies) | |
Chronic pain | 747 | M1 | 0.025–0.083 | Reduction in pain intensity and improvement in quality of life | 0.43–0.66 (p < 0.05) | O´Connell et al., 2018 47 (Review and meta‐analysis of 27 studies) |
Abbreviations: DLPFC, dorsolateral prefrontal cortex; IFG, inferior frontal gyrus; M1, primary motor cortex; ND, not determined; PFC, prefrontal cortex; SMD, standardized mean difference.
Alzheimer's disease
Studies have shown that tDCS can stabilize verbal memory in patients with AD dementia 62 and enhance the listening comprehension. 63 The stimulation of left DLPFC with tDCS for 5 days produced significant improvement in immediate and delayed recall performance of a picture memory and that this improvement persisted for one month. 64 In addition, a meta‐analysis of 7 studies with a total of 146 mild‐to‐moderate AD patients showed that tDCS stimulation significantly improved the cognitive functions. 65 Similarly, other meta‐analysis studies also found an improvement in cognitive functions of AD patients after tDCS stimulation. 66 , 67
Parkinson's disease
Several studies have shown that tDCS is beneficial in improving movement disorders in PD patients. A systematic review of 29 studies involving single tDCS session with 256 PD patients and repeated tDCS sessions with 294 PD patients found significant improvement in motor symptoms, including mobility, balance, gait velocity, and falling. 68 Similarly, meta‐analysis of 18 studies in 325 PD patients and of 9 studies in 152 PD patients revealed that tDCS stimulation significantly improved PD symptoms, including walking performance, gait, and bradykinesia. 69 , 70
Autism spectrum disorder
An application of tDCS in children and adolescents with ASD has been shown to increase brain functional connectivity 71 and cause improvement in behavioral and cognitive symptoms. 72 , 73 , 74 Both cathodal and anodal tDCS stimulation are adequate in successfully reducing ASD symptoms even in medication‐resistant patients. 75 , 76 , 77
Down syndrome
A study with 22 Down syndrome children of ages between 6 and 12 years showed that the application of 10 sessions of anodal tDCS on the primary motor cortex during the upper limb motor training enhanced motor control for a reach movement. 78 Similarly, a case report found that anodal tDCS combined with upper limb motor training led to improvement in duration and velocity of movement. 79 Even though these results are encouraging, there is lack of comprehensive studies on the effects of tDCS application in patients with Down syndrome.
Dyslexia
Studies in dyslexic children and adolescents have shown that a treatment with tDCS causes improvement in reading skills and reduction in word reading errors and wordless reading time gap. 80 , 81 , 82 , 83 A study in 10 dyslexic children further demonstrated that the application of anodal tDCS improved text accuracy, word recognition speed, motion perception, and attentional focusing. 84 In addition, tDCS stimulation combined with training for reading in children and adolescents with dyslexia produced long‐lasting improvement in reading. 85 Application of tDCS also improved reading speed and fluency in dyslexic adults. 86
Attention deficit hyperactivity disorder
Several meta‐analysis and other studies in ADHD patients have shown that the tDCS treatment increases brain connectivity and improves behavior, attention, working memory, inhibitory control, and cognitive flexibility. 87 , 88 , 89 , 90 , 91 In addition, a study in 37 ADHD patients showed that tDCS causes an improvement in impulsivity symptoms. 92
Epilepsy
Studies in children and adults with focal as well as refractory focal epilepsy have shown that a stimulation with cathodal tDCS decreases epileptiform discharges. 93 , 94 , 95 , 96 Similarly, several meta‐analysis and systematic reviews found that cathodal tDCS application in epileptic patients with either focal epilepsy or refractory focal epilepsy successfully restrained epileptiform activity and reduced seizure frequency. 97 , 98 , 99 , 100
Cerebral palsy
Cerebral palsy is a permanent movement disorder that is caused by abnormal motor development or damage to the parts of brain that control movement, balance, and posture. Recent studies in children and adolescents with cerebral palsy have shown that tDCS stimulation combined with physiotherapeutic training improves body roll speed, balance, mobility, and walking distance and decreases spasticity and gait. 101 , 102 , 103 , 104 These studies showed that single tDCS session caused improvement for a short period; however, tDCS treatment sessions ranging from several weeks to few months produced more sustained effect. A treatment with tDCS alone also improved mobility, gait, and balance in pediatric cerebral palsy patients. 105 , 106 , 107
Chronic pain
Studies have shown that a treatment with tDCS on the M1 area causes long‐lasting relief in medication‐resistant patients with chronic pain syndrome such as trigeminal neuralgia, post‐stroke pain, back pain, and fibromyalgia. 108 , 109 The efficacy of tDCS in alleviating pain has also been shown in patients with multiple sclerosis joint pain, 110 neuropathic pain, 111 spinal cord injury, 112 fibromyalgia, 113 chronic migraine, 114 foot pain, 115 and intra‐abdominal pain. 116 A meta‐analysis studies further found that a treatment with tDCS reduces chronic pain intensity. 47
3. INVASIVE BRAIN STIMULATION
3.1. Deep brain stimulation
DBS treatment implies passing electric current into the subcortical nuclei of the brain through surgically implanted electrodes. In contrast to rTMS and tDCS, DBS treatment in some of the brain nuclei has been shown to produce severe side effects.
3.1.1. Mechanism of action
Although how DBS produces improvements remains not well understood, it has been shown that DBS treatment changes brain activity in a controlled way. The effects of DBS tend to cause excitation in neighboring axons, improvement in microvascular integrity, increase in local cerebral blood flow, and stimulation in astrocytes to release calcium, which can further lead to the release of glutamate and adenosine. 117 In addition, there is evidence that DBS can induce local and possibly distal proliferation of neurons. 118 Nevertheless, from a neurophysiological point of view, the "disruption hypothesis" appears to be increasingly accepted. According to this hypothesis, DBS dissociates the input and output signals and causes a disruption in the anomalous flow of information. 119
3.1.2. DBS application to alleviate the symptoms of neurological disorders
Therapeutic benefits of DBS are summarized in Table 3.
TABLE 3.
Disorder | Participant size | Stimulation site | Stimulus (Hz) | Outcome of treatment | Effect size, SMD, or overall effect and p‐value | References and comment |
---|---|---|---|---|---|---|
Alzheimer´s disease |
132 |
Fornix (8 studies) NBM (7 studies) VC / VS (1 study) |
20–130 | Improvement in memory and reduction in cognitive decline | ND | Luo et al., 2021 124 (Review of 16 studies) |
Parkinson´s disease | 1189 |
STN (5 studies) STN/GPI (2 studies) CZI (1 study) |
130–167 | Improvement in motor function and activities of daily living | 2.40–6.36 (p < 0.02) | Bratsos et al., 2018 126 (Meta‐analysis of 8 studies) |
1252 |
STN (1 study) GPI/STN (9 studies) GPI (2 studies) PPN (2 studies) VIM (2 studies) |
25–185 | Improvement in motor functions | 3.43 (p < 0.01) | Mao et al., 2019 127 (Meta‐analysis of 16 studies) | |
Essential tremor | 1202 | VIM | 50–200 | Improvement in tremor severity (>60%) and quality of life (>56%) | ND | Giordano et al., 2020 131 (Systematic review of 38 studies) |
430 | VIM | 50–157 | Significant improvement in essential tremor | ND | Flora et al., 2010 130 (Systematic review of 17 studies) | |
Epilepsy | 328 |
ANT (20 studies) CMT (7 studies) Hippocampus (10 studies) |
60–185 | Significant reduction in seizure frequency (>56%) | ND | Zhou et al., 2018 139 (Review of 37 studies) |
150 |
ANT (1 study) CMT (2 studies) Hippocampus (4 studies) |
10–190 | Reduction in seizure frequency | 2.26–9.27 (p < 0.02) | Sprengers et al., 2017 137 (Meta‐analysis of 7 clinical trials) | |
Chronic pain | 304 | PAG/PVG and/or VPL/VPM | 5–162 | Significant reduction in pain intensity (upto 60%) | ND | Galafassi et al., 2021 141 (Systematic review of 11 studies) |
228 |
PAG/PVG and/or VPL/VPM (18 studies) ACC (2 studies) VS/ALIC (1 study) PLIC (1 study) |
5–130 | Significant reduction in pain intensity (upto 60%) | ND | Frizon et al., 2020 140 (Systematic review of 22 studies) | |
Tourette syndrome | 162 |
GPI (11 studies) Thalamus (4 study) GPI/Thalamus (6 studies) |
20–185 | Significant reduction in tic severity (>57%) | 1.96 (p < 0.001) | Coulombe et al., 2018 145 (Meta‐analysis of 21 studies) |
150 |
GPI (19 studies) Thalamus (17 studies) GPI/Thalamus (4 studies) ALIC/NAC (7 studies) STN (1 study) |
20–185 | Significant reduction in tic severity (>52%) | 0.96 (p = 0.002) | Baldermann et al., 2016 147 (Meta‐analysis of 48 studies |
Abbreviations: ACC, anterior cingulate cortex; ALIC/NAC, anterior limb of the internal capsule/nucleus accumbens; ANT, anterior nucleus of thalamus; CMT, centromedian nucleus of thalamus; CZI, caudal zona incerta; GPI, globus pallidus internus; NBM, nucleus basalis de Meynert; ND, not determined; PAG/PVG, periaqueductal/periventricular gray matter region; PLIC, posterior limb of internal capsule; PPN, pedunculopontine nucleus; SMD, standardized mean difference; STN, subthalamic nucleus; VC/VS, ventral capsule/ventral striatum; VIM, thalamic ventral intermediate nucleus; VPL/VPM, ventral posterior lateral/posterior medial thalamus; VS/ALIC, ventral striatum/anterior limb of the internal capsule.
Alzheimer's disease
A case study found that the forniceal DBS in a patient with severe AD symptoms improved the activities of daily living but had no effect on cognition 120 and a phase II and two‐year follow‐up study in 42 patients with more than 65 years of age and mild AD showed that the application of DBS in the fornix improved memory. 121 , 122 Similarly, a review of 16 studies with 174 AD patients and another review of 9 studies with 45 AD patients found that a stimulation with DBS in fornix caused improvement in memory and slowed down the cognitive decline. 123 , 124 In addition, application of DBS in entorhinal cortex and nucleus basalis of Meynert has also been shown to be beneficial for improving memory in AD patients. 125
Parkinson's disease
DBS is effectively used in the management of motor functions in PD patients and the most common target areas have been globus pallidus pars interna (GPi) and subthalamic nucleus (STN). Several meta‐analysis studies found that the application of DBS improved motor functions as well as daily living activities. 126 , 127 , 128 In addition, a study of combined effect of DBS in STN and levodopa medication showed that the DBS stimulation and levodopa medication independently improved motor symptoms to a similar extent in PD patients; however, the combined effect was greater than either one of the treatments. 129
Essential tremor
DBS is considered as an effective and safe therapy for essential tremor. Several meta‐analysis studies in essential tremor patients found significant improvement after DBS treatment. 130 , 131
Autism spectrum disorder
In a case report, application of DBS in basolateral amygdala caused improvement in the core symptoms of ASD and the related self‐injurious behavior in a patient of 13 years of age. 132 Similarly, in another case report, a 14‐year‐old boy with ASD and self‐injurious behavior treated with DBS in nucleus accumbens showed significant improvement as well. 133 Nevertheless, there is lack of comprehensive study in a larger number of patients to demonstrate the efficacy of DBS in ASD.
Epilepsy
Four patients with partial and generalized epileptic seizures who received DBS treatment in thalamus showed 49% reduction in seizures over a period of 44 months, and one of the patients did not suffer seizures for 15 months. 134 A multicenter, double‐blind, randomized study in 110 adults with refractory partial seizures showed decrease in seizures for 2 years 135 ; however, long‐term follow‐up of the same study further confirmed the efficacy of this therapy even 5 years after the treatment. 136 In addition, several reviews and meta‐analysis studies have shown that DBS treatment induces significant reduction in seizures frequency in epileptic as well as refractory epileptic patients. 137 , 138 , 139
Chronic pain
DBS has been shown to be effective in reducing chronic pain up to 60% in patients. 140 , 141 A study in 16 patients with chronic pain showed that DBS‐mediated stimulation of thalamus produced considerable reduction in pain and this effect persisted 36 months after the treatment. 142 Similar to the treatment in thalamus, a study of DBS in anterior cingulate cortex also found significant improvement in pain, and the effect of the treatment lasted for an average of 18 months 143 and 39 months after the treatment. 144
Tourette syndrome
Tourette syndrome is a neurodevelopmental disorder characterized by the appearance of involuntary repetitive motor and vocal tics. High percentage of patients also present other brain disorders, such as attention deficit hyperactivity disorder (ADHD) and obsessive‐compulsive disorder (OCD). A meta‐analysis study found that DBS‐mediated stimulation of both the GPi and the thalamic nucleus improved tics and decreased OCD in patients, 145 and a review of 48 studies in 120 patients with Tourette syndrome found substantial improvement in the severity of tics. 146 Similarly, other reviews and meta‐analysis studies identified that the stimulation of thalamus, globus pallidus, or nucleus accumbens produced overall improvement in the symptoms of Tourette syndrome. 147 , 148 , 149
4. CONCLUDING REMARKS
The success of brain stimulation treatment lies in the availability of an effective tool and the most desirable device would be the one which not only can penetrate deep into the brain and focally modulate a specific region and only that region but also is cheap, portable, and painless, and can be applied in awake, alert humans. However, currently available devices fall short of such expectations. Considering that brain stimulation technologies continue to evolve and advancing rapidly, more versatile tools are expected to develop in near future. Nonetheless, within the currently available non‐invasive devices, tDCS involves passing relatively weak direct current in the brain and is inexpensive and relatively safe. While TMS is more expensive and might occasionally cause a seizure (<1%), it is powerful. In contrast, tDCS cannot cause a seizure and is weak. DBS, which is an invasive technique, is often used as a last resort for treating patients who have shown no relief after other viable therapies, and compared to tDCS and TMS, DBS produces serious side effects. For example, there is high rate of suicide in patients treated with DBS, particularly with stimulation in STN and GPi areas of brain. 150 Within TMS, tDCS, and DBS techniques of brain stimulation, TMS is the most used in clinical applications. Currently, more than 2000 clinical trials are registered in clinicaltrials.gov for TMS. This number is in fact almost twice of clinical trials registered for either tDCS or DBS. In addition, TMS also supersedes in the number of publications recorded in PubMed. Considering that TMS technology continues to evolve as we have seen with the development of new broad and deep TMS coils, it is likely that TMS may adopt in future and become the most desirable and sophisticated device.
CONFLICT OF INTEREST
Authors declare no conflict of interest.
ACKNOWLEDGMENTS
J. A. Camacho‐Conde received Postdoctoral Fellowship from Intramural Research Funds of Universidad de Malaga. M. Carretero‐Rey is Research Fellow of project CTS‐586 from Junta de Andalucía.
Camacho‐Conde JA, Gonzalez‐Bermudez MDR, Carretero‐Rey M, Khan ZU. Brain stimulation: a therapeutic approach for the treatment of neurological disorders. CNS Neurosci Ther.2022;28:5–18. doi: 10.1111/cns.13769
The first two authors Jose Antonio Camacho‐Conde and Maria del Rosario Gonzalez‐Bermudez contributed equally to this work.
Funding information
This study received funding from Research, Development, and Innovation Plan of Junta de Andalucía in Spain, group grant/award number: CTS 586/20
REFERENCES
- 1. Barker AT, Jalinous R, Freeston IL. Non‐invasive magnetic stimulation of human motor cortex. Lancet. 1985;1(8437):1106‐1107. [DOI] [PubMed] [Google Scholar]
- 2. Deng ZD, Lisanby SH, Peterchev AV. Electric field depth‐focality tradeoff in transcranial magnetic stimulation: simulation comparison of 50 coil designs. Brain Stimul. 2013;6(1):1‐13. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3. Kobayashi M, Pascual‐Leone A. Transcranial magnetic stimulation in neurology. Lancet Neurol. 2003;2(3):145‐156. [DOI] [PubMed] [Google Scholar]
- 4. Klomjai W, Katz R, Lackmy‐Vallée A. Basic principles of transcranial magnetic stimulation (TMS) and repetitive TMS (rTMS). Ann Phys Rehabil Med. 2015;58(4):208‐213. [DOI] [PubMed] [Google Scholar]
- 5. Richieri R, Boyer L, Padovani R, et al. Equivalent brain SPECT perfusion changes underlying therapeutic efficiency in pharmacoresistant depression using either high‐frequency left or low‐frequency right prefrontal rTMS. Prog Neuropsychopharmacol Biol Psychiatry. 2012;39(2):364‐370. [DOI] [PubMed] [Google Scholar]
- 6. Yamanaka K, Tomioka H, Kawasaki S, et al. Effect of parietal transcranial magnetic stimulation on spatial working memory in healthy elderly persons ‐ comparison of near infrared spectroscopy for young and elderly. PLoS One. 2014;9(7):e102306. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. Lenz M, Galanis C, Muller‐Dahlhaus F, et al. Repetitive magnetic stimulation induces plasticity of inhibitory synapses. Nat Commun. 2016;7:10020. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. Su L, Cai Y, Xu Y, Dutt A, Shi S, Bramon E. Cerebral metabolism in major depressive disorder: a voxel‐based meta‐analysis of positron emission tomography studies. BMC Psychiatry. 2014;14:321. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Beynel L, Appelbaum LG, Luber B, et al. Effects of online repetitive transcranial magnetic stimulation (rTMS) on cognitive processing: A meta‐analysis and recommendations for future studies. Neurosci Biobehav Rev. 2019;107:47‐58. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Sathappan AV, Luber BM, Lisanby SH. The Dynamic Duo: Combining noninvasive brain stimulation with cognitive interventions. Prog Neuropsychopharmacol Biol Psychiatry. 2019;89:347‐360. [DOI] [PubMed] [Google Scholar]
- 11. Khedr EM, Rothwell JC, Shawky OA, Ahmed MA, Hamdy A. Effect of daily repetitive transcranial magnetic stimulation on motor performance in Parkinson's disease. Mov Disord. 2006;21(12):2201‐2205. [DOI] [PubMed] [Google Scholar]
- 12. Mally J, Farkas R, Tothfalusi L, Stone TW. Long‐term follow‐up study with repetitive transcranial magnetic stimulation (rTMS) in Parkinson's disease. Brain Res Bull. 2004;64(3):259‐263. [DOI] [PubMed] [Google Scholar]
- 13. Pascual‐Leone A, Valls‐Sole J, Wassermann EM, Hallett M. Responses to rapid‐rate transcranial magnetic stimulation of the human motor cortex. Brain. 1994;117(Pt 4):847‐858. [DOI] [PubMed] [Google Scholar]
- 14. Yang C, Guo Z, Peng H, et al. Repetitive transcranial magnetic stimulation therapy for motor recovery in Parkinson's disease: A Meta‐analysis. Brain Behav. 2018;8(11):e01132. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15. Yokoe M, Mano T, Maruo T, et al. The optimal stimulation site for high‐frequency repetitive transcranial magnetic stimulation in Parkinson's disease: A double‐blind crossover pilot study. J Clin Neurosci. 2018;47:72‐78. [DOI] [PubMed] [Google Scholar]
- 16. González‐García N, Armony JL, Soto J, Trejo D, Alegría MA, Drucker‐Colín R. Effects of rTMS on Parkinson’s disease: a longitudinal fMRI study. J Neurol. 2011;258(7):1268‐1280. [DOI] [PubMed] [Google Scholar]
- 17. Alagona G, Bella R, Ferri R, et al. Transcranial magnetic stimulation in Alzheimer disease: motor cortex excitability and cognitive severity. Neurosci Lett. 2001;314(1–2):57‐60. [DOI] [PubMed] [Google Scholar]
- 18. Julkunen P, Jauhiainen AM, Westeren‐Punnonen S, et al. Navigated TMS combined with EEG in mild cognitive impairment and Alzheimer's disease: a pilot study. J Neurosci Methods. 2008;172(2):270‐276. [DOI] [PubMed] [Google Scholar]
- 19. Bentwich J, Dobronevsky E, Aichenbaum S, et al. Beneficial effect of repetitive transcranial magnetic stimulation combined with cognitive training for the treatment of Alzheimer's disease: a proof of concept study. J Neural Transm (Vienna). 2011;118(3):463‐471. [DOI] [PubMed] [Google Scholar]
- 20. Zhao J, Li Z, Cong Y, et al. Repetitive transcranial magnetic stimulation improves cognitive function of Alzheimer's disease patients. Oncotarget. 2017;8(20):33864‐33871. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21. Nguyen JP, Suarez A, Kemoun G, et al. Repetitive transcranial magnetic stimulation combined with cognitive training for the treatment of Alzheimer's disease. Neurophysiol Clin. 2017;47(1):47‐53. [DOI] [PubMed] [Google Scholar]
- 22. Alcala‐Lozano R, Morelos‐Santana E, Cortes‐Sotres JF, Garza‐Villarreal EA, Sosa‐Ortiz AL, Gonzalez‐Olvera JJ. Similar clinical improvement and maintenance after rTMS at 5 Hz using a simple vs. complex protocol in Alzheimer's disease. Brain Stimul. 2018;11(3):625‐627. [DOI] [PubMed] [Google Scholar]
- 23. Lee J, Choi BH, Oh E, Sohn EH, Lee AY. Treatment of Alzheimer's disease with repetitive transcranial magnetic stimulation combined with cognitive training: a prospective, randomized, double‐blind, placebo‐controlled study. J Clin Neurol. 2016;12(1):57‐64. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24. Rabey JM, Dobronevsky E, Aichenbaum S, Gonen O, Marton RG, Khaigrekht M. Repetitive transcranial magnetic stimulation combined with cognitive training is a safe and effective modality for the treatment of Alzheimer's disease: a randomized, double‐blind study. J Neural Transm (Vienna). 2013;120(5):813‐819. [DOI] [PubMed] [Google Scholar]
- 25. Chou YH, Ton That V, Sundman M. A systematic review and meta‐analysis of rTMS effects on cognitive enhancement in mild cognitive impairment and Alzheimer's disease. Neurobiol Aging. 2020;86:1‐10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26. Liao X, Li G, Wang A, et al. Repetitive transcranial magnetic stimulation as an alternative therapy for cognitive impairment in Alzheimer's disease: a meta‐analysis. J Alzheimers Dis. 2015;48(2):463‐472. [DOI] [PubMed] [Google Scholar]
- 27. Zhang N, Xing M, Wang Y, Tao H, Cheng Y. Repetitive transcranial magnetic stimulation enhances spatial learning and synaptic plasticity via the VEGF and BDNF‐NMDAR pathways in a rat model of vascular dementia. Neuroscience. 2015;311:284‐291. [DOI] [PubMed] [Google Scholar]
- 28. Yang HY, Liu Y, Xie JC, Liu NN, Tian X. Effects of repetitive transcranial magnetic stimulation on synaptic plasticity and apoptosis in vascular dementia rats. Behav Brain Res. 2015;281:149‐155. [DOI] [PubMed] [Google Scholar]
- 29. Zhang XQ, Li L, Huo JT, Cheng M, Li LH. Effects of repetitive transcranial magnetic stimulation on cognitive function and cholinergic activity in the rat hippocampus after vascular dementia. Neural Regen Res. 2018;13(8):1384‐1389. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30. Rektorova I, Megova S, Bares M, Rektor I. Cognitive functioning after repetitive transcranial magnetic stimulation in patients with cerebrovascular disease without dementia: a pilot study of seven patients. J Neurol Sci. 2005;229:157‐161. [DOI] [PubMed] [Google Scholar]
- 31. Sedlackova S, Rektorova I, Fanfrdlova Z, Rektor I. Neurocognitive effects of repetitive transcranial magnetic stimulation in patients with cerebrovascular disease without dementia. J Psychophysiol. 2008;22(1):14‐19. [Google Scholar]
- 32. Weaver L, Rostain AL, Mace W, Akhtar U, Moss E, O'Reardon JP. Transcranial magnetic stimulation (TMS) in the treatment of attention‐deficit/hyperactivity disorder in adolescents and young adults: a pilot study. J ECT. 2012;28(2):98‐103. [DOI] [PubMed] [Google Scholar]
- 33. Alyagon U, Shahar H, Hadar A, et al. Alleviation of ADHD symptoms by non‐invasive right prefrontal stimulation is correlated with EEG activity. Neuroimage Clin. 2020;26:102206. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34. Paz Y, Friedwald K, Levkovitz Y, et al. Randomised sham‐controlled study of high‐frequency bilateral deep transcranial magnetic stimulation (dTMS) to treat adult attention hyperactive disorder (ADHD): Negative results. World J Biol Psychiatry. 2018;19(7):561‐566. [DOI] [PubMed] [Google Scholar]
- 35. Costanzo F, Menghini D, Caltagirone C, Oliveri M, Vicari S. How to improve reading skills in dyslexics: the effect of high frequency rTMS. Neuropsychologia. 2013;51(14):2953‐2959. [DOI] [PubMed] [Google Scholar]
- 36. Baron‐Cohen S, Scott FJ, Allison C, et al. Prevalence of autism‐spectrum conditions: UK school‐based population study. Br J Psychiatry. 2009;194(6):500‐509. [DOI] [PubMed] [Google Scholar]
- 37. Braun JM, Kalkbrenner AE, Just AC, et al. Gestational exposure to endocrine‐disrupting chemicals and reciprocal social, repetitive, and stereotypic behaviors in 4‐and 5‐year‐old children: the HOME study. Environ Health Perspect. 2014;122(5):513‐520. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38. Oberman L, Eldaief M, Fecteau S, Ifert‐Miller F, Tormos JM, Pascual‐Leone A. Abnormal modulation of corticospinal excitability in adults with Asperger’s syndrome. Eur J Neurosci. 2012;36(6):2782‐2788. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 39. Sokhadze EM, El‐Baz AS, Tasman A, et al. Neuromodulation integrating rTMS and neurofeedback for the treatment of autism spectrum disorder: an exploratory study. Appl Psychophysiol Biofeedback. 2014;39(3–4):237‐257. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 40. Ameis SH, Blumberger DM, Croarkin PE, et al. Treatment of Executive Function Deficits in autism spectrum disorder with repetitive transcranial magnetic stimulation: A double‐blind, sham‐controlled, pilot trial. Brain Stimul. 2020;13(3):539‐547. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 41. Barahona‐Correa JB, Velosa A, Chainho A, Lopes R, Oliveira‐Maia AJ. Repetitive transcranial magnetic stimulation for treatment of autism spectrum disorder: a systematic review and meta‐analysis. Front Integr Neurosci. 2018;12:27. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 42. Khaleghi A, Zarafshan H, Vand SR, Mohammadi MR. Effects of non‐invasive neurostimulation on autism spectrum disorder: a systematic review. Clin Psychopharmacol Neurosci. 2020;18(4):527‐552. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 43. Bomono L, Rosseti C. Aspects in perceptual‐motor development and sensory‐motor intelligence in down syndrome. Rev Bras Crescimento Desenvolv Hum. 2010;3:723‐734. [Google Scholar]
- 44. Robles‐Bello MA, Sánchez‐Teruel D, Camacho‐Conde JA. Variables that predict the potential efficacy of early intervention in reading in Down syndrome. Psicología Educativa. 2020;26(2):95‐100. [Google Scholar]
- 45. Roch M, Florit E, Levorato C. Follow‐up study on reading comprehension in Down's syndrome: the role of reading skills and listening comprehension. Int J Lang Commun Disord; 2015:1‐12. [DOI] [PubMed] [Google Scholar]
- 46. Battaglia F, Quartarone A, Rizzo V, et al. Early impairment of synaptic plasticity in patients with Down's syndrome. Neurobiol Aging. 2008;29(8):1272‐1275. [DOI] [PubMed] [Google Scholar]
- 47. O'Connell NE, Marston L, Spencer S, DeSouza LH, Wand BM. Non‐invasive brain stimulation techniques for chronic pain. Cochrane Database Syst Rev. 2018;4:CD008208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 48. Hamid P, Malik BH, Hussain ML. Noninvasive transcranial magnetic stimulation (TMS) in chronic refractory pain: a systematic review. Cureus. 2019;11(10):e6019. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 49. Galhardoni R, Correia GS, Araujo H, et al. Repetitive transcranial magnetic stimulation in chronic pain: a review of the literature. Arch Phys Med Rehabil. 2015;96(4 Suppl):S156‐172. [DOI] [PubMed] [Google Scholar]
- 50. Gatzinsky K, Bergh C, Liljegren A, et al. Repetitive transcranial magnetic stimulation of the primary motor cortex in management of chronic neuropathic pain: a systematic review. Scand J Pain. 2021;21(1):8‐21. [DOI] [PubMed] [Google Scholar]
- 51. Cardenas‐Rojas A, Pacheco‐Barrios K, Giannoni‐Luza S, Rivera‐Torrejon O, Fregni F. Noninvasive brain stimulation combined with exercise in chronic pain: a systematic review and meta‐analysis. Expert Rev Neurother. 2020;20(4):401‐412. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 52. Guleyupoglu B, Schestatsky P, Edwards D, Fregni F, Bikson M. Classification of methods in transcranial electrical stimulation (tES) and evolving strategy from historical approaches to contemporary innovations. J Neurosci Methods. 2013;219(2):297‐311. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 53. Bachtiar V, Near J, Johansen‐Berg H, Stagg CJ. Modulation of GABA and resting state functional connectivity by transcranial direct current stimulation. Elife. 2015;4:e08789. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 54. Hunter MA, Coffman BA, Gasparovic C, Calhoun VD, Trumbo MC, Clark VP. Baseline effects of transcranial direct current stimulation on glutamatergic neurotransmission and large‐scale network connectivity. Brain Res. 2015;1594:92‐107. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 55. Stagg CJ, Bachtiar V, Amadi U, et al. Local GABA concentration is related to network‐level resting functional connectivity. Elife. 2014;3:e01465. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 56. Yamada Y, Sumiyoshi T. Neurobiological mechanisms of transcranial direct current stimulation for psychiatric disorders; neurophysiological, chemical, and anatomical considerations. Front Hum Neurosci. 2021;15:631838. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 57. Fonteneau C, Redoute J, Haesebaert F, et al. Frontal transcranial direct current stimulation induces dopamine release in the ventral striatum in human. Cereb Cortex. 2018;28(7):2636‐2646. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 58. Ranieri F, Podda MV, Riccardi E, et al. Modulation of LTP at rat hippocampal CA3‐CA1 synapses by direct current stimulation. J Neurophysiol. 2012;107(7):1868‐1880. [DOI] [PubMed] [Google Scholar]
- 59. Hattori Y, Moriwaki A, Hori Y. Biphasic effects of polarizing current on adenosine‐sensitive generation of cyclic AMP in rat cerebral cortex. Neurosci Lett. 1990;116(3):320‐324. [DOI] [PubMed] [Google Scholar]
- 60. Jiang T, Xu RX, Zhang AW, et al. Effects of transcranial direct current stimulation on hemichannel pannexin‐1 and neural plasticity in rat model of cerebral infarction. Neuroscience. 2012;226:421‐426. [DOI] [PubMed] [Google Scholar]
- 61. Podda MV, Cocco S, Mastrodonato A, et al. Anodal transcranial direct current stimulation boosts synaptic plasticity and memory in mice via epigenetic regulation of Bdnf expression. Sci Rep. 2016;6:22180. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 62. Bystad M, Rasmussen ID, Abeler K, Aslaksen PM. Accelerated transcranial direct current stimulation in Alzheimer's Disease: a case study. Brain Stimul. 2016;9(4):634‐635. [DOI] [PubMed] [Google Scholar]
- 63. Costa V, Brighina F, Piccoli T, Realmuto S, Fierro B. Anodal transcranial direct current stimulation over the right hemisphere improves auditory comprehension in a case of dementia. NeuroRehabilitation. 2017;41(2):567‐575. [DOI] [PubMed] [Google Scholar]
- 64. Murugaraja V, Shivakumar V, Sivakumar PT, Sinha P, Venkatasubramanian G. Clinical utility and tolerability of transcranial direct current stimulation in mild cognitive impairment. Asian J Psychiatry. 2017;30:135‐140. [DOI] [PubMed] [Google Scholar]
- 65. Cai M, Guo Z, Xing G, et al. Transcranial direct current stimulation improves cognitive function in mild to moderate Alzheimer disease: a meta‐analysis. Alzheimer Dis Assoc Disord. 2019;33(2):170‐178. [DOI] [PubMed] [Google Scholar]
- 66. Freitas C, Mondragon‐Llorca H, Pascual‐Leone A. Noninvasive brain stimulation in Alzheimer's disease: systematic review and perspectives for the future. Exp Gerontol. 2011;46(8):611‐627. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 67. Hsu WY, Ku Y, Zanto TP, Gazzaley A. Effects of noninvasive brain stimulation on cognitive function in healthy aging and Alzheimer's disease: a systematic review and meta‐analysis. Neurobiol Aging. 2015;36(8):2348‐2359. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 68. Orru G, Baroni M, Cesari V, Conversano C, Hitchcott PK, Gemignani A. The effect of single and repeated tDCS sessions on motor symptoms in Parkinson's disease: a systematic review. Arch Ital Biol. 2019;157(2–3):89‐101. [DOI] [PubMed] [Google Scholar]
- 69. Lee HK, Ahn SJ, Shin YM, Kang N, Cauraugh JH. Does transcranial direct current stimulation improve functional locomotion in people with Parkinson's disease? A systematic review and meta‐analysis. J Neuroeng Rehabil. 2019;16(1):84. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 70. Goodwill AM, Lum JAG, Hendy AM, et al. Using non‐invasive transcranial stimulation to improve motor and cognitive function in Parkinson's disease: a systematic review and meta‐analysis. Sci Rep. 2017;7(1):14840. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 71. Zhou T, Kang J, Li Z, Chen H, Li X. Transcranial direct current stimulation modulates brain functional connectivity in autism. Neuroimage Clin. 2020;28:102500. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 72. Garcia‐Gonzalez S, Lugo‐Marin J, Setien‐Ramos I, et al. Transcranial direct current stimulation in Autism Spectrum Disorder: A systematic review and meta‐analysis. Eur Neuropsychopharmacol. 2021;48:89‐109. [DOI] [PubMed] [Google Scholar]
- 73. Hadoush H, Nazzal M, Almasri NA, Khalil H, Alafeef M. Therapeutic effects of bilateral anodal transcranial direct current stimulation on prefrontal and motor cortical areas in children with autism spectrum disorders: a pilot study. Autism Res. 2020;13(5):828‐836. [DOI] [PubMed] [Google Scholar]
- 74. Osório AAC, Brunoni AR. Transcranial direct current stimulation in children with autism spectrum disorder: a systematic scoping review. Dev Med Child Neurol. 2019;61(3):298‐304. [DOI] [PubMed] [Google Scholar]
- 75. Amatachaya A, Auvichayapat N, Patjanasoontorn N, et al. Effect of anodal transcranial direct current stimulation on autism: a randomized double‐blind crossover trial. Behav Neurol. 2014;2014:1‐7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 76. D'Urso G, Ferrucci R, Bruzzese D, et al. Transcranial direct current stimulation for autistic disorder. Biol Psychiatry. 2014;76(5):e5‐6. [DOI] [PubMed] [Google Scholar]
- 77. Gómez L, Vidal B, Maragoto C, et al. Non‐invasive brain stimulation for children with autism spectrum disorders: a short‐term outcome study. Behav Sci. 2017;7(3):63. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 78. Lopes JBP, Grecco LAC, Moura RCFd, et al. Protocol study for a randomised, controlled, double‐blind, clinical trial involving virtual reality and anodal transcranial direct current stimulation for the improvement of upper limb motor function in children with Down syndrome. BMJ Open. 2017;7(8):e016260. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 79. Lopes JBP, Miziara IM, Galli M, Cimolin V, Oliveira CS. Effect of transcranial direct current stimulation combined with xbox‐kinect game experience on upper limb movement in down syndrome: a case report. Front Bioeng Biotechnol. 2020;8:514. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 80. Cancer A, Antonietti A. tDCS modulatory effect on reading processes: a review of studies on typical readers and individuals with dyslexia. Front Behav Neurosci. 2018;12:162. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 81. Costanzo F, Varuzza C, Rossi S, et al. Evidence for reading improvement following tDCS treatment in children and adolescents with Dyslexia. Restor Neurol Neurosci. 2016;34(2):215‐226. [DOI] [PubMed] [Google Scholar]
- 82. Finisguerra A, Borgatti R, Urgesi C. Non‐invasive brain stimulation for the rehabilitation of children and adolescents with neurodevelopmental disorders: a systematic review. Front Psychol. 2019;10:135. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 83. Rios DM, Correia Rios M, Bandeira ID, Queiros Campbell F, de Carvalho VD, Lucena R. Impact of transcranial direct current stimulation on reading skills of children and adolescents with dyslexia. Child Neurol Open. 2018;5:2329048X1879825. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 84. Lazzaro G, Bertoni S, Menghini D, et al. Beyond reading modulation: temporo‐parietal tDCS alters visuo‐spatial attention and motion perception in dyslexia. Brain Sci. 2021;11(2):263. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 85. Costanzo F, Rossi S, Varuzza C, Varvara P, Vicari S, Menghini D. Long‐lasting improvement following tDCS treatment combined with a training for reading in children and adolescents with dyslexia. Neuropsychologia. 2019;130:38‐43. [DOI] [PubMed] [Google Scholar]
- 86. Heth I, Lavidor M. Improved reading measures in adults with dyslexia following transcranial direct current stimulation treatment. Neuropsychologia. 2015;70:107‐113. [DOI] [PubMed] [Google Scholar]
- 87. Cosmo C, Baptista AF, de Araujo AN, et al. A randomized, double‐blind, sham‐controlled trial of transcranial direct current stimulation in attention‐deficit/hyperactivity disorder. PLoS One. 2015;10(8):e0135371. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 88. Cosmo C, DiBiasi M, Lima V, et al. A systematic review of transcranial direct current stimulation effects in attention‐deficit/hyperactivity disorder. J Affect Disord. 2020;276:1‐13. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 89. Dubreuil‐Vall L, Gomez‐Bernal F, Villegas AC, et al. Transcranial direct current stimulation to the left dorsolateral prefrontal cortex improves cognitive control in patients with attention‐deficit/hyperactivity disorder: a randomized behavioral and neurophysiological study. Biol Psychiatry Cogn Neurosci Neuroimaging. 2021;6(4):439‐448. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 90. Salehinejad MA, Nejati V, Mosayebi‐Samani M, et al. Transcranial direct current stimulation in ADHD: A systematic review of efficacy, safety, and protocol‐induced electrical field modeling results. Neurosci Bull. 2020;36(10):1191‐1212. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 91. Salehinejad MA, Wischnewski M, Nejati V, Vicario CM, Nitsche MA. Transcranial direct current stimulation in attention‐deficit hyperactivity disorder: A meta‐analysis of neuropsychological deficits. PLoS One. 2019;14(4):e0215095. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 92. Allenby C, Falcone M, Bernardo L, et al. Transcranial direct current brain stimulation decreases impulsivity in ADHD. Brain Stimul. 2018;11(5):974‐981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 93. Auvichayapat N, Rotenberg A, Gersner R, et al. Transcranial direct current stimulation for treatment of refractory childhood focal epilepsy. Brain Stimul. 2013;6(4):696‐700. [DOI] [PubMed] [Google Scholar]
- 94. Faria P, Fregni F, Sebastiao F, Dias AI, Leal A. Feasibility of focal transcranial DC polarization with simultaneous EEG recording: preliminary assessment in healthy subjects and human epilepsy. Epilepsy Behav. 2012;25(3):417‐425. [DOI] [PubMed] [Google Scholar]
- 95. Yang D, Wang Q, Xu C, et al. Transcranial direct current stimulation reduces seizure frequency in patients with refractory focal epilepsy: A randomized, double‐blind, sham‐controlled, and three‐arm parallel multicenter study. Brain Stimul. 2020;13(1):109‐116. [DOI] [PubMed] [Google Scholar]
- 96. Yook SW, Park SH, Seo JH, Kim SJ, Ko MH. Suppression of seizure by cathodal transcranial direct current stimulation in an epileptic patient ‐ a case report. Ann Rehabil Med. 2011;35(4):579‐582. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 97. Gschwind M, Seeck M. Transcranial direct‐current stimulation as treatment in epilepsy. Expert Rev Neurother. 2016;16(12):1427‐1441. [DOI] [PubMed] [Google Scholar]
- 98. Regner GG, Pereira P, Leffa DT, et al. Preclinical to clinical translation of studies of transcranial direct‐current stimulation in the treatment of epilepsy: a systematic review. Front Neurosci. 2018;12:189. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 99. San‐Juan D, Morales‐Quezada L, Orozco Garduno AJ, et al. Transcranial direct current stimulation in epilepsy. Brain Stimul. 2015;8(3):455‐464. [DOI] [PubMed] [Google Scholar]
- 100. Sudbrack‐Oliveira P, Barbosa MZ, Thome‐Souza S, et al. Transcranial direct current stimulation (tDCS) in the management of epilepsy: A systematic review. Seizure. 2021;86:85‐95. [DOI] [PubMed] [Google Scholar]
- 101. Collange Grecco LA, de Almeida Carvalho Duarte N, Mendonça ME, Galli M, Fregni F, Oliveira CS. Effects of anodal transcranial direct current stimulation combined with virtual reality for improving gait in children with spastic diparetic cerebral palsy: a pilot, randomized, controlled, double‐blind, clinical trial. Clin Rehabil. 2015;29(12):1212‐1223. [DOI] [PubMed] [Google Scholar]
- 102. Gillick B, Menk J, Mueller B, et al. Synergistic effect of combined transcranial direct current stimulation/constraint‐induced movement therapy in children and young adults with hemiparesis: study protocol. BMC Pediatr. 2015;15:178. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 103. Grecco LA, Duarte Nde A, de Mendonca ME, et al. Effect of transcranial direct current stimulation combined with gait and mobility training on functionality in children with cerebral palsy: study protocol for a double‐blind randomized controlled clinical trial. BMC Pediatr. 2013;13:168. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 104. Lazzari RD, Politti F, Santos CA, et al. Effect of a single session of transcranial direct‐current stimulation combined with virtual reality training on the balance of children with cerebral palsy: a randomized, controlled, double‐blind trial. J Phys Ther Sci. 2015;27(3):763‐768. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 105. Fleming MK, Theologis T, Buckingham R, Johansen‐Berg H. Transcranial direct current stimulation for promoting motor function in cerebral palsy: a review. J Neuroeng Rehabil. 2018;15(1):121. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 106. Hamilton A, Wakely L, Marquez J. Transcranial direct‐current stimulation on motor function in pediatric cerebral palsy: a systematic review. Pediatr Phys Ther. 2018;30(4):291‐301. [DOI] [PubMed] [Google Scholar]
- 107. Saleem GT, Crasta JE, Slomine BS, Cantarero GL, Suskauer SJ. Transcranial direct current stimulation in pediatric motor disorders: a systematic review and meta‐analysis. Arch Phys Med Rehabil. 2019;100(4):724‐738. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 108. Antal A, Terney D, Kuhnl S, Paulus W. Anodal transcranial direct current stimulation of the motor cortex ameliorates chronic pain and reduces short intracortical inhibition. J Pain Symptom Manage. 2010;39(5):890‐903. [DOI] [PubMed] [Google Scholar]
- 109. Pinto CB, Teixeira Costa B, Duarte D, Fregni F. Transcranial direct current stimulation as a therapeutic tool for chronic pain. J ECT. 2018;34(3):e36‐e50. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 110. De Souza CG, Pegado R, Costa J, et al. Alternate sessions of transcranial direct current stimulation (tDCS) reduce chronic pain in women affected by chikungunya. A randomized clinical trial. Brain Stimul. 2021;14(3):541‐548. [DOI] [PubMed] [Google Scholar]
- 111. Ferreira CM, de Carvalho CD, Gomes R, Bonifacio de Assis ED, Andrade SM. Transcranial direct current stimulation and mirror therapy for neuropathic pain after brachial plexus avulsion: a randomized, double‐blind, controlled pilot study. Front Neurol. 2020;11:568261. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 112. Yeh NC, Yang YR, Huang SF, Ku PH, Wang RY. Effects of transcranial direct current stimulation followed by exercise on neuropathic pain in chronic spinal cord injury: a double‐blinded randomized controlled pilot trial. Spinal Cord. 2021;59(6):684‐692. [DOI] [PubMed] [Google Scholar]
- 113. Conde‐Antón Á, Hernando‐Garijo I, Jiménez‐del‐Barrio S, Mingo‐Gómez MT, Medrano‐de‐la‐Fuente R, Ceballos‐Laita L. Efectos de la estimulación transcraneal por corriente directa y de la estimulación magnética transcraneal en pacientes con fibromialgia. Revisión sistemática. Neurología. 2020. 10.1016/j.nrl.2020.07.024 [DOI] [PubMed] [Google Scholar]
- 114. De Icco R, Putorti A, De Paoli I, et al. Anodal transcranial direct current stimulation in chronic migraine and medication overuse headache: A pilot double‐blind randomized sham‐controlled trial. Clin Neurophysiol. 2021;132(1):126‐136. [DOI] [PubMed] [Google Scholar]
- 115. Concerto C, Al Sawah M, Chusid E, et al. Anodal transcranial direct current stimulation for chronic pain in the elderly: a pilot study. Aging Clin Exp Res. 2016;28(2):231‐237. [DOI] [PubMed] [Google Scholar]
- 116. Bayer KE, Neeb L, Bayer A, Wiese JJ, Siegmund B, Pruss MS. Reduction of intra‐abdominal pain through transcranial direct current stimulation: A systematic review. Medicine (Baltimore). 2019;98(39):e17017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 117. Pienaar IS, Lee CH, Elson JL, et al. Deep‐brain stimulation associates with improved microvascular integrity in the subthalamic nucleus in Parkinson's disease. Neurobiol Dis. 2015;74:392‐405. [DOI] [PubMed] [Google Scholar]
- 118. Okun MS, Foote KD. Multiple lead method for deep brain stimulation. In: Google Patents. 2012.
- 119. Chiken S, Nambu A. Mechanism of deep brain stimulation: inhibition, excitation, or disruption? Neuroscientist. 2016;22(3):313‐322. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 120. Lin W, Bao WQ, Ge JJ, et al. Forniceal deep brain stimulation in severe Alzheimer's disease: A case report. World J Clin Cases. 2020;8(20):4938‐4945. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 121. Lozano AM, Fosdick L, Chakravarty MM, et al. A phase II study of fornix deep brain stimulation in mild Alzheimer's disease. J Alzheimers Dis. 2016;54(2):777‐787. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 122. Leoutsakos JS, Yan H, Anderson WS, et al. Deep brain stimulation targeting the fornix for mild Alzheimer Dementia (the ADvance Trial): A two year follow‐up including results of delayed activation. J Alzheimers Dis. 2018;64(2):597‐606. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 123. Liu H, Temel Y, Boonstra J, Hescham S. The effect of fornix deep brain stimulation in brain diseases. Cell Mol Life Sci. 2020;77(17):3279‐3291. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 124. Luo Y, Sun Y, Tian X, et al. Deep brain stimulation for Alzheimer's disease: stimulation parameters and potential mechanisms of action. Front Aging Neurosci. 2021;13:619543. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 125. Khan IS, D'Agostino EN, Calnan DR, Lee JE, Aronson JP. Deep brain stimulation for memory modulation: a new frontier. World Neurosurg. 2019;126:638‐646. [DOI] [PubMed] [Google Scholar]
- 126. Bratsos S, Karponis D, Saleh SN. Efficacy and safety of deep brain stimulation in the treatment of Parkinson's disease: a systematic review and meta‐analysis of randomized controlled trials. Cureus. 2018;10(10):e3474. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 127. Mao Z, Ling Z, Pan L, et al. Comparison of efficacy of deep brain stimulation of different targets in parkinson's disease: a network meta‐analysis. Front Aging Neurosci. 2019;11:23. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 128. Peng L, Fu J, Ming Y, Zeng S, He H, Chen L. The long‐term efficacy of STN vs GPi deep brain stimulation for Parkinson disease: A meta‐analysis. Medicine (Baltimore). 2018;97(35):e12153. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 129. Vizcarra JA, Situ‐Kcomt M, Artusi CA, et al. Subthalamic deep brain stimulation and levodopa in Parkinson's disease: a meta‐analysis of combined effects. J Neurol. 2019;266(2):289‐297. [DOI] [PubMed] [Google Scholar]
- 130. Flora ED, Perera CL, Cameron AL, Maddern GJ. Deep brain stimulation for essential tremor: a systematic review. Mov Disord. 2010;25(11):1550‐1559. [DOI] [PubMed] [Google Scholar]
- 131. Giordano M, Caccavella VM, Zaed I, et al. Comparison between deep brain stimulation and magnetic resonance‐guided focused ultrasound in the treatment of essential tremor: a systematic review and pooled analysis of functional outcomes. J Neurol Neurosurg Psychiatry. 2020;91(12):1270‐1278. [DOI] [PubMed] [Google Scholar]
- 132. Sturm V, Fricke O, Buhrle CP, et al. DBS in the basolateral amygdala improves symptoms of autism and related self‐injurious behavior: a case report and hypothesis on the pathogenesis of the disorder. Front Hum Neurosci. 2012;6:341. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 133. Park HR, Kim IH, Kang H, et al. Nucleus accumbens deep brain stimulation for a patient with self‐injurious behavior and autism spectrum disorder: functional and structural changes of the brain: report of a case and review of literature. Acta Neurochir (Wien). 2017;159(1):137‐143. [DOI] [PubMed] [Google Scholar]
- 134. Lim SN, Lee ST, Tsai YT, et al. Electrical stimulation of the anterior nucleus of the thalamus for intractable epilepsy: a long‐term follow‐up study. Epilepsia. 2007;48(2):342‐347. [DOI] [PubMed] [Google Scholar]
- 135. Fisher R, Salanova V, Witt T, et al. Electrical stimulation of the anterior nucleus of thalamus for treatment of refractory epilepsy. Epilepsia. 2010;51(5):899‐908. [DOI] [PubMed] [Google Scholar]
- 136. Salanova V, Witt T, Worth R, et al. Long‐term efficacy and safety of thalamic stimulation for drug‐resistant partial epilepsy. Neurology. 2015;84(10):1017‐1025. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 137. Sprengers M, Vonck K, Carrette E, Marson AG, Boon P. Deep brain and cortical stimulation for epilepsy. Cochrane Database Syst Rev. 2017;7:CD008497. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 138. Yan H, Toyota E, Anderson M, et al. A systematic review of deep brain stimulation for the treatment of drug‐resistant epilepsy in childhood. J Neurosurg Pediatr. 2018;23(3):274‐284. [DOI] [PubMed] [Google Scholar]
- 139. Zhou JJ, Chen T, Farber SH, Shetter AG, Ponce FA. Open‐loop deep brain stimulation for the treatment of epilepsy: a systematic review of clinical outcomes over the past decade (2008‐present). Neurosurg Focus. 2018;45(2):E5. [DOI] [PubMed] [Google Scholar]
- 140. Frizon LA, Yamamoto EA, Nagel SJ, Simonson MT, Hogue O, Machado AG. Deep brain stimulation for pain in the modern era: a systematic review. Neurosurgery. 2020;86(2):191‐202. [DOI] [PubMed] [Google Scholar]
- 141. Galafassi GZ, Pires S, de Aguiar PH, et al. Neuromodulation for medically refractory neuropathic pain: spinal cord stimulation, deep brain stimulation, motor cortex stimulation, and posterior insula stimulation. World Neurosurg. 2021;146:246‐260. [DOI] [PubMed] [Google Scholar]
- 142. Abreu V, Vaz R, Rebelo V, et al. Thalamic deep brain stimulation for neuropathic pain: efficacy at three years’ follow‐up. Neuromodulation. 2017;20(5):504‐513. [DOI] [PubMed] [Google Scholar]
- 143. Levi V, Cordella R, D'Ammando A, et al. Dorsal anterior cingulate cortex (ACC) deep brain stimulation (DBS): a promising surgical option for the treatment of refractory thalamic pain syndrome (TPS). Acta Neurochir (Wien). 2019;161(8):1579‐1588. [DOI] [PubMed] [Google Scholar]
- 144. Boccard SGJ, Prangnell SJ, Pycroft L, et al. Long‐term results of deep brain stimulation of the anterior cingulate cortex for neuropathic pain. World Neurosurg. 2017;106:625‐637. [DOI] [PubMed] [Google Scholar]
- 145. Coulombe MA, Elkaim LM, Alotaibi NM, et al. Deep brain stimulation for Gilles de la Tourette syndrome in children and youth: a meta‐analysis with individual participant data. J Neurosurg Pediatr. 2018;23(2):236‐246. [DOI] [PubMed] [Google Scholar]
- 146. Schrock LE, Mink JW, Woods DW, et al. Tourette syndrome deep brain stimulation: a review and updated recommendations. Mov Disord. 2015;30(4):448‐471. [DOI] [PubMed] [Google Scholar]
- 147. Baldermann JC, Schuller T, Huys D, et al. Deep brain stimulation for tourette‐syndrome: a systematic review and meta‐analysis. Brain Stimul. 2016;9(2):296‐304. [DOI] [PubMed] [Google Scholar]
- 148. Servello D, Zekaj E, Saleh C, Zanaboni Dina C, Porta M. Sixteen years of deep brain stimulation in Tourette's Syndrome: a critical review. J Neurosurg Sci. 2016;60(2):218‐229. [PubMed] [Google Scholar]
- 149. Xu W, Zhang C, Deeb W, et al. Deep brain stimulation for Tourette's syndrome. Transl Neurodegener. 2020;9:4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 150. Appleby BS, Duggan PS, Regenberg A, Rabins PV. Psychiatric and neuropsychiatric adverse events associated with deep brain stimulation: A meta‐analysis of ten years’ experience. Mov Disord. 2007;22(12):1722‐1728. [DOI] [PubMed] [Google Scholar]