Table 2.
Summary of studies using NIBS to influence memory function in MCI patients.
| Experiment | Participants | NIBS | Study design | Stimulation protocol | Target area | Stimulated cognitive process and outcome | Control condition | Tests/ follow-up | Results |
|---|---|---|---|---|---|---|---|---|---|
| Anderkova et al. (2015) | 8 MCI and 12 AD patients Age: 73 ± 7 | rTMS | Crossover design. Each patient received one stimulation session in a random order, over each target area | Three 22-min sessions at 10 Hz. (1/day) | IFG-STG | Sustained attention, psychomotor speed, processing efficacy, set-switching, executive functions, processing speed, attentional and visual processing, encoding and recognition | VTX | Prior and immediately after each session | Enhanced speed processing |
| Eliasova et al. (2014) | 10 aMCI patient Age: 72 ± 8 | rTMS | Cross Overdesign. Each patient received one stimulation sessions in a random order, over each target area | Two 22-min sessions at 10 Hz. (1/day) | IFG | Sustained attention, psychomotor speed, efficacy of cognitive processing, set-switching, executive functions, speed cognitive process attentional and visual processing, encoding and recognition | VTX | Prior and immediately after each session. | improvement of attention and psychomotor speed |
| Cotelli et al. (2012) | 1 aMCI patient Age: 69 22 healthy controls Age: 64 ± 4 | rTMS | Uncontrolled pre-post study | Ten 25-min sessions at 20 Hz (5/week) | IPL | Associative memory, reasoning language, learning, short and long term memory, praxis attention, executive functions | Uncontrolled | 2 baselines, immediately after stimulation protocol (2 weeks), 24 weeks | Enhanced associative memory, long term memory |
| Drumond Marra et al. (2015) | 34 MCI patients Age: 60–74 | rTMS | Double blind controlled study | Ten 25-min sessions at 10 HZ (5/week) | Left DLPFC | Cognitive processing, everyday memory, logical memory, long-term narrative memory, short-term auditory-verbal memory, rate of learning, learning and retrieval, working memory, executive functions | Sham group with a placebo coil. | Immediately and 30 days after stimulation protocol | Improved everyday memory for at least 1 month |
| Meinzer et al. (2015) | 18 MCI patients Age: 69.56 ± 5.56 18 healthy controls Age: 67.44 ± 7.27 | atDCS | Double-blind, cross-over, randomized, sham stimulation. During Cognitive Task and resting state fMRI | One session at 1 mA during 20 min. | Left ventral IFG | Cognitive processing. | Sham group: atDCS turned off after 30 s | During stimulation No follow-up | Improved word retrieval. Reduced activity in the bilateral prefrontal cortex, right middle temporal gyrus, left basal ganglia and thalamus |
| Sedlackova et al. (2008) | 7 MCI-V patients Age: 70.3 ± 8.7 | rTMS | Randomized, blind, cross-over study | One 30-min session at 10 HZ (1/day) | Left DLPFC | Executive function, working memory, and psychomotor speed. | MC (control site) | During stimulationNo follow-up | No effects |
| Turriziani et al. (2012) | 8 MCI patients 66.4 ± 5.7 100 healthy controls Age: 20–35 | rTMS | Blind, crossover study | One 10-min session at 1 Hz. | Left and right DLPFC | Cognitive processing, non-verbal recognition memory, verbal recognition memory | Sham group: coil held close to the DLPFC but angled away | Immediately after stimulation. No follow-up | Improved the performance on the non-verbal recognition memory test |
| Solé-Padullés et al. (2006) | 40 adults with SCI Age: 66.95 ± 9.43 | rTMS | Pre-post fMRI, randomized double blind sham stimulation | One 5-min session at 5 Hz | PFC | Associative memory | Sham group: coil held tangentially to the head, with its edge resting on the scalp. | Immediately after stimulation during post fMRI | Improvement in associative memory task. Higher activation of the right inferior and middle frontal giry together with the middle and superior occipital gyri. |
| Manenti et al. (2016) | 20 PD patients with MCI Age: 67.1 ± 7.2 | atDCS | Double-blind, cross-over, randomized, sham stimulation. During physical therapy. | One session at 2 mA during 25 min per (5/week) | DLPFC | Motor physical therapist for PD. Outcome evaluated: clinical neuropsychological, and motor task, | Sham group: atDCS turned off after 30 s | Prior and immediately after and 3 month follow up | Improvement in motor abilities, reduction of depressive symptoms in sham and atDCS. Improvement in the PD cognitive Rating Scale and verbal fluency test, only in tDCS. |
NIBS, Non-invasive brain stimulation; atDCS, anodal transcranial direct current stimulation; rTMS, repetitive transcranial magnetic stimulation; AD, Alzheimer’s disease; MCI, mild cognitive impairment; VMCI, vascular mild cognitive impairment; PD, Parkinson’s disease; SCI, subjective cognitive impairment; DLPFC, dorsolateral prefrontal cortex; IFG, inferior frontal gyrus; IPL, inferior parietal lobule; MC, motor cortex; PFC, prefrontal cortex; STG, superior temporal gyrus; VTX, vertex.