Rehabilitation for Impaired Attention in the Acute and Post-Acute Phase After Traumatic Brain Injury: A Narrative Review

Abstract

Impaired attention is the most common and debilitating cognitive deficit following a traumatic brain injury (TBI). Attention is a fundamental function that profoundly influences the performance of other cognitive components such as memory and execution. Intriguingly, attention can be improved through cognitive rehabilitation. This narrative review summarizes the essential elements of rehabilitation for attention problems in acute and post-acute TBI. In the acute phase of mild TBI, investigations into the medical history and daily life performance, neurological examination, screening and management of concomitant sleep-wake disorders or neuropsychiatric disorders, and support and education on the natural course of concussion are covered. Rehabilitation for patients with moderate-to-severe TBI consists of serial assessment for patients with disorders of consciousness and a post-traumatic confusion state. In the post-acute phase after TBI, components of rehabilitation include investigating medical history; neurological, imaging, and electrophysiological tests; evaluation and treatment of factors that may impact attention, including sleep-wake, emotional, and behavioral disorders; evaluation of attention function; and cognitive rehabilitation as a matter of course. We summarized metacognitive strategy, direct attention training, computer-based cognitive interventions, medication, and environmental control as interventions to enhance attention.

INTRODUCTION

Traumatic brain injury (TBI) affects approximately 69 million people worldwide each year and imposes varying degrees of short-and long-term disability.¹⁵⁾ In Korea, approximately 480,000 new TBI cases, including mild, moderate, and severe head injuries, occur annually, and the total medical costs of TBI have steadily increased over the last decade.¹⁹,²⁴⁾ Impairments following TBI include somatic, psychiatric, and cognitive sequelae. Treatment guidelines have not yet been established for many diseases or impairments induced by TBI.³¹⁾ Cognitive impairment is a significant barrier to returning to society as it interferes with work, relationships, and activities of daily living.³³⁾ Exacting the types of cognitive impairment following TBI is challenging because any region of the brain can potentially be affected by TBI through primary or secondary injury.⁴⁾ For this reason, more than 700 studies on cognitive rehabilitation have been conducted; however, standard treatment protocols utilized in clinical practice are still lacking.²⁸⁾

Attention is a multifaceted state function that mediates general information-processing tone and affects channel functions such as language and memory.³⁴⁾ Thus, enhancing attention is one of the key goals of cognitive rehabilitation for patients with TBI, and treatment of attention is performed prior to other cognitive treatments.³³⁾

Attentional processes are mediated by diffuse networks, including the dopaminergic and noradrenergic afferent pathways to the dorsolateral prefrontal cortex, parietal lobes, and thalamic projection system.²⁸⁾ The attention matrix is the basis of the cognitive functions of vigilance, concentration, short-term memory, and working memory, and decreased attention may manifest as perseveration, distractibility, impulsivity, and disinhibition.³⁴⁾ Currently, there is no single test for diagnosing attention impairment following TBI; hence, attention is tested using a multitude of specific cognitive tasks.

According to the model of attention described by Sohlberg and Mateer,³⁸⁾ there are 5 components of attention: focused attention, sustained attention, selective attention, alternating attention, and divided attention. Focused attention is the ability to respond discretely to specific stimuli, which may be auditory, visual, tactile, or cognitive. Sustained attention is the continuous response to the presented stimuli. Selective attention involves focusing on one task while avoiding distracting stimuli. Alternating attention concerns the ability to control attentional allocations to switch attention from one task or stimulus to another. Finally, divided attention refers to the ability to process multiple cognitive inputs simultaneously. Sustained and selective attention is needed to focus attention on one task at a time, while alternating and divided attention is required to concentrate on more than one task.

Attention problems after TBI are among the most common cognitive dysfunctions reported by patients, family members, and clinicians that limit the speed and efficiency of cognitive processing.⁴¹⁾ Attention deficits may affect more than 60% of patients with moderate to severe TBI as long as 10 years post-injury.³³⁾ In this review, we summarize the assessment and management of attentional problems encountered in the acute and post-acute phases after TBI and comprehensively incorporate recommendations and guidelines to better understand the current evidence of cognitive rehabilitation for decreased attention after TBI.

REHABILITATION OF ATTENTION IN THE ACUTE PHASE AFTER TBI

When a patient is referred for the rehabilitation of attentional problems, the rehabilitation team evaluates TBI severity and implements a systematic approach.

Rehabilitation of attention deficit after a concussion or mild TBI (mTBI)

The common cognitive domains typically affected by mTBI involve the speed of information processing, sustained attention, divided attention, executive function, and memory. Neurocognitive symptoms following mTBI resolve within days to weeks, with complete resolution by 3 months after the injury (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition [DSM-5]).⁴²⁾ When a patient is referred for attention impairment after a concussion, a comprehensive history and neurological examination should be performed (TABLE 1). Validated self-reporting questionnaires, such as the Rivermead Post-Concussion Symptoms Questionnaire or Post-Concussion Symptom Scale, are used to evaluate the presence and severity of post-concussion symptoms. The differential diagnoses and treatment of factors influencing attentional problems (i.e., pain, cognitive fatigue, sleep-wake, or neuropsychological disorders, and vestibular or visual dysfunction) should be considered.

TABLE 1. Key elements of history taking and neurological examination common across all severity and phases after traumatic brain injury in a rehabilitation setting.

Variables	Key elements
History taking	• History of present illness
	• Injury history
		- Traumatic event details, duration of loss of consciousness and/or post-traumatic amnesia
		- Glasgow coma scale score at the time of trauma presence
	• Preinjury and postinjury medical history
		- Smoking, hypertension, diabetes, hyperlipidemia, hyperhomocysteinemia, headache before injury
		- Current and past medications
	• Preinjury and postinjury mental health history
		- Premorbid personality, psychiatric conditions, substance use
	• Allergies and sensitivities
	• Social history
		- Intellectual and social development, occupation, education, place of residence, relationship and marital status, financial status, insurance, family support, patient motivation, litigation status
	• Family history
		- Medical, neurological, psychiatric and substance use disorders in first-degree relatives
Neurological examination	• Corneal light reflex test (tropia)
	• Cover test (phoria)
	• Extra-ocular movement
	• Convergence insufficiency
	• Symmetricity of facial sense & expression
	• Carotid bruit and ophthalmic bruit
	• Palatal arch elevation
	• Gag reflex
	• Vestibular function
		- Spontaneous nystagmus, head-shaking nystagmus
		- Head-impulse test
	• Motor and sensory function
	• Deep tendon reflex and pathological signs of upper motor neuron disease
	• Cerebellar function test
		- Finger to nose, tandem, 1-leg standing (with eyes open, with eyes closed)

Insomnia has been reported in up to 92% of mTBI patients; hence, screening for sleep difficulties should be performed and the first approach should always be a review of sleep hygiene behaviors.³²⁾ Current evidence recommends treatment of sleep-wake disturbances to recover from cognitive problems (Guideline for Concussion/Mild Traumatic Brain Injury and Persistent Symptoms: 3rd Edition [ONF], level of evidence B).²⁶⁾ Cognitive behavioral therapy (CBT) for insomnia is established as the treatment of choice for either primary insomnia or insomnia comorbid with a medical or psychiatric condition (ONF, level of evidence B). Furthermore, common post-concussive mental health symptoms (e.g., depressive disorders, anxiety disorders, behavioral changes, substance use disorders, and somatoform disorders) should be screened and treated (ONF, level of evidence B).¹²,³⁷⁾ Because the neuropsychological problems are associated with cognitive function after mTBI, CBT, and other psychotherapy approaches should be recommended for patients with persistent mental health problems (ONF, level of evidence A).¹⁰,³⁵⁾ Pharmacotherapy may serve as an effective adjunct to CBT in alleviating sustained neuropsychiatric problems (ONF, level of evidence C). Selective serotonin reuptake inhibitors (SSRIs) are generally recommended as the first-line pharmacological treatment for mood and anxiety disorders (ONF, level of evidence A), and SSRIs or serotonin and norepinephrine reuptake inhibitors (SNRIs) are considered first-line pharmacotherapy for post-traumatic stress disorder (PTSD) (ONF, level of evidence C).⁴⁶⁾

A patient with a first-time concussion without concurrent neuropsychiatric disorders should receive early education about concussion and post-concussive syndrome, and reassurance that most patients recover within 4 weeks to 3 months (ONF, level of evidence A). If attentional problems do not improve beyond 4 weeks, specialized neuropsychological assessment and cognitive rehabilitation should be considered to facilitate recovery and return to activity or work (ONF, level of evidence A).

Rehabilitation of attention deficit after moderate to severe TBI

Patients with the disorder of consciousness (DOC) should be placed on regular neurological assessments and serial monitoring (Canadian Clinical Practice Guideline for Rehabilitation of Adults with Moderate to Severe TBI [INESSS-ONF], level of evidence C).²¹⁾ The JFK Coma Recovery Scale-Revised is the gold standard diagnostic tool for assessing patients with DOC and differentiating between the minimally conscious state and vegetative state/unresponsive wakefulness syndrome after severe acquired brain injury.²,²³⁾ The recent practice guidelines of the American Academy of Neurology (AAN), American Congress of Rehabilitation Medicine (ACRM), and National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) present recommendations on the essential rehabilitation program required for effective recovery of awareness and attention.⁹⁾ Regular assessment of environmental factors (e.g., positioning, lighting, time of day, level of stimulation, distractions, and restraint) is important because these may impact arousal. Amantadine hydrochloride, a selective non-competitive N-methyl-D-aspartate receptor antagonist, is the only medication recommended in the AAN-ACRM-NIDILRR DOC practice guidelines.¹⁰⁾ Zolpidem may be considered case by case because it may show transient paradoxical improvement in consciousness in approximately 5% of patients treated.⁴³,⁴⁴⁾

Post-traumatic confusional state (PTCS) or post-traumatic amnesia (PTA) is common during early recovery from DOC after TBI.²⁹⁾ Key neurobehavioral findings include impaired attention, orientation, memory, and excessive fluctuation.³⁶⁾ Associated neuropsychiatric features include emotional and behavioral disturbances, sleep-wake cycle disturbances, delusions, perceptual disturbances, and confabulation. Serial assessment of patients with PTCS or PTA should be performed using a validated tool until resolution (INESSS-ONF - level of evidence C). The Confusion Assessment Protocol is a standardized tool for evaluating and tracking symptoms of PTCS.³⁶⁾ To minimize agitation or confusion, a secure and supervised environment should be provided until patients recover from PTCS or PTA (INESSS-ONF - level of evidence C). The management of pain and sleep is important. Sedation and fatigue should be avoided in a rehabilitation setting. Persons with PTCS may not recognize the situation or cannot express their needs; hence, the assessment and treatment of possible medical issues that may cause a patient’s sensation of internal discomfort are crucial because these can elicit psychomotor agitation. Recommendations for acute rehabilitation settings from the INESSS-ONF are summarized in TABLE 2.

TABLE 2. Recommendations on acute rehabilitation setting for persons with post-traumatic confusional state or post-traumatic amnesia.

Recommendations
Maintain a calming and consistent environment and avoid overstimulation
Consider use of low-stimulation rooms
Evaluate the impact of visitors, assessment and therapy and limit these activities if they cause agitation or excessive fatigue, allowing rest as needed
Minimize the use of restraints while facilitating the use of alternate measures in order to allow the person to move around freely
Have consistent healthcare professionals or trained caregivers working with the person with TBI
Establish the most reliable means of communication
Provide frequent reassurance
Present familiarizing information as tolerated by the patient
Help family members understand post-traumatic amnesia and how to minimize triggering agitation

Adapted from Canadian Clinical Practice Guideline for Rehabilitation of Adults with Moderate to Severe TBI, level of evidence C.

TBI: traumatic brain injury.

Pharmacological treatment should be limited to minimum medications, rather than adding multiple medications. Frequent weaning off of medications has a positive effect on functional recovery. Determining the root of the attentional problem and targeting the neurotransmitter systems is important. Occasionally, SSRI and SNRI may promote vigilance and mood. In cases where the patient expresses annoyance due to overstimulation or confusion, stimulants may be useful along with environmental modifications.²⁷⁾ Stimulants improve attention and they may also have a mild antidepressant effect. Prescribing a medication that may benefit from multiple problems involving alertness, mood, and pain should always be considered.

Concerning cognitive training, retraining strategies based on errorless and procedural learning should be considered for persons with PTCS because they are likely to improve neurocognitive performance by preserving procedural memory capacity.¹¹,²²⁾ Patients who emerge from PTCS have the potential to further benefit from neurocognitive rehabilitation.³⁶⁾

REHABILITATION OF ATTENTION IN THE POST-ACUTE PHASE AFTER TBI

Key elements of the rehabilitation of attention in the post-acute phase include history taking, neurological and medical examination, assessment and intervention of concomitant sleep-wake, mood, behavioral disorders, and fatigue; assessment of overall cognitive function and extent of attention deficit; and rehabilitative treatment of attention deficit.

Assessment and treatment of sleep-wake disorder

Sleep disturbances have been reported in up to 70% of patients with TBI.²⁷⁾ Given the potential impact on neurocognitive performance, screening for and treatment of comorbid sleep-wake disorders may be useful for the remediation of attention (INESSS-ONF, level of evidence C; International Guidelines for Cognitive Rehabilitation [INCOG], level of evidence C).¹¹⁾ The Pittsburgh Sleep Quality Index and Insomnia Severity Index are the most commonly used and potentially helpful self-reported sleep quality measures. For patients with moderate-to-severe TBI who have difficulty in self-reporting, polysomnography or sleep actigraphy may be considered. Non-pharmacological interventions, including CBT and sleep hygiene education, should be considered in prior studies (INESSS-ONF, level of evidence B). Few studies have investigated the safety and efficacy of medications for sleep disturbances in TBI patients. According to the INESSS-ONF guidelines, melatonin 2–5 mg (INESSS-ONF, level of evidence B) or trazodone 25–100 mg (INESSS-ONF, level of evidence C) should be considered prior to benzodiazepines (e.g., lorazepam) and other non-benzodiazepine hypnotic medications (e.g., zolpidem), the prescriptions of which should not exceed 7 days (INESSS-ONF, level of evidence C). If sleep disturbances persist, consultation with a sleep specialist should be considered.

Assessment and treatment of post-traumatic neuropsychiatric disturbances

During the post-acute phase of TBI, screening for post-traumatic neuropsychiatric disorders should be considered because they may exacerbate attentional problems.³³⁾ Furthermore, if neurobehavioral performance does not improve as expected, assessment by a licensed specialist should be considered (INESSS-ONF, level of evidence C).

Depression is the most prevalent emotional disturbance after TBI.²²,³⁰⁾ The Beck Depression Inventory-2 and Patient Health Questionnaire-9 are self-report measures, while the Hamilton Rating Scale for Depression is a clinician-rated evaluation tool commonly used for depression. Medications involve several classes of antidepressants, including SSRIs, SNRIs, tricyclic antidepressants, stimulants, and dopamine-norepinephrine reuptake inhibitors (TABLE 3). The SSRIs class is the first-line pharmacotherapy for depression after TBI owing to its efficacy and tolerability (INESSS-ONF, level of evidence C). Among SSRIs, sertraline and citalopram have the best available evidence.¹¹,²²,³⁰⁾ For some patients, psychotherapeutic intervention should be considered. The INESSS-ONF recommends mindfulness-based cognitive therapy with a level of evidence A. CBT has shown efficacy in previous studies in which depression affects attentional function following TBI (INESSS-ONF, level of evidence B; INCOG, level of evidence B). For patients who have a good awareness of difficulties, coping skills training in groups may be helpful (INESSS-ONF, level of evidence C).

TABLE 3. Pharmacological treatment for depression after traumatic brain injury.

Class	Medication	Daily dose range (mg)	Comments	Common side effects
SSRIs	Sertraline*	25–250	Relatively short half-life; Monitor for serotonin syndrome; Contraindicated with MAOIs	Nausea, diarrhea, tremor, decreased libido
	Escitalopram	5–30	Relatively short half-life, few drug-drug interaction; Monitor for serotonin syndrome; Contraindicated with MAOIs	Suicide risk, nausea, diarrhea, insomnia, decreased libido
	Citalopram†	5–40	Relatively short half-life, few drug-drug interaction; Monitor for serotonin syndrome; Contraindicated with MAOIs	QT prolongation, nausea, dizziness, decreased libido
	Fluoxetine	10–60	Long half-life of active metabolite, increased risk of problematic drug-drug interaction; Contraindicated with MAOIs	Unusual dreams, decreased libido, anorexia, tremor
SNRI	Venlafaxine XR	37.5–225	Contraindicated with MAOIs and narrow-angle glaucoma	Hypertension, insomnia, dizziness
TCA	Nortriptyline	25–150	Relatively less anticholinergic than older TCAs	Nausea, drowsiness, dry mouth
Stimulants	Methylphenidate‡	10–60	May usefully augment partial responses to SSRIs	Anorexia, dependence/abuse, insomnia
NDRI	Bupropion XL or SR	150–450	Less associated with sexual side effects, sedation, and weight gain seen in the SSRIs	Risk of lowering the seizure threshold

MAOI: monoamine oxidase inhibitor, NDRI: norepinephrine-dopamine reuptake inhibitor, SNRI: Serotonin and norepinephrine reuptake inhibitors, SSRI: selective serotonin reuptake inhibitor, TCA: tricyclic antidepressants, XR: extended release, XL: extra long, SR: sustained release.

^*,†Canadian Clinical Practice Guideline for Rehabilitation of Adults with Moderate to Severe TBI, level of evidence C; ^‡Canadian Clinical Practice Guideline for Rehabilitation of Adults with Moderate to Severe TBI, level of evidence B.

Anxiety disorders, including generalized anxiety disorder, panic disorder, obsessive-compulsive disorder, and PTSD are the second most frequent psychiatric conditions following TBI after depression.¹,¹⁸⁾ The Beck Anxiety Inventory or State-Trait Anxiety Inventory is used for the self-report test, and the Hamilton Anxiety Rating Scale is used for clinician-rated measure. Pharmacological treatment with SSRI (e.g., sertraline, fluoxetine, paroxetine, and citalopram), anxiolytics such as buspirone, and benzodiazepines (e.g., lorazepam, alprazolam, diazepam, and clonazepam) may be required, and SSRIs are the preferred treatment for post-traumatic anxiety in general (INESSS-ONF, level of evidence C). Buspirone may be an effective alternative or adjunctive treatment to SSRI because of the lower risk of cognitive dysfunction than benzodiazepines, and it is not related to discontinuation syndrome.¹³⁾ It is initiated at 5 mg 2 or 3 times daily, and adequate anxiolysis may require higher doses, such as 15 mg twice daily. The short-term use of benzodiazepines may be useful during periods of crisis or acute distress (INESSS-ONF, level of evidence C). CBT was recommended to alleviate anxiety (INESSS-ONF, level of evidence A; INCOG, level of evidence B). PTSD is most likely to develop in the first year post-injury, particularly 6–12 months after injury, with rates remaining stable up to 2 years post-injury and declining afterwards.¹⁴,⁴⁰⁾ For PTSD, the PTSD Checklist for DSM-5 and the Clinician-Administered PTSD Scale for DSM-5 are used for self-report and clinician-rated measures, respectively. Non-pharmacological treatments (e.g., CBT, virtual reality exposure therapy, Cognitive Symptom Management and Rehabilitation Therapy) are provided prior to pharmacological treatment.²⁰⁾ Pharmacological treatment includes the use of SSRIs. Prazosin may be considered for nightmare-related PTSD.⁶⁾

Post-TBI fatigue is one of the most common symptoms in the years after TBI.²⁵⁾ Fatigue Severity Scale is a widely used self-report measure. When considering pharmacotherapy options, it is necessary to consider the comorbidities that may impact fatigue. Short-term treatment with stimulants and methylphenidate may be useful for the treatment of excessive daytime sleepiness (INESSS-ONF, level of evidence C).¹⁷⁾ Modafinil may also be considered for post-traumatic fatigue.¹⁶⁾ Behavioral intervention for the reduction of fatigue, balanced life, stress management, and reduction of cognitive overload should be provided.

The incidence rate of post-traumatic aggression ranges from 15% to 51% in cases of severe TBI.³⁾ It complicates rehabilitation because it disturbs rehabilitation efforts and may cause critical safety concerns and negative social or legal consequences.⁴⁵⁾ The State-Trait Anger Expression Inventory-2 or UPPS-P Impulsive Behavior Scale is used for self-report assessment and the Agitated Behavior Scale, Modified Overt Aggression Scale, or Neuropsychiatric Inventory is used for the clinician-rated measure. For severe aggression, second-generation neuroleptic medications, such as quetiapine, ziprasidone, olanzapine, and risperidone are preferred (INESSS-ONF, level of evidence C). Other medications used for aggression include mood stabilizers such as valproate, SSRI, and amantadine.⁵⁾

Neuroimaging and neurodiagnostic testing

Neuroimaging identifies the pathoanatomic findings and provides outcome predictions for TBI. Electrophysiological techniques involving evoked potentials and electroencephalograms provide supplementary guidance for preparing rehabilitation plans.

Assessment of attentional problems

Assessment of attentional problems involve 4 components: screening for overall cognitive function, comprehensive neuropsychological assessment to distinguish attention deficit from other cognitive domains (e.g., memory, language, visuospatial function, frontal, or executive function), identification of types and extent of attentional problems, and evaluation of the impact of decreased attention on activities of daily living (TABLE 4).

TABLE 4. Essential elements of assessment of attentional problems after traumatic brain injury in Korea.

Element		Assessment tools
Screening for overall cognitive function		(Common) K-MMSE-2 or MMSE-KC
		(Supplementary) K-MOCA
Comprehensive neuropsychological assessment using standardized neuropsychological test batteries to distinguish attention deficit from other cognitive domains		SNSB, CERAD-K, SIB-K
Identification of types and extent of attentional problem		(Common) Paper-and-Pencil or Computerized Individual Attention Function Test
	• Vigilance	Auditory Vigilance Test, Visual Vigilance Test
	• Attention and awareness	Line Bisection Test, Albert’s Test, Star Cancellation Test
	• Visual selective attention, sustained attention	(Common) TMT A, Visual CPT
		(Supplementary) Corsi Bock-Tapping Test, Symbol Span Test
	• Auditory selective attention, sustained attention	(Common) Auditory CPT
	• Attention shift, working memory	TMT B
	• Auditory attention and short-term memory	Forward Digit or Word Span Test
Evaluation of the impact of decreased attention on activities of daily living		(Supplementary) Rating Scale of Attentional Behavior, Moss Attention Rating Scale, Test of Everyday Attention

K-MMSE: Korean-Mini Mental Status Examination, MMSE-KC: Mini-Mental Statue Examination-Korea Child, K-MOCA: Korean-Montreal Cognitive Assessment, SNSB: Seoul Neuropsychological Screening Battery, CERAD-K: Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease Assessment Packet, SIB-K: Korean version of the Severe Impairment Battery, TMT: trail making test, CPT: continuous performance task.

Rehabilitation for impaired attention

Sohlberg suggested 6 principles of attentional training. First, the training strategy should be based on each theoretical model of the 5 levels of attention—focused, sustained, selective, alternating, and divided.³⁹⁾ The task should be provided sequentially from easy to difficult. Furthermore, patients should have a sufficient opportunity to repeat all tasks until they can complete the task with ease and automaticity is acquired. During each rehabilitation session, the patient’s level of attention should be assessed and recorded. These assessments should cover both the qualitative evaluation of performance and quantitative assessments, such as speed and accuracy. These records should be used to guide treatment and to motivate patients to become more proactive. The repetitive practice of cognitive tasks should lead to generalization and adaptation for daily use. The ultimate goal of cognitive rehabilitation for mild-to-moderate attention deficits is to enable as many independent activities of daily living as possible.

The Brain Injury Interdisciplinary Special Interest Group (BI-ISIG) of the ACRM recommends remediation of attention deficits during post-acute rehabilitation after TBI (Practice Standard or “substantive evidence” of effectiveness). This should involve direct attention training and metacognitive strategy training to establish compensatory strategies and facilitate generalization to real-world tasks.⁷⁾

According to the INCOG recommendation, metacognitive strategy training using everyday functional activities should be considered, especially for patients with mild to moderate attention deficits (INCOG, level of evidence A). Patients who can recognize their cognitive impairment and participate in setting rehabilitation goals and strategies benefit from strategy training. This enables patients to develop strategies beforehand to avoid or plan a course of action for the problems expected to arise. Therefore, the goal of treatment is to establish the strategies necessary for the patient to successfully perform the task before starting the task and to enable patients to self-monitor their performance during the task. Self-monitoring and reflection on feedback for future performance are essential elements of metacognitive strategy training to improve attention. Time pressure management (TPM) and working memory training (e.g., N-back) are highly evidenced strategy-training methods. TPM training teaches structured problem-solving strategies to effectively cope with mental slowness (INCOG, level of evidence A) to the patients. N-back is a type of working memory training in which numbers are presented to the patient in random order; the patients are then asked to guess the number presented at a specific turn. Working memory training helps improve attention and respond to the information provided in an accurate and timely manner by remediating the fundamental problems of the executive component of working memory (INCOG, level of evidence C). Through working memory training, patients can learn to utilize their attention in the right place and use strategies that help manage the speed of processing information.

Direct attention training includes Attention Process Training (APT-III) developed by Sohlberg and Mateer and dual-task training.⁸,³⁸⁾ APT-III provides a computerized program that focuses on various aspects of attention (INCOG, level of evidence B). It consists of 3 stages in the learning process: acquisition, application, and adaptation. In the acquisition phase, the patient becomes aware of the cognitive deficits and benefits of the treatment. In the application stage, the efficiency of the attention process is enhanced by compensation and the strategies are internalized. Active intervention by therapists is important during the application stage. In the adaptation stage, tabletop tasks are transitioned to new and complex tasks and are generalized to assignments that can be performed at home, in the community, or at work.

Dual-task training should be considered to improve dual-tasking skills on tasks comparable to those trained (INCOG, level of evidence A). This can be applied only when the patient can perform a single task without any problems. Two possible single tasks are offered as dual tasks to be performed simultaneously, and the difficulty of these tasks gradually increases. The elements of time pressure, the complexity of the performance methods, and the need for additional working memory are then added.

BI-ISIG recommends computer-based cognitive interventions that may be helpful as an adjunct to clinician-guided treatment (Practice Option or “possible effectiveness” but require further evidence for a stronger recommendation). However, reliance on the repeated practice of de-contextualized computer-based attentional tasks or computer-based tasks without the involvement of a therapist is not recommended (BI-ISIG, Practice Option; INCOG, level of evidence B). Moreover, training with periodic random auditory alerting tones or mindfulness-based meditation techniques is not recommended because the current evidence is conflicting or lacking (INCOG, level of evidence B; INCOG, level of evidence A, respectively).

Regarding pharmacological treatment, methylphenidate is recommended to enhance the speed of information processing (INCOG, level of evidence A). While amantadine may help improve arousal in patients in a minimally conscious state, evidence that amantadine enhances complex attentional function after emergence from DOC is lacking (INCOG, level of evidence C).

To improve independence by expanding the trained cognitive tasks to similar real-world tasks, modifications of the environment and tasks may help lessen the impact of attentional problems on daily activities (INCOG, level of evidence B). Making oneself comfortable, removing visual and auditory distractions, setting the phone or timer to signal a rest break, or keeping written cues in front of the patient are examples of modifying the working environment.

CONCLUSION

TBI, unlike other brain disorders such as stroke, occurs not only in the elderly but also in adolescents and adults who need to return to school or work. Cognitive dysfunction following TBI imposes a great social and economic burden. A comprehensive evaluation of the various facets of cognitive function is essential, as is individualized treatment, based on these findings.

Although there is a compelling need for effective medications and rehabilitation strategies to mitigate cognitive deficits following TBI, the current level of evidence is not solid. More clinical trials are warranted to determine the safety and effectiveness of cognitive rehabilitation strategies, including medications targeting the modulation of specific neurotransmitters, reduction of neuroinflammation, and noninvasive neuromodulation techniques (e.g., transcranial direct current stimulation) to enhance attention after TBI.