Transcranial direct current stimulation for fatigue in neurological conditions: A systematic scoping review

Abstract

Background and PurposeFatigue following neurological conditions negatively impacts daily activities, reducing overall quality of life. Transcranial direct current stimulation (tDCS) for fatigue management is still underexplored. This scoping review explores its use in managing fatigue among various neurological conditions.MethodsA thorough literature search was carried out using PubMed, Scopus, CINAHL, Web of Science, Embase, ProQuest, and the Cochrane Library. Google Scholar and clinicaltrials.gov were manually searched for gray literature and ongoing trials, respectively. Regardless of the study design, all studies utilizing tDCS for the management of fatigue in various neurological conditions were considered. Two reviewers independently screened all the studies, following which the data were retrieved.ResultsStudies employing tDCS for fatigue management across neurological conditions is as follows: Multiple sclerosis (MS) (n = 28, 66%), stroke (n = 5, 12%), Parkinson's disease (PD) (n = 4, 10%), post‐polio syndrome (PPS) (n = 2, 5%), traumatic brain injury (TBI) (n = 2, 5%), and amyotrophic lateral sclerosis (n = 1, 2%). All the studies used anodal stimulation, with the common stimulation site being the left dorsolateral prefrontal cortex for MS, stroke, and PD. A stimulation intensity of 1.0–4.0 mA with a duration ranging from 15 to 30 min in 1 to 24 sessions were commonly reported. The Fatigue Severity Scale (n = 21) and Modified Fatigue Impact Scale (n = 17) were frequently implemented outcome measures. Regardless of the study design, 36/42 (85.7%) studies reported an improvement in fatigue scores in the tDCS group. The common adverse events noted were tingling (n = 8, 35%), headache (n = 6, 26%), and itching (n = 6, 26%).DiscussionApplication of tDCS for fatigue was explored in individuals with stroke, PD, PPS, and TBI after MS. Even though a wide range of treatment parameters and outcome measures were adopted to assess and target fatigue, tDCS proves to have a promising role in alleviating this symptom.

Prefrontal tDCS for improving mental health and cognitive deficits in patients with Multiple Sclerosis: a randomized, double-blind, parallel-group study

“…Pro-cognitive effects were also shown in neurological disorders such as Parkinson's disease and stroke [52,53] and major neurodevelopmental disorders such as ADHD and autism [54][55][56]. It has been also effectively used for improving fatigue and quality of life [57,58]. The rationale behind the use of prefrontal tDCS for enhancing cognition mostly comes from the involvement of different regions of the prefrontal cortex in various aspects of cognitive functions [59][60][61] which seems to be at least partially applicable for MS.…”

Study protocol of a double-blind randomized control trial of transcranial direct current stimulation in post-stroke fatigue

“…The above stimulation site and parameters were chosen based on the following rationale. First, association observed between increased fatigue scores and decreased functional connectivity of supplementary and primary motor areas ( 42 ). In addition, stimulation of motor cortex has been shown to improve fatigue in stroke patients and healthy individuals ( 31 , 71 ).…”

“…In addition, stimulation of motor cortex has been shown to improve fatigue in stroke patients and healthy individuals ( 31 , 71 ). Second, the duration of stimulation per session was 20 min in all five published studies of tDCS on PSF ( 42 ). Third, consecutive sessions of tDCS has been employed were employed in previous studies of tDCS on PSF ( 32 , 34 , 71 ).…”

“…In 36 out of 42 (85.7%) of studies reported an improvement in fatigue scores in the tDCS group. Side effects of tDCS are usually mild ( 42 ). Hence tDCS proves to have a promising simple, low-cost, portable, non-invasive and risk-free procedure for reducing fatigue symptoms in alleviating PSF.…”

Effect of high-definition transcranial direct current stimulation among late-subacute and chronic stroke survivors with fatigue: A randomized-controlled crossover trial protocol

“…In stroke, tDCS has been explored for the recovery of motor [17] and language functions [18] but there are only limited studies focusing on reducing PSF [19][20][21] . Furthermore, the distinct cortical regions targeted in these studies exhibit considerable diversity [22] . The outcomes of these studies have demonstrated varying results, underscoring the need for additional exploration.…”