Transcranial Direct Current Stimulation (tDCS) Paired with Occupation-Centered Bimanual Training in Children with Unilateral Cerebral Palsy: A Preliminary Study

Abstract

Objective We investigated the preliminary efficacy of cathodal transcranial direct current stimulation (tDCS) combined with bimanual training in children and young adults with unilateral cerebral palsy based on the principle of exaggerated interhemispheric inhibition (IHI). Methods Eight participants with corticospinal tract (CST) connectivity from the lesioned hemisphere participated in an open-label study of 10 sessions of cathodal tDCS to the nonlesioned hemisphere (20 minutes) concurrently with bimanual, goal-directed training (120 minutes). We measured the frequency of adverse events and intervention efficacy with performance (bimanual—Assisting Hand Assessment (AHA)—and unimanual—Box and Blocks), self-report (Canadian Occupational Performance Measure (COPM), ABILHAND), and neurophysiologic (motor-evoked potential amplitude, cortical silent period (CSP) duration, and motor mapping) assessments. Results All participants completed the study with no serious adverse events. Three of 8 participants showed gains on the AHA, and 4 of 8 participants showed gains in Box and Blocks (more affected hand). Nonlesioned CSP duration decreased in 6 of 6 participants with analyzable data. Cortical representation of the first dorsal interosseous expanded in the nonlesioned hemisphere in 4 of 6 participants and decreased in the lesioned hemisphere in 3 of 4 participants with analyzable data. Conclusions While goal achievement was observed, objective measures of hand function showed inconsistent gains. Neurophysiologic data suggests nonlinear responses to cathodal stimulation of the nonlesioned hemisphere. Future studies examining the contributions of activity-dependent competition and cortical excitability imbalances are indicated.

Influence of Combined Transcranial Direct Current Stimulation and Motor Training on Corticospinal Excitability in Children With Unilateral Cerebral Palsy

“…Our rationale was that the activity of inhibitory circuits within contralesional M1 may also increase following cathodal tDCS, as demonstrated in a prior study investigating rehabilitation and tDCS in adults with stroke (Goodwill et al, 2016). Using a similar assessment of CSP duration to Rich et al (2018), we observed increased CSP duration in three of eight individuals in the Active+CIMT group and zero of seven in the Sham+CIMT. Still, the changes in CSP duration were highly variable and were not statistically significant at the group level.…”

“…Combined tDCS and intensive motor training interventions have recently been investigated in children with UCP, with results showing some positive changes in neurophysiologic responses, motor function, and activities of daily living skills (Grecco et al, 2014; Collange Grecco et al, 2015; Kirton et al, 2017; Gillick et al, 2018b; Rich et al, 2018). While these initial studies have focused on establishing the safety of these combined tDCS and rehabilitation interventions and their effects on behavioral, little is known regarding their on influence corticospinal excitability in children with UCP.…”

“…CSP is the duration of inhibition during voluntary muscle contraction with contributions from both spinal and supraspinal inhibitory inputs, and may reflect GABA B activity in these areas (Cantello et al, 1992; McDonnell et al, 2006). Prior studies have examined these measures of corticospinal excitability, both before and after interventions to begin to identify neurophysiology mechanisms in children with UCP (Chen et al, 2016; Zewdie et al, 2017; Kuo et al, 2018; Rich et al, 2018). Specifically, Kuo et al (2018) describe intervention-induced changes in contralesional corticospinal excitability following intensive therapy and repetitive TMS, and their relationship to motor function outcomes.…”

“…Specifically, Kuo et al (2018) describe intervention-induced changes in contralesional corticospinal excitability following intensive therapy and repetitive TMS, and their relationship to motor function outcomes. Unique to tDCS, some decreases in contralesional corticospinal excitability were found in an open-label study of combining cathodal tDCS and bimanual therapy (Rich et al, 2018). Although promising, the current paucity of available data of the effects of combined tDCS and motor training interventions on brain excitability reveal gaps in our understanding of how tDCS modulates the developing brain in children with UCP.…”

Modulating Observation-Execution-Related Motor Cortex Activity by Cathodal Transcranial Direct Current Stimulation

“…With respect to treatment of brain diseases associated with pathological enhancement of cortical activity or excitability via cathodal tDCS, some studies have reported that ctDCS applied over an epileptogenic focus reduces epileptic EEG abnormalities [11,12] and seizure frequency in epilepsy [13]. Clinical studies moreover showed that cathodal tDCS over the contralesional M1 combined with motor training rebalances bi-hemispheric activity and facilitates motor performance in stroke patients [14,15] and in children with cerebral palsy [16,17]. Furuya et al describe that ctDCS applied over the affected motor cortex in musicians cramp, combined with anodal tDCS over the contralateral motor cortex and bimanual finger movements, reduces dystonic symptoms in these patients, most probably due to a reduction of pathologically enhanced activity of the affected M1 [18].…”