Transcranial Direct Current Stimulation Improves Audioverbal Memory in Stroke Patients

Abstract

ObjectiveThe aim of this study was to investigate whether anodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance in stroke patients.DesignTwelve stroke patients with audioverbal memory impairment participated in a single-masked, crossover, and sham-controlled experiment. The anodal or sham transcranial direct current stimulation was applied during the Rey Auditory Verbal Learning Test, which evaluates the ability to recall a list of 15 heard words over five trials. The number of correctly recalled words was compared between the anodal and sham conditions and the influence of transcranial direct current stimulation on serial position effect of the 15 words was also examined.ResultsThe increase in the number of correctly recalled words from the first to the fifth trial was significantly greater in the anodal condition than in the sham condition (P < 0.01). There was a significant difference (P < 0.01) between the anodal and sham conditions in the number of correctly recalled words within the first five words (primacy region) over the second to fifth trial trials, but not in the middle (next five words) or recency (last five words) regions.ConclusionsAnodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance and induced the primacy effect in stroke patients.

The Effect of Noninvasive Brain Stimulation on Poststroke Cognitive Function: A Systematic Review

“…53 tDCS Studies. A crossover study by Kazuta et al 54 with a low risk of bias included 12 patients with auditory verbal memory deficits (3-12 months poststroke). Irrespective of lesion location, the left temporoparietal area was stimulated with anodal tDCS and resulted in an increase in the number of correctly remembered words in the fifth and first to fifth trials (5 trials to recall a list of 15 heard words).…”

Anodal tDCS over Wernicke’s area improves verbal memory and prevents the interference effect during words learning.

“…In addition to the effects of tDCS on language functions in healthy humans, its potential usefulness for clinical application has also been demonstrated, particularly in chronic aphasia (Fiori et al, 2011; Flöel et al, 2011; Galletta, Conner, Vogel-Eyny, & Marangolo, 2016; Kazuta et al, 2017; Monti et al, 2013; Wortman-Jutt & Edwards, 2017). In aphasic patients, repeated sessions of anodal tDCS applied over Wernicke’s area resulted however in heterogeneous outcomes in different studies on verbal production (Fiori et al, 2013; Marangolo et al, 2013).…”

Effect of transcranial direct-current stimulation on cognitive function in stroke patients: A systematic review and meta-analysis

“…After screening the titles and abstracts, we excluded records and obtained the full texts of the remaining 49 studies. After further full-text assessment, we determined that 15 studies with 16 trials met the inclusion criteria [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]; one of the studies contained 2 independent trials [16]. Two studies were excluded from the metaanalysis since there were no available data [24,38].…”

“…Several systematic reviews have evaluated the efficacy of tDCS on motor function and aphasia after stroke [10][11][12]; some preliminary studies have shown beneficial effects of tDCS on cognitive function in healthy subjects as well as in stroke patients [13][14][15][16]. However, it remains largely uncertain whether tDCS promotes the recovery of cognitive function after stroke.…”