The Factors Associated with Good Responses to Speech Therapy Combined with Transcranial Direct Current Stimulation in Post-stroke Aphasic Patients

Abstract

ObjectiveTo determine factors associated with good responses to speech therapy combined with transcranial direct current stimulation (tDCS) in aphasic patients after stroke.MethodThe language function was evaluated using Korean version of Western aphasia battery (K-WAB) before and after speech therapy with tDCS in 37 stroke patients. Patients received speech therapy for 30 minutes over 2 to 3 weeks (10 sessions) while the cathodal tDCS was performed to the Brodmann area 45 with 1 mA for 20 minutes. We compared the improvement of aphasia quotient % (AQ%) between two evaluation times according to age, sex, days after onset, stroke type, aphasia type, brain lesion confirmed by magnetic resonance image and initial severity of aphasia. The factors related with good responses were also checked.ResultsAQ% improved from pre- to post-therapy (14.94±6.73%, p<0.001). AQ% improvement was greater in patients with less severe, fluent type of aphasia who received treatment before 30 days since stroke was developed (p<0.05). The adjusted logistic regression model revealed that patients with hemorrhagic stroke were more likely to achieve good responses (odds ratio=4.897, p<0.05) relative to infarction. Initial severity over 10% in AQ% was also found to be significantly associated with good improvement (odds ratio=8.618, p<0.05).ConclusionSpeech therapy with tDCS was established as a treatment tool for aphasic patients after stroke. Lower initial severity was associated with good responses.

Use of Computational Modeling to Inform tDCS Electrode Montages for the Promotion of Language Recovery in Post-stroke Aphasia

“…In the past decade, researchers have investigated the use of noninvasive neuromodulation techniques and, in particular, transcranial direct current stimulation (tDCS) to promote language recovery in poststroke aphasia [3]. While the first published study [4] that documented tDCS use for aphasia rehabilitation did not include a behavioral treatment protocol, studies since then have combined tDCS with speech-language therapy [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. These initial studies generally included behavioral treatment for anomia and implemented noun retrieval as the outcome measure; more recent studies have included additional behavioral treatments for the recovery of verbs [5,7,13], articulation [9] and discourse productivity [6,8].…”

The Use of Transcranial Direct Current Stimulation for Cognitive Enhancement

“…These studies all showed positive effects of tDCS on participants' language performance (see reviews by Floel, 2013, andMonti et al, 2012). Some studies also highlighted the influence of the severity of baseline naming deficits on the effect size of tDCS-induced improvements (e.g., Floel et al, 2012;Jung et al, 2011). In terms of language, tDCS has been shown to improve various language abilities such as word acquisition (Floel et al, 2012), production (Iyer et al, 2005), and retrieval (Fiori et al, 2011), depending on stimulation parameters such as stimulation site, dosage, and participants' initial language abilities.…”

“…For example, Jung et al (2011) investigated the factors associated with better results when combining tDCS with speech therapy. They found that patients who received C-tDCS over the right IFG improved significantly in terms of the aphasia quotient.…”

“…The application of tDCS in this domain is typically over the language-related frontal-temporal network, including the left dlPFC (e.g., Fertonani et al, 2010;Iyer et al, 2005;Wirth et al, 2011), left IFG (e.g., Cattaneo et al, 2011;de Vries et al, 2010), left inferior frontal cortex (e.g., Holland et al, 2011;Marangolo et al, 2011), left posterior perisylvian area (e.g., Fiori et al, 2011;Floel et al, 2008;Sparing et al, 2008), left anterior frontal lobe (e.g., Ross et al, 2010a), and the right IFG (e.g., Jung et al, 2011;Kang et al, 2011;Vines et al, 2011); for reviews, see Floel (2013) and Monti et al (2012). Lasting enhancement effects of tDCS were reported for 1 week (Baker et al, 2010), 2 weeks (Floel et al, 2008), 3 weeks (Fiori et al, 2011), and up to 2 months (Marangolo et al, 2011).…”

Update in Aphasia Research

“…In studies of chronic stroke, anodal tDCS applied to the structurally intact perilesional left cortex facilitated naming performance post treatment [86-88, 89••]. In acute stroke, tDCS was used to stimulate the right hemisphere to improve spontaneous speech, auditory verbal comprehension, and test performance as reflected by aphasia quotients [90,91].…”