Category: Stroke; Geriatric Rehabilitation
Objective : To investigate white matter changes associated with transcranial direct current stimulation (TDCS) induced language recovery in aphasic stroke patients.
Design : A double-blind randomized controlled design was carried out. Before and after the intervention, behavioral and neuroimaging (MRI, EEG) data were collected. For the purpose of this study, we only analyzed diffusion tensor imaging (DTI) data and Western Aphasia Battery Revised (WAB-R) scores. Fractional anisotropy (FA) changes in selected white matter regions from the Johns Hopkins atlas were examined. However, majority of the left hemispheric regions of interest were excluded due to poor registration of the lesioned side.
Setting : The study was conducted at the research center of a brain injury rehabilitation hospital.
Participants (or Animals, Specimens, Cadavers) : Chronic stroke patients with aphasia, either due to ischemic or hemorrhagic stroke, were eligible for this study. As a part of an ongoing study, our preliminary sample included 26 patients, but 8 did not complete their MRIs. This resulted in 10 patients in the tDCS group and 8 in the sham group for the current analysis.
Interventions : Both groups underwent five consecutive days of 20-minute speech therapy concurrent with either tDCS or sham.
Main Outcome Measure(s) : WAB-R
Results : Correlating FA with WAB-R measures, we found a positive correlation between change (post-pre) in auditory verbal comprehension (AVC) subscore and change in FA in the pontine crossing tract (PCT) (rs=.63, p=.05), right medial lemniscus (rs=.68, p=.03), and right superior corona radiata (rs=.69, p=.026) for the tDCS group, while none were observed for sham. FA in PCT was also positively correlated with AVC pre-intervention in both groups.
Conclusions : Our findings suggest that the brainstem pathways may underlie language recovery promoted by tDCS.
Zhong Sheng Zheng– Research Scientist, Casa Colina Hospital and Centers for Healthcare, Pomona, California
Henry Millan– Research associate, Research Institute, Casa Colina Hospitals and Centers for Healthcare, Pomona, California
Sharon Lee– Speech therapist4v, Casa Colina Hospitals and Centers for Healthcare, Pomona, California
Melissa Howard– Speech therapist, Casa Colina Hospitals and Centers for Healthcare, Pomona, California
Aaron Rothbart– Speech Therapist, Casa Colina Hospital and Centers for Healthcare, Pomona, California
Caroline Schnakers– Assistant Director, Research Institute, Casa Colina Hospitals and Centers for Healthcare, Pomona, California
Emily Rosario– Director of the Research Institute, Casa Colina hospital and Centers for Healthcare, Los Angeles, California