Abstract T P113: Structural Changes In The Corticospinal Tract After 10 Days Of Combined Physical Therapy And Transcranial Direct Current Stimulation

Abstract

A few studies have shown that long-term skill acquisition can lead to changes in white matter tracts. Studies examining structural changes in the corticospinal tract in patients recovering from a stroke have yielded mixed results. The current study examines whether 10 days of combined physical therapy (PT) and non-invasive brain-stimulation (using dual transcranial direct current stimulation) can lead to changes in the corticospinal tract (CST) on the affected hemisphere. Seven stroke patients participated in an intense 10-day long treatment of physical therapy (1 hour/day) and tDCS (30 minutes per session) with anodal stimulation applied over the affected motor cortex and cathodal stimulation over the unaffected motor cortex. Each patient also underwent Fugl-Meyer assessments (UE-FM) and diffusion tensor imaging (DTI) before and after the treatment phase. A control group of seven patients were also scanned at two time points and assessed without any intervening therapy. The DTI images were processed using the standard algorithms provided by FSL and normalized to FSL's FA template. We used a section of the CST derived from the JHU atlas, between the internal capsule (below each patient’s lesion) and upper brain stem as our region of interest to extract FA and other diffusivity values before and after therapy. All patients showed an increase in proportional UE-FM scores (+21%; SD 10%) and an increase in average FA (+0.013; SD 0.01) of the descending CST below the lesion after the intervention and no significant change was seen in the patient that were assessed two times but had no treatment. In addition, we found a strong correlation between the change in FA and a proportional improvement in the UE-FM score (r=0.689). These findings support the notion that focal white matter changes can be detected with DTI and that an intense course of an experimental treatment (2x5 days of combined PT+tDCS) induced structural changes in the descending CST that were not seen in patients scanned twice without treatment.