Abstract 154: Changes in Task fMRI After Stroke Rehabilitation Using Closed-Loop Neurofeedback

Abstract

Introduction: Brain-computer interface (BCI) is an emerging technology for stroke rehabilitation, but little is known about brain changes associated with its use. We examine changes in laterality index (LI) and functional connectivity (FC) during hand movements associated with BCI interventional therapy. Methods: We collected anatomical and functional MRI of 8 stroke patients with upper extremity motor impairment before, during, and after up to 6 weeks of therapy using a BCI system with tongue and functional electrical stimulations. We acquired functional images during imagined (MI) and executed (ME) tapping and squeezing of each hand; not all subjects performed all tasks. Two subjects’ scans were flipped so that as a group the lesion was left (L) and the impaired limb right (R). We computed LI using 3 mask sets: whole brain, motor network, and motor cortex. Group-level analyses examined FC changes to motor network seeds using AFNI and Matlab NBS toolbox. Results: BCI intervention led to decreased average LI during tapping. Overall, R taps shifted L to bilateral; all L taps shifted bilateral to R. Trends were consistent across all masks at thresholds p<.05 & p<.001 and were linearly modeled (r2 0.614 to 0.999). During R-ME, FC increased between each thalamus with L M1 and the cingulum. During L-ME, most FC increases were intrahemispheric (R M1 to R thalamus; within L M1). L-ME FC also decreased between each thalamus and contralateral frontal regions and between the cerebellum and frontal lobes. This pattern of inter- and intrahemispheric FC increases during respective R and L movement was also observed with MI, and many FC findings persisted in a subanalysis excluding flipped scans. A network of 6 seeds and 9 edges within the motor network had increased FC during R-ME. All FC changes p<.05. Conclusions: BCI interventional therapy of the impaired hand leads to more bilateral brain activity, while more lateralized activation was seen of the unimpaired hand to its corresponding contralateral motor regions. With different patterns of change observed during tasks using the impaired or unimpaired hand, lesioned brain areas may respond differently to BCI than unlesioned counterparts.