Dose-response relationships using brain-computer interface technology impact stroke rehabilitation.

Brittany M Young,Zack Nigogosyan,Justin A Sattin,Vivek Prabhakaran,Léo M Walton,Alexander Remsik,Kristin Caldera,Justin C Williams,Veena A Nair,Jie Song,Mitchell E Tyler,Dorothy F Edwards

doi:10.3389/fnhum.2015.00361

Abstract

Brain–computer interfaces (BCIs) are an emerging novel technology for stroke rehabilitation. Little is known about how dose-response relationships for BCI therapies affect brain and behavior changes. We report preliminary results on stroke patients (n = 16, 11 M) with persistent upper extremity motor impairment who received therapy using a BCI system with functional electrical stimulation of the hand and tongue stimulation. We collected MRI scans and behavioral data using the Action Research Arm Test (ARAT), 9-Hole Peg Test (9-HPT), and Stroke Impact Scale (SIS) before, during, and after the therapy period. Using anatomical and functional MRI, we computed Laterality Index (LI) for brain activity in the motor network during impaired hand finger tapping. Changes from baseline LI and behavioral scores were assessed for relationships with dose, intensity, and frequency of BCI therapy. We found that gains in SIS Strength were directly responsive to BCI therapy: therapy dose and intensity correlated positively with increased SIS Strength (p ≤ 0.05), although no direct relationships were identified with ARAT or 9-HPT scores. We found behavioral measures that were not directly sensitive to differences in BCI therapy administration but were associated with concurrent brain changes correlated with BCI therapy administration parameters: therapy dose and intensity showed significant (p ≤ 0.05) or trending (0.05 < p < 0.1) negative correlations with LI changes, while therapy frequency did not affect LI. Reductions in LI were then correlated (p ≤ 0.05) with increased SIS Activities of Daily Living scores and improved 9-HPT performance. Therefore, some behavioral changes may be reflected by brain changes sensitive to differences in BCI therapy administration, while others such as SIS Strength may be directly responsive to BCI therapy administration. Data preliminarily suggest that when using BCI in stroke rehabilitation, therapy frequency may be less important than dose and intensity.

Highlights

There is a growing need for the study and development of advancements in the field of stroke rehabilitation
General Approach We take advantage of random events and factors that affected the effective dose, intensity, and frequency of therapy administered in the context of an on-going stroke rehabilitation study using Brain–computer interfaces (BCIs) therapy to examine how differences in these factors relate to changes observed in brain and behavioral measures assessed at different points relative to therapy administration
This study focused on the Activities of Daily Living (SIS ADL), Hand Function (SIS HF), and Strength (SIS Strength) domains of the Stroke Impact Scale (SIS), as the SIS ADL was the domain most reflective of global function, the SIS HF domain was the one most closely related to motor functions practiced during BCI therapy, and the SIS Strength was a second domain reflecting more general motor function

Summary

Introduction

There is a growing need for the study and development of advancements in the field of stroke rehabilitation. Reductions in stroke mortality (Lackland et al, 2014) and continued growth of the aging population have contributed to an increasing number of stroke survivors for whom new options in rehabilitation are needed to facilitate further recovery of function, independence, and improvements in overall quality of life. One emerging approach to stroke rehabilitation uses brain– computer interface (BCI) technology. These devices allow for real-time feedback of neural activity, which can be used to train and/or modulate neural activity while performing guided rehabilitative tasks. The development of BCI devices to address persistent motor impairment after stroke may hold promise for additional meaningful recovery in stroke survivors (Young et al, 2014d). Applications intended to facilitate improvements in upper extremity motor function are an area of great need, as the upper extremity is more severely involved than the lower extremity in most stroke survivors with motor impairments (Shelton and Reding, 2001)

Methods

Results

Conclusion