Changes in functional connectivity correlate with behavioral gains in stroke patients after therapy using a brain-computer interface device.

Brittany Mei Young,Vivek Prabhakaran,Justin C Williams,Dorothy Farrar Edwards,Veena A Nair,Mitchell E Tyler,Kristin Caldera,Justin A Sattin,Alexander Remsik,Zack Nigogosyan,Lã©O M Walton,Jie Song,Scott W Grogan

doi:10.3389/fneng.2014.00025

Brittany Mei Young, Vivek Prabhakaran + Show 11 more

Open Access

https://doi.org/10.3389/fneng.2014.00025

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Abstract

Brain-computer interface (BCI) technology is being incorporated into new stroke rehabilitation devices, but little is known about brain changes associated with its use. We collected anatomical and functional MRI of nine stroke patients with persistent upper extremity motor impairment before, during, and after therapy using a BCI system. Subjects were asked to perform finger tapping of the impaired hand during fMRI. Action Research Arm Test (ARAT), 9-Hole Peg Test (9-HPT), and Stroke Impact Scale (SIS) domains of Hand Function (HF) and Activities of Daily Living (ADL) were also assessed. Group-level analyses examined changes in whole-brain task-based functional connectivity (FC) to seed regions in the motor network observed during and after BCI therapy. Whole-brain FC analyses seeded in each thalamus showed FC increases from baseline at mid-therapy and post-therapy (p < 0.05). Changes in FC between seeds at both the network and the connection levels were examined for correlations with changes in behavioral measures. Average motor network FC was increased post-therapy, and changes in average network FC correlated (p < 0.05) with changes in performance on ARAT (R2 = 0.21), 9-HPT (R2 = 0.41), SIS HF (R2 = 0.27), and SIS ADL (R2 = 0.40). Multiple individual connections within the motor network were found to correlate in change from baseline with changes in behavioral measures. Many of these connections involved the thalamus, with change in each of four behavioral measures significantly correlating with change from baseline FC of at least one thalamic connection. These preliminary results show changes in FC that occur with the administration of rehabilitative therapy using a BCI system. The correlations noted between changes in FC measures and changes in behavioral outcomes indicate that both adaptive and maladaptive changes in FC may develop with this therapy and also suggest a brain-behavior relationship that may be stimulated by the neuromodulatory component of BCI therapy.

Highlights

Decreases in stroke mortality rates began accelerating in the 1970s (Lackland et al, 2014), and reduced stroke mortality was named as one of the 10 great public health achievements in the United States from 2001 to 2010 by the Centers for Disease Control and Prevention (2011)
Of the domains of the Stroke Impact Scale (SIS), this study focused on the Activities of Daily Living (SIS ADL) and Hand Function (SIS HF) domains, as these represent the domain most closely related to the motor functions practiced with the Brain-computer interface (BCI) therapy administered (SIS HF) and the domain most reflective of global function (SIS ADL) that may inform the clinical implications of the results
BEHAVIORAL CORRELATIONS WITH CHANGES IN INDIVIDUAL CONNECTION STRENGTHS A summary of Pearson’s correlations found to be significant after fdr correction that survived generalized estimating equations (GEE) analysis between changes in individual connection strength within the motor network and DISCUSSION The results of these preliminary analyses are suggestive of a relationship between the changes in Functional connectivity (FC) and those in behavioral outcomes observed with the administration of BCI therapy

Summary

Introduction

Decreases in stroke mortality rates began accelerating in the 1970s (Lackland et al, 2014), and reduced stroke mortality was named as one of the 10 great public health achievements in the United States from 2001 to 2010 by the Centers for Disease Control and Prevention (2011). These trends have contributed to a growing population of stroke survivors currently estimated at 4 million individuals in the United States alone (Go et al, 2014). There is much to be learned in the process of characterizing changes in FC observed in stroke patients and in understanding how these changes may be modulated during recovery facilitated by rehabilitative therapies

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