Changes in functional brain organization and behavioral correlations after rehabilitative therapy using a brain-computer interface

Abstract

This study aims to examine the changes in task-related brain activity induced by rehabilitative therapy using brain-computer interface (BCI) technologies and whether these changes are relevant to functional gains achieved through the use of these therapies. Stroke patients with persistent upper-extremity motor deficits received interventional rehabilitation therapy using a closed-loop neurofeedback BCI device (n = 8) or no therapy (n = 6). Behavioral assessments using the Stroke Impact Scale, the Action Research Arm Test (ARAT), and the Nine-Hole Peg Test (9-HPT) as well as task-based fMRI scans were conducted before, during, after, and 1 month after therapy administration or at analogous intervals in the absence of therapy. Laterality Index (LI) values during finger tapping of each hand were calculated for each time point and assessed for correlation with behavioral outcomes. Brain activity during finger tapping of each hand shifted over the course of BCI therapy, but not in the absence of therapy, to greater involvement of the non-lesioned hemisphere (and lesser involvement of the stroke-lesioned hemisphere) as measured by LI. Moreover, changes from baseline LI values during finger tapping of the impaired hand were correlated with gains in both objective and subjective behavioral measures. These findings suggest that the administration of interventional BCI therapy can induce differential changes in brain activity patterns between the lesioned and non-lesioned hemispheres and that these brain changes are associated with changes in specific motor functions.

A review of the progression and future implications of brain-computer interface therapies for restoration of distal upper extremity motor function after stroke

“…Such pathways are very small remnants of neuronal pathways that were once much larger and are the compromised neurological and neuroanatomical profiles of typical BCI users that may exist following the neurological trauma which resulted in the user’s distal motor impairment. The possible recruitment of these vestigial pathways has the potential for the restoration of functional motor capacities, selection of letters from an array [2,20], or movement of a virtual cursor [7,12,21–26]. …”

“…Therapies that incorporate BCI devices can be explained by conventional learning theories and replication of the BCI-driven motor learning outcomes observed in the healthy brain [7,12,29]. Reinforcement of motor behaviors is a key mechanism evident in the training and use of BCI therapies.…”

“…This basic mechanism of synaptic plasticity can be assumed to operate in stroke afflicted brains similar to the way it operates in the healthy brain [32]. In fact, neuroimaging studies using functional magnetic resonance imaging (fMRI) have shown increased cortical activation in areas damaged by stroke following BCI therapy and training [4,7,12,31,33]. Specifically, Hebbian learning may facilitate rehabilitation in stroke survivors by retraining or recreating synaptic connections necessary for the functional cortical activity essential for smooth and controlled motor output [4,7,12,19,24,30,31,33,34].…”

“…In fact, neuroimaging studies using functional magnetic resonance imaging (fMRI) have shown increased cortical activation in areas damaged by stroke following BCI therapy and training [4,7,12,31,33]. Specifically, Hebbian learning may facilitate rehabilitation in stroke survivors by retraining or recreating synaptic connections necessary for the functional cortical activity essential for smooth and controlled motor output [4,7,12,19,24,30,31,33,34]. This mechanism may offer predictive indications about the relative likelihood of extinction or retention of the newly learned behavior [16,27,31,33–36].…”

Interaction of BCI with the underlying neurological conditions in patients: pros and cons

“…They also used fMRI to measure brain activity in stroke patients in a simple tapping task before and after a BCI intervention, showing that task-based functional connectivity correlates with gain in the motor outcome. However they also gave a word of warning indicating that BCI therapy might produce both adaptive and maladaptive changes (Young et al, 2014c).…”