Abstract TP86: Stroke-Impaired Proprioception Limits Motor Recovery With BCI-FES Device

Abstract

Introduction: Non-invasive brain-computer interface (BCI) therapy with contingent (i.e., closed-loop) functional electrical stimulation (FES) shows efficacy improving motor function. However, it is not well understood why some stroke survivors respond better to closed-looped BCI-FES intervention than others. Contingent BCI-FES intervention drives neuroplastic change toward adaptive functional connectivity in stroke-impaired sensorimotor brain areas by enriching the afferent feedback environment. The interruption of afferent-efferent feedback circuits is a neural correlate of long-term acquired disability and intactness of functional connections predicts recovery capacity. Studies suggest that proprioception is essential for motor learning and performance. Therefore, we hypothesize that proprioceptive intactness is essential for recovery of motor performance when using a BCI-FES. Methods: Participants with upper extremity motor loss resulting from stroke (n=35) completed up to 30 hours of closed-loop BCI-FES. Results: Change in ARAT scores over the course of the control period were compared to ARAT change scores over the intervention period at a one-month follow up assessment. On average, participants in the intervention realized greater change in ARAT (M = 2.11, SD = 4.68) than during the control phase (M = 0.294, SD = 3.53). An independent-samples t-test indicated this difference, 1.82, 95%CI [-4.17, 0.534], was not statistically significant, t (40.901) = -1.56, p = 0.126. Preliminary results indicate that Proprioceptive sensory loss has a greater limiting effect on recovery than cutaneous somatosensory loss. Discussion: Rehabilitating motor capacity after stroke depends on the intactness of sensorimotor neural circuits. If afference signals are missing or degraded due to stroke, motor recovery is poor. When the stroke spares afferent connectivity to the peripheral muscles, the sensorimotor cortex can leverage plasticity-based motor rehab strategies such as BCI-FES. Conclusion: Intactness of sensorimotor circuits is related to baseline severity of motor impairment as well as recovery of motor function. Efficacious prescription of BCI-FES intervention is best suited for patients with stroke-spared proprioception.