Directional brain functional interaction analysis in patients with amyotrophic lateral sclerosis

Recent work has shown that a P300-based brain-computer interface (BCI) can provide effective long-term communication for individuals with amyotrophic lateral sclerosis (ALS). BCI users can experience significant variation in day-to-day BCI performance that can both frustrate and discourage users and caregivers alike. This study seeks to characterize this performance variation using measures of causality between electrode locations in scalp-EEG recorded from individuals with and without ALS during use of a P300-based BCI. Results show that there are statistically significant causal relationships between channels, particularly in the high beta frequency range, that are consistent across subject groups. Moreover, the connectivity patterns in the group with ALS appear to be more diffuse when compared to controls. These preliminary findings suggest that there may be differences in brain activity between individuals with and without ALS, as well as in the activity across successful and unsuccessful task sessions using a P300-based BCI. Ultimately, this information may lead more reliable BCI use for people with ALS.