title: Single-Trial Analysis of Inter-Beat Interval Perturbations Accompanying Single-Switch Scanning: Case Series of Three Children With Severe Spastic Quadriplegic Cerebral Palsy.
abstract: Single-switch access in conjunction with scanning remains a fundamental solution in restoring communication for many children with profound physical disabilities. However, untimely switch inaction and unintentional switch activations can lead to user frustration and impede functional communication. A previous preliminary study, in the context of a case series with three single-switch users, reported that correct, accidental and missed switch activations could elicit cardiac deceleration and increased phasic skin conductance on average, while deliberate switch non-use was associated with autonomic nonresponse. The present study investigated the possibility of using blood volume pulse recordings from the same three pediatric single-switch users to track the aforementioned switch events on a single-trial basis. Peaks of the line length time series derived from the empirical mode decomposition of the inter-beat interval time series matched, on average, a high percentage (above 80%) of single-switch events, while unmatched peaks coincided moderately (below 37%) with idle time during scanning. These results encourage further study of autonomic measures as complementary information channels to enhance single-switch access.
authors.forename: Brian
authors.initials: B
authors.lastname: Leung
authors.forename: Tom
authors.initials: T
authors.lastname: Chau
mesh_terms: D000465:Algorithms; D001810:Blood Volume; D002547:Cerebral Palsy / Q000534:rehabilitation*; D002648:Child; D003143:Communication Devices for People with Disabilities; D005712:Galvanic Skin Response / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007831:Larynx, Artificial; D008297:Male; D011782:Quadriplegia / Q000534:rehabilitation*; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D012881:Skin Temperature; D014732:Vibration