High-Speed Video Blink Analysis Improves Detection of Facial Palsy in Early Guillain-Barré Syndrome.

Introduction/aims: Electrophysiological investigations in early Guillain-Barré Syndrome (GBS) can be nondiagnostic. Improved testing for facial weakness in the early phase of GBS may improve diagnostic processes, as such weakness is found in approximately 50% of patients with GBS. This work pilots the utility of high-speed video analysis to complement blink reflex testing in early GBS.

Methods: This work prospectively evaluated consecutive patients admitted to a metropolitan teaching hospital in Melbourne, Australia, with suspected acute GBS within the first 14 days of neurological symptoms and compared them to a cohort of healthy controls. Blink reflex testing, mechanically-activated masseter reflexes, and analysis of high-speed video recordings of the evoked blinks were performed at admission (day 0), day 7, and day 21 (±2 days).

Results: 19 suspected GBS patients (12 GBS and 7 mimics) were compared to 22 healthy controls. At the first test, 83% of GBS patients and 29% of mimics demonstrated blink reflex abnormalities. 50% of GBS manifested video abnormalities (14% mimics), but abnormalities preceded electrophysiological changes in two GBS patients. The calculated reference values for peak lid velocity and lid excursion by video analysis were ~160 mm/s and 7-8 mm, respectively, with slightly different values for ipsilateral versus contralateral responses.

Discussion: Combining high-speed video analysis and blink reflex testing improves the detection of facial involvement in early GBS and helps discriminate from mimic disorders. Further work in a larger cohort is required to validate the sensitivity and specificity of this technique.