EVALUATION OF THE SOMATOSENSORY-EVOKED BLINK RESPONSE IN PATIENTS WITH NEUROLOGICAL DISORDERS

Background-The somatosensory evoked blink response (SBR) is a characte ristic reflex blink elicited by electrical stimulation of peripheral n erves or other anatomical sites. Methods-139 patients with neurologica l disorders were examined for presence of the SBR. Although the SBR wa s not usually elicitable, it was present in a subset of patients with Parkinson's disease and with hemifacial spasm. It was also present in a patient with Guillain-Barre syndrome before the recovery phase. The latency of the EMG activities responsible for the SBR was significantl y shorter than that of the startle blink. Conclusions-The SBR is not a variant of the startle blink, but is a release phenomenon transmitted via the brainstem reticular formation. This response may be clinicall y relevant in disorders associated with brainstem lesions and abnormal blinking.