Speech-induced blepharospasm

Abstract

Primary blepharospasm is an adult-onset dystonia typically present at rest and exacerbated by bright light, stress and voluntary movements of eyes and eyelids. Inconsistency or inducibility by activities involving muscles other than orbicularis oculi muscles are considered incongruous with typical primary blepharospasm, heralding the suspicion of psychogenicity. We report the clinical vignette of two patients manifesting an unusual presentation of primary blepharospasm, specifically triggered by voiced speech and associated with an otherwise 'typical' presentation of primary adult-onset dystonia in the lower face, larynx or upper limb. Speech-induced primary blepharospasm seems a rare occurrence, representing 1.3% of our clinic-based series of 149 patients with primary adult-onset primary blepharospasm. In these atypical patients, the feature of speech inducibility suggests that the abnormal surrounding inhibition between cortical subregions representing laryngeal and orbicularis oculi muscles might underlie dystonic overflow to the orbicularis oculi muscles following the voiced speech.