Stiff-person syndrome with acute recurrent peripheral vertigo: Possible evidence of gamma aminobutyric acid as a neurotransmitter in the vestibular periphery

Objective: We report a case of a 58-year-old man suffering from stiff-person syndrome and recurrent peripheral vertigo. Method: A case report and a review of the recent literature on stiff-person syndrome are presented. Results: The patient presented with recurrent episodes of vertigo with a pure peripheral pattern and with concomitant episodes of burning muscle pain, muscle twitching, weight gain and fatigue, worsening with tension or stress that also occurred in periods without vertigo. Cochlear examinations only showed presbyacusis-like hearing loss. The diagnosis of stiff-person syndrome was made with electromyographic examination and from findings in the blood and cerebrospinal fluid of high titres of anti-glutamic acid decarboxylase (GAD67) autoantibodies. In a two-year follow-up period, therapy for stiff-person syndrome abolished episodes of both stiffness and vertigo. Conclusion: As far as we know, no other clinical case of acute vestibular damage with a possible correlation with anti-glutamic acid decarboxylase antibodies has been described. Peripheral vertigo possibly related to a lack of gamma aminobutyric acid underlines a possible role of gamma aminobutyric acid as a neurotransmitter in the peripheral vestibular system.