Teaching Video NeuroImage: Disabling Jaw Clonus in a Patient With Bulbar-Onset Amyotrophic Lateral Sclerosis Successfully Treated With Botulinum Toxin

Jaw clonus is a rare neurologic finding associated with supranuclear lesions of the trigeminal nerve. It is rare in amyotrophic lateral sclerosis (ALS).1 We describe a 63-year-old patient with ALS who presented with a disabling and sustained jaw clonus, reduced by mouth resting and elicited by mouth opening (Video 1). Association of baclofen (25 mg/3id), tizanidine (2 mg/id), and benzodiazepine treatments were ineffective. Onabotulinum toxin A injections were administered into the temporal (13 units) and masseter (25 units) muscles bilaterally. She experienced a complete relief of her symptom up to 4–5 months, with no side effects (Video 1). She confirmed improvement in quality of life.