title: Tremor on smiling.
abstract: Facial tremor occurring on smiling is a rare phenomenon and has been described (to the best of our knowledge) in the literature only once. We describe two patients who presented with a bilateral facial tremor that occurred only on smiling and other activation of therisorii muscles and had a high frequency of 9 Hz. One patient additionally suffered from young-onset Parkinson's disease, whereas the other had no further neurological symptoms or signs apart from this tremor. Anti-parkinsonian medication was unhelpful for the facial tremor in the patient with Parkinson's disease. Tremor on smiling may be a discrete entity or may be associated in some cases of Parkinson's disease.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, UCL, Institute of Neurology, Queen Square, London, United Kingdom.
authors.forename: Petra
authors.initials: P
authors.lastname: Schwingenschuh
authors.forename: Carla
authors.initials: C
authors.lastname: Cordivari
authors.forename: Julia
authors.initials: J
authors.lastname: Czerny
authors.forename: Marcello
authors.initials: M
authors.lastname: Esposito
authors.forename: Kailash P
authors.initials: KP
authors.lastname: Bhatia
mesh_terms: D000328:Adult; D004576:Electromyography / Q000379:methods; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D012904:Smiling / Q000502:physiology*; D014202:Tremor / Q000503:physiopathology*