title: What's in a smile?: Quantification of the vertical smile of patients with myasthenia gravis.
abstract: Many patients with myasthenia gravis who experience bulbar symptoms show a vertical smile, which may have a considerable, and often underestimated, impact on social life. Peri-oral muscle function can be quantified by calculating lip-length and snout indices, which indicate the degree to which a person is capable of smiling and of pursing the lips, respectively. In the present study patients with bulbar myasthenia gravis were compared to patients with ocular myasthenia gravis, patients now in remission (but previously suffering from bulbar myasthenia gravis), and healthy subjects. The lip-length and snout indices of patients with bulbar myasthenia gravis were significantly lower than those of the other groups. The facial impairments were no longer detectable in patients with bulbar myasthenia gravis in remission and no subclinical impairments in lip-length and snout indices were found in the ocular myasthenia gravis group. These findings were consistent with the patients' reports of impairment of smiling and other oral functions. The patients suffering from a vertical smile or other oral impairments were well aware of their condition, most probably because of the social consequences of being unable to smile. The indices could be of importance in the longitudinal evaluation of therapy in individual patients and in pharmacotherapeutical research. We found a low correlation between the lip-length and snout indices, which reflects the capricious pattern of involvement of separate muscles in myasthenia gravis. Therefore both indices deserve special attention if they are used for monitoring myasthenic symptoms.
authors.affiliation: Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, Universiteit Utrecht, Utrecht, The Netherlands. F.G.Weijnen@med.uu.nl
authors.forename: F G
authors.initials: FG
authors.lastname: Weijnen
authors.forename: A
authors.initials: A
authors.lastname: van der Bilt
authors.forename: J H
authors.initials: JH
authors.lastname: Wokke
authors.forename: J B
authors.initials: JB
authors.lastname: Kuks
authors.forename: H W
authors.initials: HW
authors.lastname: van der Glas
authors.forename: F
authors.initials: F
authors.lastname: Bosman
mesh_terms: D000328:Adult; D000886:Anthropometry; D001933:Brain Stem / Q000503:physiopathology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D005152:Facial Muscles / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008046:Lip / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000145:classification / Q000188:drug therapy / Q000503:physiopathology*; D009666:Nose / Q000473:pathology; D012904:Smiling / Q000502:physiology*
chemical_list: D002800:Cholinesterase Inhibitors