title: Convergence spasm in conversion disorders: prevalence in psychogenic and other movement disorders compared with controls.
abstract: BACKGROUND
  Convergence spasm refers to transient ocular convergence, miosis and accommodation associated with disconjugate gaze mimicking abducens palsy. While it may be a manifestation of brainstem pathology, this sign is often associated with conversion (somatisation) disorders and, if unrecognised as a sign of a psychogenic disorder, it may lead to unnecessary and occasionally invasive evaluation.
  
  
  METHODS
  To better characterise this neuro-ophthalmologic sign, 36 subjects were studied, 13 with psychogenic movement disorders, 11 with organic movement disorders and 12 normal controls. Patients were recorded during a manoeuvre to elicit convergence spasm and the videotapes were rated by two blinded raters on a scale of 0=normal, 1=mild convergence spasm and 2=marked convergence spasm.
  
  
  RESULTS
  Convergence spasm was present in 9/13 (69%) psychogenic movement disorders cases, 4/11 (36%) non-psychogenic movement disorders cases and 4/12 (33%) controls (p=0.049 when psychogenic vs non-psychogenic disorders or controls were compared). Inter-rater reliability analysis of the presence (rating 1 or 2) versus absence (rating 0) showed good agreement (27/36 or 75%; kappa 0.491, SE 0.141, p=0.002). Analysis for the presence of marked convergence spasm (rating 2) yielded agreement in 32/36 (88.9%) examinations (kappa 0.652, SE 0.154, p<0.001) with a specificity of 87% (sensitivity 15%).
  
  
  CONCLUSIONS
  Convergence spasm may provide benefit in the clinical examination of psychogenic movement disorders patients.
authors.affiliation: Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, The Smith Tower, Suite 1801, 6550 Fannin St Houston, TX 77030, USA. robertfekete@hotmail.com
authors.forename: Robert
authors.initials: R
authors.lastname: Fekete
authors.forename: Jose Fidel
authors.initials: JF
authors.lastname: Baizabal-Carvallo
authors.forename: Ainhi D
authors.initials: AD
authors.lastname: Ha
authors.forename: Anthony
authors.initials: A
authors.lastname: Davidson
authors.forename: Joseph
authors.initials: J
authors.lastname: Jankovic
mesh_terms: D000328:Adult; D000368:Aged; D003291:Conversion Disorder / Q000150:complications* / Q000503:physiopathology*; D003937:Diagnosis, Differential; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology / Q000503:physiopathology*; D017120:Nystagmus, Optokinetic / Q000502:physiology; D009759:Nystagmus, Pathologic / Q000209:etiology / Q000503:physiopathology*; D015588:Observer Variation; D011698:Pursuit, Smooth / Q000502:physiology