title: Sensitivity and specificity of the finger tapping task for the detection of psychogenic movement disorders.
abstract: Psychogenic movement disorders (PMD) represent a diagnostically challenging group of patients in movement disorders. Finger tapping tests (FTT) have been used in neuropsychiatric evaluations to identify psychogenic conditions, but their use in movement disorders has been limited to the quantification of upper extremity disability in idiopathic Parkinson disease (IPD). We evaluated the ability of the FTT to objectively identify PMD by screening 195 individuals from a movement disorder clinic with IPD, dystonia, essential tremor, or PMD and compared them to 130 normal adults. All subjects performed six-30 s trials using alternate hands. We compared mean FTT score and the coefficient of variation between diagnostic groups. FTT scores in IPD were inversely correlated with Hoehn and Yahr stage (p < 0.001) and the United Parkinson Disease Rating Scale III (motor) subscale (p < 0.001). FTT scores were significantly lower in PMD (mean = 41.72) when compared to the other diagnostic groups after controlling for age. The coefficient of variation was not significantly different between diagnostic groups. ROC analysis identified a cutoff FTT ratio of 0.670 or less was 89.1% specific and 76.9% sensitive for the diagnosis of PMD. We conclude the FTT can provide supportive evidence for the diagnosis of PMD.
authors.affiliation: Department of Neurology, Washington University School of Medicine, 660 South Euclid Ave, Box 8111, St Louis, MO 63110, USA. criswells@neuro.wustl.edu
authors.forename: Susan
authors.initials: S
authors.lastname: Criswell
authors.forename: Callen
authors.initials: C
authors.lastname: Sterling
authors.forename: Laura
authors.initials: L
authors.lastname: Swisher
authors.forename: Brad
authors.initials: B
authors.lastname: Evanoff
authors.forename: Brad A
authors.initials: BA
authors.lastname: Racette
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004185:Disability Evaluation; D005260:Female; D005385:Fingers / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000175:diagnosis; D011597:Psychomotor Performance / Q000502:physiology*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014202:Tremor / Q000175:diagnosis