title: Alternating two finger tapping with contralateral activation is an objective measure of clinical severity in Parkinson's disease and correlates with PET
abstract: We explored an objective method of measuring clinical severity of Parkinson's disease. Eighty-six patients with PD and 136 healthy subjects were studied. We serially carried out four types of finger tapping (FT) using a computerized drum machine: (i) repetitive one-finger tapping with an index-finger (F1K1); (ii) one-finger tapping on two keys separated by 20cm (F1K2); (iii) alternate tapping with index and middle fingers on two adjacent keys (F2K2); and (iv) F2K2 with contralateral activation (aF2K2). Analyses on FT included: (i) age and gender effects in healthy volunteers and Parkinson's disease; (ii) comparison between Parkinson patients and controls of similar age distribution; (iii) correlation with the Purdue Pegboard and Modified Columbia Scale in Disease; and (iv) in a subset of patients in whom PET scans were performed (n=30), correlation with 18F-DOPA uptake constant (Ki). In healthy subjects, there was a negative age effect on FT scores and a gender effect, with males scoring higher than females. All FT scores were significantly lower in the Parkinson patients, correlated with Purdue Peg Board, and inversely with the duration of illness, and with the Modified Columbia Scale. The 18F-DOPA Ki correlated significantly with aF2K2 (p=0.024), less so with PPB (p=0.038), but not with the Modified Columbia Scale. We conclude that alternating two-finger tapping with contralateral hand activation is a simple, objective test for measuring the severity of Parkinson's disease.
authors.affiliation: Neurodegenerative Disorders Centre, Vancouver Hospital and Health Sciences Centre, University of British Columbia, Purdy Pavilion, 2221 Westbrook Mall, British Columbia, V6T 2B5, Vancouver, Canada
authors.forename: P K.
authors.initials: PK
authors.lastname: Pal
authors.forename: C S.
authors.initials: CS
authors.lastname: Lee
authors.forename: A
authors.initials: A
authors.lastname: Samii
authors.forename: M
authors.initials: M
authors.lastname: Schulzer
authors.forename: A J.
authors.initials: AJ
authors.lastname: Stoessl
authors.forename: E K.
authors.initials: EK
authors.lastname: Mak
authors.forename: J
authors.initials: J
authors.lastname: Wudel
authors.forename: T
authors.initials: T
authors.lastname: Dobko
authors.forename: J K.C.
authors.initials: JK
authors.lastname: Tsui