title: Abnormal maximal finger tapping in abstinent cannabis users.
abstract: OBJECTIVE
  To investigate movement speed and rhythmicity in abstinent cannabis users, we hypothesized that abstinent cannabis users exhibit decreased maximal finger tapping frequency and increased variability of tapping compared with non-drug users.
  
  
  METHODS
  The study involved 10 healthy adult cannabis users and 10 age-matched and gender-matched controls with no history of illicit drug use. Subjects underwent a series of screening tests prior to participation. Subjects were then asked to tap a strain gauge as fast as possible with the index finger of their dominant hand (duration 5 s).
  
  
  RESULTS
  The average intertap interval did not significantly differ between groups, but the coefficient of variation of the intertap interval was significantly greater in the cannabis group than in controls (p=0.011). The cannabis group also exhibited a slow tapping frequency at the beginning of the task.
  
  
  CONCLUSIONS
  Rhythmicity of finger tapping is abnormal in individuals with a history of cannabis use. The abnormality appears to be long lasting and adds to the list of functional changes present in abstinent cannabis users.
authors.affiliation: Advanced Facility for Avian Research, Univ of Western Ontario, London, ON, N6A 3K7.
authors.forename: Stanley C
authors.initials: SC
authors.lastname: Flavel
authors.forename: Jason M
authors.initials: JM
authors.lastname: White
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Todd
mesh_terms: D002188:Cannabis / Q000009:adverse effects; D005260:Female; D005385:Fingers / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D002189:Marijuana Abuse / Q000503:physiopathology*; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D010507:Periodicity; D013997:Time Factors; D055815:Young Adult
keywords: cannabis; finger tapping; psychomotor; rhythmicity