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Consistency of handwriting movements in dementia of the Alzheimer's type: A comparison with Huntington's and Parkinson's diseases

Published online by Cambridge University Press:  01 January 1999

MELISSA J. SLAVIN
Affiliation:
Department of Psychology, Monash University, Clayton, VIC, 3168, Australia
JAMES G. PHILLIPS
Affiliation:
Department of Psychology, Monash University, Clayton, VIC, 3168, Australia
JOHN L. BRADSHAW
Affiliation:
Department of Psychology, Monash University, Clayton, VIC, 3168, Australia
KATHRYN A. HALL
Affiliation:
Memory Clinic, Caulfield General Medical Centre, Caulfield, VIC, 3162, Australia
IAN PRESNELL
Affiliation:
Heatherton Hospital, Heatherton, VIC, 3202, Australia

Abstract

Patients with dementia of the Alzheimer's type (DAT) and their matched controls wrote, on a computer graphics tablet, 4 consecutive, cursive letter ‘l’s, with varying levels of visual feedback: noninking pen and blank paper so that only the hand movements could be seen, noninking pen and lined paper to constrain their writing, goggles to occlude the lower visual field and eliminate all relevant visual feedback, and inking pen with full vision. The kinematic measures of stroke length, duration, and peak velocity were expressed in terms of consistency via a signal-to-noise ratio (M value of each parameter divided by its SD). Irrespective of medication or severity, DAT patients had writing strokes of significantly less consistent lengths than controls', and were disproportionately impaired by reduced visual feedback. Again irrespective of medication or severity, patients' strokes were of significantly less consistent duration, and significantly less consistent peak velocity than controls', independent of feedback conditions. Patients, unlike controls, frequently perseverated, producing more than 4 ‘l’s, or multiple sets of responses, which was not differentially affected by level of visual feedback. The more variable performance of patients supports a degradation of the base motor program, and resembles that of Huntington's rather than Parkinson's disease patients. It may indeed reflect frontal rather than basal ganglia dysfunction. (JINS, 1999, 5, 20–25.)

Type
Research Article
Copyright
© 1999 The International Neuropsychological Society

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