title: Tactile spatial acuity and roughness discrimination: impairments due to aging and Parkinson's disease.
abstract: We used gratings of alternating ridges and grooves in a quantitative psychophysical investigation of tactile perception in patients with Parkinson's disease (PD) and age-matched normal controls. The groove width required for threshold discrimination of grating orientation was 25% higher in the control subjects compared to younger individuals studied previously (p = 0.004), indicating a small but significant decline in tactile spatial acuity with age. Relative to age-matched controls, patients with PD showed a twofold increase in the tactile spatial threshold (p = 3.07 x 10(-8), with somewhat greater impairment on the side more affected clinically (p = 0.03). Testing with the forearm prone, as compared to supine, produced a small improvement in the acuity of patients (p = 0.01) but not controls (p = 0.26). PD patients were also impaired in tactually discriminating grating roughness: their difference limens were over three times higher than those of controls (p = 5.74 x 10(-5)) for gratings differing in groove width, and over twice as high (p = 0.0003) for gratings differing in ridge width. We conclude that PD significantly impairs performance on these tactile tasks.
authors.affiliation: Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: K
authors.initials: K
authors.lastname: Sathian
authors.forename: A
authors.initials: A
authors.lastname: Zangaladze
authors.forename: J
authors.initials: J
authors.lastname: Green
authors.forename: J L
authors.initials: JL
authors.lastname: Vitek
authors.forename: M R
authors.initials: MR
authors.lastname: DeLong
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D013028:Space Perception / Q000502:physiology*; D013647:Task Performance and Analysis