title: Efficiency of temporal order discrimination as an indicator of bradyphrenia in Parkinson's disease: the inspection time loop task.
abstract: To investigate the bradyphrenia hypothesis of Parkinson's disease (PD), 32 patients undertook an information-processing task which measured their efficiency of temporal order discrimination. Their performance was compared with 31 non-PD controls matched on age, sex, years of full-time education and pre-morbid IQ. The task was novel and designed to be sensitive to the clinical phenomenon of bradyphrenia (slowing of mental abilities), in the context of temporal order discrimination without confounding from motor ability deficits. The test (the inspection time loop task; ITloop) required judgements as to the temporal sequence of four single letters. The stimulus duration of the letters in each sequence ranged from 100 to 700ms. The PD group had a significantly lower mean score on the ITloop task than did controls (P=0.02). PD patients perform more poorly on temporal order discrimination judgements even when the task makes no motor demands.
authors.affiliation: Department of Psychology, University of Edinburgh, Scotland, UK.
authors.forename: Beverly A
authors.initials: BA
authors.lastname: Shipley
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
authors.forename: Jennifer
authors.initials: J
authors.lastname: Tan
authors.forename: Gayle
authors.initials: G
authors.lastname: Christie
authors.forename: John M
authors.initials: JM
authors.lastname: Starr
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001288:Attention; D004193:Discrimination Learning; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000175:diagnosis*; D010364:Pattern Recognition, Visual; D011597:Psychomotor Performance; D011930:Reaction Time; D012691:Serial Learning; D013998:Time Perception