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Different influence of backward masking on visual pattern recognition in the early stages of presenile dementia and normal ageing
Author(s) -
Müller Gottfried,
Weisbrod Steffen,
Klingberg Fritz
Publication year - 1992
Publication title -
international journal of geriatric psychiatry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 129
eISSN - 1099-1166
pISSN - 0885-6230
DOI - 10.1002/gps.930070607
Subject(s) - audiology , dementia , backward masking , ageing , stimulus (psychology) , medicine , masking (illustration) , analysis of variance , psychology , disease , neuroscience , art , perception , visual arts , psychotherapist
The effect of backward masking with illumination of all fields or with a checkerboard pattern, respectively, on the recognition of pattern + or T was measured on four groups of subjects: 21 presenile onset DAT patients, 16 patients with a questionable vascular dementia of the same age (CVD group), 15 age‐matched control subjects (EC group) and 16 younger control subjects (YC group, mean age 22 years). The pattern stimulus had a duration of 20 ms and was followed by the masking stimulus pattern (20 ms duration) with increasing intervals in steps of 5 ms. The mean recognition threshold (RT) for each of the four possible pattern–mask combinations was measured in five trials. The RTs decreased within the five trials in all groups. DAT patients and CVD patients adapted with different speeds during the five trials. We found a small significant RT difference between elder and younger control subjects, whereas patients had increased RTs in the first trial and differences in the four variants in the further trials compared with age‐matched controls. The test contributes to a set of data for diagnosis and differential diagnosis in the early stages of presenile dementia.