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Harry S. Orbach, Ross M. Henderson, Gordon N. Dutton, Daphne L. McCulloch, Fiona Gilchrist, Alan Conway; Distinguishing deficits in change detection from deficits in spatial attention in older adults. Journal of Vision 2005;5(8):557. doi: https://doi.org/10.1167/5.8.557.
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© ARVO (1962-2015); The Authors (2016-present)
Accurate assessment of visual function in older adults is important for determining competence for everyday tasks. Standard acuity testing is inadequate, therefore measures such as ‘useful field of view’ have been introduced, showing attention deficits. How do change detection deficits compare with attention deficits in older subjects?
We compared two groups of healthy adults: young (18–30 years, n=15) and older (60–70 years, n=9). In all tasks the subject indicated by a key-press where an “odd” pattern occurred. Subjects viewed a computer screen which was subdivided into four quadrants, each of which contained one pattern. Each pattern in the single element (acuity) condition was a single line, the odd pattern had a different orientation. In the uniform (attention) and mixed (change detection) conditions, each pattern consisted of four lines arranged in a ring. To control for pop-out effects in the uniform condition, the four patterns had different base orientations. The attention task involved searching for a (target) uniform pattern among non-uniform patterns (where one element had an incremented orientation). In the mixed condition, each pattern had elements of mixed orientations. Corresponding elements of the patterns were identical except the target which had an element with an incremented orientation. The stimulus was free viewed for 4 seconds.
Young subjects did somewhat better than the older group (5° vs 8° orientation thresholds) on single element discrimination. Performance on the attention task showed little change for the young adults (6° threshold), in contrast to significant impairment (15° threshold) for older subjects. For the change detection task, both groups had considerably poorer thresholds (41° for the young adults and 57° for older subjects).
Our results suggest that standard acuity tests and even ‘useful field of view’ tests significantly underestimate the degree and nature of impairments in real world situations.
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