Sex differences in cognition in healthy elderly individuals

Sex differences in patterns of cognitive test performance have been attributed to factors, such as sex hormones or sexual dimorphisms in brain structure, that change with normal aging. The current study examined sex differences in patterns of cognitive test performance in healthy elderly individuals. Cognitive test scores of 957 men and women (age 67-89), matched for overall level of cognitive test performance, age, education, and depression scale score, were compared. Men and women were indistinguishable on tests of auditory divided attention, category fluency, and executive functioning. In contrast, women performed better than men on tests of psychomotor speed and verbal learning and memory, whereas men outperformed women on tests of visuoconstruction and visual perception. Our finding that the pattern of sex differences in cognition observed in young adults is observed in old age has implications for future studies of both healthy elderly individuals and of those with cognitive disorders

Predictors of lane-change errors in older drivers

OBJECTIVES: To determine the factors that predict errors in executing proper lane changes among older drivers. DESIGN: Cross-sectional analysis of data from a longitudinal study. SETTING: Maryland's Eastern Shore. PARTICIPANTS: One thousand eighty drivers aged 67 to 87 enrolled in the Salisbury Eye Evaluation Driving Study. MEASUREMENTS: Tests of vision, cognition, health status, and self-reported distress and a driving monitoring system in each participant's car, used to quantify lane-change errors. RESULTS: In regression models, measures of neither vision nor perceived stress were related to lane-change errors after controlling for age, sex, race, and residence location. In contrast, cognitive variables, specifically performance on the Brief Test of Attention and the Beery-Buktenicka Test of Visual-Motor Integration, were related to lane-change errors. CONCLUSION: The current findings underscore the importance of specific cognitive skills, particularly auditory attention and visual perception, in the execution of driving maneuvers in older individuals

Visual and cognitive deficits predict stopping or restricting driving: The salisbury eye evaluation driving study (SEEDS)

PURPOSE. To determine the visual and other factors that predict stopping or restricting driving in older drivers. METHODS. A group of 1425 licensed drivers aged 67 to 87 years, who were residents of greater Salisbury, participated. At 1 year after enrollment, this group was categorized into those who had stopped driving, drove only within their neighborhood, or continued to drive beyond their neighborhood. At baseline, a battery of structured questionnaires, vision, and cognitive tests were administered. Multivariate analysis determined the factors predictive of stopping or restricting driving 12 months later. RESULTS. Of the 1425 enrolled, 1237 (87%) were followed up at 1 year. Excluding those who were already limiting their driving at baseline (n = 35), 1.5% (18/1202) had stopped and 3.4% (41/1202) had restricted their driving. The women (odds ratio [OR], 4.01; 95% confidence interval [CI], 2.05- 8.20) and those who prefer to be driven (OR, 3.91; 95% CI, 1.91- 8.00) were more likely to stop or restrict driving. Depressive symptoms increased likelihood of restricting or stopping driving (OR, 1.08; 95% CI, 1.009 -1.16 per point Geriatric Depression Scale). Slow visual scanning and psychomotor speed (Trail Making Test, Part A: OR, 1.02; 95% CI, 1.01-1.03), poor visuoconstructional skills (Beery-Buktenica Test of Visual Motor Integration: OR, 1.14; 95% CI, 1.05-1.25), and reduced contrast sensitivity (OR, 1.15; 95% CI, 1.03-1.28) predicted stopping or reducing driving. Visual field loss and visual attention were not associated. The effect of vision on changing driving behavior was partially mediated by cognition, depression, and baseline driving preferences. CONCLUSIONS. In this cohort, contrast sensitivity and cognitive function were independently associated with incident cessation or restriction of driving space. These data suggest drivers with functional deficits make difficult decisions to restrict or stop driving

The Optimal Motion Stimulus

Contrast energy thresholds were measured for discriminating the direction of a drifting sinusoidal grating multiplied by an independently drifting space-time Gaussian (a generalized Gabor). We argue that the stimulus with the lowest contrast energy threshold identifies the receptive field of the most efficient linear motion filter. This optimal motion stimulus is found to be at 3 cycles/degree and 5 Hz, with a width and height of 0.44 degree and a duration of 0.133 seconds, corresponding to spatial and temporal bandwidths of 1.1 and 2.5 octaves, respectively. The spectral receptive field is aligned more nearly to the Cartesian axes than to the velocity contour. 2 October 20, 1994 3:33 PM Theory Early thinking on the nature of motion detecting mechanisms in human vision was dominated by the notion of a matching process operating over space and time. Activity at one point in space and time was matched to activity at another point in space and time, and motion between the two points w..