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Abstract
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Purpose: Cognitive function in older adults is related to independent living and the need for formal care. The ACTIVE clinical trial addresses whether improving cognitive functions (memory, reasoning, speed of processing) might have short or long-term effects on activities related to living independently, including mobility and driving.
Methods: A volunteer sample of 2,832 older adults between the ages of 65 and 94 years was recruited from March 1998 to October 1999, and data have been collected thus far through the fifth annual follow-up. Each intervention improved its targeted cognitive ability, and participants in each of the training groups were performing significantly better than controls, as well as significantly better than their own baseline performance, after five years. The training results of the ACTIVE trial will be discussed for several outcomes.
Results: 1. Rates of Mobility and Driving Difficulty Random effects modeling was used to investigate the impact of training on longitudinal driving trajectories. Results revealed that participants in the reasoning training group reported less driving difficulty and had less decline in the amount of driving over the five years following training compared to the rate of decline of the no-contact control group (p <.05). Similarly, participants in the speed training group who received more training sessions reported greater driving frequency, greater driving exposure, and less driving difficulty over time relative to the control group.
2. Driving Cessation Older drivers with poorer cognitive abilities including speed of processing, memory, and reasoning, have a higher probability of driving cessation. Data from ACTIVE were aggregated from those of another study (SKILL) to investigate the effectiveness of cognitive training in delaying driving cessation. The resulting sample consisted of 561 adults (276 in speed of processing training and 285 in control conditions). Cox Regression analyses were used to examine training group as a predictor of driving cessation together with both baseline driving and visual acuity. Older drivers who initially drove more often and those with better vision were less likely to cease driving (p<.01). Older drivers who completed speed of processing training were 40% less likely to cease driving over the subsequent three years (HR = 0.597, 95% CI 0.358-0.995, p = .048).
3. Driving Competence – Crash Risk Prior studies have indicated that declining cognitive function is one of the better predictors of subsequent crash involvement among older adults. Crash records for older drivers participating in the ACTIVE clinical trial were obtained. Crash records spanning up to six years for 908 independently living older adults, averaging 73 years of age, who were current drivers at baseline and who were randomized to one of the interventions or the control group were analyzed. Poisson regression was used to calculate the crude and adjusted rate ratio and 95% confidence interval for the association between cognitive training and at-fault motor vehicle collision rates per person- year and person-mile of travel. Relative to controls, speed of processing training resulted in significantly reduced risk for at-fault crash involvement. Reasoning training was also observed to have a protective effect, though this association was not statistically significant. |