Visual and medical risk factors for motor vehicle collision involvement among older drivers.

AIMS: To identify visual and medical risk factors for motor vehicle collisions (MVCs). METHODS: Data from four cohorts of older drivers from three states were pooled (n = 3158). Health information was collected at baseline, and MVC data were obtained prospectively. Cox proportional hazards regression was used to estimate rate ratios (RRs) and 95% CIs for associations between medical characteristics and MVCs. RESULTS: A total of 363 MVCs were observed during the study period (1990-1997), of which 145 were at fault, and 62 were injurious. Falls and impaired useful field of view (UFOV) were positively associated with overall MVCs. At-fault MVCs were also positively associated with falls and UFOV impairment, and inversely with cancer. Injurious MVCs were positively associated with arthritis and neurological disease, and inversely with hypertension. CONCLUSIONS: These findings show similarities and differences across the risk factors for all, at-fault and injurious MVCs, and point to the need for verification and possible interventions.

The impact of speed of processing training on cognitive and everyday performance.

The purpose of the present investigation was to examine the impact of speed of processing training on the cognitive and everyday abilities of older adults with initial processing speed or processing difficulty. Participants were randomized to either a speed of processing intervention or a social- and computer-contact control group. Results indicate that speed of processing training not only improves processing speed, as indicated by performance on the Useful Field of View test (UFOV), but also transfers to certain everyday functions, as indicated by improved performance on Timed Instrumental Activities of Daily Living (Timed IADL). Transfer of speed of processing training to other cognitive domains was not evident. This study provides additional evidence that speed of processing training has the potential to enhance everyday functions that maintain independence and quality of life, particularly when the training is targeted toward individuals who most need it. Further study is needed to learn about the long-term effects of such training in relation to everyday abilities.

A note on state individual differences in accuracy of response imagery: aftereffects and reminiscence.

In two sessions, separated by 7 days, subjects imagined themselves performing a tracking task under a massed practice schedule. After conditions of interpolated rest and no-rest, which were counterbalanced across sessions, subjects actually performed the tracking task. During imagery practice, subjects verbally reported the temporal component of the task. The temporal accuracy of verbal reports varied widely across subjects, but not within subjects. Furthermore, a performance gain was demonstrated as a function of interpolated rest versus no-rest (reminiscence effect). Finally, the accuracy of verbal reports predicted imagery aftereffects, but not reminiscence effects.

Driving avoidance and functional impairment in older drivers.

The purpose of this study was to examine the association between visual and cognitive impairment in older drivers and their avoidance of potentially challenging, driving situation. A group of 257 older drivers participated in assessments of visual sensory function, eye health and cognitive function including the useful field of view test, and completed a structured questionnaire on driving exposure and how frequently they avoided challenging driving situations. Results replicated earlier studies showing that many older drivers limit their exposure to driving situations which are generally believed to be more difficult (e.g. rain, night, heavy traffic, rush hour). Furthermore, older drivers with objectively determined visual and/or attentional impairments reported more avoidance than those free of impairments; those with the most impairment reported avoiding more types of situations than other less impaired or non-impaired drivers. Older drivers with a history of at-fault crashes in the prior five years reported more avoidance than those who had crash-free records. Future research should evaluate the potentially beneficial role of self-regulation in enhancing older driver safety, particularly in those older drivers with visual and attentional processing impairments who have elevated crash risk.

Visual processing impairment and risk of motor vehicle crash among older adults.

CONTEXT: Motor vehicle crash risk in older drivers has been associated with visual acuity loss, but only weakly so, suggesting other factors contribute. The useful field of view is a measure that reflects decline in visual sensory function, slowed visual processing speed, and impaired visual attention skills. OBJECTIVE: To identify whether measures of visual processing ability, including the useful field of view test, are associated with crash involvement by older drivers. DESIGN: Prospective cohort study with 3 years of follow-up, 1990-1993. SETTING: Ophthalmology clinic assessment of community-based sample. PATIENTS: A total of 294 drivers aged 55 to 87 years at enrollment. MAIN OUTCOME MEASURE: Motor vehicle crash occurrence. RESULTS: Older drivers with a 40% or greater impairment in the useful field of view were 2.2 times (95% confidence interval, 1.2-4.1) more likely to incur a crash during 3 years of follow-up, after adjusting for age, sex, race, chronic medical conditions, mental status, and days driven per week. This association was primarily mediated by difficulty in dividing attention under brief target durations. CONCLUSION: Reduction in the useful field of view increases crash risk in older drivers. Given the relatively high prevalence of visual processing impairment among the elderly, visual dysfunction and eye disease deserve further examination as causes of motor vehicle crashes and injury.

Response imagery: aftereffects and reminiscence.

In two experiments, subjects imagined themselves performing a tracking task under a massed practice schedule. After interpolated rest or no rest, subjects actually performed the criterion task. Some subjects' imagery was augmented with sounds that matched the temporal characteristics of the criterion task. These subjects produced greater aftereffects than subjects who imaged without augmentation or subjects provided with imagery augmentation matching a variation of the criterion. Reminiscence (performance gain attributed to interpolated rest) was demonstrated with imagery, except when the accompanying augmentation was faster than the criterion.

Visual attention problems as a predictor of vehicle crashes in older drivers.

PURPOSE: To identify visual factors that are significantly associated with increased vehicle crashes in older drivers. METHODS: Several aspects of vision and visual information processing were assessed in 294 drivers aged 55 to 90 years. The sample was stratified with respect to age and crash frequency during the 5-year period before the test date. Variables assessed included eye health status, visual sensory function, the size of the useful field of view, and cognitive status. Crash data were obtained from state records. RESULTS: The size of the useful field of view, a test of visual attention, had high sensitivity (89%) and specificity (81%) in predicting which older drivers had a history of crash problems. This level of predictability is unprecedented in research on crash risk in older drivers. Older adults with substantial shrinkage in the useful field of view were six times more likely to have incurred one or more crashes in the previous 5-year period. Eye health status, visual sensory function, cognitive status, and chronological age were significantly correlated with crashes, but were relatively poor at discriminating between crash-involved versus crash-free drivers. CONCLUSIONS: This study suggests that policies that restrict driving privileges based solely on age or on common stereotypes of age-related declines in vision and cognition are scientifically unfounded. With the identification of a visual attention measure highly predictive of crash problems in the elderly, this study points to a way in which the suitability of licensure in the older adult population could be based on objective, performance-based criteria.

Alternating actual and imagery practice: preliminary theoretical considerations.

The main purpose of the following experiments was to reexamine the acquisition effects of alternating actual and imagery practice on retention. This was accomplished by making retention comparisons between groups that either alternated actual and imagery practice, alternated actual practice and rest, employed all actual or all imagery practice, or performed an unrelated task (the control) during acquisition. Results from Experiment 1 indicated that the actual practice and the alternating actual and imagery practice groups produced equivalent scores that were greater than the equivalent scores of the imagery practice and alternating actual practice and rest groups. All experimental groups performed better than the control. Because the retention test was identical to the actual practice protocol, practice specificity may have biased the retention relative standings in favor of the actual practice group. Experiment 2 was identical to Experiment 1 except subjects were transferred to a contralateral limb retention test. Results indicated that the alternating actual and imagery practice group produced better retention scores than the equivalent retention scores of the actual practice and imagery practice groups. These three groups produced higher retention scores than the alternating actual practice and rest group, which was better than the control. These results support the notion that alternating actual and imagery practice facilitates motor learning and suggest that practice specificity may be a factor in response imagery experiments. Based on the notion that actual and imagery practice activate shared and unique mechanisms, several hypotheses were offered to explain these results.

Visual/cognitive correlates of vehicle accidents in older drivers.

Older drivers have more accidents per miles driven than any other age group and tend to have significant impairments in their visual function, which could interfere with driving. Previous research has largely failed to document a link between vision and driving in the elderly. We have taken a comprehensive approach by examining how accident frequency in older drivers relates to the visual/cognitive system at a number of levels: ophthalmological disease, visual function, visual attention, and cognitive function. The best predictor of accident frequency as recorded by the state was a model incorporating measures of early visual attention and mental status, which together accounted for 20% of the variance, a much stronger model than in earlier studies. Those older drivers with a visual attentional disorder or with poor scores on a mental status test had 3-4 times more accidents (of any type) and 15 times more intersection accidents than those without these problems.

Age and visual search: expanding the useful field of view.

The useful field of view is defined as the visual area in which information can be acquired within one eye fixation. We studied visual search within this context and found a reduction in the size of the field as a function of age. This loss, however, was recovered partially with practice. Standard acuity and perimetric tests of visual field, although diagnostic of disease, underestimate the degree of difficulty experienced by visually healthy older adults in everyday activities requiring the use of peripheral vision. To aid in predicting such performance, a model incorporating the effects of distractors and secondary task demands was developed.

Scaling task complexity along a single dimension.

Time-on-target on pursuit rotor tracking tasks has been shown to decrease for triangle, square, and circle templates, respectively. Since these templates are unrelated geometric shapes they cannot be scaled along a single continuous dimension. For the present study, templates were constructed to be continuously scaled by eccentricity. It was demonstrated that time-on-target on pursuit rotor tracking was a decreasing function of template eccentricity. Also, it was concluded that elliptical templates were preferred over the usual geometric templates because time-on-target relationships among templates can be examined.

Toward a central-peripheralist model of work decrement.

Payne and others, within a Hullian framework, have analytically defined reactive inhibition in terms of a negative drive occurring within the effector system. In strong support, they have demonstrated that the maintenance of work decrement is dependent upon limb, but not task, specificity. However, equally creditable research by Adams allows interpretations of inhibition based on the processing of information. These contrasting arguments are evaluated, and an initial model integrating the two is proposed.

Mechanism involvement during skill imagery.

Explanations of the effects of initial mental imagery practice on the subsequent performance of a motor task may be divided into two categories. In-flow explanations propose that proprioceptive feedback generated during imagery practice serves as the underlying mechanism while outflow explanations claim that cognitive operations (e.g., motor programs) generated during skill imagery serve as the basis for physical performance. A test of these two models was conducted by comparing unilateral and bilateral transfer in a rotary pursuit task following either imagery or physical practice (cf. Wallace, 1977). The results showed that all transfer groups produced positive transfer relative to a no-practice control group. Further, unilateral transfer was greater than bilateral transfer for physical practice. There was no difference between unilateral and bilateral transfer for imagery practice. These data were interpreted as evidence for an outflow explanation of skill imagery.

Bilateral transfer as a function of mental imagery.

Three experiments are reported which investigate the role of mental imagery in the bilateral transfer from right to Ie ft hand of rotary pursuit skill. In Experiment 1 both mental imagery and physical rehearsal showed significant positive transfer relative to a control condition. However, work decrement may have accumulated and transferred in the physical rehearsal group thereby depressing this group's left-hand performance. Experiment 2 was conducted under conditions designed to allow work decrement to dissipate prior to transfer to the contralateral limb. The data still showed no difference between physical rehearsal and mental imagery. One interpretation of these data is that work decrement was present under both the physical rehearsal and mental imagery manipulations in Experiment 1. The data from Experiment 3 confirmed this interpretation as well as replicated the positive transfer effects found for mental imagery in Experiments 1 and 2. The data are discussed in terms of central versus peripheral explanatory mechanisms.