Chronological age and age-related cognitive deficits are associated with an increase in multiple types of driving errors in late life.

Objective: Older driver research has mostly focused on identifying that small proportion of older drivers who are unsafe. Little is known about how normal cognitive changes in aging affect driving in the wider population of adults who drive regularly. We evaluated the association of cognitive function and age with driving errors. Method: A sample of 266 drivers aged 70 to 88 years were assessed on abilities that decline in normal aging (visual attention, processing speed, inhibition, reaction time, task switching) and the UFOV?, which is a validated screening instrument for older drivers. Participants completed an on-road driving test. Generalized linear models were used to estimate the associations of cognitive factors with specific driving errors and number of errors in self-directed and instructor navigated conditions. Results: All error types increased with chronological age. Reaction time was not associated with driving errors in multivariate analyses. A cognitive factor measuring speeded selective attention and switching was uniquely associated with the most errors types. The UFOV? predicted blind-spot errors and errors on dual carriageways. After adjusting for age, education, and gender, the cognitive factors explained 7% of variance in the total number of errors in the instructor-navigated condition and 4% of variance in the self-navigated condition. Conclusion: We conclude that among older drivers, errors increase with age and are associated with speeded selective attention, particularly when that requires attending to the stimuli in the periphery of the visual field, task switching, errors inhibiting responses, and visual discrimination. These abilities should be the target of cognitive training. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

What predicts changes in useful field of view test performance?

The Useful Field of View Test (UFOV) has been used as an examination of age-related changes in visual processing and cognition and as an indicator of everyday performance outcomes, particularly driving, for over 20 years. How UFOV performance changes with age and what may impact such changes have not previously been investigated longitudinally. Predictors of change in UFOV performance over a 5-year period among control group participants (N = 690) from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study were examined. Random effects models were estimated with 4-subtest-total UFOV as the outcome and with baseline age, education, gender, race, visual acuity, depressive symptoms, mental status, and self-rated health, as well as attrition, as predictors. UFOV performance generally followed a curvilinear pattern, improving and then declining over time. Only increased age was consistently related to greater declines in UFOV performance over time. UFOV and Digit Symbol Substitution subtest, a standard measure of cognitive speed, had similar trajectories of change. The implications of these results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simulator driving performance predicts accident reports five years later.

L. Hoffman, J. M. McDowd, P. Atchley, and R. A. Dubinsky (2005) reported that visual and attentional impairment (measured by the Useful Field of View test and DriverScan) and performance in a low-fidelity driving simulator did not predict self-reported accidents in the previous 3 years. The present study applied these data to predict accidents occurring within a subsequent 5-year period (N = 114 older adults, 75% retention rate). Multivariate path models revealed that accidents in which the driver was at least partially at fault were significantly more likely in persons who had shown impaired simulator performance. These results suggest that even low-fidelity driving simulators may be useful in predicting real-world outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention improves or impairs visual performance by enhancing spatial resolution

Covert attention, the selective processing of visual information at a given location in the absence of eye movements, improves performance in several tasks, such as visual search and detection of luminance and vernier targets. An important unsettled issue is whether this improvement is due to a reduction in noise (internal or external), a change in decisional criteria, or signal enhancement. Here we show that attention can affect performance by signal enhancement. For a texture segregation task in which performance is actually diminished when spatial resolution is too high, we observed that attention improved performance at peripheral locations where spatial resolution was too low, but impaired performance at central locations where spatial resolution was too high. The counterintuitive impairment of performance that we found at the central retinal locations appears to have only one possible explanation: attention enhances spatial resolution.     

Orienting attention in visual working memory reduces interference from memory probes.

Given a changing visual environment, and the limited capacity of visual working memory (VWM), the contents of VWM must be in constant flux. Using a change detection task, the authors show that VWM is subject to obligatory updating in the face of new information. Change detection performance is enhanced when the item that may change is retrospectively cued 1 s after memory encoding and 0.5 s before testing. The retro-cue benefit cannot be explained by memory decay or by a reduction in interference from other items held in VWM. Rather, orienting attention to a single memory item makes VWM more resistant to interference from the test probe. The authors conclude that the content of VWM is volatile unless it receives focused attention, and that the standard change detection task underestimates VWM capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual localization in dyslexia.

Individuals with specific reading disability (SRD) may exhibit visual psychophysical abnormalities that include prolonged visual persistence, decreased luminance contrast sensitivity, lower flicker fusion thresholds, abnormal metacontrast masking, and lower motion detection sensitivity. These abnormalities could result from impairment of the magnocellular division of the visual afferent pathway to the cortex. The authors predicted that an impairment of this pathway would also cause abnormalities in ability to localize visual stimuli. This prediction was tested in 2 experiments. Results of both experiments showed that adults who reported a history of SRD and who currently had lower reading performance were less able than non-SRD participants to report the locations of small visual stimuli that were briefly flashed at positions similar to the ends of lines of text. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simulation training of psychomotor skills: Teaching the brain-injured to drive.

13 brain-injured individuals (average age 24.2 yrs) completed a set of 7 exercises simulating specific cognitive and behavioral aspects of motor vehicle operation, using an electric-powered vehicle, to test whether training would generalize to a complex functional task (i.e., automobile driving). Training exercises involved visuomotor tracking, divided attention, successive increases in difficulty level, performance feedback, and social reinforcement. Ss were compared with 11 closed-head-injured controls of the same average age, who received experience with the electric vehicle but no training exercises, and with 11 normal high-school students, who had driver's licenses and were trained in some of the exercises (e.g., divided attention). Training consisted of 8 2-hr sessions; at the conclusion of training, experimental and control Ss were evaluated in an on-the-road automobile test. Results indicate that experimental Ss showed improvements on the specific exercises, and training resulted in improved performance on tests of on-the-road driving when compared with closed-head-injured controls, who did not show improvement in their driving performance. Results suggest a significant therapeutic effect of the specific training exercises. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simulated driving performance of adults with ADHD: Comparisons with alcohol intoxication.

Previous research has demonstrated that adults with attention deficit/hyperactivity disorder (ADHD) are more likely to experience driving-related problems, which suggests that they may exhibit poorer driving performance. However, direct experimental evidence of this hypothesis is limited. The current study involved 2 experiments that evaluated driving performance in adults with ADHD in terms of the types of driving decrements typically associated with alcohol intoxication. Experiment 1 compared the simulated driving performance of 15 adults with ADHD to 23 adult control participants, who performed the task both while sober and intoxicated. Results showed that sober adults with ADHD exhibited decrements in driving performance compared to sober controls, and that the profile of impairment for the sober ADHD group did in fact resemble that of intoxicated drivers at the blood alcohol concentration level for legally impaired driving in the United States. Driving impairment of the intoxicated individuals was characterized by greater deviation of lane position, faster and more abrupt steering maneuvers, and increased speed variability. Experiment 2 was a dose-challenge study in which 8 adults with ADHD and 8 controls performed the driving simulation task under 3 doses of alcohol: 0.65g/kg, 0.45g/kg, and 0.0g/kg (placebo). Results showed that driving performance in both groups was impaired in response to alcohol, and that individuals with ADHD exhibited generally poorer driving performance than did controls across all dose conditions. Together the findings provide compelling evidence to suggest that the cognitive and behavioral deficits associated with ADHD might impair driving performance in such a manner as to resemble that of an alcohol intoxicated driver. Moreover, alcohol might impair the performance of drivers with ADHD in an additive fashion that could considerably compromise their driving skill even at blood alcohol concentrations below the legal limit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Driver training conditions affect sensitivity to the impairing effects of alcohol on a simulated driving test to the impairing effects of alcohol on a simulated driving test.

[Correction Notice: An erratum for this article was reported in Vol 16(2) of Experimental and Clinical Psychopharmacology (see record 2008-03846-009). The correct title of the article should read "Driver training conditions affect sensitivity to the impairing effects of alcohol on a simulated driving test".] Research shows that prior behavioral training in a challenging environment reduces alcohol-induced impairment on simple psychomotor tasks. However, no studies have examined if this relationship generalizes to driving performance. The present study examined simulated driving performance and tested the hypothesis that a challenging training history would protect against the impairing effects of alcohol on driving performance. The challenging training history involved driving in a visually-impoverished environment. Thirty adults were randomly assigned to one of three groups. Two groups were tested under alcohol (0.65 g/kg) after prior experience performing the task under either a visually-impoverished environment or a normal visual environment. The remaining group served as a control and was trained and tested under the visually-impoverished condition environment. Results showed that individuals trained in the impoverished environment displayed sober levels of performance when their performance was subsequently tested under alcohol. By contrast, volunteers trained in a normal environment showed impairment under alcohol. The findings suggest that differences in driving training history can affect a driver's sensitivity to the impairing effects of alcohol. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychology of drivers in traffic accidents.

50 automobile drivers whose driving involved them in accidents serious enough to require hospitalization were paired with 50 drivers without accident histories but matched according to sex, approximate age, race, and educational level. The Ss were compared on the basis of their driving experiences and performance on written tests. The accident victims differed from the comparison Ss in a higher incidence of previous traffic violations but were not distinguishable from the comparison Ss on any written tests. The accident Ss were similar to the "safe" drivers in describing themselves as much closer to "expert" than "very poor" on a driving performance continuum. In fixing the responsibility for the accidents and in estimating their driving competence at the time of the accidents, the accident Ss' reports are at considerable variance with police reports. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Harrison et al. (2007).

Reports an error in "Driver training conditions affect sensitivity to the impairing effects of alcohol on a simulated driving test to the impairing effects of alcohol on a simulated driving test" by Emily L. R. Harrison, Cecile A. Marczinski and Mark T. Fillmore (Experimental and Clinical Psychopharmacology, 2007[Dec], Vol 15[6], 588-598). The correct title of the article should read "Driver training conditions affect sensitivity to the impairing effects of alcohol on a simulated driving test". (The following abstract of the original article appeared in record 2007-18976-010.) Research shows that prior behavioral training in a challenging environment reduces alcohol-induced impairment on simple psychomotor tasks. However, no studies have examined if this relationship generalizes to driving performance. The present study examined simulated driving performance and tested the hypothesis that a challenging training history would protect against the impairing effects of alcohol on driving performance. The challenging training history involved driving in a visually-impoverished environment. Thirty adults were randomly assigned to one of three groups. Two groups were tested under alcohol (0.65 g/kg) after prior experience performing the task under either a visually-impoverished environment or a normal visual environment. The remaining group served as a control and was trained and tested under the visually-impoverished condition environment. Results showed that individuals trained in the impoverished environment displayed sober levels of performance when their performance was subsequently tested under alcohol. By contrast, volunteers trained in a normal environment showed impairment under alcohol. The findings suggest that differences in driving training history can affect a driver's sensitivity to the impairing effects of alcohol. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overt orienting in the rat: Parametric studies of cued detection of visual targets.

Covert shifts of visual attention in space have been quantified by measuring the effects of visual cues on the detection of visual targets in humans and monkeys maintaining visual fixation. These observations of "covert orienting" have provided important information regarding the neurobiology of visual attention in primates. This article describes a cued spatial target detection task for physically unrestrained rats. Valid cues (spatially contiguous with the target) enhanced target detection, and invalid cues (spatially discontiguous with the target) degraded target detection. Both visual and auditory cues were effective. These validity effects could not be explained by stimulus additivity or response preparation mechanisms, whereas a cue-independent "alerting effect" appeared to reflect response preparation. The effects compare favorably with primate work and suggest that this method may enable assessment of visual attention shifts in rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention and driving performance in Alzheimer's disease

The present study examined the relationship between visual attention measures and driving performance in healthy older adults and individuals with very mild and mild dementia of the Alzheimer type (DAT). Subjects were administered an on-road driving assessment and three visual attention tasks (visual search, visual monitoring, and useful field of view). The results indicated that error rate and reaction time during visual search were the best predictors of driving performance. Furthermore, visual search performance was predictive of driving performance above and beyond simple dementia severity and several traditional psychometric tests. The results suggest that general cognitive status may be useful for identifying individuals "at risk" for unsafe driving. However, measures of selective attention may serve to better differentiate safe versus unsafe drivers, especially in the DAT population.     

Assessment of attention: relationship between psychological testing and information processing approaches

Examined the relationship between the psychological testing and information processing approaches in assessing attention. Eighty-seven subjects (57 females, 30 males) undertook eight psychological tests of attention and a visual-spatial reaction-time task. Using the cognitive-correlate method (Posner & McLeod, 1982), it was found that three components of attention (viz., visual-motor scanning, sustained selective processing, and visual/auditory spanning) derived from the psychological tests could be significantly predicted by specific, yet different, combinations of six indices of information processing (mean reaction time (RT), mean movement time (MT), feature extraction, identification, response selection, and motor adjustment): (a) mean RT and mean MT were found to be the most important indices for predicting performance on visual-motor scanning; (b) the motor-adjustment stage was found to be the most important index for predicting performance on sustained selective processing; (c) the response-selection stage was found to be the most important index for predicting performance on visual/auditory spanning. These relationships are important for supporting the construct-related validity of the psychological tests of attention and for extending the generality and applicability of the RT task.     

Simulated car crashes and crash predictors in drivers with Alzheimer disease

BACKGROUND: Alzheimer disease (AD) is the most common cause of dementia and can impair cognitive abilities crucial to the task of driving. Rational decisions about whether such impaired individuals should continue to drive require objective assessments of driver performance. OBJECTIVE: To measure relevant performance factors using high-fidelity driving simulation. DESIGN: We examined the effect of AD on driver collision avoidance using the Iowa Driving Simulator, which provided a high-fidelity, closely controlled environment in which to observe serious errors by at-risk drivers. We determined how such unsafe events are predicted by visual and cognitive factors sensitive to decline in aging and AD. SETTING: The University of Iowa Hospitals and Clinics, Iowa City, and the Iowa Driving Simulator. PARTICIPANTS: Thirty-nine licensed drivers: 21 with AD and 18 controls without dementia. MAIN OUTCOME MEASURES: We determined the number of crashes and related performance errors and analyzed how these occurrences were predicted by visual and cognitive factors. RESULTS: Six participants (29%) with AD experienced crashes vs 0 of 18 control participants (P = .022). Drivers with AD were more than twice as likely to experience close calls (P = .042). Plots of critical control factors in the moments preceding a crash revealed patterns of driver in-attention and error. Strong predictors of crashes included visuospatial impairment, reduction in the useful field of view, and reduced perception of 3-dimensional structure-from-motion. CONCLUSIONS: High-fidelity driving simulation provides a unique new source of performance parameters to standardize the assessment of driver fitness. Detailed observations of crashes and other safety errors provide unbiased evidence to aid in the difficult clinical decision of whether older or medically impaired individuals should continue to drive. The findings are complementary to evidence currently being gathered using techniques from epidemiology and cognitive neuroscience.     

Neuropsychological functioning in HIV-positive African-American women with a history of drug use

This preliminary investigation examined neuropsychological performance in a sample of human immunodeficiency virus (HIV)-positive and HIV-negative African-American women with a history of drug use. The study population was comprised of 10 HIV-negative, 9 asymptomatic HIV-positive, 13 symptomatic HIV-positive, and 10 acquired immunodeficiency virus (AIDS) patients. A neuropsychological battery designed to assess attention, psychomotor processing, verbal memory, and visual memory was administered to participants. No evidence of HIV-related cognitive impairment was found in patients in the early stages of HIV infection. Multivariate analyses of variance revealed significant deficits in psychomotor processing and verbal recall in persons with AIDS. These individuals showed greater difficulty in tasks requiring maintained attention and performed poorly on measures of immediate and delayed verbal recall. In contrast, HIV status was not related to visual memory, verbal recognition, or the number of errors made during a verbal recall task. The pattern of cognitive deficits observed in persons with AIDS resembles that commonly associated with subcortical pathology. The cognitive deficits observed were not related to depression or recentness of drug use.     

Visual attention deficits in Alzheimer's disease: Simple versus conjoined feature search.

The authors investigated selective attention in patients with Alzheimer's disease (AD), using a well-known visual search procedure. In simple feature search, the deficit observed in AD patients represented a baseline shift in the median hit reaction time (RT). On the conjoined feature search task, the median hit RT for AD patients increased disproportionately with increasing array size, indicating an additional cognitive impairment on this task. Of particular importance, the cognitive deficit observed in conjunction search was more profound than that predicted on the basis of previous reports of global cognitive slowing in AD. There was some evidence that the performance of AD patients improved more than the performance of controls over the duration of the experimental test session. Patients also had more difficulty in detecting targets on the right side of hemispace and in more peripheral locations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual task performance after diazepam intake: can resource depletion explain the benzodiazepine-induced amnesia?

It was tested whether a depletion in resources can account for the benzodiazepine-induced memory impairment. In two experiments, it was examined whether dividing attention had a disproportionately detrimental effect on learning semantically related and unrelated word pairs after diazepam intake. Word pairs had to be learned in both a single task condition and while performing a visual discrimination task concurrently (dual task condition). Moreover, the complexity of the visual discrimination task was manipulated systematically. Diazepam (15 mg, orally) or placebo was administered in a double-blind, between-subjects design. Subjects after diazepam intake were clearly impaired in learning unrelated word pairs, but not in learning related word pairs. Dividing attention in the dual task condition was associated with a reduction in learning unrelated word pairs, but this was not disproportionately reduced after diazepam intake. Moreover, the magnitude of resource depletion did not correlate with the severity of the diazepam-induced memory impairment. In general, the pattern of results does not support the hypothesis that a depletion of resources can explain the benzodiazepine-induced memory impairment.     

Noise and driver performance.

The demands of actual automobile driving and concurrent noise stress on human information-processing capacity for 8 licensed, college-aged drivers were estimated from the decrement in performance on the delayed digit recall subsidiary task, using multivariate techniques and a counterbalanced design. Under high load, drivers were much more likely to reduce accuracy than sacrifice speed; however, noise did not result in driving error when presented in the absence of additional load. This conclusion parallels the 1973 findings of H. Moscowitz, who investigated the effect of alcohol on driving performance. As expected, the subsidiary task measure was sensitive to the additional information-processing demands imposed by the unpredictable noise stimulus; but contrary to expectation, inclusion of the subsidiary task tended to interact slightly with noise in impairing driving performance. It is suggested that perhaps in the low-risk driving environment, maintenance of performance on the subsidiary task may have had sufficiently high subjective utility to demand a disproportionately large share of information-processing capacity. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hands up: Attentional prioritization of space near the hand.

This study explored whether hand location affected spatial attention. The authors used a visual covert-orienting paradigm to examine whether spatial attention mechanisms--location prioritization and shifting attention--were supported by bimodal, hand-centered representations of space. Placing 1 hand next to a target location, participants detected visual targets following highly predictive visual cues. There was no a priori reason for the hand to influence task performance unless hand presence influenced attention. Results showed that target detection near the hand was facilitated relative to detection away from the hand, regardless of cue validity. Similar facilitation was found with only proprioceptive or visual hand location information but not with arbitrary visual anchors or distant targets. Hand presence affected attentional prioritization of space, not the shifting of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)