Wiebo Brouwer

DIVIDED ATTENTION IN EXPERIENCED YOUNG AND OLDER DRIVERS - LANE TRACKING AND VISUAL ANALYSIS IN A DYNAMIC DRIVING SIMULATOR

A simulated driving task that required the simultaneous execution of two continuous visual tasks was administered to 12 healthy young (mean age 26.1 years) and 12 healthy older (mean age 64.4 years) experienced and currently active drivers. The first task was a compensatory lane-tracking task involving a three dimensional road display. The second task was a timed, self-paced visual analysis task involving either a vocal or manual binary response to dot patterns projected within the road display. Using adaptive tasks, single-task difficulty was individually adjusted for each subject. To control for individual differences in attention allocation strategy, the dual task was performed according to three different sets of instructions based on the relative importance of each task. Compared with young adults, older adults showed a significantly decreased ability to divide attention. This effect was apparent in lane tracking and in the accuracy of visual analysis. The impairment of divided attention was less pronounced in the vocal condition than in the manual one. This suggests that difficulty in integrating responses may be an important determinant of poor dual-task performance in old age.

Time Pressure Management as a Compensatory Strategy Training after Closed Head Injury

Following severe closed head injury, deficits in speed of information processing are common. As a result, many head-injured patients experience a feeling of “information overload” in daily tasks that once were relatively easy. Many remedial programmes have been designed that treat different aspects of attention (often including mental speed requirements) by repetitive exercises. In the present study, a different approach to slow information processing has been taken, namely Time Pressure Management (TPM). TPM consists of a set of alternative cognitive strategies that allow head-injured patients in real-life tasks to compensate for their mental slowness. In a randomised pre-training vs. post-training vs. follow-up group study, the effectiveness of TPM training was compared with concentration training in which verbal instruction was the key element. The results indicate that specific TPM strategies are learned by the experimental subjects but that both treatments improve task performance significantly for an information intake task. TPM, however, produces greater gains than concentration training and also appears to generalise to other measures of speed and memory function.

Fitness to drive in older drivers with cognitive impairment

This paper is a literature review on assessment of fitness to drive in older drivers with cognitive impairment. Early studies on dementia and driving generally failed to distinguish between safe and unsafe drivers on the basis of cognitive test performance. Predictive studies demonstrated that cognitively impaired persons as a group perform significantly worse than controls on both neuropsychological and driving measures. A high prevalence of cognitive impairment was found in groups of older drivers involved in traffic accidents and crashes. However, a large range in neuropsychological test scores has been found. Low to moderate correlations could be established between neuropsychological test results and on-road driving performance, making it difficult to discriminate between cognitively impaired subjects who are fit or unfit to drive. The review concludes with a discussion of methodological difficulties in the field of dementia and driving, including participant selection, the choice of neuropsychological tests, and the operationalization of driving performance.

Driving competence in older persons

Older drivers form a growing segment of the driving population which in comparison to most other modes of transportation, is relatively user-friendly for older people. There are two important problems. The first is the increase of physical vulnerability with age which means that the same accident often leads to much more severe injury in an older than a younger adult driver. The second problem is the decline of sensory, perceptual-motor and cognitive abilities (impairments) because of ageing-related degenerative processes and diseases. As a result, processing of and responding to traffic information is slowed and activities cannot well be performed simultaneously. Much of this may be compensated by behavioural changes. However, studies of accident characteristics and driving skill in relation to ageing suggest that compensation breaks down in complex and ambiguous traffic situations and in individuals with strongly impaired perceptual and cognitive function. Possible changes to reduce ageing-related accidents, and which make driving more user-friendly for older drivers, are discussed.

DEMENTIA AND DRIVING: AN ATTEMPT AT CONSENSUS

Summary:The number of older drivers in Sweden will be rapidly increasing during the next decades. A possible relationship exists between the increased relative crash risk of older drivers and the prevalence of age-related diseases such as dementia. However, a clear-cut policy for evaluating driving competence in demented persons is still lacking. In recognition of this fact, the Swedish National Road Administration invited a group of researchers to formulate a consensus on the issue of driving and dementia. This consensus document is aimed at providing primary care physicians with practical advice concerning the assessment of cognitive status in relation to driving. Suggestions are based on a review of existing research and discuss the use of general and driving-specific sources of information available to the physician. Consensus was reached on the statement that a diagnosis of moderate to severe dementia precludes driving and that certain individuals with mild dementia should be considered for a specialized assessment of their driving competence.

Central executive aspects of attention in subacute severe and very severe closed head injury patients: planning, inhibition, flexibility, and divided attention

Central executive aspects of attention were investigated in a group of 20 closed head injury (CHI) patients with an average posttraumatic amnesia duration of 23.9 days, tested in the first half year after injury. Four aspects were distinguished: planning, inhibition, flexibility, and divided attention. Tasks allowed assessment of these with experimental or statistical control for the individual speed of information processing. This precaution appears necessary because slow information processing is a pervasive effect of CHI and may cause spurious effects on complex cognitive tasks under time pressure. Strong effects of CHI were shown on speed of information processing. Controlling this factor, central executive aspects of attention were normal, on average. A tentative analysis of the results in relation to severity indicated that less severely injured patients are better in this respect than controls, and more severely injured patients are worse. In comparison with the healthy control group, the performance of those with milder injuries appears to be characterized by greater cautiousness and increased mental effort.

The predictive value of measures of social cognition for community functioning in schizophrenia: implications for neuropsychological assessment.

The objective of this study was to examine the unique contribution of social cognition to the prediction of community functioning and to explore the relevance of social cognition for clinical practice. Forty-six schizophrenia patients and 53 healthy controls were assessed with tests of social cognition [emotion perception and Theory of Mind (ToM)], general cognition, and, within the patient sample, psychiatric symptoms. Community functioning was rated by nurses or family members. Social cognition was a better predictor of community functioning than general cognition or psychiatric symptoms. When the contributions of emotion perception and ToM were examined separately, only ToM contributed significantly to the prediction of community functioning. Independent living skills were poor in patients with impaired social cognition. In controls, social cognition was not related to community functioning. ToM was the best predictor of community functioning in schizophrenia. However, to fully understand a patients strengths and weaknesses, assessment of social cognition should always be combined with assessment of general cognition and psychiatric symptoms.

The efficacy of SMS text messages to compensate for the effects of cognitive impairments in schizophrenia

BACKGROUND AND AIMS Many people with schizophrenia have severe cognitive impairments that hamper their activities. The effect of pharmacological and behavioural interventions on cognitive functioning has been demonstrated, but even after successful intervention considerable impairments can remain. Therefore, we sought for alternative ways to help patients cope with the effects of their cognitive impairments. In the present study, we have evaluated the efficacy of short message service (SMS) text messages to compensate for the effects of cognitive impairments in schizophrenia in daily life. DESIGN A waiting list controlled trial was conducted: patients were quasi-randomly assigned to an A-B-A (baseline-intervention-follow-up) condition or an A-A-B-A condition that included an additional 7-week waiting list. The waiting list was included to control for the effect of time on relevant outcome. METHOD Sixty-two people with schizophrenia or related psychotic disorders were included in the study. All patients showed impaired goal-directed behaviour in daily life-situations. Patients were prompted with SMS text messages to improve their everyday functioning. The primary outcome measure was the percentage of goals achieved. RESULTS The overall percentage of goals achieved increased with prompting, while performance dropped to baseline level after withdrawing the prompts. Keeping appointments with mental health workers and carrying out leisure activities increased with prompting, while medication adherence and attendance at training sessions remained unchanged. A majority of the patients enjoyed receiving the SMS text messages. DISCUSSION Prompting can significantly improve achievement of a number of relevant goals. For other goals, combining prompting with interventions that enhance motivation seems indicated.

Divided attention 5 to 10 years after severe closed head injury.

The ability to divide attention of persons who had sustained a severe Closed Head Injury 5 to 10 years before (chronic CHI patients), was examined in a dual-task experiment administered to 15 CHI patients and 34 control subjects. Both the patient group and the control group consisted of active licenced drivers at the time of the investigation. One task was a compensatory tracking task requiring lane tracking, a basic skill or car driving. The other task was a self-paced visual choice reaction time task. Single-task difficulty was individually adjusted by adaptive task procedures (on both tasks CHI patients reached significantly lower performance levels in single task conditions). With individual differences in single-task performance thus controlled, the ability to divide attention was found to be approximately equal in the chronic CHI patients and the control group. A surprising finding in this light, however, was the significant positive correlation between severity of injury (PTA duration) and divided attention costs in the patient group.

Fitness to Drive After Traumatic Brain Injury

This paper deals with the issue of fitness to drive in patients suffering from traumatic brain injury (TBI). Guidelines for assessment are proposed and three types of studies are reviewed: studies about impairments of attention and information processing, studies of driving competence, and driver selection studies, applying and evaluating the procedures for assessing fitness to drive. From these reviews a relicensing rate emerges of slightly over 50% for very severe TBI patients. Failures in relicensing particularly occur in patients with a very long duration of post-traumatic amnesia (exceeding 1 month), and with severe impairments of perception and judgement. Furthermore, a review of studies describing training of driving competence in traumatically brain-injured patients is presented. It is argued that graded procedures for (re)training should be developed and assessment should extend to training advice and prediction of training success. When expanding assessments according to this suggestion, evaluat...