Training compensatory viewing strategies:feasiblity and effect on practical fitness to drive in subjects with visual field defects

Fifty-one subjects with visual field defects were trained to use compensatory viewing strategies.The subjects were referred to the training program by an official driving examiner of the Dutch Central Bureau of Driving Licenses. Three training programs were compared: laboratory training, mobility training, and motor traffic training. Viewing behavior, visual attention, and practical fitness to drive were assessed before and after training. Practical fitness to drive was assessed on the road as well as in a driving simulator. It was observed that compensatory viewing behavior and practical fitness to drive could be improved by training. Subjects in the motor traffic training showed a small advantage with regard to practical fitness to drive, suggesting that training is task-specific and that generalization is limited. The effect of visual field defect on viewing behavior and practical fitness to drive was analyzed separately for subjects with central or peripheral visual field defects. It was observed that none of the outcome measures differed between the central and peripheral visual field defect groups

Car Driving Performance in Hemianopia:An On-Road Driving Study

PURPOSE. To study driving performance in people with homonymous hemianopia (HH) assessed in the official on-road test of practical fitness to drive by the Dutch driver's licensing authority (CBR).METHODS. Data were collected from a cohort (January 2010-July 2012) of all people with HH following the official relicensure trajectory at Royal Dutch Visio and the CBR in the Netherlands. Driving performance during the official on-road tests of practical fitness to drive was scored by professional experts on practical fitness to drive, using the visual impairments protocol and a standardized scoring of visual, tactical and operational aspects. Age ranged from 27 to 72 years (mean = 52, SD = 11.7) and time since onset of the visual field defect ranged from 6 to 41 months (mean = 15, SD = 7.5).RESULTS. Fourteen (54%) participants were judged as fit to drive. Besides poor visual scanning during driving, specific tactical, and operational weaknesses were observed in people with HH that were evaluated as unfit to drive. Results suggest that judgement on practical fitness to drive cannot be based on solely the visual field size. Visual scanning and operational handling of the car were found to be more impaired with longer time not driven, while such an effect was not found for tactical choices during driving.CONCLUSIONS. Training programs aimed at improving practical fitness to drive in people with HH should focus on improving both visual scanning, as well as driving aspects such as steering stability, speed adaptation, and anticipating environmental changes.</p

Vision-related fitness to drive mobility scooters:A practical driving test

Objective: To investigate practical fitness to drive mobility scooters, comparing visually impaired participants with healthy controls. Design: Between-subjects design. Subjects: Forty-six visually impaired (13 with very low visual acuity, 10 with low visual acuity, 11 with peripheral field defects, 12 with multiple visual impairment) and 35 normal-sighted controls. Methods: Participants completed a practical mobility scooter test-drive, which was recorded on video. Two independent occupational therapists specialized in orientation and mobility evaluated the videos systematically. Results: Approximately 90% of the visually impaired participants passed the driving test. On average, participants with visual impairments performed worse than normal-sighted controls, but were judged sufficiently safe. In particular, difficulties were observed in participants with peripheral visual field defects and those with a combination of low visual acuity and visual field defects. Conclusion: People with visual impairment are, in practice, fit to drive mobility scooters; thus visual impairment on its own should not be viewed as a determinant of safety to drive mobility scooters. However, special attention should be paid to individuals with visual field defects with or without a combined low visual acuity. The use of an individual practical fitness-to-drive test is advised

Assessing fitness to drive:A validation study on patients with mild cognitive impairment

Objectives: There is no consensus yet on how to determine which patients with cognitive impairment are able to drive a car safely and which are not. Recently, a strategy was composed for the assessment of fitness to drive, consisting of clinical interviews, a neuropsychological assessment, and driving simulator rides, which was compared with the outcome of an expert evaluation of an on-road driving assessment. A selection of tests and parameters of the new approach revealed a predictive accuracy of 97.4% for the prediction of practical fitness to drive on an initial sample of patients with Alzheimer's dementia. The aim of the present study was to explore whether the selected variables would be equally predictive (i.e., valid) for a closely related group of patients; that is, patients with mild cognitive impairment (MCI).Methods: Eighteen patients with mild cognitive impairment completed the proposed approach to the measurement of fitness to drive, including clinical interviews, a neuropsychological assessment, and driving simulator rides. The criterion fitness to drive was again assessed by means of an on-road driving evaluation. The predictive validity of the fitness to drive assessment strategy was evaluated by receiver operating characteristic (ROC) analyses.Results: Twelve patients with MCI (66.7%) passed and 6 patients (33.3%) failed the on-road driving assessment. The previously proposed approach to the measurement of fitness to drive achieved an overall predictive accuracy of 94.4% in these patients. The application of an optimal cutoff resulted in a diagnostic accuracy of 100% sensitivity toward unfit to drive and 83.3% specificity toward fit to drive. Further analyses revealed that the neuropsychological assessment and the driving simulator rides produced rather stable prediction rates, whereas clinical interviews were not significantly predictive for practical fitness to drive in the MCI patient sample.Conclusions: The selected measures of the previously proposed approach revealed adequate accuracy in identifying fitness to drive in patients with MCI. Furthermore, a combination of neuropsychological test performance and simulated driving behavior proved to be the most valid predictor of practical fitness to drive.</p

The Introduction of Bioptic Driving in the Netherlands

Background: In many US states, people with moderately reduced visual acuity (eg, 20/50–20/200) can legally drive with the aid of a small, spectacle-mounted (“bioptic”) telescope.We conducted a demonstration project to assess the viability of implementing bioptic driving in the Netherlands. In this article, we describe the framework of the project from conception through to realization of our primary objective—the introduction of bioptic driving as a legal option for visually impaired people in the Netherlands. Methods: The project was based on bioptic driving programs in the United States, which were adapted to fit into current driving training and assessment practices in the Netherlands. The project convened a consortium of organizations including the Netherlands Bureau of Driving Skills Certificates, service organizations for the visually impaired, and research departments at universities investigating driving and vision. All organizations were educated about bioptic driving and participating professionals were trained in their specific aspects of the project. Media publicity led to significant interest and helped recruitment that enabled the screening and selection of potential participants. Outcomes: The project demonstrated that people with moderately reduced visual acuity can be trained to achieve an adequate level of proficient and safe driving (as assessed by the local official driving licensing professionals) when using a bioptic telescope for the road conditions in the Netherlands. Based on the successful project outcomes, a request was made to the minister to allow bioptic driving in the Netherlands. This request has been accepted; the legal procedures for implementation are in process

Executive Functioning in Daily Life in Parkinson's Disease: Initiative, Planning and Multi-Task Performance

Impairments in executive functioning are frequently observed in Parkinson's disease (PD). However, executive functioning needed in daily life is difficult to measure. Considering this difficulty the Cognitive Effort Test (CET) was recently developed. In this multi-task test the goals are specified but participants are free in their approach. This study applies the CET in PD patients and investigates whether initiative, planning and multi-tasking are associated with aspects of executive functions and psychomotor speed. Thirty-six PD patients with a mild to moderate disease severity and thirty-four healthy participants were included in this study. PD patients planned and demonstrated more sequential task execution, which was associated with a decreased psychomotor speed. Furthermore, patients with a moderate PD planned to execute fewer tasks at the same time than patients with a mild PD. No differences were found between these groups for multi-tasking. In conclusion, PD patients planned and executed the tasks of the CET sequentially rather than in parallel presumably reflecting a compensation strategy for a decreased psychomotor speed. Furthermore, patients with moderate PD appeared to take their impairments into consideration when planning how to engage the tasks of the test. This compensation could not be detected in patients with mild PD

Age-related differences in timing of position and velocity identification

The aim of this investigation was to study age-related differences in timing of position and velocity identification in a laboratory task. The skills required for performing this task are thought to be similar to those needed in real traffic situations. From this perspective, the results of this study may be taken into account in studies on accident analysis and prevention. To control for differences in the conscious experience of time and for simple reaction time to visual stimuli, young (25–34) and old (58–70) adults had to produce timed periods of 20 seconds and to time the arrival of a visible moving object at its goal. In these simple tasks no differences were found between young and old subjects. In the proper, more complex experiment, timing of position and velocity identification of a moving object were assessed with or without feedback on timing and velocity in the same old and young group. The object, moving from left to right at a constant velocity, was shown on a video screen during the first 40% of its trajectory. The moving object could have any of four (fixed) velocities which were presented in blocks with a regular or a mixed order. By pushing a button subjects estimated at which time the object would have reached the marked end of a trajectory. In a condition without feedback on timing of position, the timing error of older adults was higher than that of young adults and particularly with higher object velocities. In the condition with mixed velocities, subjects also had to indicate which of four velocities they thought was presented. Paradoxically, the older subjects now significantly over-estimated velocity. Possible explanations for these findings are considered