Bart Melis-Dankers

Compensatory viewing training improves practical fitness to drive of subjects with impaired vision

In many countries strict legal requirements for obtaining a drivers license are in effect for visual acuity and visual field. We studied the relationship between these characteristics and driving safety and driving proficiency in an on-the-road test of practical fitness to drive in subjects with visual disorders, including many subjects scoring below current criteria. We further studied how far the relationship between the on-the-road test and visual measures improved if compensatory eye movements and visual attention were included in the criteria. Lastly, we studied the effects of training compensatory viewing strategies. METHODS: In two studies subjects with visual field defects due to retinal pathology (n = 100) and post-chiasmal damage (n = 28) performed the on-the-road test before and after training. Training consisted of laboratory and mobility training, including driving instruction. Visual function assessment included acuity, visual field, contrast sensitivity, visual attention, compensatory view...

The effects of compensatory scanning training on mobility in patients with homonymous visual field defects: A randomized controlled Trial

Introduction Homonymous visual field defects (HVFD) are a common consequence of postchiasmatic acquired brain injury and often lead to mobility-related difficulties. Different types of compensatory scanning training have been developed, aimed at decreasing consequences of the HVFD by changing visual scanning. Aim The aim of the present study is to examine the effects of a compensatory scanning training program using horizontal scanning on mobility-related activities and participation in daily life. Method The main interest of this study is to assess the effectiveness of training on mobility-related activities and participation in daily life. Visual scanning tests, such as dot counting and visual search, and control measures for visual functions and reading have been included as well. First, it is examined how performance on scanning and mobility-related measures is affected in patients with HVFD by comparing scores with scores of a healthy control group (n = 25). Second, the effect of training is assessed using an RCT design, in which performance of 26 patients before and after training is compared to performance of 23 patients in a waiting list control group. Results Self-reported improvements after training were found, accompanied by improvements in detecting peripheral stimuli and avoiding obstacles during walking, especially in dual task situations in which a second task limits the attentional capacity available for compensatory scanning. Training only improved mobility-related activities in which detection of peripheral stimuli is important, while no improvement was found on tests that require other visual skills, such as reading, visual counting and visual search. Conclusion This is the first RCT to evaluate the effects of a compensatory scanning training that is based on a systematic horizontal scanning rhythm. This training improved mobility-related activities. The results suggest that different types of compensatory scanning strategies are appropriate for different types of activities. Trial Registration ISRCTN Registry ISRCTN16833414

A Demonstration Project on Driving with Reduced Visual Acuity and a Bioptic Telescope System in the Netherlands

Background: In Europe, driving a passenger car is prohibited if binocular best corrected visual acuity (BCVA) is below 0.5 (20/40). Some US states allow people with reduced visual acuity to use a bioptic telescope system when driving. The aim of our study is to introduce a bioptic telescope system for driving in the Netherlands and to investigate whether it enables people with reduced visual acuity to gain sufficient practical fitness to drive in a European setting. Results: Out of 378 persons who applied for information following media attention for the project, 160 candidates volunteered to participate. Based on the available information, 36 subjects (binocular BCVA: 0.16–0.5 [20/125–20/40]) were invited for assessment (vision, mobility, cognitive function, and driving skills). Of these, 16 did not meet the inclusion criteria and 2 decided not to participate. The remaining 18 subjects were trained in the use of a monocular bioptic telescope (3× magnification). They all completed the predriving training ...

Difficulties in daily life reported by patients with homonymous visual field defects

Background: Homonymous visual field defects (HVFD) are common after postchiasmatic acquired brain injury and may have a significant impact on independent living and participation in society. Vision-related difficulties experienced in daily life are usually assessed using questionnaires. The current study 1) links the content of 3 of these questionnaires to the International Classification of Functioning, Disability and Health (ICF) and 2) provides analyses of vision-related difficulties reported by patients with HVFD and minimal comorbidities. Methods: Fifty-four patients with homonymous hemianopia or quadrantanopia were asked about difficulties experienced in daily life because of their HVFD. This was performed during a structured interview including 3 standardized questionnaires: National Eye Institute Visual Functioning Questionnaire, Independent Mobility Questionnaire, and Cerebral Visual Disorders Questionnaire. The reported difficulties were linked to the ICF according to the ICF linking rules. Main outcome measures were presence or absence of experienced difficulties. Results: The ICF linking procedure resulted in a classification table that can be used in future studies of vision-related difficulties. Besides well-known difficulties related to reading, orientation, and mobility, a high proportion of patients with HVFD reported problems that previously have not been documented in the literature, such as impaired light sensitivity, color vision, and perception of depth. Conclusions: A systematic inventory of difficulties experienced in daily life by patients with HVFD was performed using the ICF. These findings have implications for future study, assessment and rehabilitation of patients with HVFD.

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 drivers 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.

The Effects of Compensatory Scanning Training on Mobility in Patients with Homonymous Visual Field Defects: Further Support, Predictive Variables and Follow-up

Introduction People with homonymous visual field defects (HVFD) often report difficulty detecting obstacles in the periphery on their blind side in time when moving around. Recently, a randomized controlled trial showed that the InSight-Hemianopia Compensatory Scanning Training (IH-CST) specifically improved detection of peripheral stimuli and avoiding obstacles when moving around, especially in dual task situations. Method The within-group training effects of the previously reported IH-CST are examined in an extended patient group. Performance of patients with HVFD on a pre-assessment, post-assessment and follow-up assessment and performance of a healthy control group are compared. Furthermore, it is examined whether training effects can be predicted by demographic characteristics, variables related to the visual disorder, and neuropsychological test results. Results Performance on both subjective and objective measures of mobility-related scanning was improved after training, while no evidence was found for improvement in visual functions (including visual fields), reading, visual search and dot counting. Self-reported improvement did not correlate with improvement in objective mobility performance. According to the participants, the positive effects were still present six to ten months after training. No demographic characteristics, variables related to the visual disorder, and neuropsychological test results were found to predict the size of training effect, although some inconclusive evidence was found for more improvement in patients with left-sided HVFD than in patients with right-sided HFVD. Conclusion Further support was found for a positive effect of IH-CST on detection of visual stimuli during mobility-related activities specifically. Based on the reports given by patients, these effects appear to be long-term effects. However, no conclusions can be drawn on the objective long-term training effects.

Accessibility of Shared Space for visually impaired persons : An inventory in the Netherlands

Shared Space is a concept that comprises the design and planning process of a public space. There are concerns about the accessibility of Shared Spaces for people who are visually impaired. This study provides a systematic overview of the appearance of Shared Spaces in the Netherlands and the consequences that these spaces may have for the independent mobility of visually impaired persons. Environmental characteristics of ten typical Shared-Space locations in the Netherlands were registered. The level of hindrance that these characteristics could cause visually impaired users of these spaces was judged by a group of experts in the field of orientation and mobility. In addition, compliance of the selected locations with existing guidelines for accessibility was assessed. None of the selected Shared-Space locations were free of potential problems for visually impaired persons.

Effects of a multidisciplinary group rehabilitation programme on participation of the visually impaired elderly: a pilot study

Purpose: To pilot test the newly developed multidisciplinary group rehabilitation programme Visually Impaired elderly Persons Participating (VIPP). Method: A single group pretest–posttest design pilot study included 29 visually impaired persons (≥55 years). The intervention (20 weekly meetings) consisted of four components (practical training; education, social interaction, counselling and training of problem-solving skills; individual and group goal setting; home-based exercise programme). Participation was assessed with the Utrecht Scale for Evaluation of Rehabilitation–Participation (USER-P) and the Impact on Participation and Autonomy (IPA) questionnaire at baseline, immediately and 6 months after the intervention. Results: At scale level, no statistical significant changes over time were found whereas the effect size indicated small effects for restrictions and satisfaction with participation, and a medium effect for autonomy outdoors. At item level, improvements tended to occur in frequency of housekeeping, in restrictions in housekeeping and outdoor activities and in satisfaction with the partner relationship. Satisfaction with leisure indoors and autonomy regarding using leisure time tended to increase as well. Conclusions: The tentative conclusion of this small-scale pilot study is that the VIPP programme modestly benefits perceived restrictions in participation, satisfaction with participation and autonomy outdoors of the visually impaired elderly. These preliminary findings warrant further investigation. Implications for Rehabilitation Visually impaired elderly persons perceive restrictions in participation and participate less in society compared to peers. Since participation contributes to quality of life and well-being, it is important that visually impaired elderly persons maintain or enhance their level of participation in society. This pilot study showed that the multidisciplinary group rehabilitation programme Visually Impaired elderly Persons Participating (VIPP) modestly benefits perceived restrictions in participation, satisfaction with participation and autonomy outdoors of the visually impaired elderly.

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.

Driving slow motorised vehicles with visual impairment : A simulator study

Abstract Purpose: To compare different driving parameters between visually impaired people and normal sighted controls in a mobility scooter and microcar driving simulator. Materials and methods: A mobility scooter and microcar driving simulator and different virtual environments were developed for the purpose of this experiment. Participants completed 4 drives in the microcar driving simulator and 8 drives in the mobility scooter driving simulator. Driving performance was compared between visually impaired and normal sighted participants, using the parameters speed, lateral position, time-to-collision, and number and type of collision. Results: Visually impaired participants did not differ significantly from normal sighted controls with regard to speed and overall lateral position. In contrast, number of collisions was higher in visually impaired participants in almost all drives. Time-to-collision differed in some, but not all of the drives. Small obstacles with low contrast posed the highest risk of collision for impaired drivers. Conclusions: The present findings showed that visually impaired participants were able to maintain a steady position on the street, but showed more difficulties in traffic situations that included obstacles and other traffic participants. Familiarity with the driving tasks seemed to improve performance, however, further research is necessary to confirm this observation.