[Safety measures in traffic; how risk compensation affects our behaviour]

In 2020, more than 600 people died as a result of a traffic crash in the Netherlands and 6,500 were hospitalized after they had sustained a serious injury (MAIS 3+). These numbers are much lower than those in the beginning of the seventies of the last century, when there were more than 3,000 road fatalities. To reduce the number of fatalities, many measures have been taken to avoid road crashes and reduce injury severity. By road design that makes it impossible for road users to collide, by improving the safety of vehicles, and by educating road users. Traffic psychologists often warn for behavioural adaptations that nullify the expected effect of road safety measures (risk compensation). Numerous studies have shown examples of risk compensation in traffic. What is the psychological mechanism behind risk compensation? Which factors enhance risk compensation? And are there any advantages of risk compensation?

Adherence to driving cessation advice given to patients with cognitive impairment and consequences for mobility

BACKGROUND

Driving is related to social participation; therefore older drivers may be reluctant to cease driving. Continuation of driving has also been reported in a large proportion of patients with cognitive impairment. The aim of this study is to investigate whether patients with cognitive impairment adhere to driving cessation advice after a fitness-to-drive assessment and what the consequences are with regard to mobility.

METHODS

Patients with cognitive impairment (n = 172) participated in a fitness-to-drive assessment study, including an on-road driving assessment. Afterwards, patients were advised to either continue driving, to follow driving lessons, or to cease driving. Approximately seven months thereafter, patients were asked in a follow-up interview about their adherence to the driving recommendation. Factors influencing driving cessation were identified using a binary logistic regression analysis. Use of alternative transportation was also evaluated.

RESULTS

Respectively 92 and 79% of the patients adhered to the recommendation to continue or cease driving. Female gender, a higher Clinical Dementia Rating-score, perceived health decline, and driving cessation advice facilitated driving cessation. Patients who ceased driving made use of less alternative modes of transportation than patients who still drove. Nonetheless, around 40% of the patients who ceased driving increased their frequency of cycling and/or public transport use.

CONCLUSIONS

Adherence to the recommendations given after the fitness-to-drive assessments was high. Female patients were in general more likely to cease driving. However, a minority of patients did not adhere to driving cessation advice. These drivers with dementia should be made aware of the progression of their cognitive impairment and general health decline to facilitate driving cessation. There are large differences in mobility between patients with cognitive impairment. Physicians should discuss options for alternative transportation in order to promote sustained safe mobility of patients with cognitive impairment.

Mobility scooter driving ability in visually impaired individuals

PURPOSE

To investigate how well visually impaired individuals can learn to use mobility scooters and which parts of the driving task deserve special attention.

MATERIALS AND METHODS

A mobility scooter driving skill test was developed to compare driving skills (e.g. reverse driving, turning) between 48 visually impaired (very low visual acuity = 14, low visual acuity = 10, peripheral field defects = 11, multiple visual impairments = 13) and 37 normal-sighted controls without any prior experience with mobility scooters. Performance on this test was rated on a three-point scale. Furthermore, the number of extra repetitions on the different elements were noted.

RESULTS

Results showed that visually impaired participants were able to gain sufficient driving skills to be able to use mobility scooters. Participants with visual field defects combined with low visual acuity showed most problems learning different skills and needed more training. Reverse driving and stopping seemed to be most difficult.

CONCLUSIONS

The present findings suggest that visually impaired individuals are able to learn to drive mobility scooters. Mobility scooter allocators should be aware that these individuals might need more training on certain elements of the driving task. Implications for rehabilitation Visual impairments do not necessarily lead to an inability to acquire mobility scooter driving skills. Individuals with peripheral field defects (especially in combination with reduced visual acuity) need more driving ability training compared to normal-sighted people - especially to accomplish reversing. Individual assessment of visually impaired people is recommended, since participants in this study showed a wide variation in ability to learn driving a mobility scooter.

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.

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.

Correction: The Effects of Compensatory Scanning Training on Mobility in Patients with Homonymous Visual Field Defects: A Randomized Controlled Trial

[This corrects the article DOI: 10.1371/journal.pone.0134459.].

Prediction of Fitness to Drive in Patients with Alzheimer's Dementia

The number of patients with Alzheimer’s disease (AD) is increasing and so is the number of patients driving a car. To enable patients to retain their mobility while at the same time not endangering public safety, each patient should be assessed for fitness to drive. The aim of this study is to develop a method to assess fitness to drive in a clinical setting, using three types of assessments, i.e. clinical interviews, neuropsychological assessment and driving simulator rides. The goals are (1) to determine for each type of assessment which combination of measures is most predictive for on-road driving performance, (2) to compare the predictive value of clinical interviews, neuropsychological assessment and driving simulator evaluation and (3) to determine which combination of these assessments provides the best prediction of fitness to drive. Eighty-one patients with AD and 45 healthy individuals participated. All participated in a clinical interview, and were administered a neuropsychological test battery and a driving simulator ride (predictors). The criterion fitness to drive was determined in an on-road driving assessment by experts of the CBR Dutch driving test organisation according to their official protocol. The validity of the predictors to determine fitness to drive was explored by means of logistic regression analyses, discriminant function analyses, as well as receiver operating curve analyses. We found that all three types of assessments are predictive of on-road driving performance. Neuropsychological assessment had the highest classification accuracy followed by driving simulator rides and clinical interviews. However, combining all three types of assessments yielded the best prediction for fitness to drive in patients with AD with an overall accuracy of 92.7%, which makes this method highly valid for assessing fitness to drive in AD. This method may be used to advise patients with AD and their family members about fitness to drive.

Behavioral adaptation of young and older drivers to an intersection crossing advisory system

An advanced driver assistance system (ADAS) provided information about the right of way regulation and safety to cross an upcoming intersection. Effects were studied in a longer-term study involving 18 healthy older drivers between the ages of 65 and 82 years and 18 healthy young drivers between the ages of 20 and 25 years. Participants repeatedly drove 25 km city routes in eight sessions on separate days over a period of two months in a driving simulator. In each age group, participants were randomly assigned to the control (no ADAS) and treatment (ADAS) group. The control group completed the whole experiment without the ADAS. The treatment group drove two sessions without (sessions 1 and 7) and six times with ADAS. Results indicate effects of ADAS on driving safety for young and older drivers, as intersection time and percentage of stops decreased, speed and critical intersection crossings increased, the number of crashes was lower for treatment groups than for control groups. The implications of results are discussed in terms of behavioral adaptation and safety.

Longer-term effects of ADAS use on speed and headway control in drivers diagnosed with Parkinson's disease

OBJECTIVE

An advanced driver assistance system (ADAS) provided information about speed limits, speed, speeding, and following distance. Information was presented to the participants by means of a head-up display.

METHODS

Effects of the information on speed and headway control were studied in a longer-term driving simulator study including 12 repeated measures spread out over 4 weeks. Nine healthy older drivers between the ages of 65 and 82 years and 9 drivers between the ages of 68 and 82 years diagnosed with Parkinson's disease (PD) participated in the study. Within the 4 weeks, groups completed 12 consecutive sessions (10 with ADAS and 2 without ADAS) in a driving simulator.

RESULTS

Results indicate an effect of ADAS use on performance. Removing ADAS after short-term exposure led to deterioration of performance in all speed measures in the group of drivers diagnosed with PD.

CONCLUSIONS

These results suggest that provision of traffic information was utilized by drivers diagnosed with PD in order to control their speed.

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.

Neurobehavioural changes in a patient with bilateral lesions of the globus pallidus

This study has characterized the long-term neurobehavioural changes in a woman who, following the intake of an unidentified substance, sustained subtotal bilateral lesions of the globus pallidus and small lesions at selective sites adjacent to it. Associated with these lesions was a significantly reduced blood flow in multiple frontal cortical regions, most prominently in area 10, the anterior cingulate and the supplementary motor cortex. Her cognitive deficits were generally consistent with those found in patients with frontal lobe dysfunction but some deficits, i.e. in visual memory and learning, were more compatible with temporal lobe dysfunction. Incapacitating personality or obsessive compulsive changes as reported by others with similar lesions were absent and she could live independently. The cognitive changes are consistent with the view that the globus pallidus has important functions in mediating how internal representations of stimulus input are converted into various forms of action, for example, in planning solutions to problems and in working memory.

Spontaneous recovery and treatment effects in patients with homonymous visual field defects: a meta-analysis of existing literature in terms of the ICF framework

Homonymous visual field defects (HVFDs) are a common consequence of posterior brain injury. Most patients do not recover spontaneously and require rehabiliation. To determine whether a certain intervention may help an individual patient, it is necessary to predict the patient's level of functioning and the effect of specific training. We provide an overview of both the existing literature on HVFDs in terms of the International Classification of Functioning, Disability, and Health (ICF) components and the variables predicting the functioning of HVFD patients or the effect of treatment. We systematically analyzed 221 publications on HVFD. All variables included in these articles were classified according to the ICF, as developed by the World Health Organization, and checked for their predictive value. We found that ICF helps to clarify the scope of the existing literature and provides a framework for designing future studies, which should consider including more outcome measures related to Activities and Participation. Although several factors have been described that predict HVFD patients' level of functioning or the effects of training, additional research is necessary to identify more.

Intersection assistance: a safe solution for older drivers?

Within the next few decades, the number of older drivers operating a vehicle will increase rapidly (Eurostat, 2011). As age increases so does physical vulnerability, age-related impairments, and the risk of being involved in a fatal crashes. Older drivers experience problems in driving situations that require divided attention and decision making under time pressure as reflected by their overrepresentation in at-fault crashes on intersections. Advanced Driver Assistance Systems (ADAS) especially designed to support older drivers crossing intersections might counteract these difficulties. In a longer-term driving simulator study, the effects of an intersection assistant on driving were evaluated. 18 older drivers (M=71.44 years) returned repeatedly completing a ride either with or without a support system in a driving simulator. In order to test the intersection assistance, eight intersections were depicted for further analyses. Results show that ADAS affects driving. Equipped with ADAS, drivers allocated more attention to the road center rather than the left and right, crossed intersections in shorter time, engaged in higher speeds, and crossed more often with a critical time-to-collision (TTC) value. The implications of results are discussed in terms of behavioral adaptation and safety.

Physical predictors of cognitive performance in healthy older adults: a cross-sectional analysis

There is ample evidence that physical and cognitive performance are related, but the results of studies investigating this relationship show great variability. Both physical performance and cognitive performance are constructs consisting of several subdomains, but it is presently unknown if the relationship between physical and cognitive performance depends on subdomain of either construct and whether gender and age moderate this relationship. The aim of this study is to identify the strongest physical predictors of cognitive performance, to determine the specificity of these predictors for various cognitive subdomains, and to examine gender and age as potential moderators of the relationship between physical and cognitive performance in a sample of community-dwelling older adults. In total, 98 men and 122 women (average age 74.0±5.6 years) were subjected to a series of performance-based physical fitness and neuropsychological tests. Muscle strength, balance, functional reach, and walking ability (combined score of walking speed and endurance) were considered to predict cognitive performance across several domains (i.e. memory, verbal attention, visual attention, set-shifting, visuo-motor attention, inhibition and intelligence). Results showed that muscle strength was a significant predictor of cognitive performance for men and women. Walking ability and balance were significant predictors of cognitive performance for men, whereas only walking ability was significant for women. We did not find a moderating effect of age, nor did we find support for a differential effect of the physical predictors across different cognitive subdomains. In summary, our results showed a significant relationship between cognitive and physical performance, with a moderating effect of gender.

When family looks strange and strangers look normal: a case of impaired face perception and recognition after stroke

We describe a patient (JS) with impaired recognition and distorted visual perception of faces after an ischemic stroke. Strikingly, JS reports that the faces of family members look distorted, while faces of other people look normal. After neurological and neuropsychological examination, we assessed response accuracy, response times, and skin conductance responses on a face recognition task in which photographs of close family members, celebrities and unfamiliar people were presented. JS' performance was compared to the performance of three healthy control participants. Results indicate that three aspects of face perception appear to be impaired in JS. First, she has impaired recognition of basic emotional expressions. Second, JS has poor recognition of familiar faces in general, but recognition of close family members is disproportionally impaired compared to faces of celebrities. Third, JS perceives faces of family members as distorted. In this paper we consider whether these impairments can be interpreted in terms of previously described disorders of face perception and recent models for face perception.

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.

Conscious and unconscious processing of fear after right amygdala damage: a single case ERP-study

In this study, we describe a 58-year-old male patient (FZ) with a right-amygdala lesion after temporal lobe infarction. FZ is unable to recognize fearful facial expressions. Instead, he consistently misinterprets expressions of fear for expressions of surprise. Employing EEG/ERP measures, we investigated whether presentation of fearful and surprised facial expressions would lead to different response patterns. We also measured ERPs to aversively conditioned and unconditioned fearful faces. We compared ERPs elicited by supraliminally and subliminally presented conditioned fearful faces (CS+), unconditioned fearful faces (CS-) and surprised faces. Despite FZ's inability to recognize fearful facial expressions in emotion recognition tasks, ERP components showed different response patterns to pictures of surprised and fearful facial expressions, indicating that covert or implicit recognition of fear is still intact. Differences between ERPs to CS+ and CS- were only found when these stimuli were presented subliminally. This indicates that intact right amygdala function is not necessary for aversive conditioning. Previous studies have stressed the importance of the right amygdala for discriminating facial emotional expressions and for classical conditioning. Our study suggests that the right amygdala is necessary for explicit recognition of fear, while implicit recognition of fear and classical conditioning may still occur following lesion of the right amygdala.

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.

Effects of in-car support on mental workload and driving performance of older drivers

OBJECTIVE

This study examined the extent to which driving performance of 10 older (70-88 years old) and 30 younger participants (30-50 years old) improves as a result of support by a driver assistance system.

BACKGROUND

Various studies have indicated that advanced driver assistance systems (ADAS) may provide tailored assistance for older drivers and thereby improve their safe mobility.

METHOD

While drivers followed an urban route in a driving simulator, an ADAS provided them with prior knowledge on the next intersection. The system was evaluated in terms of effects on workload and safety performance.

RESULTS

Messages informing drivers about the right-of-way regulation, obstructed view of an intersection, and safe gaps to join or cross traffic streams led to safer driving performance. A message regarding an unexpected one-way street led to fewer route errors. In general, effects were the same for all age groups. Workload was not reduced by the support system.

CONCLUSION

The evaluated support system shows promising effects for all age groups. Longer evaluation periods are needed to determine long-term effects.

APPLICATION

The messages provided by the evaluated system are currently not provided by existing ADAS such as advanced cruise control and navigation systems, but they could possibly be added to them in the future.

The Introduction of Bioptic Driving in The Netherlands

BACKGROUND: In many states of the U.S.A., people with moderately reduced visual acuity e.g., 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 paper 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 U.S.A., which were adapted to fit within current driving training and assessment practices in The Netherlands. The project convened a consortium of organizations including the Netherlands Bureau of Driving Skills Certificates (CBR), 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.

Cognitive dysfunction in non-demented Parkinson's disease patients: controlled and automatic behavior

The evidence with regard to impaired automatic and controlled information processing in non-demented patients with Parkinson's disease (PD) is critically discussed. We use a comprehensive mental schema framework of executive functioning, that is the planning and regulation of behavior in complex everyday tasks (International Classification of Functioning - ICF - activity level). In this framework monitoring, inhibition, mental effort, planning, working memory and flexibility are important elements of controlled processing (supervisory attentional control) and controlled processing can only influence performance by modulating automatic processes. The striatum plays an important role in the interface between controlled and automatic processes. It is wel documented that PD patients show impairments applying and achieving automaticities. With sustained cortical control of task performance during both automatic and controlled processing, not showing the transition to striatal control, which is normal in the case of skill learning. In addition, PD patients have been shown to be limited in executive functioning. Many authors have interpreted this as evidence for impaired executive functions (ICF body level). But the question must be asked to what extent these limitations are an indirect effect of impaired automatic processing. To answer this question, studies on executive functioning are critically assessed with regard to the control they have provided for impaired automaticity. It is concluded that only for cognitive flexibility and working memory, the evidence for impairments is convincing because significant limitations have also been shown in tasks with very low automatic processing demands. Impairments in other executive functions, such as monitoring, inhibition and planning have not been convincingly shown in non-demented PD patients and are likely to be due to treatment strategies and factors such as fatigue.

Neuroticism, recall bias and attention bias for valenced probes: a twin study

BACKGROUND

Prior research on the nature of the vulnerability of neuroticism to psychopathology suggests biases in information processing towards emotional rather than neutral information. It is unclear to what extent this relationship can be explained by genetic or environmental factors.

METHOD

The genetic relationship between a neuroticism composite score and free recall of pleasant and unpleasant words and the reaction time on negative probes (dot-probe task) was investigated in 125 female twin pairs. Interaction effects were modelled to test whether the correlation between neuroticism and cognitive measures depended on the level of the neuroticism score.

RESULTS

The only significant correlation was between neuroticism and the proportion of recalled unpleasant words (heritability is 30%), and was only detectable at the higher end of the neuroticism distribution. This interaction effect seems to be due to environmental effects that make people in the same family more similar (e.g. parental discipline style), rather than genetic factors. An interesting sub-finding was that faster reaction times for left versus right visual field probes in the dot-probe task suggest that cognitive processing in the right hemisphere is more sensitive to subliminal (biologically relevant) cues and that this characteristic is under substantial genetic control (49%). Individual differences in reaction times on right visual field probes were due to environmental effects only.

CONCLUSIONS

There is no evidence that the predisposition of individuals to focus on negative (emotional) stimuli is a possible underlying genetic mechanism of neuroticism.

Simulated driving in obstructive sleep apnoea-hypopnoea; effects of oral appliances and continuous positive airway pressure

Impaired simulated driving performance has been demonstrated in obstructive sleep apnoea-hypopnoea syndrome (OSAHS) patients. Although continuous positive airway pressure (CPAP) generally improves simulated driving performance, the effects of oral-appliance (OA) therapy are unknown. The aims of this study were to determine to what extent OSAHS patients have more difficulty with a monotonous simulated driving test when compared with control subjects and to compare the effects of OA with CPAP therapy. Simulated driving performance was evaluated in 20 OSAHS patients and 16 control subjects during a 25-min driving test. After randomization, ten patients started OA and CPAP therapy, respectively. After 2 to 3 months of treatment, patients repeated the driving test. At baseline, the total number of lapses of attention during driving was significantly higher in OSAHS patients as compared with control subjects. As a result of treatment, the total number of lapses of attention was significantly decreased in both the OA and CPAP group. When comparing driving performance between the OA and CPAP group, no significant differences were noted. OSAHS patients perform worse on a simulated driving test when compared with control subjects. When evaluating the effects of treatment, adequate OSAHS management with either OA or CPAP therapy usually resulted in substantial improvements of simulated driving. Conclusions beyond both treatments improving simulated driving performance are, however, not justified by the data in the present study.

Impaired perception of negative emotional prosody in schizophrenia

This paper aims to report on the perception of emotional prosody in schizophrenia and to discuss its relationship with performance on neurocognitive measures. It consists of a comparison of 20 clinically stable schizophrenia patients with 20 healthy controls. Schizophrenia patients were impaired in emotional prosody perception, in particular in the perception of negative emotions. This impairment could not be explained on the basis of task difficulty or a general impairment in the decoding of speech intonation. Emotional prosody perception correlated moderately strongly with neurocognitive measures. We did not find a negative bias in the perception of emotional prosody.

Psychological and physical activity training for older persons: who does not attend?

BACKGROUND

Interventions to promote successful aging include psychological and physical activity programs. Identification of determinants of attendance of older persons may be useful to develop strategies to improve attendance. For physical activity programs determinants of attendance have been investigated extensively. For psychological programs hardly any knowledge is available. Determinants of attendance at psychological and physical activity programs have never been investigated simultaneously.

OBJECTIVE

To identify demographic, physical and psychological determinants of attendance of older subjects following multifaceted psychological training - aimed at promoting active social participation - and physical activity training and to compare the variation of these determinants between the two training programs.

METHOD

118 subjects aged 65-92 years were randomized over psychological and physical activity training. Determinants of attendance were obtained at pretest with questionnaires and performance-based tests.

RESULTS

Mean attendance was 62%. Attendance was not related to type of program. Having chronic diseases facilitated attendance in the psychological training group and limited attendance in the physical activity training group. Low and high levels of Activities of Daily Living performance (ADLs) and walking endurance were related to a high attendance in the psychological training group. A low level of activities of daily living (ADL) and a low walking endurance were related to a low attendance in the physical activity training group. For both training groups, persons living with a partner had higher attendance rates than persons living alone, and persons with a low level of anxiety had higher attendance rates than persons with a moderate or a high level of anxiety.

CONCLUSION

Psychological training may be more suitable for frail older persons with chronic diseases, low ADL levels and low walking endurance than physical activity training, and may help to prepare such persons for physical activity.

Walking trajectory in neglect patients

A lateral deviation of the walking trajectory is often observed in stroke patients with unilateral spatial neglect. However, existing research appears to be contradictory regarding the direction of this deviation. The aim of the present study was to gain more insight into the walking trajectory of neglect patients. Twelve right hemisphere stroke patients (six neglect, six no neglect), eight left hemisphere stroke patients (none neglect) and 10 healthy control subjects were instructed to walk towards a target while a two-dimensional ultrasonic positioning system recorded their walking trajectory. Patients' recovery of walking ability was assessed and they were tested for the presence of neglect. Neglect patients showed a larger lateral deviation in their walking trajectory compared to stroke patients without neglect or controls. Neglect patients with good walking ability showed a deviation to the contralesional side. Neglect patients with limited walking ability showed a deviation to the ipsilesional side. Within the neglect group we found no relation between the severity of neglect and lateral deviation. Differences in walking ability may account for the contradictory results between studies regarding the lateral deviation in neglect patients' walking trajectory. We suggest that when a neglect patient's walking ability is limited, walking towards a target becomes a dual task: heading control and walking. A limited walking ability will cause a higher task priority of walking compared to heading control. This shift in task priority may be causing the change in walking trajectory deviation.

[Is the Activities-specific Balance Confidence Scale suitable for Dutch older persons living in the community?]

BACKGROUND

In ageing populations fear of falling is an important issue. International studies and collaborations require scales suitable to more cultures. Scales developed in one culture require adaptation and additional investigation of psychometric properties for use in other countries.

OBJECTIVE

To investigate the psychometric properties of a Dutch version of the Activities-specific Balance Confidence scale (ABC-NL) and whether adding questions about complex/dual tasks improves the discriminatory power.

METHOD

Subjects were 106 men and 140 women aged 65-92 years. Measures were the 16-item ABC-NL and seven additional more complex items, fall history, general and physical self-efficacy, a functional reach test and a balance platform test.

RESULTS

The ABC-NL had a weak ceiling effect. Internal consistency (Cronbachs alpha) was high. The relationship between ABC-NL and physical self-efficacy was significantly stronger than between the ABC-NL and general self-efficacy. Relationships with performance-based measures of balance were moderate. Differences between fallers and non-fallers and between activity avoiders and non-avoiders were significant. Adding questions about complex tasks hardly improved discriminatory power, reliability and validity.

CONCLUSION

Psychometric properties of the ABC-NL were satisfactory. Further research is needed for use in high-functioning older persons.

Cognitive, physiological, and personality correlates of recurrence of depression

BACKGROUND

The risk of recurrence in depressive disorder is high and increases with the number of episodes. We investigated whether individuals with a history of recurrent depression deviate from individuals with a single episode, as regards risk-related variables in 3 different domains of depression research.

METHODS

Participants were 102 outpatients with major depressive disorder remitted from an episode (60 recurrent, 42 nonrecurrent). We assessed the perception of emotions from vocal stimuli, 24-h urinary free cortisol, and neuroticism.

RESULTS

The recurrent group had higher cortisol levels than the nonrecurrent group, and recurrent women also had a more negative perception than nonrecurrent women. These results were independent of each other, and could also not be accounted for by neuroticism or residual symptoms. Gender differences were found in all 3 domains.

LIMITATIONS

The cross-sectional design limits the possibility to draw conclusions on the causality of the observed effects.

CONCLUSIONS

Remitted outpatients with recurrent depression deviate from remitted outpatients with single episode depression as regards physiology and social cognition, in a way that may increase their risk of the development of subsequent episodes. The results may have implications for prophylactic treatment strategies.

Is de Activities-specific Balance Confidence Scale geschikt voor het meten van valangst bij Nederlandse niet-geïnstitutionaliseerde ouderen?

Is the Activities-specific Balance Confidence Scale suitable for Dutch older persons living in the community? Background: In ageing populations fear of falling is an important issue. International studies and collaborations require scales suitable to more cultures. Scales developed in one culture require adaptation and additional investigation of psychometric properties for use in other countries.Objective: To investigate the psychometric properties of a Dutch version of the Activities-specific Balance Confidence scale (ABC-NL) and whether adding questions about complex/dual tasks improves the discriminatory power.Method: Subjects were 106 men and 140 women aged 65-92 years. Measures were the 16-item ABC-NL and seven additional more complex items, fall history, general and physical self-efficacy, a functional reach test and a balance platform test.Results: The ABC-NL had a weak ceiling effect. Internal consistency (Cronbachs alpha) was high. The relationship between ABC-NL and physical self-efficacy was significantly stronger than between the ABC-NL and general self-efficacy. Relationships with performance-based measures of balance were moderate. Differences between fallers and non-fallers and between activity avoiders and non-avoiders were significant. Adding questions about complex tasks hardly improved discriminatory power, reliability and validity.Conclusion: Psychometric properties of the ABC-NL were satisfactory. Further research is needed for use in high-functioning older persons.

P300 component identification in auditory oddball and novel paradigms using source analysis techniques: reduced latency variability in the elderly

P300 latency variability in normal subjects limits its diagnostic applicability as a test for cognitive function. One of the causes of variation is the overlap in P300 (P3A and P3B) components resulting in inaccurate latency determination. Recently, we have shown that identification of P3A and P3B components using source analysis techniques significantly reduces P300 latency variability in healthy younger subjects. Here, we included a novel paradigm to enhance sensitivity and investigated the efficiency of the source analysis technique in reducing the P300 latency variability in healthy older subjects. Data were recorded with a 128-channel EEG system in 28 healthy subjects (aged 53-82 years, 12 males). We used a standard two-tone and a novel three-tone auditory oddball paradigm and an established source analysis technique, and compared the latencies to those obtained with conventional P300 analysis. The source analysis method identified both P3A and P3B components in a substantially larger percentage of subjects (93% versus 32%) than the conventional method. Both for the standard and novel paradigm, the source analysis method yielded a later mean P3B latency (361.4 versus 344.2 milliseconds, P = 0.017, and 374.4 milliseconds versus 354.3 milliseconds, P = 0.014, respectively) with a smaller standard deviation (15.8 versus 26.2 milliseconds, P = 0.013, and 18.9 versus 30.0 milliseconds, P = 0.052, borderline significant, respectively) than the conventional P300 method, for subjects aged 50 to 70 years. When applying the source analysis technique, as in young healthy subjects, a considerable reduction of P300 latency variability was thus found in healthy older subjects aged 50 to 70 years for both paradigms. This may have important consequences for applications of clinical event-related potential research in the early diagnosis of dementia, because the first signs of this disease are mostly observed in this age category.

Differences between participants and non-participants in an RCT on physical activity and psychological interventions for older persons

BACKGROUND AND AIMS

Volunteer bias in intervention studies on successful aging has been poorly explored. This paper investigated differences between participants and non-participants of the Groningen Intervention Study on Successful Aging (GISSA) over a wide range of demographic, physical, psychological and social subject characteristics.

METHODS

Subjects were recruited among a longitudinal cohort study (Groningen Longitudinal Aging Study) and included 558 men and 711 women, aged 65-96 years, who were invited to participate in the GISSA. Measures were obtained by questionnaires at the moment of invitation and eight years before invitation. Participants were compared with three groups of non-participants: persons who refused to participate, those who did not respond after a reminder, and those who intended to participate but withdrew before pre-test.

RESULTS

At the moment of invitation, participants were younger, better educated, and functionally and physically more active than the three groups of non-participants. They also had better scores on the physical functioning subscale of the medical outcome scale, better ADL, iADL and vigorous ADL functions and fewer depressive symptoms, and perceived less social support in everyday and problem situations. Participants reported a less strong rate of decline in physical and psychological functioning in the eight years prior to the invitation than did the other groups.

CONCLUSION

Due to volunteer bias, results of intervention studies on successful aging may have limited generalizability.

Effect of ageing on the ability to adapt to a visual distortion during walking

Degradation of major sensory systems such as proprioception, the vestibular system and vision may be a factor that contributes to the decline in walking stability in older people. In the present study this was examined by introducing a visual distortion by means of prism glasses shifting subject's view 10 degrees to the right while subjects walked towards a target (exposure condition). Shifting the view while walking towards a target will cause subjects to alter their heading in such a way that their walking trajectory describes a curvilinear path. It was expected that older people, when compared to young people, would have greater difficulty adjusting their heading and would show a greater decrease in heading stability, quantified by means of the standard deviation of the lateral position (SDLP). This was indeed the case. When performance in a pre- and post-exposure condition, in which subjects walked without prism glasses, were compared to each other, older people (O group) showed a greater decrease in heading stability than young people (Y group) and middle aged people (M group). Furthermore, it appeared that during the exposure condition adaptation effects were present in the Y and M group, which were absent in the O group. It is discussed that this adaptation is a form of realignment of the proprioceptive and visual system. The absence of realignment in the O group is argued to be caused by degradation of the proprioceptive system, which results in a lowering of the proprioceptive bias of vision.

Functional recovery of gait and joint kinematics after right hemispheric stroke

OBJECTIVE

To gain insight into the relation between changes in gait patterns over time and functional recovery of walking ability in stroke patients.

DESIGN

Cohort study.

SETTING

Inpatient rehabilitation center of a university hospital in the Netherlands.

PARTICIPANTS

Thirteen stroke patients admitted, or awaiting admission, for inpatient rehabilitation 3 weeks poststroke, and 16 healthy control subjects.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

At 3, 6, 12, 24, and 48 weeks poststroke, functional recovery of walking ability was assessed with the Rivermead Mobility Index (RMI) and the Functional Ambulation Categories (FAC). When possible, kinematics of the knee, hip, and pelvis were assessed through gait analysis in an 8 x 4 m gait laboratory. Minimal scores of 8 on the RMI and 4 on the FAC were necessary before patients were classified as functionally recovered.

RESULTS

Patients whose joint kinematics during ambulation had recovered to within the range of the control group showed functional recovery of walking ability. However, some patients whose kinematics had developed toward an abnormal pattern also showed functional recovery.

CONCLUSIONS

Recovery of joint kinematics toward a normal pattern is not required for functional recovery of walking ability. Early recognition of compensatory walking patterns that facilitate functional recovery may have implications for rehabilitation programs.

Age-related changes in the functional visual field: further evidence for an inverse Age x Eccentricity effect

We assessed the performance of younger and older individuals by using the Attended Field of View test, a visual search task in which eye movements were allowed. When adjusting for slower processing in the older age group by log transformation, we observed significant effects of age, eccentricity, and Age x Eccentricity. Contrary to most previous findings, the Age x Eccentricity effect was "inverted" in that the difference between the age groups decreased as a function of eccentricity. The finding that the eccentricity effect of younger individuals was larger than that of older individuals was caused by large age-related differences in sensitivity for centrally located targets, even though differences with regard to foveal resolution were controlled. The results further indicated that, given a brief amount of time, older persons could process a smaller field of view than younger persons. Consequently, older persons were forced to resort to serial scanning for a larger part of the display, whereas younger persons could process a larger area in parallel.

Predicting practical fitness to drive in drivers with visual field defects caused by ocular pathology

Vision, viewing efficiency, visual attention, and on-road driving performance were assessed in 100 participants with central and/or peripheral visual field defects caused by ocular pathology. Driving was evaluated by the Dutch driving license authority making use of the protocol for investigating practical fitness to drive. A smaller percentage of participants with central visual field defects passed the on-road driving test, in comparison with participants with peripheral or mild field defects. The predictive power of a model based on the current vision requirements for driving significantly increased when taking compensatory viewing efficiency into account. The results of the latter model were comparable to those of a model based on tests of visual attention and contrast sensitivity. Despite the increased explained variance of practical fitness to drive when taking higher-order visual functions into account, sensitivity and specificity remained quite low, limiting the use of these tests in identifying unfit drivers. Actual or potential applications of this research include the development of training programs to improve practical fitness to drive in drivers with visual field defects.

The effect of visual field defects on driving performance: a driving simulator study

OBJECTIVES

To investigate the effect of visual field defects on driving performance, and to predict practical fitness to drive.

METHODS

The driving performance of 87 subjects with visual field defects due to ocular abnormalities was assessed on a driving simulator and during an on-road driving test.

OUTCOME MEASURES

The final score on the on-road driving test and simulator indexes, such as driving speed, viewing behavior, lateral position, time-headway, and time to collision.

RESULTS

Subjects with visual field defects showed differential performance on measures of driving speed, steering stability, lateral position, time to collision, and time-headway. Effective compensation consisted of reduced driving speed in cases of central visual field defects and increased scanning in cases of peripheral visual field defects. The sensitivity and specificity of models based on vision, visual attention, and compensatory viewing efficiency were increased when the distance at which the subject started to scan was taken into account.

CONCLUSIONS

Subjects with visual field defects demonstrated differential performance on several driving simulator indexes. Driving examiners considered reduced speed and increased scanning to be valid compensation for central and peripheral visual field defects, respectively. Predicting practical fitness to drive was improved by taking driving simulator indexes into account.

Grey scales uncover similar attentional effects in homonymous hemianopia and visual hemi-neglect

Multi-component models of visual hemi-neglect have postulated that visual hemi-neglect is characterised by various attentional deficits. A grey scales task has been developed to quantify the early, automatic, (perhaps obligatory) ipsilesional orienting of visual attention, frequently assumed as the first of these attentional deficits. Explanations for this attentional imbalance are up until now mainly formulated in terms of right hemisphere activation. This lateral attentional bias has also been demonstrated in controls, in whom it is expressed as a leftward perceptual asymmetry. We reproduced previous literature findings on a grey scales task, considering controls and neglect patients. Three patients with neglect showed an extreme ipsilesional lateral bias. This bias did not change during or after cognitive rehabilitation. Additionally, we presented this grey scale task to 32 patients with left- and right-sided homonymous hemianopia (HP). HP is the loss of sight in one visual hemi-field. The HH patients had no clinical signs of impaired lateralised attention. Results revealed that HH patients showed a similar ipsilesional bias, albeit to a lesser degree than in neglect. Left-sided HH patients presented a quantitatively similar, but qualitatively opposite bias than the right-sided HH patients. We suggest that sensory effects can be an alternative source of attentional imbalance, which can interact with the previously proposed (right) hemispheric effects. This suggests that the perceptual asymmetry in the grey scales task is not necessarily an indicator of impaired right hemisphere attention. It rather suggests a pattern of functional cerebral asymmetry, which can also be caused by asymmetric sensory input.

Age-related changes in event-related prospective memory performance: a comparison of four prospective memory tasks

The primary purpose of the study was to identify event-based prospective-memory tasks that provide sensitive and reliable tools for assessing effects of normal aging in prospective-memory performance. Four prospective-memory tasks were selected from the literature or were newly developed, with the tasks differing on various dimensions that, for theoretical reasons or based on previous evidence, might determine task sensitivity to age effects on prospective-memory performance: perceptual saliency of prospective target events, frequency of occurrence of prospective target events, complexity of prospective-memory instructions, and provision of feedback after prospective-memory errors. Two of the four tasks yielded large and robust age effects on prospective-memory performance. Correlational analyses suggested that these age effects on prospective-memory performance were mediated, at least in part, by a reduced ability of older adults to maintain prospective intentions in a highly activated state and not by age effects on basic mental speed alone.

Hemianopic visual field defects elicit hemianopic scanning

Previous explanations for the variability in success of compensating for homonymous hemianopia (HH) has been in terms of extent of the brain injury. In using on-line eye movement registrations, we simulated HH in 16 healthy subjects and compared their scanning performance on a dot counting task to their own "normal" condition and to real HH patients' performance. We evidenced clear parallels between simulated and real HH, suggesting that hemianopic scanning behaviour is primarily visually elicited, namely by the visual field defect, and not by the additional brain damage. We further observed age-related processes in compensating for the HH.