Alzheimer changes are common in aged drivers killed in single car crashes and at intersections

Driving assessment in preclinical Alzheimer’s disease: progress to date and the path forward

Background

Changes in driving behaviour may start at the preclinical stage of Alzheimer’s disease (AD), where the underlying AD biological process has begun in the presence of cognitive normality. Here, we summarize the emerging evidence suggesting that preclinical AD may impact everyday driving behaviour.

Main

Increasing evidence links driving performance and behaviour with AD biomarkers in cognitively intact older adults. These studies have found subtle yet detectable differences in driving associated with AD biomarker status among cognitively intact older adults.

Conclusion

Recent studies suggest that changes in driving, a highly complex activity, are linked to, and can indicate the presence of, neuropathological AD. Future research must now examine the internal and external validity of driving for widespread use in identifying biological AD.

Evaluation of Naturalistic Driving Behavior Using In-Vehicle Monitoring Technology in Preclinical and Early Alzheimer's Disease

Cognitive impairment is a significant risk factor for hazardous driving among older drivers with Alzheimer's dementia, but little is known about how the driving behavior of mildly symptomatic compares with those in the preclinical, asymptomatic phase of Alzheimer's disease (AD). This study utilized two in-car technologies to characterize driving behavior in symptomatic and preclinical AD. The goals of this pilot study were to (1) describe unsafe driving behaviors in individuals with symptomatic early AD using G-force triggered video capture and (2) compare the driving habits of these symptomatic AD drivers to two groups of cognitively normal drivers, those with and those without evidence of cerebral amyloidosis (CN/A+ and CN/A-) using a global positioning system (GPS) datalogger. Thirty-three drivers (aged 60+ years) were studied over 3 months. G-force triggered video events captured instances of near-misses/collisions, traffic violations, risky driver conduct, and driving fundamentals. GPS data were sampled every 30 s and all instances of speeding, hard braking, and sudden acceleration were recorded. For the early AD participants, video capture identified driving unbelted, late response, driving too fast for conditions, traffic violations, poor judgment, and not scanning intersections as the most frequently occurring safety errors. When evaluating driving using the GPS datalogger, hard breaking events occurred most frequently on a per trip basis across all three groups. The CN/A+ group had the lowest event rate across all three event types with lower instances of speeding. Slower psychomotor speed (Trail Making Part A) was associated with fewer speeding events, more hard acceleration events, and more overall events. GPS tracked instances of speeding were correlated with total number of video-captured near-collisions/collisions and driving fundamentals. Results demonstrate the utility of electronic monitoring to identify potentially unsafe driving events in symptomatic and preclinical AD. Results suggest that drivers with preclinical AD may compensate for early, subtle cognitive changes by driving more slowly and cautiously than healthy older drivers or those with cognitive impairment. Self-regulatory changes in driving behavior appear to occur in the preclinical phase of AD, but safety concerns may not arise until symptoms of cognitive impairment emerge and the ability to self-monitor declines.

Early stages of Alzheimer's disease are alarming signs in injury deaths caused by traffic accidents in elderly people (≥60 years of age): A neuropathological study

BACKGROUND

There is little information available in the literature concerning the contribution of dementia in injury deaths in elderly people (≥60 years).

AIM

This study was intended to investigate the extent of dementia-related pathologies in the brains of elderly people who died in traffic accidents or by suicide and to compare our findings with age- and sex-matched natural deaths in an elderly population.

MATERIALS AND METHODS

Autopsy-derived human brain samples from nine injury death victims (5 suicide and 4 traffic accidents) and nine age- and sex-matched natural death victims were screened for neurodegenerative and cerebrovascular pathologies using histopathological and immunohistochemical techniques. For the analysis, Statistical Package for the Social Sciences (SPSS) version 16.0 was used.

RESULTS

There was a greater likelihood for Alzheimer's disease (AD)-related changes in the elders who succumbed to traffic accidents (1 out of 4) compared to age- and sex-matched suicides (0 out of 5) or natural deaths (0 out of 9) as assessed by the National Institute on Aging - Alzheimer's Association guidelines. Actual burden of both neurofibrillary tangles (NFTs) and (SPs) was comparatively higher in the brains of traffic accidents, and the mean NFT counts were significantly higher in the region of entorhinal cortex (P < 0.05). However, associations obtained for other dementia-related pathologies were not statistically important.

CONCLUSION

Our findings suggest that early Alzheimer stages may be a contributing factor to injury deaths caused by traffic accidents in elderly people whereas suicidal brain neuropathologies resembled natural deaths.

Brain amyloid in preclinical Alzheimer's disease is associated with increased driving risk

Introduction

Postmortem studies suggest that fibrillar brain amyloid places people at higher risk for hazardous driving in the preclinical stage of Alzheimer's disease (AD).

Methods

We administered driving questionnaires to 104 older drivers (19 AD, 24 mild cognitive impairment, and 61 cognitive normal) who had a recent ¹⁸F-florbetapir positron emission tomography scan. We examined associations of amyloid standardized uptake value ratios with driving behaviors: traffic violations or accidents in the past 3 years.

Results

The frequency of violations or accidents was curvilinear with respect to standardized uptake value ratios, peaking around a value of 1.1 (model r² = 0.10, P = .002); moreover, this relationship was evident for the cognitively normal participants.

Discussion

We found that driving risk is strongly related to accumulating amyloid on positron emission tomography, and that this trend is evident in the preclinical stage of AD. Brain amyloid burden may in part explain the increased crash risk reported in older adults.

Compromised visually guided motor control in individuals with Alzheimer's disease: can reliable distinctions be observed?

Identifying the multitude of deficits associated with dementia-related illnesses such as Alzheimer's disease (AD) presents a significant challenge for many health care facilities, particularly as current screening procedures may lack the sensitivity to highlight all the relative functional deficits within these populations. Although quick assessment screening tools, such as the Mini Mental State Exam (MMSE), have been the mainstay in screening patients worldwide, there are limitations to their ability in identifying visuomotor (VM) impairment. Thus, the primary objective of this research was to evaluate the presence and level of VM ability/deficits in healthy normal controls (NC) and populations with AD. The research also aimed to demonstrate that a VM measure can be utilized successfully in a busy health care setting. Results showed a clear distinction between the AD and NC groups on the VM measure. Large effect size differences were observed between groups, particularly as the VM task progressed through its varying conditions. In addition, this novel VM assessment measure demonstrated good presentation and speed and was appropriate for frontline staff in a primary healthcare setting to undertake further examination of an individual's overall visually guided ability/control.

Assessment of cognition in early dementia

Better tools for assessing cognitive impairment in the early stages of Alzheimer's disease (AD) are required to enable diagnosis of the disease before substantial neurodegeneration has taken place and to allow detection of subtle changes in the early stages of progression of the disease. The National Institute on Aging and the Alzheimer's Association convened a meeting to discuss state of the art methods for cognitive assessment, including computerized batteries, as well as new approaches in the pipeline. Speakers described research using novel tests of object recognition, spatial navigation, attentional control, semantic memory, semantic interference, prospective memory, false memory and executive function as among the tools that could provide earlier identification of individuals with AD. In addition to early detection, there is a need for assessments that reflect real-world situations in order to better assess functional disability. It is especially important to develop assessment tools that are useful in ethnically, culturally and linguistically diverse populations as well as in individuals with neurodegenerative disease other than AD.

Older drivers' road traffic crashes in the UK

A sample of over 2000 crashes involving drivers aged 60 years or over was considered, from three UK midland police forces, from the years 1994-2007 inclusive. Each case was summarized on a database including the main objective features (such as time and place), a summary narrative, a sketch plan and a list of explanatory factors. The main findings were that older drivers have significant problems with intersection collisions and failing to give right of way; these formed the largest single class of crashes in the sample. Possible behavioural explanations for this will be discussed, along with other findings regarding older driver blameworthiness, fatigue and illness, time of day factors, and 'unintended accelerations'.

Driving and neurodegenerative diseases

The proportion of elderly people in the general population is rising, resulting in greater numbers of drivers with neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. These neurodegenerative disorders impair cognition, visual perception, and motor function, leading to reduced driver fitness and greater crash risk. Yet neither medical diagnosis nor age alone is reliable enough to predict driver safety or crashes or to revoke the driving privileges of these individuals. Driving research utilizes tools such as questionnaires about driving habits and history, driving simulators, standardized road tests utilizing instrumented vehicles, and state driving records. Research challenges include outlining the evolution of driving safety, understanding the mechanisms of driving impairment, and developing a reliable and efficient standardized test battery for prediction of driver safety in neurodegenerative disorders. This information will enable healthcare providers to advise their patients with neurodegenerative disorders with more certainty, affect policy, and help develop rehabilitative measures for driving.

Mild neuritic changes are increased in the brains of fatally injured older motor vehicle drivers

Given the expected increase in the older population and driving in this age group, concerns have been raised about the safety of older drivers. People over 65 years are over-represented in motor vehicle fatalities when calculated by distance driven. They are also at risk of neurodegenerative diseases, such as Alzheimer's disease, that affect cognitive function. We have examined the brains of older drivers (15M:12F) who died as a result of a motor vehicle accident (MVA) to determine the extent of Alzheimer's disease-related neurofibrillary changes (neuritic plaques and neurofibrillary tangles), Lewy body pathology and cerebrovascular disease and compared them to a control group of older licenced drivers (23M:5F) who died of other causes. The prevalence of moderate or severe neuritic plaque pathology was less than expected for the general population of this age and there was no difference between the groups. However, mild neuritic plaque pathology was increased for MVA deaths compared to controls. There was no evidence of vascular dementia or dementia with Lewy bodies. The current mandatory age-related re-licencing procedures in NSW may contribute to the low percentage of drivers with severe pathology. Further research into the role of mild pathology in cognitive impairment and older drivers is warranted.

Increased neurofibrillary tangles in the brains of older pedestrians killed in traffic accidents

BACKGROUND/AIMS

Older people are over-represented in pedestrian fatalities, and it has been suggested that the presence of cognitive impairment or dementia in these individuals may contribute to their accidents. Using neuropathological methods, we aimed to compare the prevalence of dementia pathology in fatally injured older pedestrians with similarly aged ambulatory subjects who died from other causes.

METHODS

The brains of 52 pedestrians (65-93 years) and 52 controls (65-92 years) were assessed for neurofibrillary tangles (NFT), neuritic plaques, Lewy bodies and vascular lesions using established neuropathological criteria.

RESULTS

The examination for Alzheimer's disease (AD) pathology showed that 43% of the pedestrians had NFT scores of III-VI using Braak and Braak staging, compared with 23% of the controls (p < 0.05, Fisher's exact test), indicating incipient, possible or probable AD. There were no differences in the prevalence of pathology for vascular dementia or dementia with Lewy bodies.

CONCLUSION

These results suggest that cognitive decline associated with AD, even in the earliest stages of the disease, may be a factor in fatal traffic accidents for older pedestrians. Special measures for pedestrian safety are necessary in areas with high densities of older citizens and especially for those diagnosed as having a mild cognitive impairment or AD.

Neuropathological diagnosis of Alzheimer's disease in forensic autopsy of elderly persons with fatal accident

Cognitive dysfunction in Alzheimer's disease may lead to accidental deaths in the elderly. Neuropathological diagnosis of the disease is, therefore, an important issue in forensic autopsy to determine the causal relation to accidents. To evaluate the suitability of the current histopathological diagnostic criteria for Alzheimer's disease by Khachaturian and Mirra et al. in elderly persons dying from accidents and coming for forensic autopsy, we studied the brains of nine demented and 12 non-demented persons by silver stain and immunohistochemistry. When the density of senile plaque was applied to the criteria, only four out of nine demented persons met the criteria for definite Alzheimer's disease. The demented persons had significantly higher density of diffuse plaque and higher frequencies of amyloid angiopathy, neurofibrillary tangle and neuropil thread than the non-demented persons. These results indicated that the current diagnostic criteria do not always diagnose Alzheimer's disease in forensic autopsy of elderly persons with fatal accident. The presence of abundant diffuse plaque, neurofibrillary tangle, amyloid angiopathy and neuropil thread may help to diagnose Alzheimer's disease in forensic autopsy.

Incipient Alzheimer's disease as the underlying cause of a motor vehicle crash

A 75-year-old female driver died in a single vehicle crash. A forensic autopsy diagnosed the cause of death as blood loss due to laceration of the liver caused by the crash. Although she had neither clinical history of dementia nor gross abnormalities of the brain, neuropathological examinations showed a substantial number of senile plaques indicative of Alzheimer's disease (AD). An interview with a family member revealed that she had symptoms of dementia. Cognitive dysfunction due to AD was proposed as the underlying cause of the crash. It is recommended that forensic autopsy of older drivers should include neuropathological examinations to identify incipient AD. Recognition of AD as an underlying cause of crashes is also important to promote the health care of older people.