Vision screening of older drivers for preventing road traffic injuries and fatalities.

BACKGROUND: Demographic data in North America, Europe, Asia, Australia and New Zealand suggest a rapid growth in the number of persons over the age of 65 years as the baby boomer generation passes retirement age. As older adults make up an increasing proportion of the population, they are an important consideration when designing future evidence-based traffic safety policies, particularly those that lead to restrictions or cessation of driving. Research has shown that cessation of driving among older drivers can lead to negative emotional consequences such as depression and loss of independence. Older adults who continue to drive tend to do so less frequently than other demographic groups and are more likely to be involved in a road traffic crash, possibly due to what is termed the "low mileage bias". Available research suggests that older driver crash risk estimates based on traditional exposure measures are prone to bias. When annual driving distances are taken in to consideration, older drivers with low driving distances have an increased crash risk, while those with average or high driving distances tend to be safer drivers when compared to other age groups. In addition, older drivers with lower distance driving tend to drive in urban areas which, due to more complex and demanding traffic patterns, tend to be more accident-prone. Failure to control for actual annual driving distances and driving locations among older drivers is referred to as "low mileage bias" in older driver mobility research. It is also important to note that older drivers are more vulnerable to serious injury and death in the event of a traffic crash due to changes in physiology associated with normal ageing. Vision, cognition, and motor functions or skills (e.g., strength, co-ordination, and flexibility) are three key domains required for safe driving. To drive safely, an individual needs to be able to see road signs, road side objects, traffic lights, roadway markings, other vulnerable road users, and other vehicles on the road, among many other cues-all while moving, and under varying light and weather conditions. It is equally important that drivers must have appropriate peripheral vision to monitor objects and movement to identify possible threats in the driving environment. It is, therefore, not surprising that there is agreement among researchers that vision plays a significant role in driving performance. Several age-related processes/conditions impair vision, thus it follows that vision testing of older drivers is an important road safety issue. The components of visual function essential for driving are acuity, static acuity, dynamic acuity, visual fields, visual attention, depth perception, and contrast sensitivity. These indices are typically not fully assessed by licensing agencies. Also, current vision screening regulations and cut-off values required to pass a licensing test vary from country to country. Although there is a clear need to develop evidence-based and validated tools for vision screening for driving, the effectiveness of existing vision screening tools remains unclear. This represents an important and highly warranted initiative to increase road safety worldwide. OBJECTIVES: To assess the effects of vision screening interventions for older drivers to prevent road traffic injuries and fatalities. SEARCH METHODS: For the update of this review we searched the Cochrane Injuries Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE (OvidSP), Embase (OvidSP), PsycINFO (OvidSP) and ISI Web of Science: (CPCI-S & SSCI). The searches were conducted up to 26 September 2013. SELECTION CRITERIA: Randomised controlled trials (RCTs) and controlled before and after studies comparing vision screening to non-screening of drivers aged 55 years and older, and which assessed the effect on road traffic crashes, injuries, fatalities and any involvement in traffic law violations. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the reference lists for eligible articles and independently assessed the articles for inclusion against the criteria. If suitable trials had been available, two review authors would have independently extracted data using a standardised extraction form. MAIN RESULTS: No studies were found that met the inclusion criteria for this review. AUTHORS' CONCLUSIONS: Most countries require a vision screening test for the renewal of an individual's driver's licence. There is, however, lack of methodologically sound studies to assess the effects of vision screening tests on subsequent motor vehicle crash reduction. There is a need to develop valid and reliable tools of vision screening that can predict driving performance.

Does obesity increase the risk of injury or mortality in motor vehicle crashes? A systematic review and meta-analysis.

The objective of this review was to assess the risk of obesity in injuries and fatalities resulting from motor vehicle crash (MVC), as compared with individuals with a normal-range body mass index. A systematic review of the literature was conducted yielding 824 potential studies. Nine of these studies met our inclusion criteria. Meta-analyses examining obesity as a risk factor for various injury types and risk of fatality were conducted using data from these studies. Obesity was associated with higher fatality risk (odds ratio [OR] = 1.89, 95% confidence interval [CI] = 1.51-2.37, P = .0001; pooled estimate from 6 studies), and increased risk of lower extremity fractures (OR = 1.39, 95% CI = 1.18-1.65, P = .0001; pooled estimate from 2 studies). No significant differences were observed when considering abdominal injuries or pelvic fractures. Interestingly, for head injuries obesity was a protective factor (OR = 0.67, 95% CI = 0.46-0.97, P = .0001; pooled data from 3 studies). Evidence strongly supports the association of obesity with higher fatality and fractures of the lower extremities in MVCs. Contrary to our hypothesis, 3 studies showed that obesity was a protective factor in reducing head injuries. Furthermore, the review shows that obesity was not a risk factor of MVC-related pelvic fractures and abdominal injuries.

Evaluating the benefits of second-eye cataract surgery among the elderly.

UNLABELLED: The aim of this systematic review was to synthesize and appraise the evidence of benefits of second-eye cataract extraction for visual function, patient-reported quality of life, falls, and driving ability among the elderly. We conducted a comprehensive search in MEDLINE using "surgery," "cataract extraction," "second eye," and "bilateral." Ten studies met the inclusion and quality criteria. We found "moderate" evidence supporting improvement in stereopsis, stereoacuity, and anisometropia over and above the benefits of first-eye surgery. We also found "moderate" evidence supporting improvement in visual acuity, contrast sensitivity, and self-reported visual functioning. Studies included in the review do not provide definitive evidence of second-eye surgery benefits on health-related quality of life, visual fields, falls prevention, and driving performance. However, the heterogeneity of outcome measures and the limited number of studies likely contributed to our findings. The findings have implications for clinicians and policymakers in the health-care industry and emphasize the need for additional trials examining this important and widely performed clinical procedure. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

A brief educational program improves awareness regarding whiplash prevention among a cohort of vehicle fleet managers in British Columbia, Canada.

OBJECTIVE: Previous research indicates that most vehicle occupants are unaware that a correctly adjusted, well-designed vehicular head restraint provides substantial protection against whiplash injuries. This study examined whether a brief educational intervention could improve awareness regarding whiplash injuries and prevention strategies among a cohort of vehicle fleet managers. METHODS: A brief written survey was administered prior to, and approximately 1 h after a 30-min presentation on whiplash injury and prevention measures, which was delivered at a regional fleet manager meeting held in British Columbia, Canada (n = 27 respondents). RESULTS: Respondents had low baseline knowledge levels regarding the causes, consequences, and prevention of whiplash. Following the presentation, however, respondents improved awareness in all of these domains and, most important, reported an increased motivation to implement changes based on this newly acquired knowledge. CONCLUSIONS: These results indicate that improved education practices and social marketing tools are potentially valuable to increase awareness among relevant stakeholders.

Bull bars and vulnerable road users.

OBJECTIVES: Pedestrian injuries are a leading cause of the global death and injury burden, accounting for 65 percent of the 1.2 million annual road deaths. The purpose of this brief literature review is to examine whether bull bars, a rigid aftermarket accessory fitted to the front end of passenger vehicles, increase the risk of severe and fatal injuries to vulnerable road users in the event of a collision. METHODS: Applicable peer-reviewed research, review papers, and grey literature were identified from a search of MEDLINE; the Transportation Research Board (TRB) database composed of Transportation Research Information Services (TRIS) and International Transport Research Documentation (TRID) databases; the Cochrane Database of Systematic Reviews; and Google Scholar. The following search terms were used: "bull bars" OR "nudge bars" OR "sahara bars" AND "pedestrians" OR "vulnerable road users" for 1948 to March 1, 2011. A secondary set of search terms was also included "bull bars" OR "nudge bars" OR "sahara bars" OR "vehicle frontal protective systems" AND "pedestrians" OR "vulnerable road users" for 1948 to March 1, 2011. RESULTS: Neither the MEDLINE search nor the Cochrane Review search returned any relevant literature. The TRID search returned 19 research articles, 9 of which were included. Searches using Google Scholar returned 110 items, of which 21 were included in the present review after excluding patents and citations. Seven of the articles from TRID were also found in the Google Scholar search, resulting in 23 unique articles being included in this review. The studies used included 12 real-world studies, 3 computer modeling studies, and 8 laboratory testing studies. Very few studies examined the road safety of pedal-cyclists and motorcyclists; therefore, we focused solely on studies examining pedestrian safety. CONCLUSIONS: The literature reviewed in this study indicates that vehicles fitted with bull bars, particularly those without deformable padding, concentrate crash forces over a smaller area of vulnerable road users during collisions compared to vehicles not fitted with a bull bar. Rigid bull bars, such as those made from steel or aluminum, stiffen the front end of vehicles and interfere with the vital shock absorption systems designed in vehicle fronts. These devices therefore significantly alter the collision dynamics of vehicles, resulting in an increased risk of pedestrian injury and mortality in crashes. This literature review shows that bull bars do indeed increase the severity of injuries to vulnerable road users in the event of a collision and highlights the need for current traffic safety policies to reflect the safety concerns surrounding the use of bull bars.

Dynamic morphometrics reveals contributions of dendritic growth cones and filopodia to dendritogenesis in the intact and awake embryonic brain.

Using in vivo rapid and long-interval two-photon time-lapse imaging of brain neuronal growth within the intact and unanesthetized Xenopus laevis tadpole, we characterize dynamic dendritic growth behaviors of filopodia, branches, and dendritic growth cones (DGCs), and analyze their contribution to persistent arbor morphology. The maturational progression of dynamic dendritogenesis was captured by short-term, 5 min interval, imaging for 1 h every day for 5 days, and the contribution of short-term growth to persistent structure was captured by imaging at 5 min intervals for 5 h, and at 2 h intervals for 10 h during the height of arbor growth. We find that filopodia and branch stability increases with neuronal maturation, and while the majority of dendritic filopodia rapidly retract, 3% to 7% of interstitial filopodia transition into persistent branches with lifetimes greater than 90 min. Here, we provide the first characterization of DGC dynamics, including morphology and behavior, in the intact and awake developing vertebrate brain. We find that DGCs occur on all growing branches indicating an essential role in branch elongation, and that DGC morphology correlates with dendritic branch growth behavior and varies with maturation. These results demonstrate that dendritogenesis involves a remarkable amount of continuous remodeling, with distinct roles for filopodia and DGCs across neuronal maturation. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 72: 615-627, 2012.

Baseline knowledge on vehicle safety and head restraints among Fleet Managers in British Columbia Canada: a pilot study.

BACKGROUND: Whiplash is the most common injury type arising from motor vehicle collisions, often leading to long-term suffering and disability. Prevention of such injuries is possible through the use of appropriate, correctly positioned, vehicular head restraints. OBJECTIVE: To survey the awareness and knowledge level of vehicle fleet managers in the province of British Columbia, Canada, on the topics of vehicle safety, whiplash injury, and prevention; and to better understand whether these factors influence vehicle purchase/lease decisions. METHODS: A survey was administered to municipal vehicle fleet managers at a professional meeting (n = 27). RESULTS: Although many respondents understood the effectiveness of vehicle head restraints in the prevention of whiplash injury, the majority rarely adjusted their own headrests. Fleet managers lacked knowledge about the seriousness of whiplash injuries, their associated costs for Canada's healthcare system, and appropriate head restraint positions to mitigate such injuries. The majority of respondents indicated that fleet vehicle purchase/lease decisions within their organization did not factor whiplash prevention as an explicit safety priority. CONCLUSIONS: There is relatively little awareness and enforcement of whiplash prevention strategies among municipal vehicle fleet managers.

Single cell electroporation in vivo within the intact developing brain.

Single-cell electroporation (SCE) is a specialized technique allowing the delivery of DNA or other macromolecules into individual cells within intact tissue, including in vivo preparations. The distinct advantage of this technique is that experimental manipulations may be performed on individual cells while leaving the surrounding tissue unaltered, thereby distinguishing cell-autonomous effects from those resulting from global treatments. When combined with advanced in vivo imaging techniques, SCE of fluorescent markers permits direct visualization of cellular morphology, cell growth, and intracellular events over timescales ranging from seconds to days. While this technique is used in a variety of in vivo and ex vivo preparations, we have optimized this technique for use in Xenopus laevis tadpoles. In this video article, we detail the procedure for SCE of a fluorescent dye or plasmid DNA into neurons within the intact brain of the albino Xenopus tadpole. We also discuss methods to optimize yield, and show examples of live two-photon fluorescence imaging of neurons fluorescently labeled by SCE.

In vivo imaging of seizure activity in a novel developmental seizure model.

The immature brain is exceptionally susceptible to seizures. However, it remains unclear whether seizures occurring during development affect critical processes underlying neural circuit formation, leading to long-term functional consequences. Here we characterize a novel in vivo model system of developmental seizures based on the transparent albino Xenopus laevis tadpole, which allows direct examination of seizure activity, and seizure-induced effects on neuronal development within the intact unanesthetized brain. Pentylenetetrazol (PTZ), kainic acid, bicuculline, picrotoxin, 4-aminopyridine, and pilocarpine were tested for their ability to induce behavioral seizures in freely swimming tadpoles when bath applied. All six chemoconvulsants consistently induced similar patterns of abnormal behavior in a dose-dependent manner, characterized by convulsive clonus-like motor patterns with periods of behavioral arrest. Extracellular field recordings demonstrated rhythmic synchronous epileptiform electrographic responses induced by convulsants irrespective of mechanism of action, that could be terminated by the anti-epileptic drug valproate. PTZ-induced seizures were further characterized using in vivo two-photon fluorescence imaging of neuronal calcium dynamics, in unanesthetized immobilized tadpoles. Imaging of calcium dynamics during PTZ-induced seizures revealed waves of neural activity propagating through large populations of neurons within the brain. Analysis of single-cell responses demonstrated distinct synchronized high-amplitude calcium spikes not observed under baseline conditions. Similar to other developmental seizure models, prolonged seizures failed to induce marked neuronal death within the brain, detected by cellular propidium iodide incorporation in vivo or TUNEL labeling. This novel developmental seizure model system has distinct advantages for controlled seizure induction, and direct visualization of both seizure activity and seizure-induced effects on individual developing neurons within the intact unanesthetized brain. Such a system is necessary to address important questions relating to the long-term impact of common perinatal seizures on developing neural circuits.

Propagation of amygdala-kindled seizures to the hippocampus in the rat: electroencephalographic features and behavioural correlates.

BACKGROUND: The propagation of amygdala-kindled seizures to the dorsal and ventral hippocampus was examined, in rats. The relation of contralateral seizure propagation to the onset of generalized convulsions was also studied. METHODS: In all subjects, electrodes were implanted in the amygdala. Two additional electrodes were implanted (bilaterally) in the dorsal (n = 6) or ventral (n = 8) hippocampus. Kindling stimulations were delivered twice daily (interval 4 h). RESULTS: Initially, triggered after-discharges (ADs) were recorded only in the amygdala. With repeated stimulation, the AD propagated to the hippocampus. Rates of propagation were as follows (mean # of stimulations +/- SEM): ipsilateral ventral hippocampus, 4.0 +/- 0.9; ipsilateral dorsal hippocampus, 6.2 +/- 1.4; contralateral dorsal hippocampus, 7.5 +/- 1.4; contralateral ventral hippocampus, 8.5 +/- 1.0. AD propagation to contralateral sites was significantly slower than to ipsilateral sites. Ipsilateral hippocampal recruitment occurred between stages 1 and 2 (partial seizures), whereas contralateral hippocampal recruitment occurred between stages 2 and 3 (transition to generalized seizures). SUMMARY: These results indicate that during amygdala-kindling, it takes several stimulations before discharge propagates to the hippocampus. The close link between contralateral hippocampus involvement and seizure generalization warrants further study, and may lead to a better understanding of the pathways involved in seizure spread.