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Biomedical subjects

K Ball

Publications and source records attributed to K Ball.

At least 55 records · Page 3Linked to original sources
PubMed1998

Visual processing impairment and risk of motor vehicle crash among older adults.

CONTEXT: Motor vehicle crash risk in older drivers has been associated with visual acuity loss, but only weakly so, suggesting other factors contribute. The useful field of view is a measure that reflects decline in visual sensory function, slowed visual processing speed, and impaired visual attention skills. OBJECTIVE: To identify whether measures of visual processing ability, including the useful field of view test, are associated with crash involvement by older drivers. DESIGN: Prospective cohort study with 3 years of follow-up, 1990-1993. SETTING: Ophthalmology clinic assessment of community-based sample. PATIENTS: A total of 294 drivers aged 55 to 87 years at enrollment. MAIN OUTCOME MEASURE: Motor vehicle crash occurrence. RESULTS: Older drivers with a 40% or greater impairment in the useful field of view were 2.2 times (95% confidence interval, 1.2-4.1) more likely to incur a crash during 3 years of follow-up, after adjusting for age, sex, race, chronic medical conditions, mental status, and days driven per week. This association was primarily mediated by difficulty in dividing attention under brief target durations. CONCLUSION: Reduction in the useful field of view increases crash risk in older drivers. Given the relatively high prevalence of visual processing impairment among the elderly, visual dysfunction and eye disease deserve further examination as causes of motor vehicle crashes and injury.

Accidents, Traffic↗
PubMed1998

Driving avoidance and functional impairment in older drivers.

The purpose of this study was to examine the association between visual and cognitive impairment in older drivers and their avoidance of potentially challenging, driving situation. A group of 257 older drivers participated in assessments of visual sensory function, eye health and cognitive function including the useful field of view test, and completed a structured questionnaire on driving exposure and how frequently they avoided challenging driving situations. Results replicated earlier studies showing that many older drivers limit their exposure to driving situations which are generally believed to be more difficult (e.g. rain, night, heavy traffic, rush hour). Furthermore, older drivers with objectively determined visual and/or attentional impairments reported more avoidance than those free of impairments; those with the most impairment reported avoiding more types of situations than other less impaired or non-impaired drivers. Older drivers with a history of at-fault crashes in the prior five years reported more avoidance than those who had crash-free records. Future research should evaluate the potentially beneficial role of self-regulation in enhancing older driver safety, particularly in those older drivers with visual and attentional processing impairments who have elevated crash risk.

Aged↗
PubMed1998

Identifying crash involvement among older drivers: agreement between self-report and state records.

Older drivers have a high crash rate per vehicle mile of travel. Coupled with the growth of the number of older drivers on the road, this has generated interest in the identification of factors which place older drivers at increased risk. However, much of the existing research on medical and functional risk factors for crash involvement has generally been inconsistent. Methodological differences between studies have been hypothesized as being partly responsible for such inconsistencies. The source of information used to identify crash-involved drivers has been identified as one such difference. This paper reports on the agreement between self-report and state record for identifying crash involved-older drivers. We also sought to determine whether the prevalence of visual and cognitive impairment differs across crash-involved drivers identified by either or both sources. Finally, we assessed whether risk factors for crash involvement differed when crash-involved drivers were identified by either self-report or state records. Results indicated that there was a moderate level of agreement between self-reported and state-recorded crash involvement (kappa = 0.45). However, we did find significant differences between crash-involved drivers identified via state records and/or self-report with respect to demographic (age, race), driving (annual mileage, days per week driven), and vision impairment (acuity, contrast sensitivity, peripheral visual field sensitivity, useful field of view). We also found that the possibility for biased measures of association is real. Useful field of view impairment was associated with both self-reported and state-recorded crash involvement; however, the magnitude of the associations was disparate. Moreover, glaucoma was identified as a significant risk factor when considering state-recorded crashes but not self-reported crashes. While validation of these findings is required, research designed to identify risk factors for crash involvement among older drivers should carefully consider the issue of case definition, particularly if self-report is used to identify crash-involved older drivers.

Accidents, Traffic↗
PubMed1998

Vision impairment, eye disease, and injurious motor vehicle crashes in the elderly.

The objective of this case-control study was to identify visual risk factors for vehicle crashes by elderly drivers which result in injury. The sample consisted of licensed current drivers between 55 and 87 years of age who resided in Jefferson County, Alabama. Subjects were identified through Alabama Department of Public Safety (ADPS) files. Two groups of cases were identified. One group (N = 78) was defined as those drivers who had incurred at least one vehicle crash between 1985 and 1990 resulting in an injury to anyone in the involved vehicles according to the accident report. The other case group (N = 101) consisted of drivers involved in non-injurious crashes during the same time period. Controls (N = 115), also selected from ADPS files, were older drivers not involved in crashes during the same five-year period. Subjects underwent a battery of visual processing tests and a comprehensive eye examination. The main results were that restricted useful field of view and glaucoma were the only significant independent predictors of injurious crash involvement. Odds ratios (ORs) for reductions in the useful field of view of 23-40%, 41-60% and greater than 60% were 4.2 (95% confidence interval [CI], 1.5-11.8), 13.6 (95% CI, 5.8-39.7), and 17.2 (95% CI, 5.3-55.6), respectively, compared to reductions of less than 23% (p for trend < 0.001). The OR for glaucoma was 3.6 (95% CI, 1.0-12.6). Useful field of view impairment was the only variable independently associated with non-injurious crash involvement. This study implies that impaired visual processing and glaucoma may play a role in the etiology of older driver crashes which result in injury.

Accidents, Traffic↗
PubMed1998

Attention and driving performance in Alzheimer's disease.

The present study examined the relationship between visual attention measures and driving performance in healthy older adults and individuals with very mild and mild dementia of the Alzheimer type (DAT). Subjects were administered an on-road driving assessment and three visual attention tasks (visual search, visual monitoring, and useful field of view). The results indicated that error rate and reaction time during visual search were the best predictors of driving performance. Furthermore, visual search performance was predictive of driving performance above and beyond simple dementia severity and several traditional psychometric tests. The results suggest that general cognitive status may be useful for identifying individuals "at risk" for unsafe driving. However, measures of selective attention may serve to better differentiate safe versus unsafe drivers, especially in the DAT population.

Aged↗
PubMed1998

A preliminary assessment of the medical and functional factors associated with vehicle crashes by older adults.

OBJECTIVES: To examine associations between medical and functional variables and at-fault car crashes in a cohort of older drivers. DESIGN: A case-control study. SETTING: A tertiary care medical center. PARTICIPANTS: Older drivers (ages 55-90 years) residing in Jefferson County, Alabama (n = 174). Cases were drivers who had at least one at-fault crash in the previous 6 years; controls were crash-free during the same period. MEASUREMENTS: Self-reported medical conditions, reported and observed functional measures, and urinary drug screens. The occurrence of one or more at-fault car crashes in the 6 years preceding the 1991 assessment date represented the outcome measure. RESULTS: Ninety-nine older drivers experienced between one and seven at-fault vehicle crashes during the period 1985 through 1991, whereas 75 drivers did not. Logistic regression models indicated that the following variables were independently associated with crash involvement: A 40% or greater reduction in the useful field of view (OR = 6.1; 95% CI, 2.9 to 12.7; P < 0.001), black race (OR = 6.6; 95% CI, 1.7 to 26.2; P = .007), a history of falling in the previous 2 years (OR = 2.6; CI, 1.1 to 6.1; P = .025), and not taking a beta-blocking drug (OR = 4.3; CI, 1.2 to 15.0; P = .023). CONCLUSIONS: Functional assessments, such as a comprehensive test of visual processing, a falls history, and a review of current medications may be of greater relevance than specific medical conditions in the identification of older at-risk drivers. If prospective studies determine that falling and crashing share risk factors, a unified approach to the prevention of these mobility disorders could result. The finding of an independent association of black race with at-fault crashing is in need of further clarification because of the low representation of black drivers in this sample.

Accidents, Traffic↗
PubMed1997

Dementia and driving: an attempt at consensus.

The number of older drivers in Sweden will be rapidly increasing during the next decades. A possible relationship exists between the increased relative crash risk of older drivers and the prevalence of age-related diseases such as dementia. However, a clear-cut policy for evaluating driving competence in demented persons is still lacking. In recognition of this fact, the Swedish National Road Administration invited a group of researchers to formulate a consensus on the issue of driving and dementia. This consensus document is aimed at providing primary care physicians with practical advice concerning the assessment of cognitive status in relation to driving. Suggestions are based on a review of existing research and discuss the use of general and driving-specific sources of information available to the physician. Consensus was reached on the statement that a diagnosis of moderate to severe dementia precludes driving and that certain individuals with mild dementia should be considered for a specialized assessment of their driving competence.

Aged↗
PubMed1997

Attentional problems and older drivers.

At a society level, there is a responsibility to meet the mobility needs of a growing population of older adults. Simultaneously, it is understood that some older adults will experience behavioral and/or physical changes that may preclude driving at some point in their lives. Because most older adults rely on the automobile to maintain their mobility and independence, there is sometimes reluctance to stop driving when impairments develop. Recent research has been aimed at finding ways to distinguish those drivers who may pose a threat to their own safety, as well as the safety of other road users, from the vast majority of competent drivers. These studies have indicated that measures of visual attention and cognitive function have been successful in distinguishing between these two groups. Finally, because visual attention skills can be improved with training, these findings have important implications for further evaluation of interventions to enhance the skills that underlie safe driving.

Alzheimer Disease↗
PubMed1997

The role of selective attention in driving and dementia of the Alzheimer type.

This paper examines the relationship between cognitive processes and driving in aging and dementia of the Alzheimer type. Several studies that have explored the relationship between neuropsychological test performance and various indicators of driving safety are reviewed. It is argued that deficits in selective attention are specific to impaired driving performance in dementia of the Alzheimer type. Results from a recent study supporting this notion are presented. It is suggested that screening measures that emphasize the ability to selectively attend to relevant information and inhibit irrelevant information should be used to identify mildly demented individuals who are at risk for unsafe driving.

Alzheimer Disease↗
PubMed1995

Relationship between visual sensitivity and target localization in older adults.

Older adults commonly report problems in visual search tasks and experience a higher incidence of mobility problems (e.g. falls and vehicle crashes), which involve visual skills. We examined whether target localization problems in the elderly can be adequately explained by impairments in peripheral visual sensitivity, or whether deficits in higher order visual processing are also contributory. Fifty-nine older adults (59-88 yr) who exhibited varying degrees of visual field loss (none to severe) were asked to localize briefly-presented, high-contrast targets (3 x 5 deg) in the central 60 deg (diameter) of the visual field, while simultaneously performing a visual discrimination task at fixation. Visual sensitivity accounted for only 36% of the variance in localization performance across subjects, and this relationship grew weaker (13%) when the target was embedded in distracting stimuli, suggesting that impaired attentional skills also underlie older adults' localization problems. Not surprisingly, older adults with severe visual field loss were also poor at localizing targets. However, about half of those older patients with normal or near-normal visual fields also had severe localization problems. These results indicate that despite having good visual field sensitivity, many older adults have serious difficulty locating objects of interest in the environment. This study illustrates that clinical tests for identifying visual performance problems in the elderly must embody stimulus and task features which better reflect the visual demands of everyday life.

Aged↗
PubMed1995

Video conferencing in surgery: an evolving tool for education and preceptorships.

The advent of advanced laparoscopic procedures has provided unquestioned patient benefits but has also engendered some significant concerns about whether surgical team members are able to stay current in this everchanging arena. The interactive video conferencing program at Doctors Hospital in Columbus, Ohio, was developed to improve the education and preceptoring of surgical teams. This article describes the evolution of the program and its basic technology and connectivity. Physicians and other health care professionals began to accept this teaching alternative as usage increased. Based on this initial experience, video conferencing in surgery appears to be a valuable and exciting method of enhancing the educational process and augmenting the preceptorship experience. Further studies need to be conducted to determine the actual cost-effectiveness of this teaching method.

Education, Medical, Continuing↗
PubMed1994

Allosteric sites of the large subunit of the spinach leaf ADPglucose pyrophosphorylase.

Pyridoxal-P, an analog of 3-phosphoglycerate, activates spinach leaf ADPglucose pyrophosphorylase. Reductive phosphopyridoxylation of the enzyme yields enzyme less dependent on the presence of activator for activity. Labeled pyridoxal-P is incorporated into both the 51- and 54-kDa subunits of the enzyme. The sequence of the single tryptic labeled peptide of the small subunit has been reported (Morell, M., Bloom, M., and Preiss, J. (1988) J. Biol. Chem. 263, 633-637). Three distinct labeled peptides are isolated from the tryptic digest of the large subunit. 3-Phosphoglycerate inhibits incorporation of pyridoxal-P by 80% into all three large subunit tryptic peptides, whereas inorganic phosphate, the allosteric inhibitor, inhibits incorporation into only one of those peptides. Comparison of the sequences of the labeled tryptic peptides with those of large and small subunits of the enzyme from other species indicate their positions in the primary structure of the spinach enzyme large subunit. The conservation in the amino acid sequences surrounding the lysyl residue in the small subunit and of the lysyl residue in the large subunit in higher plant and in cyanobacterial ADPglucose pyrophosphorylases, which are protected from phosphopyridoxylation by both allosteric effectors, suggests that these lysyl residues are involved in activator binding.

Allosteric Regulation↗
PubMed1994

The psychologic impact of ostomy surgery on persons 50 years of age and older.

There have been few studies on the psychologic effects and reactions to ostomy creation in persons older than 50 years. Eighty-nine patients with ostomies (42 female, 47 male) were evaluated to see how ostomy creation affected them. Six instruments were used to make these assessments: Surgery Preparedness Inventory, Surgical Adjustment Scale, Social Interaction Inventory, Self-Esteem Inventory, Geriatric Depression Scale, and Life Satisfaction Inventory-A. In addition to these six instruments, the participants in the study were asked to state their greatest concern. Older men and women showed similar patterns in surgical preparedness, adjustment to operation, and level of self-esteem. Men reported lower satisfaction with life than did women. Men also had more difficulty in social interactions than did women. Twice as many men as women reported mild to moderate depression. Older women reported poorer health status; if unmarried, they reported less satisfaction with life than younger or married women. More of those reporting good current health reported a positive adjustment to ostomy creation than did those who reported poor health. Those who did not feel hindered by their ostomies reported higher scores on well-being than did those who felt hindered. The more time that has passed after operation, the better patients felt. Four major concerns were reported: (1) concern with being able to care for themselves; (2) leakage from the pouch, odor, and gas noises; (3) other health problems; and (4) recurrence of cancer. Good current health and a sense of well-being are important to positive adjustment after ostomy creation. These areas would be well worth monitoring and should be promoted by the caregivers.

Activities of Daily Living↗