Dietary supplement comprised of ß-carotene, vitamin C, vitamin E, and magnesium: failure to prevent music-induced temporary threshold shift.

This study examined potential prevention of music-induced temporary threshold shift (TTS) in normal-hearing participants. A dietary supplement composed of ß-carotene, vitamins C and E, and magnesium was assessed using a randomized, placebo-controlled, double-blind study design. Dosing began 3 days prior to the music exposure with the final dose consumed approximately 30-min pre-exposure. There were no group differences in post-exposure TTS or music-induced decreases in distortion product otoacoustic emission (DPOAE) amplitude. Transient tinnitus was more likely to be reported by the treatment group, but there were no group differences in perceived loudness or bothersomeness. All subjects were monitored until auditory function returned to pre-exposure levels. Taken together, this supplement had no effect on noise-induced changes in hearing. Recommendations for future clinical trials are discussed.

Increased vitamin plasma levels in Swedish military personnel treated with nutrients prior to automatic weapon training.

Noise-induced hearing loss (NIHL) is a significant clinical, social, and economic issue. The development of novel therapeutic agents to reduce NIHL will potentially benefit multiple very large noise-exposed populations. Oxidative stress has been identified as a significant contributor to noise-induced sensory cell death and NIHL, and several antioxidant strategies have now been suggested for potential translation to human subjects. One such strategy is a combination of beta-carotene, vitamins C and E, and magnesium, which has shown promise for protection against NIHL in rodent models, and is being evaluated in a series of international human clinical trials using temporary (military gunfire, audio player use) and permanent (stamping factory, military airbase) threshold shift models (NCT00808470). The noise exposures used in the recently completed Swedish military gunfire study described in this report did not, on average, result in measurable changes in auditory function using conventional pure-tone thresholds and distortion product otoacoustic emission (DPOAE) amplitudes as metrics. However, analysis of the plasma samples confirmed significant elevations in the bloodstream 2 hours after oral consumption of active clinical supplies, indicating the dose is realistic. The plasma outcomes are encouraging, but clinical acceptance of any novel therapeutic critically depends on demonstration that the agent reduces noise-induced threshold shift in randomized, placebo-controlled, prospective human clinical trials. Although this noise insult did not induce hearing loss, the trial design and study protocol can be applied to other populations exposed to different noise insults.

Evidence of hearing loss in a 'normally-hearing' college-student population.

We report pure-tone hearing threshold findings in 56 college students. All subjects reported normal hearing during telephone interviews, yet not all subjects had normal sensitivity as defined by well-accepted criteria. At one or more test frequencies (0.25-8 kHz), 7% of ears had thresholds ≥25 dB HL and 12% had thresholds ≥20 dB HL. The proportion of ears with abnormal findings decreased when three-frequency pure-tone-averages were used. Low-frequency PTA hearing loss was detected in 2.7% of ears and high-frequency PTA hearing loss was detected in 7.1% of ears; however, there was little evidence for 'notched' audiograms. There was a statistically reliable relationship in which personal music player use was correlated with decreased hearing status in male subjects. Routine screening and education regarding hearing loss risk factors are critical as college students do not always self-identify early changes in hearing. Large-scale systematic investigations of college students' hearing status appear to be warranted; the current sample size was not adequate to precisely measure potential contributions of different sound sources to the elevated thresholds measured in some subjects.

Interim clinical outcomes in the Collaborative Initial Glaucoma Treatment Study comparing initial treatment randomized to medications or surgery.

PURPOSE: To report interim outcome data, using all available follow-up through 5 years after treatment initiation, in the Collaborative Initial Glaucoma Treatment Study (CIGTS). DESIGN: Randomized clinical trial. PARTICIPANTS: Six hundred seven newly diagnosed glaucoma patients. METHODS: In a randomized clinical trial, 607 patients with newly diagnosed open-angle glaucoma were initially treated with either medication or trabeculectomy (with or without 5-fluorouracil). After treatment onset and early follow-up, patients were evaluated clinically at 6-month intervals. In addition, quality of life telephone interviews were conducted at similar frequency to the clinical visits. Patients in both arms of CIGTS were treated aggressively in an effort to reduce intraocular pressure (IOP) to a level at or below a predetermined target pressure specific for each individual eye. Visual field (VF) scores were analyzed by time-specific comparisons and by repeated measures models. MAIN OUTCOME MEASURES: VF loss was the primary outcome variable in CIGTS. Secondary outcomes of visual acuity (VA), IOP, and cataract were also studied. RESULTS: On the basis of completed follow-up through 4 years and partially completed through 5 years, VF loss did not differ significantly by initial treatment. Over the entire period of follow-up, surgical patients had a greater risk of substantial VA loss compared with medical patients. However, by 4 years after treatment, the average VA in the two groups was about equal. Over the course of follow-up, IOP in the medicine group has averaged 17 to 18 mmHg, whereas that in the surgery group averaged 14 to 15 mmHg. The rate of cataract requiring removal was greater in the surgically treated group. CONCLUSIONS: Both initial medical or initial surgical therapy result in about the same VF outcome after up to 5 years of follow-up. VA loss was greater in the surgery group, but the differences between groups seem to be converging as follow-up continues. When aggressive treatment aimed at substantial reduction in IOP from baseline is used, loss of VF can be seen to be minimal in general. Because 4 to 5 years of follow-up in a chronic disease is not adequate to draw treatment conclusions, these interim CIGTS outcomes do not support altering current treatment approaches to open-angle glaucoma.

The Collaborative Initial Glaucoma Treatment Study: interim quality of life findings after initial medical or surgical treatment of glaucoma.

OBJECTIVE: To present interim quality of life (QOL) findings in the Collaborative Initial Glaucoma Treatment Study (CIGTS) using all available follow-up through 5 years from treatment initiation. DESIGN: Randomized controlled clinical trial. PARTICIPANTS: Six hundred seven newly diagnosed patients with open-angle glaucoma from 14 clinical centers. INTERVENTION: Patients were randomly assigned to either initial medical therapy or initial trabeculectomy. After treatment initiation and early follow-up, patients received clinical and QOL evaluations at 6-month intervals. QOL assessments were administered by telephone at a centralized interviewing center. MAIN OUTCOME MEASURES: The CIGTS collected comprehensive QOL information that included both generic and vision-specific QOL measures. This article focuses on initial treatment group differences related to symptom reporting, as measured by a Symptom and Health Problem Checklist, and changes in daily visual functioning, as measured by the Visual Activities Questionnaire (VAQ). RESULTS: Across both treatment groups, there was an overall decline in the percent of participants reporting symptoms over time. Of 43 possible symptoms, 12 symptoms were reported with greater frequency by the surgically treated group and 7 symptoms more frequently by the medically-treated group. The surgical patients reported more total Symptom Impact Glaucoma (P = 0.005) and, in particular, more bother related to local eye symptoms. Very few treatment group differences were noted in visual functioning, although surgical patients reported more problems with activities related to their visual acuity (P = 0.024). The percentage of patients across treatment groups reporting worry about blindness was 50% at baseline but declined to approximately 25% over time. CONCLUSIONS: Overall, the QOL impact reported by the two treatment groups as measured by instruments used in this study is remarkably similar, with relatively few significant study group differences observed after up to 5 years of follow-up in the CIGTS. When significant differences in visual function have been detected using the VAQ, they are consistent with the clinical outcomes. To date, the most persistent QOL finding is the increased impact of local eye symptoms reported by the surgical group compared with the medical group. Although no changes are recommended in the treatment of newly diagnosed glaucoma patients at the time of this interim report, further follow-up will allow for more definitive answers to the QOL impact of these two treatment approaches.

Correlation of visual field with quality-of-life measures at diagnosis in the Collaborative Initial Glaucoma Treatment Study (CIGTS).

PURPOSE: To examine the relationship between various clinical measures of visual field and patient-reported measures of symptoms and health status in a large cohort of patients with glaucoma at the time of diagnosis. PATIENTS AND METHODS: The 607 patients in the Collaborative Initial Glaucoma Treatment Study received standardized examinations of visual field at enrollment. In addition, they completed a telephone-administered, health-related quality-of-life questionnaire, which included the Visual Activities Questionnaire (VAQ) and a symptom and health problem checklist. RESULTS: The Visual Activities Questionnaire total and subscale scores, particularly the peripheral vision subscale, correlated weakly but significantly with global visual field scores. Symptoms attributed to glaucoma also correlated weakly but significantly to visual field scores. Correlations with other visual field measures, including only central and pericentral test locations in the scores, did not strengthen the association, and simulating binocular visual field scores produced only slightly stronger correlations. CONCLUSIONS: At diagnosis, most patients were relatively free of glaucoma-related impairments. Various visual field measures derived from clinical visual field test data were only modestly associated with patients' perceptions of health-related quality of life. As the Collaborative Initial Glaucoma Treatment Study population is followed up longitudinally, it will be important to see whether these pertinent associations become stronger.

Quality of life in newly diagnosed glaucoma patients : The Collaborative Initial Glaucoma Treatment Study.

OBJECTIVE: The Collaborative Initial Glaucoma Treatment Study (CIGTS) was designed to determine whether patients with newly diagnosed open-angle glaucoma are better treated initially by medicine or immediate filtering surgery. This paper describes the quality-of-life (QOL) measurement approach, instruments included, and the CIGTS participants' QOL findings at the time of diagnosis. DESIGN: Baseline results from a randomized, controlled clinical trial. PARTICIPANTS: Six hundred seven patients from 14 clinical centers were enrolled. INTERVENTION: Patients randomized to initial medication received a stepped medical regimen (n = 307). Those randomized to initial surgery underwent a trabeculectomy (n = 300). The baseline interview was conducted before treatment initiation. All baseline and posttreatment QOL assessments were conducted by telephone from a centralized interviewing center. MAIN OUTCOME MEASURES: The primary outcome measure described in this paper was QOL. The QOL instrument is multidimensional and incorporates both disease-specific and generic measures, including the Visual Activities Questionnaire, Sickness Impact Profile, and a Symptom and Health Problem CHECKLIST: RESULTS: The correlations between QOL measures and clinical outcomes were in the expected direction, but relatively weak. At initial diagnosis, difficulty with bright lights and with light and dark adaptation were the most frequently reported symptoms related to visual function, whereas visual distortion was the most bothersome. Approximately half of the patients reported at least some worry or concern about the possibility of blindness. Within the Visual Activities Questionnaire, higher scores on the Peripheral Vision subscale were associated with more field loss (P < 0.01). In regression analyses controlling for sociodemographics and nonocular comorbidities, increased visual field loss was significantly associated with higher dysfunction among five disease-specific QOL measures (P < 0.05). CONCLUSIONS: Newly diagnosed glaucoma patients reported experiencing some visual function symptoms at the time of diagnosis that would not be intuitively expected based on clinical testing. Some discussion about the association between clinical presentation and worry about blindness may reduce unnecessary concern. These results provide the basis for long-term comparisons of the QOL effects of initial medical and surgical treatment for open-angle glaucoma.

Self-reported walking ability predicts functional mobility performance in frail older adults.

OBJECTIVE: To determine how self-reported physical function relates to performance in each of three mobility domains: walking, stance maintenance, and rising from chairs. DESIGN: Cross-sectional analysis of older adults. SETTING: University-based laboratory and community-based congregate housing facilities. PARTICIPANTS: Two hundred twenty-one older adults (mean age, 79.9 years; range, 60-102 years) without clinical evidence of dementia (mean Folstein Mini-Mental State score, 28; range, 24-30). INTERVENTION AND MAIN OUTCOME MEASURES: We compared the responses of these older adults on a questionnaire battery used by the Established Populations for the Epidemiologic Study of the Elderly (EPESE) project, to performance on mobility tasks of graded difficulty. Responses to the EPESE battery included: (1) whether assistance was required to perform seven Katz activities of daily living (ADL) items, specifically with walking and transferring; (2) three Rosow-Breslau items, including the ability to walk up stairs and walk a half mile; and (3) five Nagi items, including difficulty stooping, reaching, and lifting objects. The performance measures included the ability to perform, and time taken to perform, tasks in three summary score domains: (1) walking ("Walking," seven tasks, including walking with an assistive device, turning, stair climbing, tandem walking); (2) stance maintenance ("Stance," six tasks, including unipedal, bipedal, tandem, and maximum lean); and (3) chair rise ("Chair Rise," six tasks, including rising from a variety of seat heights with and without the use of hands for assistance). A total score combines scores in each Walking, Stance, and Chair Rise domain. We also analyzed how cognitive/ behavioral factors such as depression and self-efficacy related to the residuals from the self-report and performance-based ANOVA models. RESULTS: Rosow-Breslau items have the strongest relationship with the three performance domains, Walking, Stance, and Chair Rise (eta-squared ranging from 0.21 to 0.44). These three performance domains are as strongly related to one Katz ADL item, walking (eta-squared ranging from 0.15 to 0.33) as all of the Katz ADL items combined (eta-squared ranging from 0.21 to 0.35). Tests of problem solving and psychomotor speed, the Trails A and Trails B tests, are significantly correlated with the residuals from the self-report and performance-based ANOVA models. CONCLUSIONS: Compared with the rest of the EPESE self-report items, self-report items related to walking (such as Katz walking and Rosow-Breslau items) are better predictors of functional mobility performance on tasks involving walking, stance maintenance, and rising from chairs. Compared with other self-report items, self-reported walking ability may be the best predictor of overall functional mobility.

The impact of the optic neuritis treatment trial on the practices of ophthalmologists and neurologists.

OBJECTIVE: To determine whether the Optic Neuritis Treatment Trial (ONTT) results have altered the practice patterns of ophthalmologists and neurologists. DESIGN: Mail survey. PARTICIPANTS: A random sample of 987 ophthalmologists and 900 neurologists practicing in the United States were mailed a questionnaire that inquired into decision-making with regard to management of optic neuritis before and after the publication of the ONTT results. MAIN OUTCOME MEASURES: Responses received from 202 ophthalmologists and 244 neurologists, a response rate of 47%. RESULTS: Following the ONTT reports, nearly all ophthalmologists and neurologists have reduced their use of oral prednisone alone, substituting a regimen that includes intravenous methylprednisolone. A large proportion of practitioners in both specialties mistakenly believe that intravenous methylprednisolone treatment improves final visual outcome. Only 7% of neurologists and 36% of ophthalmologists (P = 0.0001) are adhering to the ONTT suggestion to use magnetic resonance imaging as a basis for initiating treatment. CONCLUSIONS: The ONTT has led to a dramatic reduction in the use of oral prednisone without a preceding course of intravenous methylprednisolone in the treatment of acute optic neuritis. Ophthalmologists and neurologists have changed some of their practices without fully understanding the results of the ONTT.

The Collaborative Initial Glaucoma Treatment Study: study design, methods, and baseline characteristics of enrolled patients.

OBJECTIVE: The Collaborative Initial Glaucoma Treatment Study (CIGTS) is a randomized, controlled clinical trial designed to determine whether patients with newly diagnosed open-angle glaucoma (primary, pigmentary, or pseudoexfoliative) are better treated by initial treatment with medications or by immediate filtration surgery. DESIGN: Randomized, controlled clinical trial. PARTICIPANTS: A total of 607 patients with open-angle glaucoma were enrolled. INTERVENTION: Patients randomized to initial medications (n=307) received a stepped regimen of medications to lower intraocular pressure. Those randomized to initial surgery (n=300) underwent trabeculectomy to lower intraocular pressure. MAIN OUTCOME MEASURES: Progression in visual field loss constitutes the study's primary outcome variable. Secondary outcomes include health-related quality of life, visual acuity, and intraocular pressure. RESULTS: Randomized assignment resulted in a balanced distribution between treatment groups for most demographic and clinical measures assessed at enrollment. More males than females were enrolled (55% were males), and a substantial percentage (38.1 %) of enrollees were blacks. Most enrollees (90.6%) were diagnosed with primary open-angle glaucoma; the remainder had either pseudoexfoliative (4.8%) or pigmentary (4.6%) forms of open-angle glaucoma. CONCLUSIONS: Follow-up of this well-characterized group of patients should provide well-rounded guidance, based on both traditional ophthalmic measures and patients' perspectives on their health-related quality of life, on how best to initially treat open-angle glaucoma.

Diagnostic and management procedures for compensable back injuries without serious associated injuries. Modeling of the 1991 injury cohort from a major Michigan compensation insurer.

STUDY DESIGN: A retrospective cohort of 2425 workers with compensated back conditions was created from the 1991 compensated cohort of the largest compensation insurer in Michigan by linking computerized information on social and demographic factors, diagnostic and management procedures, and cumulative missed worktime. OBJECTIVE: To describe medical care use from date of injury in 1991 to mid-1993 by type of back condition, to identify factors affecting this use, to determine the effect of alternative model selection strategies on identifying such factors, to investigate the timing of surgery and the use of diagnostic studies in patients with displaced or herniated discs with and without surgery, and to compare the use of medical care in the study group with that recommended by national expert panels. SUMMARY OF BACKGROUND DATA: Despite the enormous costs involved in medical care for patients with work-related back injuries, almost no information on the use of medical care is available for compensated back injuries by diagnostic and procedure code. METHODS: Use of medical care was grouped into 18 categories for tabulation. Factors affecting use of medical care were identified by logistic regression, supplemented by Cox analysis for time to first procedure. The Hosmer-Lemeshow chi-square statistic was compared with the Bayes Information Criterion for evaluating model fit. Overall model utility was evaluated by comparing receiver operating characteristic curves generated by the model. For patients with displaced or herniated discs, algorithms were used to identify the diagnostic procedures performed before and after the first surgery and the amount of time that passed before each procedure was performed. RESULTS: In patients with diagnoses of disc displacement or herniation or vertebrogenic neuritis, approximately 80% underwent radiography to obtain plain views of the spine, 75% underwent diagnostic imaging, 45% underwent electrodiagnostic procedures, and 24% underwent spinal surgery (29.3% had surgical procedures among those with disc conditions). In patients with diagnoses of back sprain or other symptomatic diagnoses, the percentages for the first three procedures are approximately 70%, 12%, and 12%, respectively. Diagnostic category, age, gender, and cumulative missed worktime predicted the receipt of diagnostic and treatment procedures. Women were 30% less likely to undergo computed axial tomography or magnetic resonance imaging and 50% less likely to undergo spinal surgery. Median time to spinal surgery was twice as long in the group that underwent diagnostic imaging and electrodiagnostic testing before surgery (134.5 days). Of the 622 patients with disc displacement/herniation, 510 (approximately 80%) had initial diagnostic imaging studies, and, of the 510, 162 (approximately 30%) had surgery. Thirteen (8%) were reoperated. Of the 162 patients who had surgery, 46 (approximately 30%) had follow-up diagnostic imaging, and, of the 46, nine (approximately 20%) were reoperated. Of the 348 managed conservatively, 96 (approximately 30%) had follow-up diagnostic imaging. CONCLUSIONS: The data suggest only modest differences in the use of medical care between this study group and noncompensated study populations from previous reports. The authors of this study estimate that 27% of diagnostic imaging studies and 43% of plain radiography of the spine could have been avoided if then available Canadian recommendations or current American, guidelines had been followed. The gender effect remains unexplained and needs to be investigated in additional studies. There was an increase of 6% in the use of surgery in compensated patients compared with the use of surgery in a recent American series involving traditional health insurance, but this may be associated with greater work disability in the compensated group. The results of the current study suggest that the use and reporting of model selection strategies and the use of receiver operati

Is patient length of stay related to quality of care?

In this article, we investigate the relationship between hospital length-of-stay (LOS) and quality of care. We use hospital claims records from Medicare beneficiaries in Michigan to estimate condition-specific models for predicting patients' LOSs. With these models and a data set provided by Michigan Peer Review Organization, Inc. (MPRO), each patient's risk-adjusted LOS is then linked to a quality-of-care judgment (good care, poor care) from physician peer reviewers. LOS is a widely used indicator of hospital performance. Most commonly, it is viewed as an indicator of hospital efficiency and as a surrogate measure for costs, with hospitals having long average LOSs considered relatively inefficient in the use of resources and those with low LOSs considered to be efficient. Sometimes, however, LOS is assumed to relate to quality. For example, if hospitals were to respond to the financial incentives of prospective payment by attempting to lower costs by prematurely discharging patients, LOSs significantly lower than expected might be considered indicative of poor quality care. On the other hand, if poor quality of care causes complications, it would tend to extend LOSs. Under this assumption, longer than expected LOSs could be viewed as indicative of poor quality care. This article shows that in every one of the 13 clinical conditions examined, cases that received poor quality care had significantly longer risk-adjusted LOSs than cases whose care was of acceptable quality.

Factors affecting first return to work following a compensable occupational back injury.

Occupational back injuries produced $27 billion in direct and indirect costs in 1988. Predictors of prolonged disability have generally been identified in selected clinical populations, but there have been few population-based studies using statewide registries from workers' compensation systems. This study uses a 1986 cohort of 8,628 Michigan workers with compensable back injuries followed to March 1, 1990. Cox proportional hazards analyses with nine categorical covariates identified factors predicting missed worktime for the first disability episode following the injury. The model distinguished factors affecting the acute (< or = 8 weeks) and chronic disability periods (> 8 weeks). The first disability episode following injury contains 69.6% of the missed worktime observed through follow-up. In the acute phase, which contributes 15.2% of first episode missed worktime, gender, age, number of dependents, industry (construction), occupation, and type of accident predict continued work disability. Marital status, weekly wage compensation rate, and establishment size do not. Beyond 8 weeks, age, establishment size and, to a lesser degree, wage compensation rate predict duration of work disability. Graphs show the predicted disability course for injured workers with specific covariate patterns. Future efforts to reduce missed worktime may require modifications in current clinical practice by patient age group and the development of new strategies to encourage small and medium-size employers to find ways to return their injured employees to work sooner. Recent federal statutes covering disabled workers will only partially correct the strong effect of employer establishment size.

Concordance between ANSI occupational back injury codes and claim form diagnoses and a lower bound estimate of the fraction associated with disc displacement/herniation.

The current BLS Annual Survey of Occupational Illnesses and Injuries and several recent analyses of factors affecting missed worktime in occupational back injuries rely on ANSI-based injury codes derived from injury narratives to classify occupational injuries and estimate incidence and outcome. No population-based studies of the concordance between back injury codes and clinical diagnoses have been reported. Back injury cases were identified in two large work-injured populations totaling almost 80,000 cases in the states of Michigan and Minnesota. In both populations, cases had been coded by the single nature-of-injury and part-of-body-injured codes assigned by an ANSI-based injury-coding system and by as many as four (Michigan) or three (Minnesota) clinical diagnoses according to the International Classification of Diseases-Clinical Modification, 9th Revision. Concordance was measured by the sensitivity and predictive value positive (PVP, aka PV+ or PPA) of the injury coding scheme for related diagnostic groups. We also used an algorithm based on the limited clinical information available to corroborate the diagnosis of displaced/herniated disc for cases that underwent spinal surgery. Cases identified by the algorithm were then used to obtain a lower bound estimate of the fraction with disc injury. The injury coding scheme had PVPs of 82.9-90.1% and overall sensitivities of 69.7-75.9%. Sensitivities for individual diagnostic groups show that their distribution in ANSI-coded injury groups is skewed slightly toward cases with sprain and disc displacement/herniation, but these shifts are modest. The lower bound estimate of the fraction of cases with disc displacement/herniation in a population of cases with back injuries producing at least 1 day of missed worktime is 5.8%. The demographic comparisons indicate that, as the time between injury and cohort ascertainment increases during the first 8 days of missed worktime following injury, the proportion of younger workers in an injury cohort decreases. The relationship between increasing age and increasing missed worktime disability, reported in various outcome studies, is also present during the first few days following injury. The use of ANSI injury codes underestimates the contribution of back injuries to missed worktime because 24-30% of cases are missed by the ANSI coding system. However, the distribution of diagnostic groups in the injury-coded groups approximates that observed with all diagnosed cases and supports the use of such data to study outcome. Our estimate, and one from Quebec, suggest that disc displacement/herniation occurs more frequently in the subset of occupational back injuries compared to the set of back injuries from all sources.

Stepping over obstacles: dividing attention impairs performance of old more than young adults.

BACKGROUND: Tripping over an obstacle is a common cause of falls in the elderly. An earlier study of abilities to avoid stepping on suddenly appearing obstacles found that, although healthy old adults had a lower rate-of-success than young adults, the magnitude of that difference was not large. The present study inquired whether dividing attention during such a task would differentially affect young and old healthy adults. METHODS: Rates-of-success were observed in 16 young and 16 old healthy adults (mean ages 24 and 72 years) in avoiding stepping on a band of light that was suddenly projected across their gait path while they walked at their comfortable gait speed. This virtual obstacle was placed at predicted next-footfall locations to give 350 or 450 msec available response times before footfall. During most of the trials the subjects were asked, in addition to trying not to step on the obstacle, simultaneously to respond vocally as quickly as possible when red lights near the end of the walkway turned on. These attention-dividing reaction time tests were of two types: synchronized, when only red lights lit at intervals synchronized with the appearance of the obstacle, and unsynchronized, when green or yellow lights lit in addition to the red lights, with lighting intervals not synchronized with the appearance of the obstacle. RESULTS: When synchronized and unsynchronized reaction time tests were conducted concurrently with the obstacle avoidance tasks, mean rates-of-success in avoidance decreased significantly in both young and old adults. With available response times of 350 msec, mean success rates decreased from their no-division values in the young adults by 14.7% for synchronized reaction and by 19.9% for unsynchronized reaction, attention-dividing tests. Corresponding mean decreases for the old adults were 32.0 and 35.7%. This age difference in the effects of dividing attention was significant. CONCLUSION: Both young and old adults had a significantly increased risk of obstacle contact while negotiating obstacles when their attention was divided, but dividing attention degraded obstacle avoidance abilities of the old significantly more than it did in the young. Diminished abilities to respond to physical hazards present in the environment when attention is directed elsewhere may partially account for high rates of falls among the elderly.

Neuropsychological predictors of complex obstacle avoidance in healthy older adults.

Global cognitive impairment in older adults has been associated with a greater risk of falling, and tripping has been implicated as an important factor in a large percentage of these falls. In order to evaluate the role of specific cognitive domains in tripping and falling, 23 healthy older adults completed basic and complex obstacle avoidance tasks, as well as a battery of neuropsychological tests. Using multiple regression analysis, a select pattern of neuropsychological measures was found to predict the decrement in performance evident as avoidance task complexity increased. Whereas measures of problem solving, response inhibition, general anxiety, and variability in attention were found to be significant predictors (in that order) of the relative decline in successful obstacle avoidance, measures of visuo-spatial discrimination and memory did not.

Establishment size and risk of occupational injury.

For many years, the annual survey of occupational injuries and illnesses by the Federal Bureau of Labor Statistics (BLS) has consistently reported, without explanation, that injury rates in the smaller establishments (< 50 employees) are substantially lower than those for midsize establishments (100-499 employees). Also during those years, a remarkable increase has been reported in the injury rate in large companies, following the imposition of stiff fines for failure to keep required injury records. The rate patterns are identical for Michigan and the country in general. We investigated possible causes for lower injury rates in small establishments since such rates are inconsistent with reports of higher fatality rates in small establishments in the mining, construction, manufacturing, and transportation industries and higher, or at least comparable, injury rates for small establishments in the mining industry. They are also inconsistent with increased turnover and decreased availability of occupational safety services in small companies. Moreover, injury severity, as measured by missed worktime, is greater for workers in small establishments. We investigated the possibility that interactions of workforce or injury characteristics with establishment size could explain the rate differences. We also reviewed the available literature to see whether differences in labor turnover rates could explain the BLS findings. Graphical and statistical analyses of the 1988 CPS Annual Demographic File, a sample of employed persons in the U.S. workforce, failed to identify any associations between workforce characteristics and enterprise size that would explain the lower rates. Similarly, graphical and statistical analyses of all Michigan workers incurring a compensable injury in 1986 failed to indicate any associations between injury characteristics and establishment size that would explain the lower rates. The potential role of labor turnover on the injury rate was analyzed from data in the literature on turnover rate by establishment size and risk of injury by time on the job. None of these analyses explains the lower injury rates reported for small establishments. This leaves underreporting of injuries from small establishments as a substantial possibility. If small establishments were subject to the same injury incidence rates as midsize establishments, then the 1986 survey for Michigan may have missed as many as 54,000 injuries (and far more nationally). We suggest that BLS undertake methodological studies to validate the completeness of reporting from small establishments.

Radiation dose reduction in CT of the pediatric pelvis.

PURPOSE: To determine whether a lower radiation dose technique can be used for computed tomography (CT) of the pediatric pelvis without significant loss of diagnostic image quality. MATERIALS AND METHODS: Thirty-six pediatric patients underwent CT at 80 mAs (experimental group), and 42 underwent CT at 240 mAs (control group). Anatomic details, image quality, and the degree of confidence in reaching a diagnosis were graded on a scale of 1 (poor) to 4 (excellent). RESULTS: The difference in perceived image quality between the experimental and control groups was not statistically significant. The mean scores for scans evaluated by the first reader were 3.88 for the experimental group and 3.92 for the control group (P = .2804). The mean scores for the second reader were 3.78 and 3.77 for the experimental and control groups, respectively (P = .8131). CONCLUSION: A substantial dose reduction can be achieved if pelvic CT is performed at 80 mAs, without a recognizable deterioration of diagnostic image quality.

The association of diabetic status, age, and race to withdrawal from dialysis.

Higher rates of withdrawal from dialysis have been shown among young diabetic patients. This study examined the hypothesis that diabetic status has a joint effect with age as the result of an age-related increase in co-morbid conditions among nondiabetic ESRD patients. Using data collected during the 1980s by the Michigan Kidney Registry, the experience of 4,753 white and 2,988 black Michigan dialysis patients (13,863 patient years) is analyzed. During follow-up, 364 white and 80 black patients withdrew from dialysis. By use of a Cox analysis, adjusted rates of withdrawal were shown to be higher among white than black patients (rate ratio (RR) = 3.34; P < 0.001), without significant differences by diabetic status. Rates increased with age (RR = 7.9 for 80+ versus 20 to 35 yr; P < 0.001), without significantly different patterns by race. Adjusted withdrawal rates among diabetics were 2.3 times that of nondiabetics overall (P < 0.001), with a statistically significant joint effect with age, the RR being highest among young patients. Among white patients, nondiabetics using continuous ambulatory peritoneal dialysis had a lower relative withdrawal rate than those using hemodialysis (RR = 0.73; P = 0.07), whereas diabetics using continuous ambulatory peritoneal dialysis showed slightly higher although statistically insignificant rates than their counterparts using hemodialysis (RR = 1.21; P = 0.50). Between 1980 and 1989, withdrawal rates for white patients aged 20 to 34 yr tended to decrease by 20% per year (P = 0.05), whereas they increased by 11% per year for patients aged 50 to 69 yr (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Applicability of the Greulich and Pyle skeletal age standards to black and white children of today.

OBJECTIVE: The Greulich and Pyle skeletal age atlas was derived from white children of upper socioeconomic level during the 1930s. To our knowledge, the Greulich and Pyle standards have not been reassessed for both black and white children; it was the purpose of this study to reassess the applicability of these standards to today's children. DESIGN: A "blinded" review of hand roentgenograms taken for the evaluation of trauma was performed. Age of the subjects was evenly distributed between 0 and 18 years. The roentgenograms were scored for bone age by five individuals from different disciplines and levels of training. The difference between the median bone age and the child's chronologic age was calculated for each roentgenogram and stratified into four age groups: early childhood (0 to 4 years), middle childhood (4 to 8 years), late childhood (8 to 13 years), and adolescence (13 to 18 years). SETTING: The roentgenograms were obtained from four hospital emergency rooms in the Lake Erie basin area, the same geographic area from which the Greulich and Pyle standards originated. PATIENTS: There were 841 children: 452 boys and 389 girls, 461 black and 380 white children. RESULTS: The bone ages and chronologic ages were similar for white girls of all ages. Black girls were skeletally advanced by 0.4 to 0.7 year (P < .001), except during middle childhood. White boys were skeletally delayed during middle childhood by 0.9 year (P < .001) and during late childhood by 0.4 year (P < .01), but they were advanced during the adolescent years by 0.5 year (P < .01). Black boys showed no difference except for the adolescent group, which was skeletally advanced by 0.4 year (P < .02). CONCLUSIONS: The Greulich and Pyle atlas is not applicable to all children today, especially black girls. We should be aware of this information when making clinical decisions requiring accurate bone ages.