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Biomedical subjects

P M Keyl

Publications and source records attributed to P M Keyl.

At least 19 recordsLinked to original sources

Drinking and recreational boating fatalities: a population-based case-control study.

CONTEXT: Alcohol is increasingly recognized as a factor in many boating fatalities, but the association between alcohol consumption and mortality among boaters has not been well quantified. OBJECTIVES: To determine the association of alcohol use with passengers' and operators' estimated relative risk (RR) of dying while boating. DESIGN, SETTING, AND PARTICIPANTS: Case-control study of recreational boating deaths among persons aged 18 years or older from 1990-1998 in Maryland and North Carolina (n = 221), compared with control interviews obtained from a multistage probability sample of boaters in each state from 1997-1999 (n = 3943). MAIN OUTCOME MEASURE: Estimated RR of fatality associated with different levels of blood alcohol concentration (BAC) among boaters. RESULTS: Compared with the referent of a BAC of 0, the estimated RR of death increased even with a BAC of 10 mg/dL (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.2-1.4). The OR was 52.4 (95% CI, 25.9-106.1) at a BAC of 250 mg/dL. The estimated RR associated with alcohol use was similar for passengers and operators and did not vary by boat type or whether the boat was moving or stationary. CONCLUSIONS: Drinking increases the RR of dying while boating, which becomes apparent at low levels of BAC and increases as BAC increases. Prevention efforts targeted only at those operating a boat are ignoring many boaters at high risk. Countermeasures that reduce drinking by all boat occupants are therefore more likely to effectively reduce boating fatalities.

Accidents↗

Blood clot resolution in human cerebrospinal fluid: evidence of first-order kinetics.

OBJECTIVE: To determine the kinetics of blood clot resolution in human cerebrospinal fluid. METHODS: Computed tomographic scans of 17 adult patients with intraventricular hemorrhages were analyzed. Intraventricular clot volume was determined and analyzed over time to determine both a standardized percentage rate and an absolute rate of clot resolution. Results were analyzed by use of regression for cross sectional time-series data. To determine the kinetics of intraventricular clot resolution, the effect of the clot volume on the percentage rate of clot resolution, clot half-life, and absolute rate of clot resolution was analyzed. The potential effect of age, sex, type of hemorrhage, and treatment with external ventricular drainage on the percentage rate of clot resolution was assessed. RESULTS: The percentage rate of clot resolution was 10.8% per day (95% confidence interval, 9.05-12.61 %), and it was independent of initial clot volume, age, sex, type of underlying hemorrhage, and use of external ventricular drainage. The absolute rate of clot resolution varied directly with the maximal clot volume (R2 = 0.88; P < 0.001). The percentage clot resolution data are consistent with events during the first 24 to 48 hours that antagonize clot resolution. CONCLUSION: These findings demonstrate that intraventricular blood clot resolution in patients with intraventricular hemorrhage follows first-order kinetics. The thrombolytic enzyme system responsible for intraventricular clot resolution seems to be saturated at 24 to 48 hours after the initial hemorrhage.

Adult↗

Diagnostic impact of early transcranial Doppler ultrasonography on the TOAST classification subtype in acute cerebral ischemia.

OBJECTIVE: The impact of early transcranial Doppler ultrasonography (TCD) upon stroke subtype diagnosis is unknown and may affect therapeutic strategies. In this study, the diagnostic usefulness of TCD in stroke subtype diagnosis according to the criteria of the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) study was investigated in patients with acute cerebral ischemia. METHODS: TCD examination within 24 h of symptom onset was performed in 50 consecutive patients with acute cerebral ischemia. Of these 54% were female. Sixty percent of patients were black, 36% white, and 4% Asian. Initial TOAST stroke subtype diagnosis (ITSSD) was based upon clinical presentation and initial brain imaging studies. Modified TOAST stroke subtype diagnosis was determined subsequently after additional review of the TCD examination. Final TOAST stroke subtype diagnosis was determined at hospital discharge, incorporating all diagnostic studies. Using final TOAST stroke subtype diagnosis as the 'gold standard' ITSSD and modified TOAST stroke subtype diagnosis were compared in order to determine additional benefit from the information obtained by TCD. Data were collected retrospectively by a single investigator. RESULTS: ITSSD classified 23 of 50 (46%) patients correctly. After TCD, 30 of 50 (60%) patients were classified correctly, for an absolute benefit of 14% and a relative benefit of 30% (p = 0.018). Most benefit from TCD was observed in the TOAST stroke subtype category large-artery atherosclerosis, in particular in patients with intracranial vascular disease. In this category, ITSSD had a sensitivity of 27% which increased to 64% after TCD (p = 0.002). CONCLUSION: TCD within 24 h of symptom onset improves the accuracy of early stroke subtype diagnosis in patients with acute cerebral ischemia due to large-artery atherosclerosis. This may have clinical implications for early therapeutic interventions.

Acute Disease↗

Adolescent patients--healthy or hurting? Missed opportunities to screen for suicide risk in the primary care setting.

CONTEXT: Adolescent suicide rates have increased dramatically in recent decades. Suicide is the third leading cause of mortality among persons aged 10 to 19 years. Several official guidelines recommend screening for suicidal behavior in the primary care setting. OBJECTIVES: To determine the prevalence of adolescent suicidal behavior known to primary care providers and to determine the knowledge, attitudes, and practice of primary care physicians in Maryland regarding screening for risk factors for adolescent suicide. DESIGN: Cross-sectional study using mailed survey. SETTING: Maryland from May to July 1995. PARTICIPANTS: All pediatrician (n = 816) and family physician (n = 592) members of the state chapter of the American Academy of Pediatrics and the American Academy of Family Physicians, respectively, who were actively providing ambulatory care. MAIN OUTCOME MEASURES: Adolescent suicidal behavior known to primary care providers and predictors of routine screening for risk factors for adolescent suicide. RESULTS: The response rate was 66%. Three hundred twenty-eight physicians (47%) reported that 1 or more adolescent patients attempted suicide in the previous year, but only 158 (23%) either frequently or always screened adolescent patients for suicide risk factors. Significant factors correlating with routine screening for suicide risk factors included frequently or always counseling about the safer storage of firearms in the home (odds ratio [OR], 5.3; 95% confidence interval [CI], 2.8-10.2); agreeing or strongly agreeing that they were sufficiently trained and knew how to screen for risk factors (OR, 3.2; 95%/CI, 1.7-6.3); agreeing or strongly agreeing that they had enough time during the well visit to screen for mental health problems (OR, 2.9: 95% CI, 1.6-5.3); frequently or always counseling about child passenger safety (OR, 2.7; 95% CI, 1.6-4.7); spending more than 5 minutes in anticipatory guidance during the well visit (OR, 2.7: 95% CI, 1.5-4.6); practicing in an urban setting (OR, 2.3; 95)% CI, 1.2-4.7); agreeing or strongly agreeing that physicians can be effective in preventing adolescent suicide and that what they do during an office visit may help prevent adolescent suicide (OR, 2.0; 95% CI, 1.2-3.4); and female sex (OR. 1.9; 95% CI, 1.1-3.2). CONCLUSION: Despite the substantial proportion of primary care providers who encountered suicidal adolescent patients, most providers still do not routinely screen their patients for suicidality or associated risk factors. More training is needed and desired by the survey respondents. Patient confidentiality issues must be addressed. Development and widespread use of a short, easily administered, reliable, and valid screening tool are recommended to help busy clinicians obtain more complete information during all visits.

Adolescent↗

Diffusion-weighted MRI and proton MR spectroscopic imaging in the study of secondary neuronal injury after intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Cerebral ischemia has been proposed as contributing mechanism to secondary neuronal injury after intracerebral hemorrhage (ICH). Possible tools for investigating this hypothesis are diffusion-weighted (DWI) and proton magnetic resonance spectroscopic imaging ((1)H-MRSI). However, magnetic field inhomogeneity induced by paramagnetic blood products may prohibit the application of such techniques on perihematoma tissue. We report on the feasibility of DWI and (1)H-MRSI in the study of human ICH and present preliminary data on their contribution to understanding perihematoma tissue functional and metabolic profiles. METHODS: Patients with acute supratentorial ICH were prospectively evaluated using DWI and (1)H-MRSI. Obscuration of perihematoma tissue with both sequences was assessed. Obtainable apparent diffusion coefficient (Dav) and lactate spectra in perihematoma brain tissue were recorded and analyzed. RESULTS: Nine patients with mean age of 63.4 (36 to 87) years were enrolled. Mean time from symptom onset to initial MRI was 3.4 (1 to 9) days; mean hematoma volume was 35.4 (5 to 80) cm(3). Perihematoma diffusion values were attainable in 9 of 9 patients, and (1)H-MRSI measures were obtainable in 5 of 9 cases. Dav in perihematoma regions was 172.5 (120.0 to 302.5)x10(-5) mm(2)/s and 87.6 (76.5 to 102.1)x10(-5) mm(2)/s in contralateral corresponding regions of interest (P=0.002). One patient showed an additional area of reduced Dav with normal T(2) intensity, which suggests ischemia. (1)H-MRSI revealed lactate surrounding the hematoma in 2 patients. CONCLUSIONS: DWI and (1)H-MRSI can be used in the study of ICH patients. Our preliminary data are inconsistent with ischemia as the primary mechanism for perihematoma tissue injury. Further investigation with advanced MRI techniques will give a clearer understanding of the role that ischemia plays in tissue injury after ICH.

Adult↗

Treatment of intraventricular hemorrhage with urokinase : effects on 30-Day survival.

BACKGROUND AND PURPOSE: Intraventricular hemorrhage (IVH) remains associated with high morbidity and mortality. Therapy with external ventricular drainage alone has not modified outcome in these patients. METHODS: Twelve pilot IVH patients who required external ventricular drainage were prospectively treated with intraventricular urokinase followed by the randomized, double-blinded allocation of 8 patients to either treatment or placebo. Observed 30-day mortality was compared with predicted 30-day mortality obtained by use of a previously validated method. RESULTS: Twenty patients were enrolled; admission Glasgow Coma Scale score in 11 patients was </=8; 10 patients had pulse pressure <85 mm Hg. Mean+/-SD ICH volume in 16 patients was 6.21+/-7.53 cm(3) (range 0 to 23.88 cm(3)), and mean+/-SD intraventricular hematoma volume was 44.26+/-31.65 cm(3) (range 1.31 to 100.36 cm(3)). Four patients (20%) died within 30 days. Predicted mortality for these 20 patients was 68.42% (range 3% to 100%). Probability of observing </=4 deaths among 20 patients under a 68.42% expected mortality is 0.000012. CONCLUSIONS: Intraventricular urokinase may significantly improve 30-day survival in IVH patients. On the basis of current evidence, a double-blinded, placebo-controlled, multicenter study that uses thrombolysis to treat IVH has received funding and began January 1, 2000.

Adult↗

A decision guideline for emergency department utilization of noncontrast head computed tomography in HIV-infected patients.

OBJECTIVE: To determine which neurologic signs or symptoms are predictive of new focal lesions on head CT in HIV-infected patients. METHODS: Prospective study with convenience sample enrollment of HIV-infected patients who presented to a large inner-city university-based ED over an 11-month period. Patients were assessed using a standardized neurologic evaluation to ascertain whether they had developed new or changed neurologic signs or symptoms. Patients with any new or changed neurologic findings had a head CT scan in the ED. The association between individual complaints or findings and new focal lesions on head CT was assessed by univariate analysis, and sensitivity, specificity, and positive predictive values were calculated. Stepwise logistic regression analysis was then carried out to estimate the relative risk for those variables independently associated with new focal lesions on CT scans. A decision guideline was developed incorporating those variables. RESULTS: One hundred ten patients were identified as having new or changed neurologic signs or symptoms and had a head CT done in the ED. Twenty-seven patients (24%) had focal lesions on head CT, of which 19 (18%) were identified as new focal lesions; eight of these (7%) demonstrated a mass effect. Clinical findings most strongly associated with new focal findings on head CT were: 1) new seizure, relative risk (RR) = 73.5, 95% CI = 6.2 to 873.0; 2) depressed or altered orientation, RR = 39.1, 95% CI = 4.6 to 330.0; and 3) headache, different in quality, RR = 27.0, 95% CI = 3.2 to 230.1. Use of these three findings as a screen for ordering head CT in the ED would have identified 95% (18/19) of the patients with new focal intracranial lesions, and resulted in a 53% reduction in the number of head CTs ordered in the ED. Inclusion of one additional parameter (prolonged headache, > or =3 days), would have resulted in identification of 100% of all new focal lesions, with a 37% reduction in the number of head CTs ordered. Among those patients with new focal findings, 74% required emergent management (i.e., seizure control, IV antibiotics, IV steroids or surgery). The most common intracranial lesion among patients with CD4 counts less than 200 cells/microL was toxoplasmosis, while cerebrovascular accidents (ischemic or hemorrhagic) were most common in those with CD4 counts greater than 200 cells/microL. CONCLUSION: Specific clinical signs and symptoms were associated with the presence of new intracranial lesions in a group of HIV-infected patients who presented to the ED with neurologic complaints. These clinical findings can be incorporated into guidelines for determining the need for emergent head CT. Validation and widespread application of these guidelines could result in limiting the use of emergent neuroimaging to a more well-defined HIV-infected patient population.

AIDS Dementia Complex↗

Effectiveness of prenatal tetanus toxoid immunization against neonatal tetanus in a rural area in India.

BACKGROUND: Neonatal tetanus is the cause of 23 to 73% of neonatal deaths in developing countries and continues to be an important killer in many parts of India. METHODS: In this nonrandomized cohort study in a rural area in India, tetanus toxoid immunization status was recorded for 1688 pregnant women. Liveborn children were followed up for 30 days for the occurrence of neonatal tetanus. Nonimmunized and partially immunized women were asked their reasons for not receiving tetanus toxoid vaccine. RESULTS: Complete prenatal immunization with tetanus toxoid during pregnancy (two doses 1 month apart) was associated with an 88% reduction in the risk of neonatal tetanus among the newborn children [95% confidence interval (CI) 59 to 98%]. In multivariable analysis only complete immunization and the use of clean instruments for cutting the umbilical cord were independently associated with a reduction in risk of neonatal tetanus. Registration by the health care provider before 29 weeks of gestation, being 5 km or less from the vaccination facility, having two or more contacts with the health provider and having some school education were independently associated with complete immunization. CONCLUSIONS: Immunization of pregnant women with tetanus toxoid was the single most effective intervention against neonatal tetanus independent of other interventions.

Adult↗

Community support for needle exchange programs and pharmacy sale of syringes: a household survey in Baltimore, Maryland.

In October 1995, community attitudes toward needle exchange programs were assessed in Baltimore, Maryland. Household interviews were conducted with a random sample of residents living within six contiguous census tracts. Multivariate logistic regression was used to determine which factors were independently associated with acceptance of needle exchange programs. Of 274 eligible respondents contacted, 138 (50%) completed the interview. Respondents were statistically similar to the 1990 census population by income but were more likely to be female, black, between the ages of 35 and 44 years, and to have attended college or be a college graduate. Although 72% of respondents thought needle exchange programs would attract injection drug users to the neighborhood, 65% favored needle exchange, and 47% favored selling needles in a pharmacy without a prescription. Factors independently associated with acceptance of needle exchange programs included the perceptions that needle exchange programs decrease the number of discarded needles on the street, that needle exchange programs do not encourage a person's injection drug use, and that needle exchange programs decrease HIV incidence. Despite concern about attracting injection drug users to the neighborhood, support for needle exchange programs was high.

Adult↗

Epidemiology of alcohol-related emergency department visits.

OBJECTIVE: To examine the population and geographic patterns, patient characteristics, and clinical presentations and outcomes of alcohol-related ED visits at a national level. METHODS: Cross-sectional data on a probability sample of 21,886 ED visits from the 1995 National Hospital Ambulatory Medical Care Survey were analyzed with consideration of the individual patient visit weight. The annual number and rates of alcohol-related ED visits were computed based on weighted analysis in relation to demographic characteristics and geographic region. Specific variables of alcohol-related ED visits examined included demographic and medical characteristics, patient-reported reasons for visit, and physicians' principal diagnoses. RESULTS: Of the 96.5 million ED visits in 1995, an estimated 2.6 million (2.7%) were related to alcohol abuse. The overall annual rate of alcohol-related ED visits was 10.0 visits per 1,000 population [95% confidence interval (CI) 8.7-11.3]. Higher rates were found for men (14.7 per 1,000, 95% CI 12.5-16.9), adults aged 25 to 44 years (17.8 per 1,000, 95% CI 15.0-20.6), blacks (18.1 per 1,000, 95% CI 14.0-22.1), and residents living in the northeast region (15.2 per 1,000, 95% CI 12.1-18.2). Patients whose visits were alcohol-related were more likely than other patients to be uninsured, smokers, or depressive. Alcohol-related ED visits were 1.6 times as likely as other visits to be injury-related, and 1.8 times as likely to be rated as "urgent" or "emergent." The leading principal reasons for alcohol-related ED visits were complaints of pain, injury, and drinking problems. Alcohol abuse/dependence was the principal diagnosis for 20% of the alcohol-related visits. CONCLUSION: Alcohol abuse poses a major burden on the emergency medical care system. The age, gender, and geographic characteristics of alcohol-related ED visits are consistent with drinking patterns in the general population.

Adult↗

Abdominal pain in geriatric emergency patients: variables associated with adverse outcomes.

OBJECTIVE: To determine the diagnoses and outcomes of geriatric patients with abdominal pain, and to identify variables associated with adverse outcomes. METHODS: Geriatric emergency patients (aged 65 years and older) with a complaint of abdominal pain were participants in this longitudinal case series. Eligible patients were followed by telephone contact and chart review, to determine outcomes and final diagnoses. RESULTS: Of 380 eligible patients, follow-up information was available for 375 (97%), for the two months following the ED visit. Final diagnoses included infection (19.2%), mechanical-obstructive disorders (15.7%), ulcers/hypersecretory states (7.7%), urinary tract disease (7.7%), malignancy (7.2%), and others. Although 5.3% of the patients died (related to presenting condition), most (61.3%) patients ultimately recovered. Surgical intervention was required for 22.1% of the patients. Variables associated with adverse outcomes (death, and need for surgical intervention) included hypotension, abnormalities on abdominal radiography, leukocytosis, abnormal bowel sounds, and advanced age. Most physical examination findings were not helpful in identifying patients with adverse outcomes. This study demonstrated a higher incidence of malignancy (7.2%) and a lower incidence of disease necessitating surgical intervention (22.1%) than previously reported. CONCLUSIONS: The majority of geriatric emergency patients with abdominal pain have significant disease necessitating hospital admission. Morbidity and mortality among these patients are high, and specific variables are strongly associated with death and the need for surgical intervention. Absence of these variables does not preclude significant disease. Physical examination findings cannot reliably predict or exclude significant disease. These patients should be strongly considered for hospital admission, particularly when fever, hypotension, leukocytosis, or abnormal bowel sounds are present.

Abdomen, Acute↗

Alcohol and injury severity: reappraisal of the continuing controversy.

It is well recognized that alcohol increases the risk of injury. It is controversial, however, whether alcohol also has an effect on the degree and outcome of injury after controlling for the severity of impact. This review examines the evidence from experimental studies in animals regarding the potentiating effects of alcohol on trauma, and the methodologic issues that may have contributed to the contradictory findings of clinical and epidemiologic studies. Most experimental studies indicate that alcohol can adversely affect the degree and outcome of injury. In controlled laboratory conditions, alcohol is found to reduce cardiac output, to increase the susceptibility to hemorrhagic shock, and to increase the pulmonary vascular resistance after standardized experimental injuries. However, it is difficult to extrapolate these findings to humans, partly because the interactive effects of chronic and acute alcohol use on trauma are rarely considered in experimental studies. The conflicting results in studies involving trauma patients are due in part to the differences in study design, particularly selection of study populations, and in measuring and controlling for kinetic forces on the body. Studies indicating that alcohol is associated with an increased risk of serious or fatal injury are usually based on data from emergency departments or police departments. The alcohol-injury severity relationship reported in these studies is attributable to a great extent to the effects of correlates of alcohol, such as speeding and not wearing seat belts, rather than the biological effects of alcohol. Studies indicating that alcohol is not associated with the degree and outcomes of injury are mostly those involving patients who were admitted to hospitals or trauma centers. Methodologic issues concerning the alcohol-injury severity controversy, including conceptual models and future research needs, are discussed.

Alcohol Drinking↗

Estimation of age specific incidence rates of childhood burns from a prevalence survey of burn scars.

OBJECTIVES: This paper describes two methods of estimating the age specific incidence rates of childhood burns from a prevalence survey of burn scars. METHODS: A prevalence survey of burn scars was carried out in 1992 on 15,742 Ghanaian children aged 5 years or less. Nine hundred and fifty five (6.1%) of these children had scars from burn, and for 630 (66%) of these children, additional information about the burn incident, including the child's age at the time of the burn, was obtained from the mother two to three months later. Thirty four per cent of mothers of children with burn scars were not interviewed due to absence, relocation, or inaccessibility. Age specific incidence rates of burns were estimated for eight age groups using two methods. In method I, the number of incident cases of burns for each age group were estimated from the burn scars by subtracting the estimated contribution of scars from burns that had occurred at earlier ages. In method II, the estimate was based on the mother's recall of the age of the child at the time of the burn. RESULTS: Slightly different results were obtained with the two methods, and problems were noted with both methods. CONCLUSION: We recommend the use of these methods for estimating age specific incidence rates from retrospective population surveys for health conditions which result in long term residual markers.

Age Distribution↗

Characteristics of older pedestrians who have difficulty crossing the street.

OBJECTIVES: This study examined the sociodemographic and health characteristics and problems of older pedestrians. METHODS: Interviews and assessments were conducted with 1249 enrollees aged 72 or older from the New Haven, Conn, community of the Established Populations for Epidemiologic Studies of the Elderly who agreed to participate in a seventh follow-up. RESULTS: Approximately 11% of the New Haven residents reported difficulty crossing the street. Older pedestrians needing help in one or more activities of daily living were more than 10 times as likely as others, and those with the slowest walking speeds were nearly 3 times as likely as others, to report difficulty crossing the street. Fewer than 1% of these pedestrians aged 72 or older had a normal walking speed sufficient to cross the street in the time typically allotted at signalized intersections (1.22 m/sec). CONCLUSIONS: Crossing times at signalized intersectíons in areas with large populations of elders should be extended, and the recommended walking speed for timing signalized crossings should be modified to reflect the range of abilities among older pedestrians.

Activities of Daily Living↗

School-based health centers. Students' access, knowledge, and use of services.

OBJECTIVE: To examine students' knowledge, barriers to access, and use of services at two school-based health centers. DESIGN: In-person survey. SETTINGS: Two urban public schools in Baltimore, Md. PARTICIPANTS: One hundred forty-nine middle school and 131 high school African-American students. The response rate was 84%. MAIN OUTCOME MEASURES: Knowledge about center operations and services, reported barriers to access to the center, and reported use of the center. RESULTS: Knowledge about center operations and services was generally high. However, knowledge was low with respect to the need for an appointment for non-emergency visits (40% correct) and the availability of dental service referrals (51% correct). One fifth of students incorrectly reported their enrollment status. Boys were more likely to report that they knew about the availability of sports physical examinations (odds ratio, 3.7), and girls were more likely to report that they knew about reproductive services (odds ratio, 3.0). The most frequently identified barriers to access were difficulty in obtaining a teacher's permission to leave class (55%), requiring parental permission for enrollment (31%), and concern about confidentiality (26%). Barriers to access were reported more frequently by students in the middle school than by students in the high school. Seven eighths of enrolled students reported that they had used the center in the past year, but only a third would use it if they woke up on a Monday with a bad cough and needed to see a physician or nurse. CONCLUSIONS: Despite increasing the availability of primary care services by locating health centers in schools, some barriers to access remain. School-based health centers could more actively promote awareness of their operation and services among students and their parents.

Black or African American↗

Dementing illnesses in rural populations: the need for research and challenges confronting investigators.

Expansion of the world's elderly populations has increased concerns about aging-related medical disorders like Alzheimer's disease and other dementias. In the United States, one fourth of those older than age 65 and at greatest risk for developing dementia live in rural environments that may influence its manifestation. The objectives of this study were to determine the need for and potential benefits of further epidemiological research concerning dementia and similar disorders in rural U.S. populations and to identify pertinent methodological issues related to rural dementia research. This study employed a National Library of Medicine (MEDLINE) document search based on the key words "cognitive disorders," "dementia," "Alzheimer's disease," and "rural," followed by recovery of literature resources references in the bibliographies of selected articles. Nineteen studies focusing on dementia or related disorders in rural settings have been reported from around the world. While four of these were conducted in the United States, only one rural dementia prevalence study has been undertaken in this country. Because of methodological variability, comparisons of prevalence estimates between these rural studies, as well as with those from urban investigations, is difficult. Nonetheless, there is reason to believe that certain potentially dementing illnesses are more common in rural populations. There is also evidence to suggest that the screening instruments commonly used in such studies tend to misclassify rural elders as "false positive" dementia cases. Information regarding dementing disorders, particularly Alzheimer's disease, in rural populations is scarce. Preliminary observations that dementia may be more common in rural settings and that rural families are more likely to maintain their dementing elders in the community imply that further rural dementia research could yield important insights into the risk factors for these illnesses, the variables influencing their course, and the methods by which they can be more effectively managed. A determination of the reliability and validity of commonly used dementia screening instruments in rural populations would represent an important advancement in this area of research.

Adaptation, Psychological↗

Automobile driving in Huntington's disease.

We assessed the influence of the neurological and cognitive impairments of Huntington's disease (HD) on automobile driving. In a group of 73 HD outpatients, 53 (72%) continued to drive after illness onset. Those no longer driving had more severe symptoms than those still driving. Twenty-nine HD patients who were still driving and 16 healthy control subjects underwent a clinical examination, a cognitive examination, a driving-simulator assessment, and completed questionnaires about driving history and habits. HD patients performed significantly worse than control subjects on the driving-simulator tasks and were more likely to have been involved in a collision in the preceding 2 years (58% of HD vs. 11% of control subjects). Patients with collisions were less functionally impaired but had slower simple reaction time scores than did those without collisions. HD patients are at increased risk for accidents, but patients who have accidents are not easily distinguished from those who do not.

Accidents, Traffic↗

Changes in visual fixation and saccadic eye movements in Alzheimer's disease.

Visual fixation and saccadic eye movements were assessed in 31 mild to moderately demented patients with probable Alzheimer's disease (AD) and 31 age- and education-matched nondemented elderly control subjects. Seventeen AD and 17 matched control subjects were reassessed after a 9-month interval. On a fixation task, duration of fixation and number of intrusive saccades were not different between groups at baseline or follow-up. Both AD patients and control subjects showed more intrusive saccades at follow-up than at baseline. AD patients showed increased latency to initiation of saccades at baseline and on follow-up. Amplitude and velocity of saccades were not different between groups at any visit. Changes in measures of fixation, but no saccade measure, correlated with changes in MMSE scores over testing sessions. These data suggest that fixation is more sensitive than are saccades to the progession of AD.

Aged↗