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Biomedical subjects

R D Morris

Publications and source records attributed to R D Morris.

At least 37 records · Page 2Linked to original sources
PubMed1994

Meta-analysis in cancer epidemiology.

Meta-analysis has seen increasing use as a tool in epidemiology over the past five years. Although this method is relatively well accepted for use in clinical trials, its use has proved somewhat more controversial in epidemiology. If meta-analysis is viewed as an evolutionary improvement over the review article, it may become more widely acceptable. Meta-analysis should incorporate the concern for study quality and differences in study design seen in classic review articles with the concern for rigor, objectivity, and quantitative precision characteristic of meta-analysis. Available tools for consideration of differences among studies are described with several examples from the literature. The extent to which various methods are used in published meta-analyses is described. Methods for assessing publication bias, and tools for combining dose-response data, are discussed also. Evaluation of risk factors and protective factors for cancer must be based on the weight of the evidence. Tools such as meta-analysis are essential if we are to interpret the vast number of completed studies in cancer epidemiology.

Alcohol Drinking↗
PubMed1994

Geographic variability in hospital admission rates for respiratory disease among the elderly in the United States.

BACKGROUND: The elderly represent a susceptible subpopulation that experiences disproportionate levels of morbidity and mortality from respiratory disease. As a consequence, they are frequently hospitalized for these conditions. Evaluating the geographic distributions of these hospital admissions can provide useful insights concerning patterns in incidence and medical care for respiratory diseases. METHODS: All hospital admissions for pneumonia, acute respiratory infections, asthma, and chronic obstructive pulmonary disease from the United States for a 6-year period (1984 through 1989) were identified using Medicare admissions records. Age-, race-, and sex-standardized annual admission rates were calculated for each county and spatial clustering of disease specific rates was evaluated using Moran's I statistic. Ecologic analyses were conducted using multiple regression procedures with county-specific measures of average annual temperature, average income, household crowding, median educational level, population density, physicians per capita, and hospital beds per capita together with surrogate measures of cigarette consumption and occupational exposures as predictor variables. RESULTS: Hospital admission rates in the elderly for all four categories of respiratory disease showed marked regional elevations (p < 0.0001), particularly in the southeast and the northern plains states. Low median education level, low per capita income, and household crowding were all associated with elevated hospital admission rates. Surrogate measures of cigarette consumption were strongly associated with hospital admissions in all four disease groups. Hospital beds per capita demonstrated positive associations with hospital admissions, but the number of physicians per capita exhibited consistent inverse relationships with hospital admissions. CONCLUSIONS: Hospital admission rates for respiratory diseases among the elderly show marked geographic variation and are associated with regional indicators of socioeconomic status, availability of medical resources, occupational lung disease rates, and smoking.

Aged↗
PubMed1993

Aggregation of existing geographic regions to diminish spurious variability of disease rates.

The availability of large data sets together with the growth in power and storage capabilities of computers have made the analysis of the spatial distribution of disease rates an increasingly important tool in public health research. Use of existing geographic divisions or groupings tends to result either in unstable estimates of disease rates if the corresponding populations are small or in loss of spatial resolution if the areas are unnecessarily large. This paper describes a computer algorithm for combining existing geographic areas into regions with populations large enough to diminish spurious variability in disease rates while limiting the loss in resolution. The method is demonstrated using Medicare hospital admissions data for pneumonia and central nervous system cancer. Disease rates were calculated for both predefined regions and those generated by the algorithm and their frequency distributions were compared. The algorithm produces more stable rates over a variety of diseases and provides substantially more flexibility than the use of predefined aggregations.

Black or African American↗
PubMed1993

Perception of human chimeric faces by chimpanzees: evidence for a right hemisphere advantage.

The aim of this study was to investigate hemispheric advantages in the processing of human chimeric faces by chimpanzees using a free-vision task developed by Levy, Heller, Banich, and Burton (1983a). Subjects were taught a visual discrimination in which they were to select the human face that appeared "happiest" when paired with its neutral counterpart. After reaching criterion, chimeric faces were substituted as test trials, and the face the subjects selected was recorded. On 62% of the trials, three chimpanzee subjects selected the face in which the smiling half fell in the left hemispatial field. Familiarity factors appear to have accounted for some of the observed findings. We believe this is the first evidence for hemispheric advantages in the perception of human faces by great apes.

Animals↗
PubMed1993

Assessment of hand preference in two language-trained chimpanzees (Pan troglodytes): a multimethod analysis.

The nonhuman primate literature concludes that monkeys and apes do not exhibit handedness preferences at the population level. This discrepancy between human and nonhuman primate findings may be due to differences in the methods of assessment of handedness, lack of reliability between various measures of handedness, and a paucity of studies involving great apes. This paper presents the results of extensive hand preference studies with two language-trained chimpanzees (Pan troglodytes). Both naturalistic and experimental paradigms are described. In particular, various methodologic factors involved in handedness assessment, including the use of a hand preference measure previously used with human subjects were examined. Both chimpanzees exhibited a right-hand preference for fine motor tasks requiring manual dexterity.

Animals↗
PubMed1993

Neuropsychological, academic, and adaptive functioning in children who survive in-hospital cardiac arrest and resuscitation.

Children suffering cardiac arrest (CA) are not uncommon in certain pediatric populations. Due to the increasing survival rates of child CA patients, there is a growing interest in, and concern for, their long-term intellectual, academic, emotional, and adaptive functioning. This article describes the possible neurologic sequelae of CA in children and presents standardized assessment results on 25 children, 2 to 15 years of age, who survived a CA while in the hospital. A majority of these children exhibited low-average to deficient levels of performance on neuropsychologic, achievement, and adaptive behavior measures. Duration of cardiac arrest and a medical risk score were significantly correlated with decreased functioning in child CA patients. Children who suffer a cardiac arrest are at high risk for academic struggles, and many may need special education services.

Adolescent↗
PubMed1993

Handedness distribution in a nonspeaking population with mental retardation.

Fifty nonspeaking or minimally speaking subjects with moderate, severe, or profound mental retardation underwent evaluation of handedness. Results confirmed previously reported increased prevalence of non-right handedness and the occurrence of a large subtype of ambiguous handedness. Results suggest that incidence of atypical hand preference is not closely linked to level of cognitive impairment, especially as represented by significant speech-language impairment in this population, as has been previously hypothesized. Atypical handedness of persons with mental retardation probably depends on language organization, and there is little support for the view that such subtypes represent bilateral hemispheric damage.

Adolescent↗
PubMed1992

A clinical trials database as a research tool in health care.

OBJECTIVE: The rapid, efficient, and accurate communication of clinical research findings to both clinicians and researchers is essential to the process of improving medical care. This information should be conveyed in a form that facilitates the interpretation of the complete body of research on a specific condition. Unfortunately, the prevailing system for dissemination of clinical research fails to meet these criteria. This paper proposes a system for cataloging clinical trials and communicating their results in a comprehensive and comprehensible format. METHOD: The system involves the use of a hierarchical matrix structure that allows for the selection and evaluation of related groups of clinical trials. The format of the data is tailored to the requirements of metaanalysis. RESULTS: An example is presented using the treatment of acute Crohn's disease and including a sample metaanalysis of immunosuppressive therapy for this condition. CONCLUSIONS: The hierarchical matrix structure in conjunction with a comprehensive database of clinical trials holds the potential to facilitate access to and interpretation of clinical research.

Acute Disease↗
PubMed1992

Assessment of the relationship of cerebral hemisphere arousal asymmetry to perceptual asymmetry.

This study examined the hypothesis that characteristic individual differences in cerebral hemisphere arousal asymmetry are related to individual differences in perceptual asymmetry observed in verbally based visual half-field tasks. The study used electrophysiological measures of arousal asymmetry rather than behaviorally derived measures (Levy, Heller, Banich, & Burton, 1983). Measures of alpha asymmetry were obtained from 20 right-handed males during a baseline relaxation condition and during a visual half-field version of the lexical decision task. Reaction time measures of perceptual asymmetry were obtained during this task. The results indicated that a basal arousal asymmetry measured at the temporal recording location during the baseline condition was significantly related to individual perceptual asymmetry during the subsequent lexical decision task. This basal arousal asymmetry was relatively stable across different task conditions. A task-related arousal asymmetry measured at the parietal location during the lexical decision task also made a significant contribution in predicting individual perceptual asymmetry. These two measures of individual arousal asymmetry were able to predict 50% of the variance in perceptual asymmetry. The implications of the results for explaining more wide-ranging individual differences in behavioral style and personality are discussed.

Adult↗
PubMed1992

Long-term weight fluctuation and non-insulin-dependent diabetes mellitus in white women.

The association of long-term weight fluctuation with non-insulin-dependent diabetes mellitus (NIDDM) was investigated for a population of 8232 white female members of the Taking Off Pounds Sensibly (TOPS) weight-awareness program, between the ages of 40 and 50 years. An index of weight fluctuation was developed using current weight, weight at the time maximum height was reached, and recalled maximum and minimum weights for the third and fourth decades for each member of the study population. A logistic regression of diabetes prevalence as a function of weight fluctuation, waist-hip ratio, relative weight, and family history index showed standardized odds ratios of 1.10, 1.22, 1.19, and 1.06, respectively. The results suggest that the magnitude of long-term weight fluctuation is associated with the development of NIDDM.

Adult↗
PubMed1992

Hemispheric priming by meaningful and nonmeaningful symbols in language-trained chimpanzees (Pan troglodytes): further evidence of a left hemisphere advantage.

Hemispheric priming was examined in 3 language-trained chimpanzees (Pan troglodytes) using a simple reaction time paradigm. Subjects were required to hold down a response button until the occurrence of a response cue. A warning stimulus was presented to either the left visual field (LVF) or the right visual field (RVF) before the response cue occurred. No warning stimulus was presented on control trials. The warning stimuli were geometric communicative symbols from two semantic categories: foods and tools. A third set of warning stimuli were familiar geometric symbols. Dependent measures included reaction time and the number of false-positive responses. Reaction-time data indicated an RVF advantage in priming when the warning stimuli were food or tool symbols. No significant visual half-field differences were found for familiar symbols, but a trend toward an RVF advantage was observed. These effects were enhanced when subjects responded with their left hand. False-positive data also indicated an RVF advantage for the food and tool warning stimuli. The data indicate that hemispheric asymmetries for processing communicative symbols are present in language-trained chimpanzees.

Animals↗
PubMed1992

Chlorination, chlorination by-products, and cancer: a meta-analysis.

OBJECTIVES: Individual epidemiological investigations into the association between chlorination by-products in drinking water and cancer have been suggestive but inconclusive. Enough studies exist to provide the basis for a meaningful meta-analysis. METHODS: An extensive literature search was performed to identify pertinent case-control studies and cohort studies. Consumption of chlorinated water, surface water, or water with high levels of chloroform was used as a surrogate for exposure to chlorination by-products. Relative risk estimates were abstracted from the individual studies and pooled. RESULTS: A simple meta-analysis of all cancer sites yielded a relative risk estimate for exposure to chlorination by-products of 1.15 (95% CI: 1.09, 1.20). Pooled relative risk estimates for organ-specific neoplasms were 1.21 (95% CI: 1.09, 1.34) for bladder cancer and 1.38 (95% CI: 1.01, 1.87) for rectal cancer. When studies that adjusted for potential confounders were pooled separately, estimates of relative risks did not change substantially. CONCLUSIONS: The results of this meta-analysis suggest a positive association between consumption of chlorination by-products in drinking water and bladder and rectal cancer in humans.

Case-Control Studies↗
PubMed1991

The Psychology Student Stress Questionnaire.

Stressors of graduate psychology training remain relatively unexplored. The Psychology Student Stress Questionnaire (PSSQ) was developed to assess the impact of emotional, financial, and academic stressors of graduate psychology training on students. The PSSQ was administered, along with the Symptom Check List-90-R and the Health and Daily Living Form, to 133 graduate psychology students. Significant though limited correlations were obtained between the PSSQ and the two stress measures. Factor analysis of the PSSQ yielded seven underlying factors; time constraints accounted for the greatest variance in stress ratings. Female students had higher stress scores than males. These results suggest that the PSSQ could be useful in exploring student stress in graduate psychology training.

Achievement↗
PubMed1991

Evidence for asymmetrical hemispheric priming using known and unknown warning stimuli in two language-trained chimpanzees (Pan troglodytes).

In this article results are reported from 3 warning stimulus-priming experiments that assessed hemisphere-specific activation and lateralization in 2 language-trained chimpanzees (Pan troglodytes). Results from Experiment 1 indicated a right visual field advantage in priming for meaningful warning stimuli presented in blocks of 36 trials. In Experiments 2 and 3, randomized presentations of meaningful, familiar, and meaningless stimuli resulted in right visual field advantages for meaningful warning stimuli. No visual half-field differences were found for familiar or meaningless warning stimuli. The findings are similar to those found in human subjects using known-unknown symbol paradigms; they suggest that basic phylogenetic neuropsychological systems related to activation and priming processes may link nonhuman primate and human studies of lateralization.

Animals↗
PubMed1991

Travel behavior of nursing home residents perceived as wanderers and nonwanderers.

A video-based observational methodology was used to assess the travel behaviors of 40 nursing home residents, 24 of whom were identified by nursing staff as wanderers. Travel was monitored continuously for 30 days, resulting in the recording of over 5,000 unassisted travel events. Four basic travel patterns were observed: direct travel (86.8%), lapping (11.6%), random travel (.9%), and pacing (.7%). Travel efficiency (percentage of direct travel) was significantly related to cognitive status (r = .56), with inefficient travel most prevalent in severely demented participants.

Aged↗
PubMed1991

Methodological issues in the classification of attention-related disorders.

The classification and identification of children with attention deficit-hyperactivity disorder and related disorders involving learning and behavior are only rudimentarily developed. A major problem is the substantial overlap among children with attention, learning, and behavioral problems. The science of classification provides conceptual and methodological approaches addressing these problems. For successful classification of these children, major issues include (a) the need to provide explicit studies of identification criteria, (b) the need for systematic sampling strategies, (c) development of hypothetical classifications, and (d) systematic assessment of reliability and validity of hypothetical classifications. With the methodological advances provided by classification-oriented research, investigators and practitioners may be able to address issues involving definition and identification of children with attention and related disorders.

Attention Deficit Disorder with Hyperactivity↗