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Biomedical subjects

C M Clark

Publications and source records attributed to C M Clark.

At least 91 records · Page 5Linked to original sources
PubMed1993

Models of cognitive deficit and statistical hypotheses: multiple sclerosis, an example.

The purpose of the current study was to describe four models of cognitive deficit and to outline the statistical hypotheses underlying each model. The four models of cognitive deficit were (a) specific deficit; (b) subgroup deficit; (c) a syndrome dissociation model; and (d) a global function dissociation model. Neuropsychological data are analyzed to examine each of these four models in a sample of mild Multiple Sclerosis (MS) patients. The results suggest that for these subjects and tests, the specific deficit model best fits the data. The results are reviewed initially in the context of MS. There follows a consideration of statistical caveats and finally, general applications of the proposed procedures.

Adult↗
PubMed1993

Implications of statistical tests of variance and means.

The primary purpose of this paper is to illustrate that tests for the homogeneity of variance in the statistical analysis of clinical neuropsychological data may provide unique information. Specifically, tests of variance homogeneity are more sensitive to outliers than the more commonly used tests of group means. Moreover, when both a test of means and of variance are done and the results compared, the nature of the deficit within the sample can be interpreted with greater confidence.

Analysis of Variance↗
PubMed1992

Sleep disturbance, depression, and lesion site in patients with multiple sclerosis.

We examined the prevalence of sleep problems in a sample of patients with mild but clinically definite multiple sclerosis (n = 143) and sought to determine whether there was a relationship between the presence of sleep complaints and the level of depression. As magnetic resonance imaging scans were available for a subsample of the patients with multiple sclerosis (n = 117), we also wanted to determine whether there was a relationship between the site of the lesion and the presence of sleep difficulties. The prevalence of sleep difficulties was three times higher in the patients with multiple sclerosis than the control group (25.2% vs 8.2%). Moreover, the presence of sleep complaints was associated with higher levels of depression. Three lesion sites that subserve supplemental motor areas were significantly related to the presence of sleep complaints. These findings suggest that, for some patients with MS, sleep disturbance and accompanying increases in depression may be a function of the lesion site resulting in nocturnal spasms.

Adult↗
PubMed1992

Prefrontal lobotomy and hypofrontality in patients with schizophrenia: an integration of the findings.

A case of a schizophrenic patient who suffered a frontal lobotomy is presented as the impetus for a discussion of an alternative neurobiologic model of schizophrenia to integrate the findings of prefrontal lobotomy and "hypofrontality". The proposal that primary temporolimbic pathology may result in secondary hypofunction in the prefrontal lobes is examined in light of current structural neuropathologic evidence. Directions for future research suggested by such a model are explored.

Adult↗
PubMed1992

Care of diabetic pregnant women by primary-care physicians. Reported strategies for managing pregestational and gestational diabetes.

OBJECTIVE: To ascertain the strategies used by primary-care physicians for treating pregestational and gestational diabetes mellitus (GDM) during pregnancy, because many women with pregnancies complicated by these types of diabetes are treated by physicians who have no special training in intensive diabetes management. RESEARCH DESIGN AND METHODS: Two hundred twenty-four family-practice (FP) physicians and 184 obstetrics/gynecology (OB/GYN) physicians were surveyed by mail. RESULTS: When compared with OB/GYNs, FPs were less likely to screen all pregnant women for GDM (P = 0.03), use multiple-injection insulin regimens (P = 0.004) or self-monitoring of blood glucose (SMBG) (P = 0.01) for Pre-GDM patients, and refer these patients to a specialist for medical (P = 0.01) or ophthalmologic (P less than 0.001) care. FPs were more likely to implement insulin therapy (P = 0.003), SMBG (P = 0.02), and examine eyes for retinopathy (P less than 0.001) when treating gestational patients. CONCLUSIONS: These data show that there are considerable discrepancies between the strategies used by FPs and OB/GYNs and also suggest that physicians in both groups are under-utilizing recommended treatment strategies described in publications targeted specifically to primary-care physicians. Increased exposure to and dissemination of guidelines for diabetes management and additional medical school and postgraduate education programs are recommended as methods to improve utilization of these strategies.

Blood Glucose Self-Monitoring↗
PubMed1992

Standards for the care of diabetes. Origins, uses and implications for third-party payment.

Standards of care are those principles that define the appropriate environment, process, and procedures necessary for quality medical care and optimal health outcomes. The initial impetus to develop standards of care came from the medical profession when it attempted to define quality of care. More recently, standards defining the medical necessity of diagnostic tests or procedures have been developed at the request of public and private third-party payors. These efforts are the natural outgrowth of two decades of health-care delivery research and technology assessment examining the effectiveness of various medical procedures. This article reviews the development of standards by the medical profession, emphasizing current standard-setting activities of private organizations and the federal government. This study examines the characteristics of a good process for developing credible medical standards to guide patient care and the payment for that care. This study also discusses how the American Diabetes Association used this process in developing standards for care of patients with diabetes mellitus and implementation problems encountered because of coverage policy of public and private health insurer programs.

Diabetes Mellitus↗
PubMed1992

Ventricular size, cognitive function and depression in patients with multiple sclerosis.

The purpose of this study was to explore further the hypothesis that changes in cognitive function may occur in the mild stages of multiple sclerosis (MS) by determining whether ventricular enlargement was related to cognitive function. Ten measures of ventricular size were made in a sample of 123 MS patients with mild disability and 60 well-matched healthy controls. In addition, sixteen tests of cognitive function and the Beck Depression Inventory were administered. For the MS group, there were significant correlations between the ventricular measures and cognitive performance but not for the normal controls. Scores on the Beck Depression Inventory were not correlated with either cognitive performance or ventricular enlargement. These findings suggest that for the MS group cognitive impairment was related to the disease process but not to the level of depression.

Adult↗
PubMed1992

A method for comparing different procedures of estimating regional glucose metabolism using fluorine-18-fluorodeoxyglucose.

The purpose of this paper is to describe a method for determining whether a particular procedure for estimating regional metabolism using the deoxyglucose tracer analogue yields better data than another in terms of subsequent statistical analysis. The method is based on a simple model of regional cerebral glucose metabolism with three potential sources of metabolic variability, namely individual differences in cerebral metabolic rate, consistent regional differences and error. When the literature rate constants were compared to a dynamic procedure for estimating regional rate constants in patients with Huntington's Disease, the literature values were clearly superior in that the error component was approximately half (18.5 versus 39.3%). Although these results cannot be generalized to all procedures for estimating regional glucose metabolism, the method can be applied to determine if a particular procedure will be more sensitive than another to differences between groups.

Brain↗
PubMed1992

Deviant adolescent subcultures: assessment strategies and clinical interventions.

Alienation is a contributing factor in adolescents' participation in Satanism, the neo-Nazi skinhead movement, and violent street gangs. Many of their needs are met by gang and/or cult affiliation, including a sense of belonging, self-worth, companionship, and excitement. Emphasizing prevention may minimize deviant subculture involvement, but some adolescents require clinical intervention, ranging from a few outpatient sessions to lengthy inpatient hospitalization. Therapists must be knowledgeable about adolescents' involvement, empathic to their circumstances, and sophisticated in the approach to treatment.

Adaptation, Psychological↗
PubMed1991

Glucocorticoid-mediated muscle atrophy: alterations in transcriptional activity of skeletal muscle nuclei.

Glucocorticoid-induced muscle atrophy is associated with a decrease in the level of protein synthesis and a loss of RNA. This paper reports the behaviour of RNA polymerase I- and RNA polymerase II-directed transcription (EC 2.7.7.6) in nuclei isolated from skeletal muscles of rats given a catabolic dose of dexamethasone acetate (5 mg per Kg body weight) over a period of 4 days. Both activities were altered by the dexamethasone treatment. In the case of RNA polymerase I-mediated transcription there was a loss of template-engaged enzymes indicating the existence of an inhibition of initiation of transcription while the rate of elongation of bound enzymes was unaltered. The number of RNA polymerase II-chromatin bound enzymes was increased, but the mean polynucleotide elongation rate was reduced. The possibility that glucocorticoids may impair the elongation stage of transcription in skeletal muscle by increasing the frequency of premature termination of transcripts is discussed. No evidence was obtained for any increase in ribonuclease activity in muscle nuclei of dexamethasone-treated animals.

Animals↗
PubMed1991

Empirical support for psychological profiles observed in multiple sclerosis.

Though increasing attention is being paid to psychological aspects of multiple sclerosis, much research continues to examine patients as differing in quantity rather than quality of psychological abnormality or response. Cluster analysis was used to identify distinctive psychological profiles in a large sample of patients with multiple sclerosis. It employed three measures, carefully chosen to capture the main responses historically observed in multiple sclerosis. These measures were (1) the patient's physical disability-impairment, assessed by a neurologist; (2) physical disability-impairment as perceived and reported by the patient; and (3) self-reported psychological well-being (or distress) independent of physical signs and symptoms. The optimal solution from the cluster analysis separated the 99 patients into 10 clusters, which were collapsed into four profiles, consistent with the labels "depression," "denial," "exaggerated somatic," and "severity-related." These data give strong empirical support to the existence of discrete and distinctive coping styles in multiple sclerosis.

Adult↗
PubMed1991

The treatment of patients with insulin-requiring diabetes mellitus by primary care physicians.

The extent to which a sample of community based, primary care physicians follow current standards of care for the treatment of non-obese, insulin-requiring patients as defined and recently published by the American Diabetes Association (ADA) was studied. A total of 212 physicians responded with 191 indicating that they treat one or more non-obese, insulin-requiring patients. Of this sample, 97% used multiple injection, mixed insulin regimens. However, over 70% also used single injection regimens. Whereas 94% prescribed self-monitoring blood glucose (SMBG), only 31% did so for more than 75% of their patients and 37% did so for less than 50%. Twenty-five percent of respondents did not obtain HbA1 values on their patients. For respondents who do collect HbA1, only 28% did so for over 75% of their patients and 30% for less than 50%. Physicians with fewer patients were more likely to prescribe single injection insulin regimens (P = .02). Recent graduates from medical school also used HbA1's more frequently than earlier graduates (p = .001). These data suggest that while care practices recommended by the ADA are being implemented by primary care physicians, they are significantly underutilized.

Adult↗
PubMed1991

The FDG/PET methodology for early detection of disease onset: a statistical model.

The development of appropriate statistical methodologies for neuroimaging studies is dependent upon the research question of interest. Often studies are analyzed with techniques that may not be appropriate for the research question but are accepted owing to convention, familiarity, or apparent statistical sophistication. Neuroimaging data are particularly complex owing to (a) the high number of potential dependent variables (i.e., regions of interest) coupled with the practical limitations on sample size; (b) the known physical properties of scanners (e.g., resolution) interacting with the intricate and variable structure of the human brain; and (c) mathematical properties introduced into the data by the physiological model for quantification. In this article, a statistical model will be discussed for addressing a particular problem in clinical studies. Given that there is a characteristic abnormality in regional glucose metabolism in a specific disease, can a probabilistic statement be made with confidence regarding the likelihood of an individual scan being similar to those from the disease group or normal subjects? The model capitalizes on known statistical aspects of normal regional glucose metabolism. To illustrate the model, data will be presented on normal subjects, patients with confirmed Huntington's disease, and subjects at risk for the disease. Reliability and clinical validity of the model will be discussed.

Adult↗
PubMed1991

Ratings of personality change in patients being evaluated for memory disorders.

Caregivers of 35 mildly to moderately memory-impaired patients rated current and premorbid personalities with the NEO Personality Inventory. We then examined changes in the five domains of personality tapped by the NEO. There were significant changes in four of the five domains of normal personality functioning toward less conscientiousness, lower extraversion, higher neuroticism, and lower openness. The difference toward lower agreeableness was not significant when controlling for multiple comparisons. Spearman rank correlation coefficients indicated that changes in conscientiousness and vulnerability were not related to rated premorbid personality patterns and thus appear to describe shifts for all patients evaluated for memory disorders. These data suggest that personality inventories may be helpful in characterizing caregivers' observations of memory-impaired patients and thus represent a critical source of information for the clinician in charge of care.

Adult↗