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D V Dawson

Publications and source records attributed to D V Dawson.

77 records · Page 5Linked to original sources
PubMedDate not supplied

Approaches to the nonparametric analysis of limited longitudinal data sets.

The traditional goals of longitudinal studies are many: consideration of stability and change; description of patterns of development and behavior; and understanding of the processes involved in disease, including disease onset, recovery, response to treatment, natural history of the aging process, and identification of factors that predict age-related outcomes. Researchers in aging seek to unravel the impact and interaction of physical and psychological processes on human development, health, and disease. From the point of view of statistical analysis, the critical aspect of data obtained from longitudinal studies is the inherent correlational structure of multiple measurements made on a single subject or other experimental unit, which must be appropriately treated in the analysis of the data. We discuss a series of nonparametric approaches that are both analytically accessible and particularly well suited to the analysis of sparse or otherwise limited longitudinal data.

Humans↗
PubMedDate not supplied

Premorbid personality predicts level of rated personality change in patients with Alzheimer disease.

Multiple studies of individuals with Alzheimer disease have substantiated significant levels of informant-rated change in several domains and facets of the Neuroticism-Extraversion-Openness Personality Inventory, including increases in Neuroticism and decreases in Extraversion and Conscientiousness relative to premorbid personality traits. Decline in Openness was cited in some reports, and replicable changes were identified in several facets. Current and premorbid personality of 50 patients with Alzheimer disease were rated by informants using the Neuroticism-Extraversion-Openness Personality Inventory. Multiple regression analysis was used to assess possible relationships of levels of reported change with covariates, including premorbid rating, education, duration of dementia, age, gender, and Mini-Mental State Examination score. Premorbid rating was the only significant predictor of reported change for Neuroticism, Extraversion, Conscientiousness, and the facets Anxiety (N1), Assertiveness (E3), and Activity (E4). Rated change in Depression was also found to be related to duration of dementia, change in Vulnerability was influenced by gender, and reported change in both Openness and Ideas showed a relationship to level of education.

Aged↗
PubMedDate not supplied

Temporal lobectomy and independent bitemporal interictal activity: what degree of lateralization is sufficient?

We attempted to determine whether the degree of lateralization of independent bitemporal interictal spikes and sharp waves (ISSW) is correlated with good results after temporal lobectomy. Three observers independently counted ISSW in the scalp EEGs of 59 candidates for temporal lobectomy to determine the degree of lateralization of ISSW. Interobserver correlation in percentage of lateralization was excellent (r = 0.92). Thirty-one candidates were also evaluated with depth EEG (DEEG). Operative success was graded by the number of seizures reported in the second postoperative year. There was a significant progressive decrease in the number of good operative results as the degree of lateralization of ISSW lessened (p = 0.0142). Ninety-two percent of patients with greater than 90% lateralization had a good surgical outcome, whereas only 50% with less than 90% lateralization had a good outcome. Even when all DEEG-recorded seizures emerged from the side of the lobectomy, patients with greater than 90% lateralization appeared to have better outcomes than patients with less than 90% lateralization. We conclude that greater than 90% lateralization of temporal ISSW is associated with good surgical outcome, and DEEG may not be necessary in these patients. Less than 90% lateralization is associated with poor surgical outcome and the additional information provided by DEEG may be especially useful in such patients.

Adolescent↗
PubMedDate not supplied

Analysis of HLA haplotype segregation in the Schmiedeleut Hutterites of South Dakota.

HLA data from 1,085 South Dakotan Schmiedeleut Hutterites were examined for evidence of nonrandom transmission of haplotypes. The inheritance of haplotypes was viewed as a series of genetic contests between competing pairs of parental haplotypes using a maximum likelihood approach first put forward by Carlisle and Woodbury. Haplotype transmission probabilities were expressed in terms of weights, and the null hypothesis that the inheritance pattern was a random stochastic process, equivalent to the equality of the weights, was tested via the likelihood ratio. A total of 1,517 competitions was subjected to analysis, first globally using all data, and then for particular haplotypes of interest. Transmission of haplotype observed to compete with only a single other haplotype was also assessed using an exact procedure. No evidence of preferential transmission of HLA haplotypes was found. These results do not rule out transmission biases that may arise because of selection against homozygotes, mechanisms specifically affecting particular alleles or haplotypes not considered in the present study, or biases arising from maternal-fetal interactions.

Consanguinity↗