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Biomedical subjects

W R Cunningham

Publications and source records attributed to W R Cunningham.

13 recordsLinked to original sources
PubMed1992

A longitudinal analysis of adherence and health status in childhood diabetes.

Applied structural equation modeling to a longitudinal data set of 193 youngsters with insulin-dependent diabetes mellitus assessed on two occasions, an average of 1.65 years apart. Six adherence constructs, Injection, Exercise, Diet Type, Testing-Eating Frequency, Calories Consumed, and Concentrated Sweets, were quantified from 24-hr recall interviews conducted with mother and child. Glycemic control was indexed by glycosylated hemoglobin (HA1C); lipid metabolism was indexed by fasting triglyceride levels (TRIG). The relationship of each adherence construct to metabolic control was tested separately. Patient age and disease duration served as exogenous variables in all models. Testing-Eating Frequency was associated with HA1C and Injection was associated with TRIG; in both cases better adherence was associated with better metabolic control. However, the standardized regression weights and variance accounted for were small. Patient age was a predictor of both adherence and metabolic control; older youngsters were less adherent and were in worse metabolic control. Inspection of models for younger versus older children suggested that age-homogeneous models improved prediction, but adherence and metabolic control linkages remained weak. Suggestions for refining the model are provided.

Blood Glucose↗
PubMed1990

Adherence in childhood diabetes: results of a confirmatory factor analysis.

In an earlier study (Johnson, Silverstein, Rosenbloom, Carter, & Cunningham, 1986), an exploratory factor analysis identified five components of adherence in childhood diabetes. In this investigation, a simultaneous confirmatory analysis was used to test the equality of this factor pattern across two independent samples. Factors 1 through 4--Exercise, Injection, Diet Type, and Eating/Testing Frequency-were confirmed. Factor 5--Diet Amount--proved to be too complex; the adherence measures comprising this factor (total calories and concentrated sweets consumed) are best treated as separate, single-indicator constructs. The results support a multivariate conceptualization of adherence, offer insight into the nature of the components underlying diabetes adherence, and provide measurement information for reliable component estimation.

Adolescent↗
PubMed1988

Is terminal drop pervasive or specific?

The terminal drop hypothesis states that death is preceded by a decrease in cognitive functioning over an approximately five-year period prior to death (Riegel & Riegel, 1972); there is some disagreement as to whether this decrease is pervasive or restricted to specific abilities. The present study assessed the relationship between distance from death and tests of vocabulary, numerical facility, and perceptual speed for 97 subjects who had died within seven years of testing. Only vocabulary scores for those who died at age 70 or less and within two years of testing were affected by terminal drop. An additional analysis comparing the performance of the deceased subjects with a still-living sample matched for age, gender, and education produced nonsignificant results but a trend consistent with the initial analyses. Thus the terminal drop phenomenon may be limited to abilities that typically are relatively unaffected by age, such as vocabulary or other verbal abilities. Furthermore, the effects may be restricted to a time period much closer to death than had been originally proposed.

Aged↗
PubMed1979

Cognitive speed and subsequent intellectual development: a longitudinal investigation.

The hypothesis that a measure of intellectual speed assessed at one point in time would predict intellectual achievement at a later point in time was evaluated with a time-lagged cross-correlational analysis, an application of causal modeling techniques. Longitudinal data for 32 males and females, tested in 1944 (mean age 19.5 years) and in 1972 (mean age 46.7 years), supported the hypothesized relationships with an associated p less than .01. The Relations Factor of the Army Alpha Examination--consisting of scores from a highly speeded simple analogies test and a short-term memory test--administered at age 20 was highly predictive of both verbal and numerical ability in middle age. The results highlight the cognitive intellectual aspect of the speed of behavior. In addition, these findings supplement Hunt's studies of the relationships between speed of cognitive processing and psychometric abilities in young adults, and emphasize the importance of cognitive speed for subsequent intellectual development. Implications for the intellectual speed hypothesis of Birren and the utilization of time-lag designs in longitudinal research are discussed.

Adult↗
PubMed1978

Influence of contextual variables on blood pressure in the elderly.

This research evaluated determinants of blood pressure in elderly subjects. Measurements were obtained from 30 subjects in three contexts; in the home measured by the subject, in the home measured by the experimenter, and in a psychophysiological laboratory measured by the experimenter. Four measurements were obtained in the two home conditions and two were obtained in the laboratory condition. For systolic blood pressure, the effects of condition, repeated measurement, and order of treatment presentation were significant. For diastolic blood pressure, the effect of condition was significant. A comparison of sample variances revealed greater variances for systolic blood pressure. It was concluded that initial blood pressure measurements obtained in a laboratory should be regarded as distinct from those obtained later, as the early measurements may be subject to elevation imposed by the context. Due to differing patterns of results for systolic and diastolic pressures as well as differences in variability, it was concluded that there exist conceptual problems with a construct such as mean arterial pressure.

Aged↗
PubMed1978

Principles for identifying structural differences. Some methodological issues related to comparative factor analysis.

Several recent articles published in the Journal of Gerontology have been concerned with changes in factor structure of various psychological, social, and medical fitness measures. The present article reviews four principles for comparing structures and evaluates several recent articles in terms of these principles. The four principles are concerned with resolving: (1) problems of metric, (2) problems of rotation to similarity, (3) the number of factors problem, and (4) problems related to different extraction or rotational procedures across comparison groups. Utilization of a different metric in each correlation matrix implies that results may be a simple artifact of a different metric for each group. Failure to rotate to similarity and insufficient care with regard to the number of factors problem may result in artificially dissimilar structures. Finally, in comparing results across studies, differences in extraction or rotational procedures across different studies may result in differing results as artifacts of the methods employed.

Factor Analysis, Statistical↗
PubMed1978

Fatigue effects on intelligence test performance in the elderly.

The purpose of the study was to investigate effects of fatigue on intelligence test performance in the elderly. Dependent variables were Verbal Comprehension, Numerical Facility, Perceptual Speed, and Word Fluency tests. Fatigue effects were investigated by varying the number of previous tests administered, by introducing breaks between tests in some conditions, and by using a pre-test fatigue-producing condition, a modified form of the Finding A's test. Subjects' ages were between 57 to 91-years. It was hypothesized that the Finding A's test would be more fatiguing than a long battery of tests and that introducing a break condition between the Finding A's test and the main battery would alleviate fatigue effects. Analyses of Variance resulted in a main effect due to a pre-test condition for the Perceptual Speed test only, and only when the main battery was preceded by the Finding A's task (p less than .001). It appears that the elderly are not as susceptible to test fatigue as previous results seemed to suggest.

Age Factors↗
PubMed1975

Fluid and crystallized intelligence in young adulthood and old age.

The theory of fluid and crystallized intelligence predicts that the relationship between these two abilities will decline systematically across the age span after young adulthood. In order to test this hypothesis in an elderly sample, the Raven Progressive Martices and the WAIS vocabulary subtest were administered to a sample of individuals (N=40), ranging in age from 60 to 79, and also, for purposes of comparison, to a sample of young adults (N=35). It was found that the correlation was significantly lower in the elderly sample (.386) than in the young adult sample (.672).

Adult↗
PubMedDate not supplied

What is the evidence for retrieval problems in the elderly?

To determine whether older adults experience particular problems with retrieval, groups of young and elderly adults were given free recall and recognition tests of supraspan lists of unrelated words. Analysis of number of words correctly recalled and recognized yielded a significant age by retention test interaction: greater age differences were observed for recall than for recognition. In a second analysis of words recalled and recognized, corrected for guessing, the interaction disappeared. It was concluded that previous interpretations that age by retention test interactions are indicative of retrieval problems of the elderly may have been confounded by methodological problems. Furthermore, it was suggested that researchers in aging and memory need to be explicit in identifying their underlying models of error processes when analyzing recognition scores: different error models may lead to different results and interpretations.

Adult↗
PubMedDate not supplied

Age-related slowing on the Digit Symbol task: longitudinal and cross-sectional analyses.

It is generally known that slowing on tasks like the Digit Symbol Substitution task occurs with age. However, simultaneous cross-sectional and longitudinal data are rare. The results from the cross-sectional analysis of Digit Symbol performance with age are compared to results from two occasion longitudinal analyses on the same task. The longitudinal data were obtained from 79 participants who were retested after 7 years and were between the ages of 48 and 73 years old at Time 1. Results indicated that the pattern of actual change observed in the longitudinal analyses replicated the simulated change indicated in the cross-sectional analysis. Antecedents were examined using the original cross-sectional sample of 150 participants. Significant relationships with Digit Symbol performance were found for age, education, and gender, but not for ratings of physical health.

Aged↗