Generalized estimating equations (GEE) methodology as proposed by Liang and Zeger has received widespread use in the analysis of correlated binary data. Miller et al, and Lipsitz er al. extended GEE to correlated nomi...
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Generalized estimating equations (GEE) methodology as proposed by Liang and Zeger has received widespread use in the analysis of correlated binary data. Miller et al, and Lipsitz er al. extended GEE to correlated nominal and ordinal categorical data;in particular, they used GEE for fitting McCullagh's proportional odds model. In this paper, we consider robust (that is, empirically corrected) and model-based versions of both a score test and a Wald test for assessing the assumption of proportional odds in the proportional odds model fitted with GEE. The Wald test is based on fitting separate multiple logistic regression models for each dichotomization of the response variable, whereas the score test requires fitting just the proportional odds model. We evaluate the proposed tests in small to moderate samples by simulating data from a series of simple models. We illustrate the use of the tests on three data sets from medical studies. (C) 1999 John Wiley & Sons, Ltd.
Triazolam, 0.5 mg, a benzodiazepine with hypnotic properties, was compared to secobarbital, 100 mg, and placebo in a 1‐wk study conducted with 100 insomniac family practice patients. Considerable sensitivity to diffe...
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Triazolam, 0.5 mg, a benzodiazepine with hypnotic properties, was compared to secobarbital, 100 mg, and placebo in a 1‐wk study conducted with 100 insomniac family practice patients. Considerable sensitivity to differential treatment effects was demonstrated for these family practice patients as well as for a research methodology that combines a crossover design, permitting preference ratings, with a between‐patient design. in almost all sleep parameters, assessed with a variety of subjective techniques, triazolam and secobarbital were shown to be significantly more effective than placebo. Triazolam was consistently and often significantly indicated to be a more effective hypnotic, particularly for reducing nocturnal awakening, than secobarbital. Analysis of self‐report emotional distress data revealed that present insomniac patients were slightly more emotionally symptomatic than other nonpsychiatric populations. Triazolam was followed by the greatest and secobarbital the least relief of emotional symptoms and triazolam emerged as an especially effective hypnotic for initially more depressed insomniac patients. Present findings suggest that type and degree of emotional symptomatology may affect the response of insomniac patients to hypnotics.
This study evaluated the impact of insomnia and chronic use of benzodiazepines on the cognitive and psychomotor performance of older adults. Three conditions, matched on age, gender, and education, were compared: 20 p...
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This study evaluated the impact of insomnia and chronic use of benzodiazepines on the cognitive and psychomotor performance of older adults. Three conditions, matched on age, gender, and education, were compared: 20 prolonged users of benzodiazepines for insomnia, 20 unmedicated insomniacs, and 20 good sleepers. The participants completed neuropsychological tests of memory, attention/concentration, psychomotor speed, and executive functions, as well as subjective evaluations of their actual performance. Individuals with insomnia, both medicated and unmedicated, performed worse than good sleepers on the attention/concentration factor. There was no other objective evidence of performance impairments. However, unmedicated insomniacs had lower performance expectancies and subjectively rated their performance more negatively relative to medicated insomniacs and good sleepers. Both insomnia conditions also rated their performance as lower compared with their perceived potential. It is suggested that the attention/concentration difficulties experienced by medicated and unmedicated older adults with insomnia may be linked to a state of hyperarousal. The discrepancies between subjective reports of daytime deficits and objective impairments may reflect a generalized faulty appraisal of sleep and daytime functioning among individuals with insomnia complaints. The implications of those findings for the assessment and treatment of late-life insomnia are discussed.
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