Biomedical subjects

M A Machen

Publications and source records attributed to M A Machen.

4 recordsLinked to original sources

PubMed1994

A longitudinal study of laboratory- and diary-based sleep measures in healthy "old old" and "young old" volunteers.

The major aim of this study was to examine laboratory- and diary-based measures of sleep in a group of healthy ("successfully aging") "old old" subjects (> or = 75 years of age), as contrasted with a group of "young old" subjects (60-74 years of age), who were followed longitudinally for 2 years. We hypothesized that sleep would deteriorate to a greater extent over time among the old old subjects than among the young old. The study group consisted of 50 elders (21 male, 29 female; 23 old old, 27 young old), each studied at baseline and then again at 1- and 2-year follow-up. Analysis of variance was used to determine main effects of age group, gender and time on key sleep measures. Most measures were found to be remarkably stable over time. However, some decay was detected in sleep efficiency among the old old, but not among the young old. In a multiple regression model for the cohort as a whole, age, cognitive status and medical burden at baseline predicted subsequent declines in sleep efficiency over the 2-year period. To our knowledge, this is the first longitudinal data set on sleep in the healthy old old.

Aged↗

PubMed1994

The Pittsburgh Sleep Diary.

Increasingly, there is a need in both research and clinical practice to document and quantify sleep and waking behaviors in a comprehensive manner. The Pittsburgh Sleep Diary (PghSD) is an instrument with separate components to be completed at bedtime and waketime. Bedtime components relate to the events of the day preceding the sleep, waketime components to the sleep period just completed. Two-week PghSD data is presented from 234 different subjects, comprising 96 healthy young middle-aged controls, 37 older men, 44 older women, 29 young adult controls and 28 sleep disorders patients in order to demonstrate the usefulness, validity and reliability of various measures from the instrument. Comparisons are made with polysomnographic and actigraphic sleep measures, as well as personality and circadian type questionnaires. The instrument was shown to have sensitivity in detecting differences due to weekends, age, gender, personality and circadian type, and validity in agreeing with actigraphic estimates of sleep timing and quality. Over a 12-31 month delay, PghSD measures of both sleep timing and sleep quality showed correlations between 0.56 and 0.81 (n = 39, P < 0.001).

Activities of Daily Living↗

PubMed1992

Daily social rhythms in the elderly and their relation to objectively recorded sleep.

This study tested the hypothesis that the impaired sleep of healthy 71-91 year olds might be due to circadian dysfunction stemming from irregularity of life-style. Twenty-five old women, 20 old men and 21 young controls (19-28 years old) were studied in relation to 1) objective sleep as measured in the laboratory, 2) subjective sleep quality as measured by the Pittsburgh sleep quality index (PSQI) and 3) the social rhythm metric (SRM), an instrument to quantify the daily rhythms of life. Contrary to prediction, the SRM scales revealed that the older group had just as many activities completed and just as much other-person involvement as the young. Moreover, they showed a significantly greater regularity in daily life-style than the young, despite showing reliably impaired subjective and objective sleep. This suggests either that these seniors have always been regular in their life-style and that this has been protective of their health and vigor, or that their regularity has been developed as an adaptive response to age-related changes in the circadian system.

Aged↗

PubMedDate not supplied

Daytime sleepiness and performance among healthy 80 and 20 year olds.

This study investigated the relationship of daytime sleepiness and performance on a vigilance test in a sample of 10 healthy men and 13 women in their 80s (mean age 83.0 +/- 3.1 years) and 18 men and 12 women in their 20s (25.0 +/- 3.1). We hypothesized that "successfully" aged healthy individuals would have more daytime sleepiness with differentially greater decrements in performance than a younger comparison group. Daytime sleepiness was measured physiologically by the Multiple Sleep Latency Test (MSLT) and through self-report by the Stanford Sleepiness Scale (SSS). Morning and evening performance was measured with the Mackworth Clock Test of vigilance. The major findings were the absence of correlation between either MSLT or SSS daytime sleepiness with performance measures, no difference in daytime sleepiness between the old and young groups and performance decrements among the healthy elderly on all parameters. Results suggest that the modest decrements in performance among the elderly cannot be attributed to daytime sleepiness.

Adult↗