Biomedical subjects

T H Monk

Publications and source records attributed to T H Monk.

At least 19 recordsLinked to original sources

PubMed1992

Electroencephalographic sleep studies in depressed outpatients treated with interpersonal psychotherapy: I. Baseline studies in responders and nonresponders.

Electroencephalographic (EEG) sleep measures have been examined as predictors of therapeutic response in patients with major depression. Although some studies have reported that EEG sleep measures are predictive of a favorable outcome with medications, two recent studies found no differences in the baseline sleep characteristics of responders and nonresponders to psychotherapy. To clarify this issue, we compared baseline EEG sleep in a group of patients with recurrent depression who responded to interpersonal psychotherapy (n = 19) and a comparable group who did not respond (n = 18). Baseline ratings of depression severity did not differ in the groups, but some differences in baseline sleep were noted. Psychotherapy nonresponders had longer sleep latencies, lower sleep efficiency, and increased automated measures of phasic rapid eye movement (REM) activity. In addition, the two groups had different EEG sleep adaptation patterns for REM latency and phasic REM density measures across the two study nights. These preliminary results suggest that baseline EEG sleep patterns, as well as the pattern of laboratory adaptation, may differ for depressed patients who respond to psychotherapy and those who do not.

Adolescent↗

PubMed1992

Electroencephalographic sleep studies in depressed outpatients treated with interpersonal psychotherapy: II. Longitudinal studies at baseline and recovery.

Electroencephalographic (EEG) sleep studies may help to identify persistent versus episodic biological characteristics of major depressive disorder. This report examines longitudinal EEG sleep studies in depressed patients treated with psychotherapy alone. Nineteen patients were studied during a symptomatic baseline period and again during early remission after treatment with interpersonal psychotherapy (IPT). EEG sleep findings at baseline were not markedly abnormal, but they were similar to those in other published studies of young adult outpatients. No changes were found in visually scored EEG sleep measures between depression and early remission. Automated measures of delta sleep and rapid eye movement (REM) activity showed small state-related changes, with delta activity increasing from baseline to remission, and automated REM measures decreasing. Strong baseline-remission correlations were noted for most sleep measures, including slow wave sleep, phasic REM activity, and automated delta EEG counts; measures of sleep continuity and tonic REM sleep were not strongly correlated. Consistent adaptation effects across nights were observed for sleep continuity and REM measures during each clinical phase. These findings support the hypothesis that most visually scored EEG sleep measures, as well as the sleep adaptation process, are stable through the acute episode of depression, at least into early symptomatic remission. They also suggest that finer-grained automated analyses of delta and REM activity may provide more sensitive tools for examining state-related changes.

Adolescent↗

PubMed1992

Rhythmic vs homeostatic influences on mood, activation, and performance in young and old men.

Nine healthy old (80+ years) men were compared with nine healthy young (20-30 years) men in a protocol that required 36 hours of continuous wakeful bedrest. Body temperature rhythm measurement confirmed that the old had as robust an endogenous circadian (approximately 24 hours) rhythm generation mechanism as the young. However, in measures of affect, activation, visual search speed, verbal reasoning speed, manual dexterity, and vigilance hit rate, the old showed a linear decline over the 36 hours of the vigil, with little of the superimposed 24-hour rhythmicity that was apparent in the young. Thus, separate from the endogenous rhythm generation processes, there appeared to be some attenuation with advanced age, which led to the relative absence of rhythmic expression in these mood and performance variables. Such attenuation might contribute to some of the sleep and performance problems reported by elderly adults.

Adult↗

PubMed1992

Age-related differences in recovery from simulated jet lag.

Six healthy young men and eight early middle-aged men were isolated from environmental time cues for 15 days. For the first 6-7 days (one or two nights adaptation, four nights baseline), their sleep and meals were scheduled to approximate their habitual patterns. Their daily routines were then shifted 6 hours earlier by terminating the sixth or seventh sleep episode 6 hours early. The new schedules were followed for the next 8 or 9 days. Important age-related differences in adjustment to this single 6-hour schedule shift were found. For the first 4-day interval after the shift, middle-aged subjects had larger increases of waking time during the sleep period and earlier termination of sleep than young subjects. They also reported larger decreases in alertness and well-being and larger increases in sleepiness, weariness and effort required to perform daily functions. The rate of adjustment of the circadian core temperature rhythm to the new schedule did not differ between groups. These results suggest that the symptoms reported by the middle-aged subjects may be due mainly to difficulty maintaining sleep at early times of the circadian day. The compensatory response to sleep deprivation may also be less robust in middle-aged individuals traveling eastbound.

Adolescent↗

PubMed1992

Cognitive and motor performance of narcoleptic and normal subjects living in temporal isolation.

Six unmedicated narcoleptic subjects and nine normal controls lived in a temporal isolation laboratory for 18-22 days. They were permitted to "free-run" for the last 9-13 days. Brief cognitive and motor performance tests were repeated on average six times per subjective day. They consisted of serial search, complex verbal reasoning tasks and manual dexterity of each hand. Only minor differences in performance were found between the narcoleptic subjects and controls. Narcoleptic subjects showed mild impairment of accuracy on the search task that could be explained by occasional lapses and an afternoon dip in performance. Narcoleptic subjects also tended to perform some tasks more slowly, but the group differences were not significant. Neither speed nor accuracy of performance of narcoleptic subjects decreased over the course of the experiment. By one standard of performance, therefore, all or nearly all of the sleep need of these subjects was met by the sleep they obtained in the laboratory. That amount, in turn, did not exceed the total sleep obtained by the normal controls. Significant time-of-day effects were found in narcoleptic subjects for speed of verbal reasoning (progressive slowing over the course of the day), manual dexterity (fluctuations in speeds) and accuracy of serial search (afternoon dip). These variations in performance could not be attributed to changes in core body temperature or to occurrences of naps or meals.

Adult↗

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↗

PubMed1992

Concordance between habitual sleep times and laboratory recording schedules.

The validity of laboratory-based studies of sleep depends, in part, upon good concordance between habitual sleep schedule and laboratory recording schedule. Without good concordance, error variance due to the circadian misplacement of sleep and to different amounts of time in bed is probable. In an assessment of scheduling concordance in 1,762 research patient nights over two time intervals, we observed good concordance (< 30-minute discrepancy) in 71.2-77.3% of bedtimes and waketimes, discrepancy (difference of > or = 30 minutes) in 14.9-24.2% of bedtimes and waketimes, and missing data in 4.6-7.5% of times. Waketime differences were consistently in the direction of earlier laboratory than habitual waketimes, whereas differences in bedtime were about equally divided between earlier and later (laboratory vs. habitual). Subjects with schedule discordance averaged 19.5 minutes less time in bed during laboratory sessions as compared with their habitual sleep schedule, whereas subjects with schedule concordance averaged only 3.6 minutes less (p < 0.001). Our experience suggests that it may be more difficult to achieve higher rates of concordance among young adult and middle-aged subjects than among elders and that patient requests related to external constraints on scheduling were a frequent reason for discrepancy. We strongly recommend a policy of routinely including data on laboratory versus habitual sleep times in peer-reviewed publications.

Adult↗

PubMed1992

Napping and 24-hour sleep/wake patterns in healthy elderly and young adults.

OBJECTIVE: To examine differences between healthy elderly and young adults in daytime napping, nocturnal sleep, and 24-hour sleep/wake patterns. A second objective was to determine whether elderly subjects with more and less frequent naps differed in their clinical features or nocturnal sleep. DESIGN: Survey by sleep/wake logs and polysomnography. Comparison by age. SETTING: Sleep/wake logs were completed in the subjects' homes. Polysomnographic studies were conducted on an outpatient basis in a sleep and chronobiology research laboratory. SUBJECTS: Convenience samples of forty-five healthy subjects over 78 years of age (21M, 24F) and 33 healthy adults between 20 and 30 years of age (20M, 13F). MAIN OUTCOME MEASURES: Using self-reports, we estimated the frequency and timing of daytime naps; timing, duration, and quality of nocturnal sleep; and 24-hour patterns of sleep and wakefulness. Also polysomnographic sleep measures. RESULTS: Compared to young adults, elderly subjects reported a greater mean number of daytime naps (P = .004), shorter nocturnal sleep with more wakefulness and earlier sleep hours (P less than .003 for each), and a trend for a shorter 24-hour sleep fraction. Among the elderly, more-frequent and less-frequent nappers did not differ in clinical ratings, self-report sleep measures, or polysomnographic measures. There was a trend for more sleep-disordered breathing and periodic limb movements in more frequent nappers. CONCLUSIONS: These findings are consistent with an age-related decrease in amplitude of the circadian sleep propensity rhythm, or with the expression of a semi-circadian (12-hour) sleepiness rhythm. However, we cannot exclude the additional possibility that napping results from lifestyle factors and nocturnal sleep pathologies in a subset of the elderly.

Adult↗

PubMed1991

The Social Rhythm Metric (SRM): measuring daily social rhythms over 12 weeks.

A "Social Rhythm Metric" (SRM) of daily rhythmic behavior (developed previously) was given to 20 treated depressives (in remission) and 15 day-working control subjects for a continuous 12-week period. Long-term use of the SRM appeared feasible with no evidence of a deterioration in scores over the 12 weeks. Comparisons were made between intersubject and intrasubject variability, as well as a study of overall trends in SRM during the 12 weeks. Two further measures from the instrument--the Activity Level Index (ALI) and Other Person Involvement--were developed and shown to be useful adjuncts to the SRM. Although no simple differences in absolute SRM score emerged between patients and controls, there were significant differences in intersubject vs. intrasubject variability between the two groups. The patients showed more intrasubject variability and required more weeks of sampling to achieve a stable "trait" measure. Patients' social rhythms also appeared to be more "other person" prompted than those of controls.

Adult↗

PubMed1991

Sleep and circadian rhythms.

The human biological clock or "circadian system" serves the function of preparing the body and mind for restful sleep at some times of day and active wakefulness at others. The observed circadian rhythms result from three interacting processes: endogenous rhythm generation mechanisms, entrainment mechanisms to keep these rhythms "on track," and exogenous masking processes stemming from changes in environment and behavior. In both advanced age and extraterrestrial travel these processes, particularly the latter two, can be dramatically effected with a consequent disruption in sleep and daytime functioning. We are currently studying the age-related effects on these processes in healthy 80 year olds using two different protocols. The first involved 36 h of constant wakeful bedrest which "unmasked" the endogenous component of circadian rhythms in various physiological and psychological functions. This experiment revealed little difference between nine old men and four young men in the endogenous body temperature rhythm, but revealed quite marked differences between the age groups in subjective activation and objective performance rhythms. A similar pattern occurred in the second experiment, which was a phase shift study comparing five old women with eight middle-aged men in their response to an acute 6 h phase advance in routine. Despite rather short-lived age-related differences in circadian rhythms, there were dramatic differences between the age groups in measures of sleep, mood, activation, and performance efficiency lasting for a week or more after the phase shift.

Adult↗

PubMed1991

Electroencephalographic sleep in the healthy "old old": a comparison with the "young old" in visually scored and automated measures.

This report extends the normative study of sleep into healthy 80-year-olds and compares them with healthy 70- and 60-year-olds. We observed stability of sleep efficiency and rapid eye movement sleep across three decades of late life, but a slight decline of slow-wave sleep in the 80-year-olds (decreased total delta wave counts). Women showed better preservation of slow-wave sleep than men. Automated EEG period analysis of this phenomenon demonstrated higher rates of delta wave production in the first NREM sleep period of women compared to that of men, a finding associated with longer REM sleep latencies in women. Unexpectedly, 80-year-old women showed decay in sleep maintenance, while 80-year-old men demonstrated stability of sleep maintenance, relative to their respective 60- and 70-year-old counterparts. Implications for the understanding of sleep and its regulation in health and aging are discussed.

Aged↗

PubMed1991

Circadian characteristics of healthy 80-year-olds and their relationship to objectively recorded sleep.

Thirty-four healthy older adults (self-described "good sleepers") in their ninth decade of life (16m/18f, mean age 83.1) were compared to 30 young controls in their third decade (21m/9f, mean age 25.5) with regard to: (a) circadian and personality characteristics as measured by the Horne-Ostberg Morningness Questionnaire (HOM), Circadian Type Questionnaire (CTQ) and Eysenck Personality Inventory (EPI); (b) measures of habitual bedtime, waketime, and time in bed from a 2-week sleep diary; and (c) polysomnographic measures from a (post-adaptation) night of sleep recording in the laboratory. In almost all laboratory measures the older group slept poorly compared with the young, acquiring about one hour less total recorded sleep. The older group showed earlier habitual time of waking than the young, and showed higher (more "morning-type") scores on test instruments (HOM, CTQ-M) designed to assess morning-evening orientation. They also showed a lack of flexibility in sleep patterns (higher CTQ-Rs score) and less intersubject and intrasubject variability in habitual sleep timing compared to the young. Older subjects' morningness test scores were significantly associated with objectively measured sleep durations, with a tendency toward "morning-type" circadian orientation being associated with longer sleep.

Adult↗

PubMed1991

Daytime sleepiness in the healthy "old old": a comparison with young adults.

OBJECTIVE: To determine if excessive daytime sleepiness is an inevitable consequence of aging. METHODS: Daytime sleepiness was measured using Multiple Sleep Latency Tests (MSLT's) before and after a night of total sleep deprivation in a sample of 22 healthy men and women in their eighties and 29 men and women in their twenties. RESULTS: Young adults were somewhat sleepier than elders, as measured by rapidity of sleep onset during daytime nap recordings using the MSLT, and showed a higher incidence of REM sleep during naps. However, recovery from the effects of acute sleep loss was slower in the elderly, judging from the presence of more daytime sleepiness 2 days after a night of total sleep deprivation. Such persistent sleepiness was absent in the young adult control group. CONCLUSIONS: Healthy persons in late old age may have a level of daytime sleepiness no greater than, and perhaps even less than, that seen in healthy young adults.

Adult↗

PubMed1991

Is the poor sleep of shift workers a disorder?

OBJECTIVE: The purpose of this article is to describe the impact of shift work on sleep, as recently acknowledged in official nosologies of sleep disorders, and to discuss whether sleep altered by shift work actually constitutes a disorder. METHOD: The authors review subjective responses to recent survey questions about sleep and polygraphic measurements of sleep in shift workers and describe sleep clinic experiences with complaints related to shift work. FINDINGS: Shift work entails wide variation in work schedules, sleep quality, and worker tolerance and a high prevalence of night-shift sleepiness. It probably affects rates of drug use, health status, and family organization. Clinical presentations were rare, highly varied, and empirically treated. The United States, unlike other countries, has no legal restrictions on shift work. CONCLUSIONS: As a clinical phenomenon, sleep altered by shift work is common and varied, probably expresses nonphysiological sleep-wake scheduling, and is little treated. Further study of its health effects and consideration of whether it is a "disorder" or a "problem" seem warranted.

Adult↗

PubMed1991

Quantification of subjective sleep quality in healthy elderly men and women using the Pittsburgh Sleep Quality Index (PSQI)

Subjective sleep quality deteriorates with aging, but the extent to which this is a product of age itself, as opposed to the medical or psychiatric problems associated with aging, has not been carefully studied. To investigate this issue, we examined the subjective sleep quality of 44 healthy subjects over 80 years of age (20 men, 24 women), and 35 healthy subjects [corrected] between the ages of 20 and 30 (23 men, 12 women) using the Pittsburgh Sleep Quality Index (PSQI). All subjects underwent rigorous medical and psychiatric evaluations to verify that they were in excellent physical and psychological health. Significant age effects were noted for the global PSQI score and several PSQI component scores, but overall sleep quality for the majority (68.1%) of 80-yr-olds fell within a categorically defined range for "good" sleepers. Measures of habitual sleep quality did not correlate strongly with most polysomnographic sleep measures, number of medications used or circadian measures in elderly subjects. These results show that subjective sleep quality does deteriorate in the healthy elderly, but not to the level seen in patients with sleep disorders. Extremely healthy elderly subjects appear to adapt in their perception of objectively disturbed sleep.

Aged↗

PubMed1990

A comparison of rotating-shift and permanent night nurses.

This study tests the hypothesis that permanent night nurses would be no better off than rotating shift nurses on the first night of a run of duty. duty. Thirty permanent and 30 rotating shift female nurses from the same hospital participated in a study involving sleep diaries, oral temperature measurement as well as subjective ratings of well-being and the effort needed to complete their work. Although the permanent nurses fared significantly better than rotating shift nurses in subjective ratings, this did not appear to be due to the maintenance of a nocturnal orientation in the permanent group. Significant differences between the groups only emerged in the amount of night sleep before the shift. Day sleep amounts were similar between groups, as was the size of the temperature drop (0.5 degree F) between midnight and 4 a.m. Thus, lifestyle and social differences between the groups appeared to be more likely than biological rhythm adjustment ones to account for the permanent group's better subjective ratings.

Adult↗

PubMed1990

Comparison of sleep-disordered breathing among healthy elderly in the seventh, eighth, and ninth decades of life.

We investigated the prevalence of sleep-disordered breathing (SDB) in healthy 80 year-old subjects (n = 38) as compared with healthy 70-(n = 33) and 60-year-old subjects (n = 34). The apnea-hypopnea index (AHI) increased significantly across decades: 39.5% (15 of 38) of 80 year olds, 33.3% (11 of 33) of 70 year olds, and 2.9% (1 of 34) of 60 year olds had an AHI greater than or equal to 5 (chi 2 = 14.0, p less than 0.001). The prevalence of SDB as measured by a more stringent apnea index criterion of greater than or equal to 5 was 18.9% of those in their 80s, 12.1% in their 70s, and 0% in their 60s (chi 2 = 6.63, p less than 0.05). Significant gender differences were noted in the proportion of subjects with AHI greater than or equal to 10: 22.4% of men versus 5.4% of women (chi 2 = 4.25, p less than 0.05). These data suggest that SDB increases with advancing age even in the healthy elderly and may be more marked in healthy men than women.

Aged↗

PubMed1990

The Social Rhythm Metric. An instrument to quantify the daily rhythms of life.

The Social Rhythm Metric (SRM) is an instrument designed to quantify an individual's daily social rhythms. Social rhythms are important both as a way of structuring the day cognitively and as time cues (or zeitgebers) that drive the biological clock (circadian system). The development of the SRM and its pilot testing in 50 healthy control subjects is described, along with measurements of reliability and validity. The potential of the SRM for integrating psychosocial and biological research and its clinical applicability are discussed.

Circadian Rhythm↗