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Biomedical subjects

P A Coble

Publications and source records attributed to P A Coble.

At least 19 recordsLinked to original sources
PubMed1995

Automating the sleep laboratory: implementation and validation of digital recording and analysis.

OBJECTIVES: We report on the implementation of digital processing in a large clinical and research sleep laboratory. The system includes the digital collection, display, analysis, and repository of physiological signals collected during sleep. METHODS: After describing the original analog system, the computer equipment and software necessary for the digital implementation are presented and we explain our algorithms for rapid eye movement (REM) and delta-wave detection. Finally, we describe an experiment validating the digital system of display and analyses. CONCLUSIONS: The digital processing of sleep signals saves computer operator, polysomnographic technologist, and computer time. It also saves resources such as polysomnographic paper and FM tape. The digital signals lend themselves to a large array of analysis techniques and result in improved signal quality. Automated REM and delta-wave detection via digital processing correlate highly with visual counts of rapid eye movements and delta waves.

Algorithms↗
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

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↗
PubMed1991

Subtyping DSM-III-R primary insomnia: a literature review by the DSM-IV Work Group on Sleep Disorders.

OBJECTIVE: The authors review the usefulness, reliability, and validity of recently proposed subtypes of primary insomnia. DSM-III uses "primary insomnia" to indicate chronic insomnia not associated with other diagnosable mental or medical disorders, whereas the International Classification of Sleep Disorders (ICSD) recognizes three subtypes: psychophysiological insomnia, idiopathic insomnia, and sleep state misperception. METHOD: After reviewing all of the primary source references for each insomnia disorder in the ICSD and all of the additional primary sources cited in each of these, the authors conducted an automated literature search using Medline. Of the 48 primary sources located, the authors selected 27 studies that were reported in peer-reviewed journals, had the largest available subject groups, used diagnostic reliability procedures, and included control groups. RESULTS: The studies reviewed contained limited empirical support for the proposed distinction between idiopathic and psychophysiological insomnia. Sleep state misperception appears, however, to be a highly prevalent feature of chronic insomnia generally, rather than only a specific disorder per se. CONCLUSIONS: The authors conclude that there is not yet sufficient empirical evidence to warrant the abandonment of DSM-III-R "primary insomnia" and the adoption of the ICSD subtypes in DSM-IV. However, they affirm the heuristic value of the ICSD subtypes and the need for field trials to compare the performance characteristics of the DSM-III-R and ICSD systems with respect to 1) interrater reliability, 2) effects of rater expertise (generalist versus specialist) on rates of agreement, and 3) effects of polysomnographic data on rates of agreement.

Humans↗
PubMed1990

Sleep, gender, and depression: an analysis of gender effects on the electroencephalographic sleep of 302 depressed outpatients.

Gender-related differences in electroencephalographic (EEG) sleep were examined in 151 pairs of men and women with major depression, all outpatients, matched for age and severity of depression. Across five decades (age 21-69), depressed men had less slow-wave sleep than did depressed women. Gender differences were small with respect to visually scored measures of slow-wave sleep time and percent, but moderate for gender differences in automated measures of slow-wave density. The time constant of the polygraph preamplifier significantly affected both visually scored and automatically scored slow-wave sleep. Other measures such as REM sleep latency, first REM period duration, sleep efficiency, and early morning awakening, showed robust age effects, but no main effects for gender or gender-by-age interactions. Gender effects on slow-wave sleep and delta-wave counts in depression parallel gender effects seen in healthy aging. The possibility of occult alcohol use by depressed male outpatients cannot be definitely excluded as a partial explanation of the current findings. However, covarying for past alcohol abuse did not negate the statistical significance of the observed gender effects on slow-wave sleep and delta-wave density. The possibility of gender differences in slow-wave regulatory mechanisms is suggested, but similarity in temporal distribution of delta-wave density between the first and second non-rapid-eye-movement (NREM) periods does not support gender differences in slow-wave sleep regulation.

Adult↗
PubMed1988

The effects of prenatal alcohol and marijuana exposure: disturbances in neonatal sleep cycling and arousal.

Neonatal EEG and sleep findings are presented from a longitudinal study of the effects of maternal alcohol and marijuana use during pregnancy. Infant outcome has been examined relative to the trimester(s) of pregnancy during which use occurred. Disturbances in sleep cycling, motility, and arousals were noted that were both substance and trimester specific. Alcohol consumed during the first trimester of pregnancy was associated with disruptions in sleep and arousal, whereas marijuana use affected sleep and motility regardless of the trimester in which it was used. Although these findings are preliminary and based on a small sample of women exhibiting only moderate substance use during pregnancy, they do suggest that specific neurophysiological systems may be differentially affected by prenatal alcohol or marijuana exposure even in the absence of morphological abnormalities.

Arousal↗
PubMed1987

Electroencephalographic sleep of healthy children. Part II: Findings using automated delta and REM sleep measurement methods.

Using earlier developed computer-based measurement methods, delta and REM activity were examined during sleep as a function of age, gender, and time of night in 85 healthy, 6- to 16-year-old children. Chronological age was found to account most strongly for differences in automated delta and REM count measures in this age range. Increasing age was shown to be associated with a significant decline in both automated measures, but the effect was much greater for the delta count measure. The age-related decline in delta wave activity was reflected primarily in a linear decline in 2.0-3.0 Hz delta activity, that is, in the faster end of the delta frequency band. Examination of these measurements in successive NREM and REM sleep periods confirmed that, in children as in adults, delta activity decreases and REM activity increases across the night. Findings are discussed relative to those obtained in the same children using standard measurement methods.

Adolescent↗
PubMed1985

Electroencephalographic sleep of younger depressives. Comparison with normals.

The electroencephalographic sleep of younger depressives (aged 20 to 44 years) was compared with that of an age-matched group of normals. The patients demonstrated many of the typical sleep changes reported for older depressed populations: shortened rapid-eye-movement (REM) latency; REM sleep activity alterations, with a shift to the early portion of the night (first REM period); reduced delta sleep; and sleep efficiency reductions marked by sleep-onset difficulties. The traditional scoring procedures were supplemented by automated REM and delta-sleep analyses that provided more precise delineation of these differences between patients and normals, particularly the distributions of REM activity and delta-wave patterning.

Adult↗
PubMed1985

Comparison of effects of desipramine and amitriptyline on EEG sleep of depressed patients.

Despite their widespread use, there are few data concerning the effects of tricyclic antidepressants on EEG sleep in depression. The present study documented the effects of desipramine (DMI, n = 17) and amitriptyline (AT, n = 16) upon EEG sleep in hospitalized depressed patients as part of a double-blind protocol involving 28 days of active treatment. Compared to placebo, patients receiving DMI showed somewhat worsened sleep continuity, particularly after 1 week of administration when the dose was 150 mg/day. On the other hand, sleep architecture and REM measures showed a rapid suppression of REM sleep, and then partial tolerance for this effect was observed with continued administration of DMI for 3 weeks. DMI was a more potent suppressor of REM sleep, while AT was more sedative. Based on these differences in effects upon EEG sleep, a discriminant function was derived and resulted in a correct classification of 87.5% of AT cases and 76.5% of DMI cases. These results are discussed in terms of the differences in pharmacological profiles for uptake blockade and anticholinergic potency for these two compounds.

Adult↗
PubMed1985

"Paradoxical" shortening of REM latency on first recording night in major depressive disorder: clinical and polysomnographic correlates.

Among 92 inpatients with major depressive disorders, variability in REM latency (RL) during the first two recording nights was assessed by means of an "adaptation coefficient" (AC = night 1 RL--night 2 RL X 100 divided by mean RL for nights 1 and 2). Although mean RL was very similar for both nights (48.1 and 50.7 min), individual ACs showed a gaussian distribution [range: -176.5-171.4; mean: -1.2 (67.3); median: -4.4]. Forty-two patients (45.7%) exhibited shortening of RL on night 2 compared with night 1 (positive AC, corresponding to an "expected" evolution), 48 patients (52.2%) displayed the opposite pattern (negative AC, corresponding to a "paradoxical" evolution), and two patients had identical values on both nights. Extent of increase in RL from first to second night (i.e., extent of "paradoxical" evolution) correlated significantly with increasing duration of current episode, earlier age of onset, and poorer clinical response to tricyclic antidepressants. A cutoff AC of -7 correctly classified 62% of patients according to treatment response. The research diagnostic criteria-based retarded subtype of depression was associated with a more negative AC (i.e., a more "paradoxical" evolution), and the situational subtype was associated with a more positive AC (i.e., a more "expected" evolution) than the remainder of the sample. The subgroup with the most negative ACs (i.e., largest increases in RL from first to second night) also had longer sleep latencies, whereas the subgroup with the most positive ACs (i.e., largest decreases in RL) had higher REM activity and REM density as compared with the remainder of the sample. These results suggest that RL in major depression is not a static parameter and that the study of its within-subject variability can be helpful for diagnostic confirmation and prediction of treatment response.

Adaptation, Physiological↗
PubMed1985

Depression in borderline patients: a prospective EEG sleep study.

The relationship between borderline personality disorder and primary major depression was studied prospectively using Schedule for Affective Disorders and Schizophrenia-Lifetime Version (SADS-L) interviews and electroencephalographic (EEG) sleep studies. Ten consecutively admitted borderline patients (a prospective sample), defined by Gunderson's Diagnostic Interview for Borderlines (DIB), underwent EEG sleep studies on two consecutive nights and were compared to previously reported samples of nonborderline depressed patients (defined by Research Diagnostic Criteria; RDC), normal controls, and DIB-defined borderline patients who had been referred "to rule out major depression" (a retrospective sample). EEG sleep data were analyzed visually and by automated techniques. Rapid eye movement (REM) latency values were similar in depressed and both borderline groups but significantly different from controls. Eighty-five percent of REM latency values in RDC major depressives were less than or equal to 65 minutes, compared to similar rates of 75% in the prospective sample of borderline patients and 65% in the retrospective sample, versus 35% for controls (chi 2 = 10.7, p less than 0.005). The REM latency in borderline patients did not vary with the severity of depression as measured by the Hamilton Rating Scale for Depression. In the prospective borderline sample, the major SADS-L diagnoses were chronic intermittent depression (five), current major depression (four) (two unipolar, two bipolar II), and labile personality (one). A convergence of nosologic and EEG sleep data is suggested, and supports the concept of a close relationship between criteria-defined borderline personality disorder and affective illness.

Adolescent↗
PubMed1984

Application of automated REM and slow wave sleep analysis: I. Normal and depressed subjects.

Computerized analysis of rapid eye movement (REM) and delta electroencephalographic (EEG) sleep patterns in normal and depressed subjects offers opportunities to examine sleep more precisely than previously possible. In the present study, automated REM analyses demonstrated good reliability with traditional manual procedures in both normal and depressed subjects. However, automated delta analyses correlated well with traditional scoring in normal subjects, but not in depressed patients. These findings suggest the use of automated delta techniques similar to those employed in this report or spectral analytic techniques in the following types of studies: specificity of delta sleep in various psychiatric syndromes, changes in delta sleep produced by the administration of psychotropic agents, relationships between delta sleep and sleep-related neuro-endocrine patterns, and, finally, relationships between delta sleep patterns and other biological rhythms such as activity and temperature.

Adult↗
PubMed1984

Application of automated REM and slow wave sleep analysis: II. Testing the assumptions of the two-process model of sleep regulation in normal and depressed subjects.

Abnormalities in a two-process model of sleep regulation (a sleep-dependent process, termed Process S, and a sleep-independent circadian process, termed Process C) have been proposed to account for sleep abnormalities in depressive states. The major tenets of the two-process model of sleep regulation as applied to depression are: the level of process S, as reflected by the electroencephalographic (EEG) slow-wave activity, corresponds to the sleep-dependent facet of sleep propensity; the pathognomonic changes of sleep in depressives are a consequence of a deficiency in the build-up of process S. The application of automated rapid eye movement (REM) and delta wave analyses in normal subjects and younger depressed patients supports the model to some extent: The time spent asleep is positively correlated with total delta waves (normals and depressives) and average delta waves (depressives); delta sleep is lower in depressives than in normals; the average delta wave count is significantly reduced in younger depressives over the total night and in non-REM period 1. The model also postulates that measures of phasic REM activity are inversely related to process S, suggesting that process S can be regarded as exerting an inhibitory influence on phasic REM activity.

Adult↗
PubMed1984

Differential effects of amitriptyline and of zimelidine on the sleep electroencephalogram of depressed patients.

The effects of amitriptyline (n = 14) or zimelidine (n = 13) on the sleep electroencephalogram of hospitalized depressed patients were assessed in a double-blind protocol involving 28 days of active dosing. Zimelidine induced no immediate improvement in sleep continuity, and even after 3 wk on zimelidine subjects tended to have longer sleep latency, more awakenings, and lighter non-rapid eye movement (REM) sleep than before taking the drug. Zimelidine did, however, induce a rapid and persistent alteration of sleep architecture and selected REM measures. REM sleep, which was suppressed over the first two nights on zimelidine, was maximally suppressed after 1 wk, but by 3 wk there was some tolerance for selected REM measures. While zimelidine induced none of the sedative effects of amitriptyline, both were equivalent in their REM-suppressant effects. These findings are discussed in terms of the differences in uptake blockade and anticholinergic potency in these two drugs.

Adult↗
PubMed1984

EEG sleep of normal healthy children. Part I: Findings using standard measurement methods.

Despite the increasing application of all-night electroencephalographic (EEG) sleep studies to children for clinical as well as for research purposes, readily available normal EEG sleep standards for the period of childhood have remained sparse and, at present, reflect data on only approximately 100 children 6 to 16 years of age. As part of a large scale study examining various aspects of EEG sleep among children, findings derived using standard recording and scoring methods are reported for a new sample of nearly 100 normal, healthy children and are compared with existing standards. Data obtained add substantially to the existing database and generally confirm findings of previous normative reports on children in this age range.

Adolescent↗
PubMed1984

Multiple Sleep Latency Test findings in Kleine-Levin syndrome.

Multiple Sleep Latency Test (MSLT) findings in a case of Kleine-Levin syndrome are reported for the first time. MSLT data indicate sleepiness as severe as in narcolepsy or obstructive sleep apnea and the occurrence of four sleep onset rapid eye movement (REM) periods, with a greater REM propensity at 2:00 p.m. and 4:00 p.m. than at 10:00 a.m. and 12:00 noon. The replication of such findings might suggest that Kleine-Levin syndrome could be considered a form of periodic REM sleep disinhibition. Therefore, the traditional hypothesis of diencephalic dysfunction may require modification to include the role of more caudal brain stem structures specifically activated during REM sleep.

Adult↗