Rapid Eye Movement Activity Research Articles

Sleep and growth hormone secretion in women athletes

Six women athletes underwent 24 h multiple sampling studies with electroencephalographic monitoring of sleep for the assessment of growth hormone secretion and sleep pattern. The athletes tended to have more stage 4 sleep, less REM activity and a similar REM density compared to 5 normal women. The nocturnal secretion of growth hormone was elevated in the first hour following sleep onset in the athletes but was otherwise not statistically different from that of the controls. As all but one of the women athletes had exercise-related menstrual irregularities, the findings reported may be associated with exercise amenorrhea.

Sleep architecture and REM sleep measures in prepubertal children with attention deficit disorder with hyperactivity.

A 2-night polysomnographic study of 9 rigorously assessed prepubertal children who fit Diagnostic Statistical Manual-III criteria for attention deficit disorder with hyperactivity (ADDH) and a contrast group of 11 control children is reported. Despite the fact that 57% of the ADDH group were reported to experience restless sleep on structured parental rating forms, they did not show any sleep architecture abnormalities on polysomnographic recordings when compared with the normals at baseline other than decreased rapid eye movement (REM) activity. Seven of the ADDH boys were restudied after 6 months of continuous methylphenidate therapy (mean daily dose of 34.4 +/- 14.0 mg or 1.4 +/- 0.7 mg/kg). Across and within (pre-post) group comparisons showed that methylphenidate therapy was associated with delayed sleep onset, lengthened sleep, and changes in certain REM sleep variables.

EEG sleep, depression, and aging

—To date little attention has been paid to the posssible age-dependent relationships of EEG sleep measures in depression or to the implications of such relationships for diagnostic sensitivity and specificity. In a study of 108 patients with major depressive disorders (67 inpatients, 41 outpatients), age was shown to be a very powerful determinant of electroencephalographic (EEG) sleep patterns. Thus, among other sleep variables, sleep efficiency, delta sleep percent, and REM latency all showed significant linear declines with increasing age. Similar trends were seen in both inpatients and outpatients. Some variables were without age trends (age-stable), including sleep latency, REM sleep percent, and REM activity. These findings confirm those of an earlier report from our laboratory [45] and suggest that age-corrected sleep variables can be developed for clinical diagnostic application. Thus, using normative data from Gillin et al. [19] for comparison, a sensitivity level of 65% for age-corrected REM latency was demonstrated, together with a specificity of 95% and a diagnostic confidence of 92%. Data from a pilot study comparing EEG sleep measures in depression and dementia are also presented; these data suggest the potential utility of EEG sleep measures in the differential diagnosis of these two disorders, especially in patients with mixed symptoms. Additional areas for further research are reviewed with enumeration of specific testable hypotheses.

Electroencephalographic sleep in unipolar depressive subtypes: support for a biological and familial classification.

A tripartite classification of unipolar disease based on family history has been proposed by Winokur. In this study, we sought to investigate whether the familial pure depressive disorder (FPDD) and the sporadic depressive disorder (SDD) populations could be differentiated on the basis of baseline EEG sleep as effected by a tricyclic pharmacological probe. A subject group consisting of 26 females and 10 males yielding 18 FPDD/SDD pairs matched for age was selected. Both groups of patients demonstrated a considerable amount of sleep continuity disturbance with an overall sleep efficiency of 80.5 per cent in the pure depressive (FPDD) group and 83 per cent in the sporadic (SDD) group. Examination of the rapid eye movement (REM) sleep variables revealed the usual shortened REM latency as well as increased REM activity and REM density changes. However, the only significant difference between the two groups on baseline was the presence of more stage 3 and 4 sleep in the sporadic group, but stage 3 and 4 sleep was found in less than 40 per cent of the total sample. In contrast, analysis of the first two nights of EEG sleep on 50 mg of amitriptyline demonstrated several significant findings between the two groups. While considerable REM sleep suppression occurred in both groups, REM activity, REM intensity, and the number of REM periods were significantly more suppressed in the pure group than the sporadic group. Application of these variables led to a successful discrimination of 75 per cent of all the cases. These findings suggest a hyper-reactivity of sleep in patients with FPDD to a pharmacological probe.

REM Density is Dissociated from REM Sleep Timing During Free-Running Sleep Episodes

Sleep patterns of 3 normal male subjects living in an free of time cues were polygraphically recorded for a total of 26 entrained (scheduled 24 hr) and 62 free-running (self-selected) sleep- wake times. An analog tape recorder was used to record electroencephalograms, chin electromyograms, and horizontal electro-oculograms (left outer canthus - right outer canthus; time constant, 3-60 Hz). Eye movements were detected by automatic computing of the local maxima and local minima in the data after it had been filtered and digitized. During entrainment, REM density progressively increased in successive REM episodes, as did mean REM episode duration. The pattern of REM density was not significantly different during freerunning as compared to the entrained condition. In contrast, the timing of REM sleep was significantly different from that observed under the entrained condition. During free-running sleep episodes, there was a more rapid accumulation of REM sleep and an increased duration in earlier REM episodes. This dissociation of eye movement density from the timing of REM sleep suggests that eye movement density and perhaps other phasic REM activity are controlled by a different mechanism than the endogenous oscillator controlling the timing of REM sleep.

Eeg sleep and affective psychosis

EEG sleep changes in delusional depression have been reported previously but no attempt has been made to examine sleep profiles among specific delusional subtypes. In 29 psychotically depressed patients, those patients with delusions of guilt or sin demonstrated both increased sleep discontinuity and decreased REM sleep, especially during the first REM period, while patients with somatic delusions showed increased REM activity, especially in the first REM period. The implications of these findings are discussed.

Medullary respiratory neuron activity: relationship to tonic and phasic REM sleep.

This study analyzes the relationship of brain stem respiratory neuron activity to the tonic and phasic events of rapid-eye-movement (REM) sleep. Dorsal and ventral medullary respiratory neurons were recorded in sleeping cats. Discharges of inspiratory and expiratory cells increased in number and frequency with increases in pontogeniculooccipital (PGO) spiking (phasic REM activity). Across neurons the correlations between PGO wave frequency and respiratory neuron activity were positively related to the discharge levels of the neurons: the more active the cell, the greater the relationship to PGO activity. Tonic REM influences on respiratory neurons were calculated by extrapolating from the regression line relating PGO frequency and neuron activity to the hypothetical state of no PGO activity. These calculated levels, when compared to non-REM sleep levels, showed that tonic REM mechanisms reduced the activity of some neurons and activated others. Ventral medullary respiratory activity generally was decreased during tonic rem, whereas dorsal respiratory group cells were variously activated and inactivated. These results demonstrate an association of brain stem respiratory activity to nonrespiratory REM sleep variables.

Effects of loxapine on the sleep of chronic schizophrenics

The sleep patterns of four male chronic schizophrenic patients were monitored throughout the various phases of a 1-year therapeutic trial with loxapine succinate, a newly developed neuroleptic. Compared with the initial drug-free baseline, the early drug period was characterized by an increase in REM percentage, REM density, and REM activity. During the drug maintenance period, the increase in REM phasic events was accompanied by an increase in total sleep. Severe insomnia was noted during the initial period of drug withdrawal. The absence of time lag between changes in drug administration schedule and the associated alterations in sleep patterns was in contrast with the time latency of the therapeutic response. This neuroleptic on sleep and on psychopathology are mediated by different mechanisms.

ラットの逆説睡眠期における視覚誘発反応

Visual evoked response (VER) to flash was averaged at the occipital cortex during paradoxical sleep (PS) in rats. The peak-to-peak amplitude with about 30 to 80 msec latency decreased as rapid eye movement (REM) rates during PS increased. Theta frequency increased with REM rates but there was no clear relationship between VER amplitude and theta frequency when no REM occurred. Further, after the medial septal lesions which abolished hippocampal theta activity, the relationship between the VER amplitude and REM rates remained while the VER amplitude, as a whole, was enhanced. Thus cortical VER may be assumed to be controlled by two inhibitory systems associated with (a) REM and (b) hippocampal theta activity. Usually they are highly related but may function independently at least in rats.

Effects of exercise on sleep.

We tested the hypothesis that EEG sleep stages 3 and 4 (slow-wave sleep, SWS) would be increased as a function of either acute of chronic exercise. Ten distance runners were matched with 10 nonrunners, and their sleep was recorded under both habitual (runners running and nonrunners not running, 3 night) and abruptly changed (runners not running and nonrunners running, 1 night) conditions. Analyses of both visually scored SWS and computer measures of delta activity during non-rapid eye-movement (NREM) sleep failed to support the SWS-exercise hypothesis. The runners showed a significantly higher proportion and a greater absolute amount of NREM sleep than the nonrunners. The runners showed less rapid eye-movement activity during sleep than the nonrunners under both experimental conditions, indicating a strong and unexpected effect of physical fitness on this measure. Modest afternoon exercise in nonrunners was associated with a strong trend toward elevated heart rate during sleep. Mood tests and personality profiles revealed few differences, either between groups or within groups, as a function of exercise.

The application of EEG sleep for the differential diagnosis of affective disorders

On the basis of two EEG sleep criteria, REM latency and REM activity, the authors achieved 81% accuracy in distinguishing between 47 patients with primary depression and 48 patients with secondary depression using discriminant analysis. Sleep efficiency, the percentage of delta sleep, and the percentage of REM sleep discriminated between psychotic and nonpsychotic subgroups in the group with primary depression with 75% accuracy. REM activity and intermittent nocturnal awakening accurately discriminated two subtypes of patients with secondary depression at a level of 81%. These results suggest that EEG sleep measurements can yield significant data to aid in differential diagnosis in psychiatry.

Application of EEG Sleep for the Differential Diagnosis and Treatment of Affective Disorders*

In the last decade all night EEG sleep research has attempted to delineate the sleep features most characteristics of depressive states occurring in adult life. We have reported that EEG sleep variables could be used to verify a diagnostic classification for affective syndromes. This EEG sleep generated schema significantly dichotimized each major clinical category using only two or three EEG sleep measures. REM latency and REM density were sufficient to separate out primary from secondary depressed patients. Sleep efficiency, REM sleep percent, and delta sleep percent discriminated between the psychotic and nonpsychotic subgroups in the primary depressive group. Furthermore, EEG sleep variables separated secondary depression with concurrent medical disease from secondary depression without medical disease using REM activity and intermittent nocturnal awakening as the requisite variables of discrimination. Other ongoing investigations have established that the REM intensity of the first REM period is increased in primary depression. The search for EEG sleep correlates of clinical response in depressed patients receiving tricyclic antidepressants has suggested that, the more rapid the suppression of REM sleep, the more likely that the patient will respond to tricyclic antidepressants. Finally, clinical response appears to be associated with a period of sustained elevation of REM latency.

EEG Sleep Diagnosis of Medical Disease in Depression

The diagnosis of medical disease in the context of a depressive syndrome which may mimic medical illness has traditionally relied on a combination of exhaustive medical screening and neuropsychological testing. When 10 patients with primary depression were compared to 10 patients whose depression occurred in the context of concurrent medical disease, a single EEG sleep variable, total phasic REM activity (RA), correctly identified 95% of all 20 patients as either primary depressives or medical patients with depression. Conventional psychiatric assessment and neuropsychological testing were significantly less powerful discriminators among this sample.

Rapid Eye Movement Sleep Density

The electroencephalographic sleep patterns of 12 patients with a final diagnosis of primary depression and those of 12 patients admitted to the Clinical Research Unit with this diagnosis, but subsequently also found to be suffering from severe medical disease, were compared. Patients with depression concurrent with severe medical disease have significantly less phasic conjugate rapid eye movement (REM) activity during REM sleep than subjects with the diagnosis of a primary depression. These findings suggest that quantification of REM density may be used clinically to distinguish between medical-depressive syndromes and primary affective disorders.

Rapid eye movement (REM) activity in normal and autistic children during REM sleep

Thirty normal children (aged 3--68 months) and 16 autistic children (aged 36--62 months) were recorded during nonmedicated sleep and data pertaining to rapid eye movements (REM) were measured during the first three REM periods of the night. When time of night from which data were gathered was held constant, normal children showed a significant relationship between age and the organization of eye movements into discrete bursts. When autistic children were compared to age-matched normal controls, they showed an immaturity in this phenomena, their results being similar to those found in children less than 18 months of age. Such an immaturity could result from dysfunction at a number of diverse levels and sites in the central nervous system.

EEG sleep changes as predictors in depression

The authors conducted a study of 18 depressed patients to see whether EEG sleep measurements might provide a predictive tool for response to antidepressant medication. They found that although the sedative characteristics of amitriptyline did not differentiate good responders from poor responders until the third week of drug treatment, the good responders showed significant increases in REM latency, decreases in REM sleep time, decreases in REM sleep percent, and decreases in REM activity after only 2 nights of drug treatment.

Is the subjectively experienced quality of sleep related to objective sleep parameters?

The relationship between the subjectively experienced quality of sleep and awakenings and certain objective neurophysiological parameters, including the quantitatively analyzed awake evening EEG, all-night sleep EEG, computer classified sleep stages, REM activity and awake morning EEG, were investigated in a group of 35 normal healthy male volunteers. Low voltage fast activity in the awake evening EEG was found to be linked to a delayed sleep onset, light sleep, restlessness, frequent awakenings and augmented dreams during the night. In terms of the computer classified sleep, stages wake (W) and movement time (MT) were associated with increased difficulty in falling asleep, decreased sleep comfort and sleep depth, restlessness, frequent awakenings and bad dreams. Augmented movement time resulted also in more drowsiness in the morning. The more REM activity, the less “light” the subjects rated their sleep, the less difficulty they had in getting back to sleep after night-time awakenings and the more unpleasant was the process of getting up in the morning. On the other hand, a high amount of stage 2 sleep seems to be indicative of a shortened sleep latency, a restful and uninterrupted sleep process and a refreshed feeling in the morning. The positive relationship between stage 4 and “light sleep” again raises a question concerning the dubious connection between the sleep stage nomenclature and “sleep depth.” Finally, it was observed that the less alpha activity and the more beta waves in the quantitatively analyzed all-night sleep EEG and awake morning EEG, the worse the quality of sleep and the more unpleasant the awakening in the morning.

Differential Effects of Chlorpromazine, Imipramine, Nitrazepam and Amobarbital on REM Sleep and REM Density in Man

The effect of chlorpromazine (CPZ), imipramine (IMP), nitrazepam (NZP) and amobarbital sodium (AMOB) on the REM period of sleep (REMP) was investigated on four subjects by means of all-night sleep polygraphy with the schedule PPPDDDPP where P is placebo and D active drug. CPZ 25 mg resulted in a slight increase in %REMP, and no significant change in REM density (1 second fraction method) and total REM activity during the drug and withdrawal nights. IMP 25 mg produced moderate decrease in %REMP in the three drug nights, whereas REM density decreased only in the first drug night. NZP 5 mg resulted in a slight parallel suppression of %REMP, REM density and total REM activity during the drug nights. AMOB 200 mg produced a slight decrease in %REMP and marked decrease in REM density during the drug nights. Rebound increase of %REMP and a tendency of carry over decrease of REM density were observed in the withdrawal nights. Decrease in the REM density was more marked in AMOB than in NZP drug night. The importance of the simultaneous analysis of %REMP and REM density for the study of effects of psychotrophic drugs on sleep was emphasized.

Eye movements during REM sleep: The influence of personality and presleep conditions.

Male subjects scoring high (n=17) or low (n=14) on the Maudsley Neuroticism scale were randomly assigned to a positive (n=17) or negative (ego threat) (n=14) presleep condition and then slept a single night in the laboratory. The negative condition elicited significantly more rapid eye movement activity (REM density) than did the positive condition (pless than.03). There was a significant interaction for Groups X Conditions (pless than.007) indicating that low neuroticism subjects had greater REM density in the negative condition, and less REM density in the positive condition, compared to high neuroticism subjects under either condition. The low neuroticism subjects in the negative condition showed a discrepancy between greater REM density but less admission of stress on a presleep mood questionnaire compared to high neuroticism subjects. These results support the hypothesis that REM density is a correlate of stress-induced arousal that is subject to the modifying effects of individual differences.

An objective measure of REM activity

Recent emphasis on REM sleep abnormalities has begun to yield significant differences between “normals” and patients with affective syndromes or schizophrenia. In our efforts to objectively quantitate aspects of REM sleep during all-night studies in psychiatric patients, we have developed the “REM analyzer” for automatic on-line measurement. As a practical application of the REM analyzer, 20 psychiatric patients (12 inpatients and 8 outpatients) were studied. Both cross-sectional and longitudinal-sleep studies were obtained; predrug and drug periods were also compared. From the REM analyzer, the number of rapid eye movements during each REM period (Cn) and the sum of their integrals during each REM period (In) were recorded. The ratio I/C was named “REM weight” (the “average rapid-eye-movement area“). The objective measures of REM sleep which highly correlate with a number of visual methods of defining REM sleep and with diagnostic and therapeutic implications in affective and schizophrenic disorders are discussed in this paper. The method appears particularly suitable for the differentiation of tonic and phasic components of REM sleep and, thus, for the investigation of REM suppression-compensation models.