Wilse B. Webb

SLEEP PATTERNS IN YOUNG ADULTS: AN EEG STUDY.

Abstract 1. 1. EEG sleep stages do not appear in any consistent temporal sequence from night to night in a given subject nor in a group of subjects. 2. 2. The typical young adult in our study spent an individually characteristics relative amount of time in each sleep stage each night. 3. 3. The length of stages was short, usually less than 10 min, with the exception of stage 1-REM which ranged up to 39 min in length. Our subjects characteristically changed stages fewer times on successive nights. The number of sleep stage changes differed among subjects. 4. 4. The stage change was usually smooth, moving from one stage to the next when sleep was deepening, but less smooth, often “jumping”.

Stage 4 Sleep: Influence of Time Course Variables

Age, length of prior wakefulness, length of time asleep, and a circadian influence all affect stage 4 sleep. The amount of stage 4 sleep decreases as subjects age increases and as time asleep increases. Longer periods of wakefulness before sleep result in greater amounts of stage 4 sleep in the first 3 hours of sleep. Sleep periods that begin at times other than the regular onset time tend to produce less stage 4 sleep; this decrease suggests a circadian effect.

Alcohol and caffeine: effect on inferred visual dreaming.

In seven subjects, a large amount of alcohol, taken at bedtime, reduced the total duration of stage 1 electroencephalographic-rapid-eye-movement periods in the first 5 hours of sleep; a moderate amount of caffeine produced no significant change.

Nocturnal hypoxia and Neuropsychological variables

Hypoxia is a well known cause of brain dysfunction. Neuropsychological impairments have been observed in normal subjects experiencing hypoxia iatrogenically as well as in patients with chronic lung disease. Recent investigations have demonstrated significant nocturnal hypoxia in subjects with sleep-disordered breathing. In the present study, heavy-snoring males, a group known to experience frequent episodes of sleep-disordered breathing received neuropsychological testing and a night of continuous monitoring of respiratory parameters. Partial correlations, controlling for age, weight, and education, indicated reliable relationships between nocturnal hypoxia and measures of general intelligence, verbal and nonverbal memory, and expressive verbal fluency. It is proposed that heavy-snoring males may potentially serve as a population in which to model the neurobehavioral effects of hypoxia. Further research in subjects with sleep-disordered breathing may help clarify the extent of the possible cognitive deficits as well as point out possible ameliorative treatments.

Sleep Stage Characteristics of Long and Short Sleepers

The possibility of different sleep stage characteristics being associated with different sleep lengths was explored by comparing two groups of high school seniors, who characteristically slept 6� hours or less or who slept 8� hours or more, with an age-matched control group not selected on the basis of sleep length. All-night electroencephalography was used to examine the sleep stage characteristics of these groups. Compared with the unselected age-matched group, the short sleepers showed no significant diminution in their stage 4 (deep) or rapid eye movement (dream) sleep. The long sleepers were observed to obtain significantly more rapid eye movement sleep than did the other groups.

Characteristics of sleep patterns during late pregnancy and the postpartum periods

Abstract The present investigation provides an accurate description of the EEG sleep pattern characteristics of late pregnancy and early postpartum periods and compares this with age-matched controls. The over-all sleep pattern observed in gestation seemed similar in some respects to insomnia and was characterized by a longer sleep latency, frequent awakenings, shorter sleep time, and a marked reduction of deep sleep (Stage 4). In addition, immediately after delivery, there was a suppression of the dreaming (Stage 1-REM) sleep. By the second postpartum week, these profound sleep changes tended to normalize. Mechanisms of these findings and their possible relationship to postpartum emotional disturbances are discussed.

Sleep patterns in the young adult female: An EEG study

Abstract In this study of the sleep of young females additional support was found for the hypothesis that an individual spends a characteristic mount of time in each sleep stage. The length of stages was short, usually ten minutes. These stage changes were usually smooth, moving from one stage to the next when sleep was deepening, but less smooth during arousal from deeper levels. Stages IV and III showed their greatest amounts during the first third of the night and 1-REM during the ladt third. Comparisons between this group of young females and a group of males in the same age range revealed no significant differences for these EEG parameters of sleep.

Sleep during the early morning

The intrasleep EEG characteristics of Ss who returned to sleep in the early morning more closely resemble the sleep characteristics which occur late in a full nights sleep rather than the sleep which occurs at the onset of nocturnal sleep. It would appear that sleep does not simply “recycle” with sleep onset.

The measurement and characteristics of sleep in older personsv of sleep in older persons

Measures of the sleep structure, patterns and evaluative responses of 40 males and 40 females between the ages of 50-60 years are presented. Measurement methodology is emphasized. The inability to sustain sleep is clearly indexed by the sleep structure measures. These tendencies are greater in the males. The absolute diminution of slow wave sleep is questioned. Sleep pattern measures show wide inter and intra subject variability with few sex differences. Three fourths of the subjects reported naps in a two week period and men report more frequent but shorter naps. The subjective measures have limited concurrent relations to EEG measures and constitute a complex multifaceted content domain. The overall picture is of a system in change characterized by a wide range of individual differences.

SLEEP AS AN ADAPTIVE RESPONSE

It is proposed that sleep is adaptive non-responding and that the sleep characteristics of particular species reflect the adaptive requirements for non-responding in the ecological niche of species. The ecological conditions which would modify sleep length, intermittency, and diurnal placement are discussed. Sleep is viewed as a form of instinctive behavior rather than a nutritional or need satisfying state.