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Biomedical subjects

O Benoit

Publications and source records attributed to O Benoit.

At least 73 records · Page 4Linked to original sources
PubMed1981

[Intra-sleep awakenings in relation to habitual sleep length and modifications of the sleep-wake rhythms (author's transl)].

The number of episodes of intervening wakefulness, their duration and their sleep stage occurrence were analyzed in the sleep recordings of 19 young (19-23 years), good sleepers. There were 5 long sleepers (LS), 5 short sleepers (SS) and 9 regular sleepers (RS). The experimental protocol included 2 reference nights, a night sleep recovery (after 36 h of wakefulness) and a day sleep recovery (after 24 h). The night following the day sleep recovery was also recorded. The duration of waking episodes was very stable and was independent both of type of sleeper and of situation. The histogram of these durations seemed to follow an exponential law. The number of awakenings varied according to the individual, the habitual sleep length (SS had very few) and the situation (such as length of prior wakefulness or circadian factors).

Adult↗
PubMed1981

[Age and insomnia: the number and length of waking periods (author's transl)].

The role and importance of the number of awakenings and their duration in relation to increasing intervening wakefulness were investigated. The data were collected from a group of 38 subjects suffering from chronic primary insomnia, aged 17-70 years, polygraphically recorded; the analysis was made on the second night. With age, the total quantity of intervening wakefulness increases more quickly than the total number of awakenings. The amount of wakefulness due to awakenings lasting greater than or equal to 3 min increases with age. Older insomniacs wake up somewhat more often but, above all, they go back to sleep less quickly. Our hypothesis is that in old patients insomnia is linked to an increase in stability of wakefulness.

Adolescent↗
PubMed1981

[Intra-sleep awakenings in poor sleepers, 20 to 30 years of age. Correlation with anxiety level and personality (author's transl)].

Recordings were made from 43 poor sleepers between the ages of 20 and 30 for at least 4 consecutive nights. Three subject groups were formed on the basis of the awakenings occurring up to the sixth hour of sleep. The first group, with an average of 61 min wakefulness, is characterized by the abundance of long-lasting waking periods. The second group, with 18 min average wakefulness, showed the highest absolute number of awakenings, almost all of which were very brief. The third group, with 6 min average wakefulness, showed a slightly lower number of awakenings, but these were almost exclusively micro-waking periods. The temporal distribution of the waking periods was also different in the first group, in which the longest waking periods occur during the first hour of sleep and remain elevated until the fifth hour of sleep. The latency for falling asleep is particularly high for this group. A correlation exists between the amount of time awake up until the sixth hour of the night and the subject's anxiety level and the neuroticism index. 65% of the subjects obtained pathological scores on one or more MMPI scales. According to the order of frequency these were scales Sc, Pd and Pt. No preferential profile was found.

Adult↗
PubMed1981

[Polygraphic study of nocturnal waking in patients with traumatic brain stem injuries (author's transl)].

The waking periods during sleep of 16 patients, having been in post-traumatic coma for 5-40 days (aged 15-28 years), were studied electroencephalographically 1 month (T1) and 6 months (T6) after regaining consciousness and were compared with control subjects. The amount of waking (frequency and duration) increased appreciably at 1 month (20% of total sleep time and 21 awakenings per night) and was augmented even more in those cases in which the initial damage was more severe caudally and the duration of coma longer. At 6 months, the duration of waking was reduced somewhat (12% vs. 3% controls), but the frequency of awakening had not changed. By this stage the level of initial damage did not seem to produce any effect. These results show that the disturbance in the sleep-waking cycle regresses more rapidly the less severe the degree of initial damage was.

Adolescent↗
PubMed1981

Diurnal rhythm of axillary temperature in long and short sleepers: effects of sleep deprivation and sleep displacement.

Six habitual long (greater than or equal to 9 hr) sleepers (LS) and 6 habitual short (less than or equal to 6.5 hr) sleepers (SS) measured their diurnal axillary temperature (T) every 4 hr from awakening time to bedtime. For the control span of 10 days, temperature peak time was similar in both groups but occurred later in SS than in LS when measured from midsleep. Bedtime was closer to temperature peak time in LS than in SS. While experiencing the same sleep deprivations (SD 24 hr with morning sleep recovery and SD 36 hr with nocturnal sleep recovery). SS maintained a more stable body temperature curve than LS. After the nights of sleep deprivation, morning temperature increased in LS but not in SS. In both experimental conditions LS tended to advance their temperature peaks. This shift resulted in a statistically significant difference between the groups' T peaks for the 36-hour sleep deprivation. These results suggest that coupling between sleep/activity rhythm and temperature rhythm probably is different in LS and in SS, being stronger in LS.

Adult↗
PubMed1981

[Night sleep disorders during recovery of severe head injuries (author's transl)].

In 16 young (15 to 25 years) patients, sleep recordings have been performed one month (group T1, 10 cases) or 6 months (group T6,6 cases) after recovery of consciousness following severe head injury. Group T1 can be divided in two subgroups according to clinical and EEG datas: T1A (4 cases) with long duration of coma (15 to 40 days) and low level of brain stem dysfunction (diencephalic). In group T6 every duration of coma and level of dysfunction are present. Percentage of intrasleep wakefulness and number of awakenings are very increased in group T1A (31,5% and 24); these datas are less increased in group T1B (10,1% and 19) and T6 (11.8% and 19). Percentage of REM sleep is very low in group T1A (9,57%) and T1B (12,65%) because of short duration of each phase. In group T6 REM sleep is close to control subjects (16,15% and 20,52%). These results are compared to those reported in normal or insomniac subjects of same age or much older. They are very similar to sleep perturbations observed in elderly (70 years) but normal people. This may evoke an early ageing of brain stem structures involved in organization of wakefulness-sleep rhythm and REM sleep.

Adolescent↗
PubMed1981

Effects of locus coeruleus lesions on heart rate during sleep in the cat.

Bilateral electrocoagulation of the locus coeruleus (LC) were performed in 8 cats, in order to study the effects on the heart rate modulation during sleep. In 4 cats the lesions were restricted to the posterior part of LC: they induced a permanent tachycardia in all states, and a reduction of the phasic changes during paradoxical sleep (PS), while the state-linked modulations remained similar to those of controls. In another group of 4 cats, lesions extended rostrally to the anterior LC. They induced a bradycardia evidenced mostly during PS. Phasic changes persisted though the tachycardic component was greatly reduced. The state-linked modulations were opposite to those of controls: increase during transition from slow waves sleep (SWS) to PS and decrease during PS. No recovery trend was observed within the 3 weeks post-lesion experimental period. These data are discussed in relation to the well-known parasympathetic and sympathetic regulations of the heart rate, with special attention to the changes observed during transition from slow waves sleep (SWS) to PS and during the first minute of PS. This period corresponds to a shift in the balance of tonic and phasic influences.

Animals↗
PubMed1981

[Respiratory pauses in nocturnal sleep of infants].

In order to study the respiratory abnormalities during sleep that could select children with a high risk of sudden infant death syndrome (SIDS), 3 groups of children were studied: Group T: 18 control infants; Group G: 22 infants related to children who died from SIDS and group NM: 32 infants with near miss SIDS. A classic polygraphic EEG recording was performed during sleep. Apneas of 5 or more seconds and periodic respiration were analysed. Half of the infants in groups G and NM did not differ from those in group T. However, the groups G and NM differ from group T by a higher mean index of apneas during sleep and by the presence of a periodic respiration outside REM sleep in some of them. On the contrary, the mean duration of apneas and the number of apneas of more than 10 seconds did not seem to differ significantly in the 3 groups.

Female↗
PubMed1980

Habitual sleep length and patterns of recovery sleep after 24 hour and 36 hour sleep deprivation.

Five long sleepers (LS) and 5 short sleepers (SS) were selected from 310 medical students. Nine regular sleepers (RS) were used as a control. The sleep was recorded during 3 reference nights, one recovery night after a 36 h sleep deprivation (R2), one morning sleep after a 24 h sleep deprivation (D1) and the night following D1(R1). According to previous data slow wave sleep (SWS) amounts were the same in the 3 groups while stage 2 and paradoxical sleep (PS) amounts increased with the sleep duration. The hourly distribution of intervening wakefulness and SWS were similar for all groups. When compared to RS or SS the hourly distribution in LS of PS was lower until the sixth hour. As a function of experimental conditions, sleep patterns of LS were the most affected. In R2 the sleep of LS more closely resembled that of RS or SS than in reference nights, while in R1 LS' sleep was the most disturbed. Morning sleep durations were very similar for all groups, but in LS intervening wakefulness was increased and PS was decreased when compared to RS and SS. Negative correlations (Spearman rank test) were found between the morning increase of body temperature after a sleep-deprived night and both TST and PS durations. In all recorded sleep periods, SWS amounts were positively correlated with prior wakefulness duration and the PS amount with TST.

Adult↗
PubMed1978

[Study of sleep of shift workers with alternating schedules: adaptation and recovery in case of rapid shift rotation (3-4 days) (author's transl)].

An electroencephalographic study of the sleep of shift workers (3 x 8) was performed in a French oil refinery. The recordings of diurnal sleep showed: a severe disorganization of the first day sleep (very short duration, decrease of PS and SWS in absolute amount); a trend towards better sleep characteristics (duration, PS and SWS amount) through the day-sleep period. Recovery night sleep appeared different when following curtailed night sleep (morning shift) and when following curtailed day sleep (night shift). Nocturnal sleep following immediately the diurnal sleep shows only partly the characteristics of a real recovery. Thus there seems to be a beginning adaptation to schedule reversal. This result supports a rapid shift alternation (3-4 days) which restrains both the cumulated sleep deficit and the adaptation to schedule reversal.

Electroencephalography↗
PubMed1978

[Sleep in children with episodic sleep phenomena: a comparison with the normal child].

(1) The sleep pattern of 23 children, aged 5-12 years, with episodic nocturnal phenomena (night-terrors, somnambulism, rhythmic movements) was recorded during two successive nights. It was compared with that of a group of 21 normal children of the same age. (2) In the pathological group, slow wave sleep (SLP, stages 3 and 4) was significantly shortened during the 2 nights. This deficit mainly involved the first 3h of sleep. (3) As for the slow wave sleep, REM sleep (SP) modifications prevailed during the first hours of sleep. The first REM period was delayed and preceded by more numerous and atypical partial REM periods. The duration of the first REM period increased faster as a function of its latency than in the normal child. (4) In contrast with this difficulty for REM sleep to occur during the first part of the night, the subsequent REM sleep pattern was similar in the 2 groups (total REM sleep duration, mean REM period duration, mean REM cycle duration). For equal latencies, REM periods had similar duration. Finally, the total REM sleep amount was a linear function of the total sleep time, with more or less identical coefficients for the two groups. (5) The part played by these modifications during the first hours of sleep in the occurrence of night terrors and somnambulism is discussed.

Child↗
PubMed1977

[Reticular activity and intracranial pressure. Acute and chronic intracranial hypertension (author's transl)].

Modifications of mesencephalic and bulbar reticular formation activity were studied with microelectrodes during acute and chronic intracranial hypertension. In both cases, the mesencephalic reticular activity increased progressively until a pressure level of 70 to 90 cm of CSF was reached and then fell irreversibly to less than the base value. The bulbar reticular activity followed the same pattern but more slowly. Different hypotheses are advanced to explain these modifications and their meanings.

Animals↗