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Biomedical subjects

A Besset

Publications and source records attributed to A Besset.

At least 55 records · Page 3Linked to original sources

[A world record in marathon tennis: sleep deprivation and performance].

We studied the effects of marked sleep deprivation on the EEG patterns and performance of a physically fit man (age 26) on the occasion of the world record continuous marathon tennis play (147 hours, 20 minutes). Before and immediately after the marathon, the sleep patterns of the player were recorded in our laboratory. After playing for 40 and 80 hours and within 24 hours, the performance changes were evaluated each hour. Amounts of the different sleep stages during the first recovery night compared with those of the baseline indicate an increase of 56% for total sleep time, 54% for stages 1 and 2, 154% for stages 3 and 4 and 20% for REM sleep. During the second recovery night, only REM sleep showed an increase. Activity index showed a marked decrease after 80 hours of sleep deprivation compared with that after 40 hours and was dramatically worsened during nighttime. The number of faults and pauses was also increased after 80 hours, suggesting a clear performance deterioration. Our results confirmed the effects of sleep deprivation on the recovery and performance deterioration.

Adult↗

The validity of the static charge sensitive bed in detecting obstructive sleep apnoeas.

The demand for polysomnographic recordings associated with respiratory control exceeds the capacity of the few existing sleep disorder centres and therefore a simple and inexpensive method is needed for screening and diagnosing sleep-related breathing disorders. The static charge sensitive bed (SCSB) permits long-term recordings of body movements, respiratory movements and the ballistocardiogram (BCG) without electrodes or cables being attached to the subject. The aim of the present study was to test the validity of this particular method in detecting obstructive sleep apnoeas without airflow measurements. Simultaneous SCSB and spirometer recordings were compared in fourteen sleep apnoea patients and six controls. The mean sensitivity of the SCSB method to detect the obstructive apnoeas was 0.92-0.98. The specificity to detect 2 min apnoea epochs was 0.61-0.68 in the apnoea group, while in the control group it was 0.99-1.00. According to this study, the SCSB detects the obstructive events without always distinguishing between severe periodic hypopnoeas and obstructive apnoeas. The sensitivity of the SCSB makes it valuable for screening subjects suspected of having obstructive sleep apnoeas. Further studies will concentrate on a more detailed analysis of the various respiratory, BCG and body movement patterns, which may lead to additional information on the severity of the upper airway obstruction.

Aged↗

Dose-response effects of zopiclone on night sleep and on nighttime and daytime functioning.

Six normal volunteers, aged 20 to 39 years, underwent 2 adaptation nights and three sessions of 2 consecutive experimental nights and days at 1-week intervals, according to a latin-square design. In the three sessions, subjects received either zopiclone, 3.75 mg or 7.5 mg, or placebo at 2215 h in a double-blind protocol. On nights 1 and 2 of each session, subjects were continuously monitored polygraphically, except for a 45-min provoked wake episode 135 min after sleep onset on night 2. Degree of daytime somnolence was assessed during day 1 by means of a multiple sleep latency test (MSLT) and performance evaluation was carried out during night 2 (0000 h) and day 2 (800 h and 1200 h) by means of a battery of four tests. NREM sleep stages 3 and 4 increased significantly after 3.75 mg and 7.5 mg zopiclone (p less than 0.05). No significant differences between placebo and 3.75 mg and 7.5 mg zopiclone were found at any time in the MSLT. Two performance tests (eye-hand coordination test and choice reaction time test) showed a highly significant impairment (p less than 0.01) at 0000 h with 7.5 mg zopiclone; one test (eye-hand coordination test) showed a significant impairment (p less than 0.05) at 0800 h also with 7.5 mg zopiclone and none at 1200 h. From a subjective point of view, depth and quality of sleep were improved, whereas number of awakenings and feeling on awakening were not modified. Side effects (bitter taste, jitteriness, difficulty to concentrate) were reported only with 7.5 mg zopiclone.

Adult↗

[Organization of sleep in recent temporal lobe epilepsy before and after treatment with carbamazepine].

Sleep in epileptic patients with complex partial seizures has been considered as being less well organized than in normal subjects. This study attempted to precise whether this disorganization could be related to the length of the disease and could be improved by carbamazepine treatment. The study was performed in 15 patients with recently diagnosed (less than 3 months) and untreated temporal lobe epilepsy. Neurologic examination and CT scan were normal. Patients did not present a generalized seizure in the preceding 48 hours and during the study. Nocturnal sleep polygraphic recordings were performed: 2 recordings before treatment and 2 others after one month of carbamazepine administration (800 mg/day). Before treatment sleep was characterized by a marked instability (increase in awakenings, shifts in sleep stages, waking after sleep onset, stage 1 duration) when compared to normal subjects. Carbamazepine treatment improved sleep stability. Our data support the hypothesis of another possible mechanism than the occurrence of seizures to explain the disorganization of sleep in temporal lobe epilepsy. On the other hand sleep instability could not be related to the length of the disease since it existed soon after its onset. Carbamazepine treatment improved sleep stability and this improvement could play a role in the therapeutic effect of the drug.

Adolescent↗

[EEG abnormalities of late-onset epilepsy].

Interictal EEG abnormalities were evaluated in 111 epileptic patients in which the first seizure occurred after the age of 18 years. Standard day-time EEG tracings performed prior to and after antiepileptic treatment, and all-night recordings were investigated. Before treatment, waking EEG was normal in 54% of patients. The percentage of normal sleep EEG recordings was only 28.6%. Focal EEG abnormalities were found in 39% of day-time recordings and in 48.6% of sleep recordings, while the percentage of generalized epileptic discharges observed was respectively 7 and 22.8. When considering the category of epilepsy and the etiology, it appears that the primary and secondary generalization of epileptic discharges is reduced with age.

Adolescent↗

HLA-DR2 and narcolepsy.

A positive association between HLA-DR2, DQw1, and narcolepsy was documented in 23 French caucasoid narcoleptic patients, 18 who were heterozygous for DR2 and 5 who were possibly homozygous. An autoimmune mechanism of narcolepsy is proposed with three successive stages, as well as relevant methodology for further investigation. A dominant mode of inheritance of narcolepsy, with an incomplete penetrance, is suggested although not yet evidenced.

Adolescent↗

Are REM cycles in narcoleptic patients governed by an ultradian rhythm?

Twelve narcoleptic subjects experiencing at least five daytime REM sleep episodes were monitored for 34 consecutive hours in the laboratory starting at 2200 h one evening and ending at 0800 h a day and a half later. There was no significant difference between the length of the daytime and nighttime REM cycles. To test the hypothesis that an underlying rhythm governs REM episodes, a grid was constructed on the basis of the mean and the SD of the daytime cycles (starting at 0800 h the first morning) was projected on the following nighttime and its correspondence with actual night cycles was evaluated. Overall, it was observed that the number of night cycles falling within the projected grid was significantly higher than chance (p less than 0.01), indicating that nighttime REM episodes tended to fall within the same periodicity as their preceding daytime episodes. This observation supports the hypothesis that an underlying basic rest-activity cycle governs REM sleep episodes in narcoleptic subjects.

Activity Cycles↗

Daytime sleep characteristics and their relationships with night sleep in the narcoleptic patient.

Thirty-six narcoleptic patients with overwhelming sleep episodes, cataplexy, and sleep onset REM (SOREM) episodes were recorded for 34 continuous hours in the laboratory starting at 2200 h and ending at 0800 h a day and a half later. There were 94 SOREM and 60 sleep onset NREM (SONREM) episodes. While SONREM episodes were evenly distributed across daytime, SOREM episodes peaked between 0800 and 1000, 1200 and 1400, and 1600 and 1800 h. The ratio of SOREM to SONREM episodes was at its highest level between 1200 and 1400 h. Correlation coefficients between night 1 and night 2 for total sleep time (TST) and percentages of sleep stages were all positive and significant, whereas between daytime and each night, they were significant for percentages of stages 1, 2, and REM. Sleep-stage distribution across the last 24 h of continuous recording indicated that although TST levels were higher than that typical of normal subjects, REM sleep and slow wave sleep followed the same circadian distribution as that observed in normal subjects. The results are interpreted as evidence that the daytime sleep of narcoleptic patients is modified, similar to their night sleep, and that SOREM episodes are influenced by a time-of-day effect which culminates between 1200 and 1400 h.

Adolescent↗

[Diminished regional cerebral blood flow during the intercritical period in temporal lobe epilepsy].

Hemisphere and regional cerebral blood flow (CBF) were determined during interictal periods by intravenous Xenon 133 in 43 patients considered to have "temporal" epilepsy and presenting complex partial attacks with altered consciousness and lateralized EEG anomalies predominant in the temporal region. Brain scans were normal in all cases. Three subgroups were differentiated according to EEG and polygraphic examinations during sleep; temporal epilepsy with left or right EEG anomalies, with asynchronous bilateral EEG anomalies, with alternating labile unilateral EEG anomalies. Measurements of CBF were compared with those of normal subjects (n = 13) of comparable age and with those of epileptic patients with cerebral lesions on CT scan (n = 4). In epileptics with left EEG anomalies CBF was diminished by about 25 p. 100 in the left temporal region and from 15 to 22 p. 100 in other regions of the ipsi- and contralateral hemisphere. In epileptics with right EEG anomalies CBF was diminished by 20 p. 100 in the right temporal region but not on the left. CBF in the third group was comparable to that of normal subjects. In epileptics with abnormal CT scans the reduction in CBF could be correlated with EEG and CT scan findings. Studies were also conducted to determine variations in reactivity to CO2 in the areas with reduced flow, during ictal and interictal periods. Results emphasize the value of CBF measurements for investigation of epileptic foci. The importance of areas of reduced blood flow as a parameter of severity and course is discussed, as well as their pathophysiological significance.

Adolescent↗

Increase in sleep related GH and Prl secretion after chronic arginine aspartate administration in man.

Arginine aspartate was administered orally (250 mg/dg/day) for one week to 5 healthy male human volunteers aged 20-35. After this period, the 24 h patterns of growth hormone (GH) and prolactin (Prl) secretion were determined by radioimmunoassay on blood samples withdrawn every 20 min and correlated with the polygraphic recordings of electroencephalogram, electromyogram and electrooculogram. the results were compared to data obtained in identical conditions with the same subjects but after a week of placebo administration. In all 5 subjects the slow wave sleep related GH peak was about 60% higher after a week of arginine aspartate administration than in the control period, with individual changes of +24, +25, +42, +47 and +162%. The nocturnal mean plasma Prl of each subject was higher after arginine aspartate than before. The nocturnal rise of plasma Prl increased from a mean value of +21.5% during the placebo period to +95% at the end of the arginine aspartate treatment. These hormonal modifications were not accompanied by any detectable alteration of sleep organization and specially of the slow wave sleep pattern, suggesting a direct neuroendocrine action of the drug.

Adult↗

[24 hour polygraphic study of the waking-up and falling asleep periods in patients with hepatic encephalopathy (author's transl)].

24 h sleep-waking EEG records of 23 patients with hepatic cirrhosis, 18 having hepatic encephalopathy, were studied. Comparison with a group of normal controls showed an increase in diurnal somnolence (08 h-22 h) and nocturnal waking (22 h-08 h) in all the patients. There was a significant reduction in the longest duration of waking and uninterrupted sleep periods in the patients with cirrhosis. Triphasic waves (characteristic of hepatic encephalopathy) were usually increased during waking and reduced in sleep. The factors involved in this disturbance of sleep-waking patterns in hepatic encephalopathy are discussed (cerebral monoamines, false neurotransmitters, cerebral arteriovenous shunts...).

Circadian Rhythm↗

[All-night polygraphic recordings in the child with suspected epileptic seizures, in spite of normal routine and post-sleep deprivation EEGs (author's transl)].

Normal standard EEGs and normal or borderline EEGs after sleep deprivation in children with one or several suspected epileptic seizures are relatively frequent. All-night polygraphic recordings were performed on 31 children, aged 3-11, who fall into this category, in order to demonstrate epileptiform activity. Three of the recordings were normal, whereas 8 were borderline and 20 showed unequivocal epileptiform activity. The rate of sleep activation is discussed according to the types of epilepsies, the age at the first seizure, the frequency of the seizures, and the position of the seizures within the sleep-waking cycle.

Child↗

[Electrophysiological aspects of alcoholic epilepsy (author's transl)].

Two types of neurophysiological investigations (standard EEG and polygraphic recording of sleep) were performed on a group of subjects suffering from 'alcoholic epilepsy'. Results were then compared with data from normal subjects and chronic alcoholics without epilepsy. Epileptic patterns on standard EEG are rare. They are increased by sleep. Both the alteration of basal activity in wakefulness and the organization of sleep point to a dysfunction of the CNS. The role of chronic alcoholic intoxication in epileptic seizures could be explained through the slowly decreasing biochemical cerebral action after withdrawal, rather than by a local or diffuse effect in the CNS level.

Adult↗

[Hypnotics].

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Barbiturates↗

[Nycterohemeral variations of growth hormone and prolactin in 6 Parkinson's sufferers treated with bromocriptine (author's transl)].

Secretions of GH and of PRL studied over a period of 24 hours in 6 untreated Parkinson's patients showed slight changes. The normal secretion of PRL in the female shows no nocturnal increase in the male. The secretion of GH linked to sleep is identified in the male and not in the female. These variations related to sex are interpreted as an increase in those normally found in the adult and facilitated by age. Bromocriptine given continuously at a dose of 10 to 20 mg/day for periods of 20 days to 6 months, results in suppression or a marked decrease in the 24-hour secretion of PRL. It has virtually no effect upon the secretion of GH. These results show that the dopaminergic regulation of PRL is preserved in Parkinson's disease.

Aged↗