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H Bastuji

Publications and source records attributed to H Bastuji.

15 recordsLinked to original sources
PubMed1995

Brain processing of stimulus deviance during slow-wave and paradoxical sleep: a study of human auditory evoked responses using the oddball paradigm.

Auditory evoked potentials (AEPs) to frequent (90%) and deviant (10%) tones were recorded during both wakefulness and all-night sleep in eight drug-free volunteers. During presleep waking (10:00-11:00 p.m.), deviant stimuli elicited, in all subjects, a prominent "P300" wave of parieto-central topography, culminating at 344 ms (average), which was absent in response to frequent tones. This "presleep P300" was delayed and reduced relative to values obtained during full wakefulness (3:00-7:00 p.m.) in a control group. Passage from waking to sleep stage I was characterized by a progressive attenuation and delay of the P300 wave in response to deviant stimuli, without major changes in AEP morphology as compared to the waking state. Thus, in terms of cognitive evoked potentials (EPs), sleep stage I appeared more as a "weak" state of wakefulness than a true phase of sleep. During sleep stages II, III, and IV, both frequent and deviant tones evoked AEPs that closely resembled K-complexes. Responses to rare stimuli were four-to-five times larger than those to frequent tones, this likely being the result of K-complex habituation to monotonous stimuli. During paradoxical sleep (PS), AEP morphology again became comparable to that of wakefulness. Notably, a "P3" wave with similar topography as the waking P300 appeared in response to deviant stimuli exclusively. Thus, even though the brain seems able to detect stimulus deviance during all sleep stages, only during stage I and PS were the electrophysiological counterparts of deviance detection comparable to those of the waking state. Our results support the view that PS is not a state of "sensory isolation"; failure to respond to external stimuli during this stage may depend upon mechanisms occurring only after the sensory input has undergone cognitive analysis.

Adult↗
PubMed1994

[Rhythms of falling asleep persisting in adults. Two cases without mental deficiency].

Nocturnal rhythmic movements (jactatio capitis nocturnus, JCN) are very frequent in young children but persist only rarely in adults; studies including sleep recordings are exceptional in those cases. We report two new cases of young adults with JCN persisting since the first year of life, associated with restless sleep and diurnal sleepiness. Several episodes of JCN were recorded in each of the two patients; they always occurred after a period of paradoxical sleep, the waking phase preceding the rhythmic movements which are sometimes very short (1 s). The pathophysiology of adult JCN is discussed as a behavioral disorder of sleep onset conditioning or a disorder of sleep maintenance.

Adult↗
PubMed1989

[Nocturnus terrors--somnambulism].

Among disorders of sleep in children, pavor nocturnus ("night terrors") is common and considered harmless. Yet the clinical picture, the child's personality and the polygraphic electroencephalographic recordings suggest that it should be treated sooner and more often than is usually done. Somnambulism ("sleep walking") also is very frequent. It has no consequences in most cases, but it may be the cause of serious events such as falling out of a window which is rare but may result in death or disablement. Some children have repeated attack of somnambulism, and these constitute a true pathology of sleep requiring a specific treatment that will cure or improve. All this must be known to the practitioner who will inform the parents.

Adolescent↗
PubMed1989

Changes of middle latency auditory evoked potentials during natural sleep in humans.

During natural nocturnal sleep, Na and Pa middle latency auditory evoked potentials (MLAEPs) underwent significant variations which were related to sleep stages. The deepening of sleep from stage II to stage IV was paralleled by a latency shift and an amplitude decrease of Na and Pa, while MLAEPs were similar in wakefulness and REM sleep. Moreover, Na and Pa components tended to shift over the hemisphere contralateral to the stimulated ear during sleep. These findings demonstrate that the responsiveness of the auditory cortex to acoustic stimuli is modulated during sleep. Vigilance should be monitored during MLAEP recordings in patients.

Adult↗
PubMed1988

BAEP latency changes during nocturnal sleep are not correlated with sleep stages but with body temperature variations.

Serial BAEPs and polysomnograms were recorded during nocturnal sleep in 8 normal subjects. Wave V latency and the I-V interval were found to increase significantly during stages II, III + IV and paradoxical sleep when compared to waking. Trend curves of BAEP latencies showed that these shifts were independent of sleep stages and reversed at the end of the night. BAEP changes were found to be related to physiological hypothermia during the night.

Adult↗
PubMed1988

Successful treatment of idiopathic hypersomnia and narcolepsy with modafinil.

1. Modafinil, a putative central alpha 1 adrenergic agonist, was tested in idiopathic hypersomnia and narcolepsy. 2. Sleep attacks and drowsiness were significantly decreased in 83% of 18 hypersomniac subjects and 71% of 24 narcoleptics. 3. When cataplectic episodes were not totally suppressed the association of a low dose of Clomipramine was successful in improving them. 4. Modafinil, used for at least 3 years in some patients, produces, in most cases, no peripheric sides effects, does not disturb night sleep and is never responsible of tolerance of drug dependence.

Adrenergic alpha-Agonists↗
PubMed1988

[HLA and narcolepsy. Apropos of 28 cases including 2 negative HLA-DR2].

Association between narcolepsy and HLA-DR2 antigen is the strongest so far described between an HLA antigen and a disease. Among 28 narcoleptic patients, we found two HLA-DR2 negative cases: a caucasoid woman also suffering from dystrophia myotonica and a negroid. All of our patients were HLA-DQW1 positive. An hypothetical narcolepsy susceptibility gene could be located in the HLA region, closer to the DQ than to the DR gene. It could be a pathologic allele of a sleep controlling gene in linkage disequilibrium with DQW1. Presence of DQW1 is a quasi-requisite for the expression of narcolepsy. It is not sufficient as it is observed in 70 p. 100 of controls.

Adolescent↗
PubMed1986

[Comparison between good and poor sleep in the 20 to 30-year-old age range: polygraphic findings and psychopathologic aspects].

Fifty-six poor sleepers, aged from 20 to 30, were compared with 46 good sleepers of the same age regarding objective sleep parameters and personality. A gradation of sleep disorders was observed. The degree of sleep disorders was found to be directly proportional to the degree of psychological disturbance. Psychophysiological group of poor sleepers exhibited objective differences from good sleepers during the first cycle only (lack of SWS and REM sleep). Sleep organization in the first cycle seemed important for the estimation of poor or good sleep by the sleeper.

Adult↗
PubMed1986

Nocturnal continuous infusion of growth hormone (GH)-releasing hormone results in a dose-dependent accentuation of episodic GH secretion in normal men.

Fluctuations in plasma GH levels have been found in patients with acromegaly who have continuously elevated levels of ectopically produced GH-releasing hormone (GHRH). Likewise, plasma GH fluctuations have been found in normal subjects receiving continuous GHRH infusions. We report the effects of two doses of GHRH, administered by constant infusion, on nocturnal GH secretion in six normal young men. Each received, in random order, 2.5 ng/kg X min GHRH, 15 ng/kg X min GHRH, and 0.15 M NaCl. During both GHRH doses, a highly significant increase in total nocturnal GH secretion was found (P less than 0.001) as well as an increase in GH secretion during different periods of the night. Nocturnal GH secretion was episodic during the GHRH infusions, with an increase in the number and magnitude of the peaks compared to those during the NaCl infusion. Plasma immunoreactive GHRH concentrations plateaued at 1 h during the high dose and at 3 h during the low dose GHRH infusion. Sleep parameters, including total sleep time, sleep latency, and duration and timing of the different sleep stages, were not affected by GHRH infusions. We conclude that GHRH, continuously infused, increases nocturnal GH secretion according to the dose, while the episodic pattern of GH secretion is maintained.

Adult↗
PubMed1985

[Value of the sleep diary in the study of vigilance dis].

This study presents an easy and practical subjective method for evaluating vigilance disorders: the sleep diary. We used it in hypersomnia and deficits of waking. Sleep diaries were filled in by 10 control and 22 hypersomniac subjects. Twenty-four hour polyhypnographic recording allowed the classification of hypersomnia as 13 narcolepsies, 9 hypersomnias with a prevalence of PS, 2 'harmonious' hypersomnias and 1 waking deficit. The sleep diary data (amount of nocturnal sleep and diurnal sleep onset and vigilance decrease) were compared with polygraphic results. According to the diary data, 3 groups of hypersomnia appeared with regard to the time at which sleep onset occurred. The first group presented an increase of sleep onsets at 2 p.m. In the second group, almost exclusively composed of narcoleptic subjects, sleep onsets occurred every 2 h and in the third group they were distributed throughout the day. These results suggest different physiological mechanisms for these 3 groups of hypersomnia. Finally, the sleep diary seems to be an easy and cheap method of evaluating vigilance disorders in hypersomniac subjects during their everyday life.

Adult↗
PubMedDate not supplied

Mapping study of somatosensory evoked potentials during selective spatial attention.

We have investigated the effects of selective spatial attention on early and middle-latency SEPs. Baseline control responses to electrical stimulation of 2 digits of the hand were recorded first in conditions of mental relaxation, in the absence of any cognitive task, to obtain truly 'neutral' responses uncontaminated by cognitive components. Then, during a 'task condition,' identical stimuli were applied to the same two fingers, but the subject's attention was driven towards the stimulated territory by the bias of mechanical taps delivered to the same digits. The earliest effect of directing attention towards the territory stimulated was a positive shift on contralateral somatosensory responses, with onset at 27.4 +/- 4 msec post stimulus. This SEP modification: (a) did not entail any change in the scalp distribution of components, as assessed by topographic mapping, and (b) was not present when attention was directed towards the hand contralateral to that receiving electrical stimuli. A second effect was represented by a parieto-central negativity in the 60-80 msec latency range; this feature could also be observed during contralaterally driven attention and was associated with topographical changes in SEP scalp distribution. Finally, a late centro-frontal negativity beginning at 90-100 msec (N140) appeared during ipsilateral attention, while P100 was not enhanced. Subcortical P14 and primary cortical N20 were not significantly affected by the tasks. We conclude that the 'early positive shift' is linked to the spatial aspects of selective attention and represents in part modulation of obligatory components (P25 through P45) existing in control SEPs; it probably corresponds with the deflections with similar polarity and time-course that have been described by others in response to somatosensory target stimuli. Conversely, 60-80 msec negative enhancement is less spatially selective and may represent non-specific arousal effects. The late negative component (N140) shares several features with the 'processing negativity' described in auditory paradigms and could represent the equivalent of this effect in the somatosensory system.

Adult↗
PubMedDate not supplied

Unmasking of cortical SEP components by changes in stimulus rate: a topographic study.

We performed topographic mapping of somatosensory responses to median nerve stimulation delivered at 2, 5 and 10 Hz. Parietal N20 was significantly attenuated in 10 Hz somatosensory evoked potentials (SEPs), while central P22 diminished between 2 and 5 Hz, remaining stable thereafter. The single component most affected by increasing stimulus rate was N30, which abated by more than 50% in 10 Hz SEPs, as compared with basal responses. N30 attenuation disclosed the existence of an earlier negative component, N24, which appeared as a notch on the N30 ascending slope in 2 Hz SEPs, but became a well-defined peak at higher stimulus rates. The N24 negativity was not significantly modified by stimulus rate; it had a parietal counterpart (P24) with the same peak latency and identical behavior during the experimental procedure. Both P24 and N24 could be differentiated from central P22 on the basis of topographical distribution and response to stimulus frequency. P22 topography could be the result of a radially oriented generator, while P24/N24 appeared as the two poles of a neural source tangential to the scalp. P27 was seen in 40% of the subjects only; it is suggested that P27 is itself a composite potential to which the generator of N30 could contribute in part. We conclude that there is no single "optimal" stimulation rate for SEP recording. On the contrary, combination of different frequencies of stimulation should enhance the diagnostic utility of this technique by allowing a more selective assessment of overlapping activities.

Adult↗