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Biomedical subjects

J P Lanquart

Publications and source records attributed to J P Lanquart.

6 recordsLinked to original sources
PubMed2000

Characteristics of spontaneous sleep with varying NREMS Episodes in healthy men: implication for delta activity homeostasis.

STUDY OBJECTIVES: We investigated the effects of the variation in the number of NREMS episodes on human sleep, in particular on delta activity distribution. PARTICIPANTS: Forty-one medication-free healthy men without personal or family history of psychiatric disorders. INTERVENTIONS: Subjects slept four consecutive nights, the last three were analyzed. Sleep was undisturbed and uninterrupted following self-selected schedule. RESULTS: With the exception of one night out of 123, subjects slept at least four NREMS episodes with 80% presenting five or six episodes per night. Yet, only 24% slept the same number of NREMS episodes across three nights. Shorter first NREMS episode was associated with greater number of NREMS episodes, and the total number of NREMS episodes was significantly predicted by the duration of the first one. Whether subjects slept four, five or six NREMS episodes, the proportion of TST spent in REMS, total delta power, total spectral power and the rate of delta power in the first NREMS episode did not differ between subjects. In each night, the distribution of delta activity across the first four NREMS episodes was not modified by the total number of NREMS episodes. CONCLUSION: When spontaneous sleep is allowed, healthy men mostly sleep beyond the fourth NREMS episode. Based on delta activity distribution across the first four episodes, we have demonstrated that the number of NREMS episodes does not modify delta sleep homeostasis. Only duration of first NREMS episode predicts the number of NREMS episodes slept. These results suggest that sleep homeostasis and NREMS-REMS alternation may be two independent processes.

Adult↗
PubMed1999

Prenatal exposure to cigarette smoking is associated with a decrease in arousal in infants.

OBJECTIVE: Sudden infant death syndrome has been related to both exposure to prenatal cigarette smoke and impaired arousability from sleep. We evaluated whether healthy infants born to mothers who smoked during pregnancy had higher auditory arousal thresholds than those born to mothers who did not smoke and whether the effects of smoking occurred before birth. STUDY DESIGN: Twenty-six newborns were studied with polygraphic recordings for 1 night: 13 were born to mothers who did not smoke, and 13 were born to mothers who smoked (>9 cigarettes per day). Other infants with a median postnatal age of 12 weeks were also studied, 21 born to nonsmoking mothers and 21 born to smoking mothers. White noise of increasing intensity was administered during rapid eye movement sleep to evaluate arousal and awakening thresholds. RESULTS: More intense auditory stimuli were needed to induce arousals in newborns (P =.002) and infants (P =. 044) of smokers than in infants of nonsmokers. Behavioral awakening occurred significantly less frequently in the newborns of smokers (P =.002) than of nonsmokers. CONCLUSIONS: Newborns and infants born to smoking mothers had higher arousal thresholds to auditory challenges than those born to nonsmoking mothers. The impact of exposure to cigarette smoke occurred before birth.

Arousal↗
PubMed1998

Contribution to the definition of the power bands limits of sleep EEG by linear prediction.

The linear prediction method has been applied to compute the power spectra distribution in 10 healthy young men (aged 17 to 26). For each subject, the local extrema positions have been detected and grouped as a function of their frequency. The computation of a mean frequency distribution for the extrema position, on the 10 subjects, allowed for the definition of eight frequency power bands. The time evolution of these power bands during the first NREM episode has been computed and averaged for the 10 subjects. The cross-correlation analysis demonstrated the relevance of three bands in the range 0-8.10 Hz: delta ]0-2.78] Hz, theta 1 ]2.78-5.42] Hz, theta 2 ]5.42-8.10] Hz. Our extrema study leads to the division of the beta range ]16.25-25.00] Hz into three bands. However, their time evolution does not support the usefulness of the partitioning of the beta range, probably resulting from our too low sampling frequency.

Adolescent↗
PubMed1997

Distribution of delta activity across nonrapid eye movement sleep episodes in healthy young men.

The distribution of delta activity across successive nonrapid eye movement (NREM) sleep episodes and its night-to-night stability across three consecutive nights were investigated by studying delta power with spectral analysis in 31 healthy young men. Repeated-measures analysis of variance (ANOVA) with polynomial contrast was applied to grouped data of absolute delta power and three indexes: (1) the rate of delta power per NREM episode to its duration, 2) the standardized rate for the last NREM episode, and 3) the logarithm of the standardized rate. A significant linear decrease across NREM episodes was observed for each variable in each successive night. In addition, using night as a second within-subjects factor, no night effect was observed. Yet, the subsequent analysis of the logarithmic data yielded greater F values in all three nights' data as well as a linear function that accounted for a greater proportion of total variance than the analysis of the nonlogarithmic data. Since a linear decline for the logarithm of a variable implies an exponential distribution for that variable, we conclude that delta activity is distributed exponentially across NREM episodes, and this finding shows a remarkable night-to-night stability.

Adolescent↗
PubMed1996

Sleep EEG analysis by linear prediction: frequency changes of slow-wave activity within NREM and REM sleep episodes in healthy men.

The linear prediction method was applied to obtain a power spectra estimate of sleep EEG in 10 healthy young men. In order to analyze frequency changes of the slow-wave activity (EEG power in the delta band, 0.05-2.88 Hz), the delta mean frequency was computed for each 20-second sleep epoch. A mean delta mean frequency was calculated for each sleep stage in each individual. Our observations indicate that the delta mean frequency decreases during NREM periods and increases mainly at the onset of the REM episodes. This finding, in parallel with the detailed analysis of slow-wave power variations, leads to an additional description of sleep characteristics during transitions between the NREM-REM sleep episodes.

Adult↗