Accuracy of clinical evaluation in pediatric obstructive sleep apnea.

Eighty-two children underwent polysomnography (PSG) for symptoms suggestive of obstructive sleep apnea (OSA). Symptoms reported included snoring, witnessed apneic episodes, daytime somnolence, mouth breathing, and enuresis. Tonsillar size, nasal airway patency, and percentile weight were recorded. OSA was diagnosed on PSG when obstructive events were noted and apnea + hypopnea index was five or more per hour. The overall predictive accuracy of clinical suspicion of OSA was 25 (30%) of 82. Predictive accuracies (as a percentage of those with symptoms/signs who have OSA) and prevalences (as a percentage of those with OSA who have the symptom/sign), respectively, were for moderate snoring 29% (12 of 41), 48%; loud snoring 31% (11 of 35), 44%; witnessed apneas 32% (22 of 69), 88%; enuresis 46% (11 of 24), 44%; 2+ tonsillar size 37% (21 of 57), 84%; 3+ tonsillar size 33% (3 of 9), 12%; 90th percentile weight or greater 26% (7 of 27), 28%; 10th percentile weight or less 33% (5 of 15), 20%. Multiple regression analysis did not reveal a significant association between clinical parameters and the presence of OSA as defined by PSG.

Topiramate: a potent anticonvulsant in the amygdala-kindled rat.

Topiramate, a chemically novel anti-epileptic drug, was evaluated in amygdala-kindled seizures in rats. Topiramate, given at doses between 0.63 and 80 mg/kg i.p. and p.o. 4 h before kindling stimulation, exhibited a dose-related inhibition on all seizure parameters measured, i.e. behavioral seizures, forelimb clonus, amygdala and cortical afterdischarges. The ED50 values obtained with topiramate on kindled seizures in all parameters tended to be lower than those observed on maximal electroshock seizures in rats. After oral drug administration, the ED50 values were: on forelimb clonus, 7.25 mg/kg; on amygdala afterdischarges 7.09 mg/kg and on cortical afterdischarges 7.12 mg/kg. After i.p. drug administration, the ED50 values were: on forelimb clonus, 10.6 mg/kg; on amygdala afterdischarges, 13.9 mg/kg and on cortical afterdischarges, 10.4 mg/kg. The data obtained after i.p. drug administration are in line with the suggestion that topiramate primarily blocks spread of seizures.

Topographical and temporal patterns of brain activity during the transition from wakefulness to sleep.

Changes in electroencephalographic (EEG) spectral power, coherence and frequency were examined for the last minute of wakefulness and the first minute of sleep via topographical mapping. Data were also analyzed across sequential 1-minute samples of wake, stage 1 and stage 2 sleep. Not all brain regions exhibited the same EEG changes during the transition and not all brain regions were found to change at the same time. Brain sites closest to the midline (e.g. F4, C4, P4, O2) showed significant changes in EEG power (increases in theta and decreases in alpha power) during the transition to sleep, whereas brain sites most lateral to the midline (e.g. Fp2, F8, T4) showed little change. Decreases in alpha coherence were observed from wakefulness to sleep for brain site comparisons furthest away from each other (e.g. T3 vs. T4, T5 vs. T6, F7 vs. F8, F3 vs. O1, F4 vs. O2). Spectral analysis of EEG activity revealed that the time of significant change in EEG power varies among brain regions. Decreases in alpha power continued to occur later into the transition period for the posterior regions of the brain (O2, P4).

K-complexes: are they signs of arousal or sleep protective?

The number of K-complexes recorded at the central-temporal EEG derivation (C3-T3) during 5 min periods for both the ascending and descending phase of Stage 2 of NREM sleep for cycles 1, 2. etc. were counted in 10 subjects for each of the following five groups: normal persons, patients with a primary generalized form of epilepsy, narcolepsy, insomnia and obstructive sleep apnoea. The differences in time spent in different stages of sleep were as expected for these types of patients. A 2-within, 1-between factors, repeated measure ANOVA was applied to the data on K-complexes. Overall, there was no significant difference between the number of K-complexes observed during the ascending and descending phases of the different sleep cycles. Patients with a sleep disorder had significantly less well-defined K-complexes than the normals and the patients with a primary form of generalized epilepsy: for insomnia (P = 0.035), for apnoea (P = 0.011) and for narcolepsy (P = 0.001). There was a significant, but very low correlation coefficient between the number of K-complexes observed during Stage 2 of NREM sleep and the time spent during that stage for all groups combined (Rho 0.27, P = 0.002) and for the narcoleptic patients (Rho 0.44, P = 0.017). In all, the findings lend support to the hypothesis that a K-complex can be seen as a 'defensive response', or has a sleep protective function.

Changes in cerebral blood flow velocity associated with biofeedback-assisted relaxation treatment of migraine headaches are specific for the middle cerebral artery.

Twenty-five patients with diagnosed migraine headaches were randomly assigned to a biofeedback-assisted relaxation therapy group or to a group who relaxed on their own. This study confirmed that the biofeedback trained group significantly decreased pain and medication more than the self-relax group. The best responders were those with the more elevated initial cerebral blood flow values and the changes in cerebral blood flow were specific for the middle cerebral artery.

Sleep disruption in Parkinson's disease. Assessment by continuous activity monitoring.

OBJECTIVE: To assess differences in activity and immobility during sleep between patients with Parkinson's disease (PD) and healthy subjects and to evaluate the relations of clinical variables with the motor activity measures in patients with PD. DESIGN: Survey, case series. SETTING: University hospital outpatient neurology department and urban population in Leiden, the Netherlands. Motor activity was recorded during 6 successive nights at home with a wrist-worn activity monitor. PARTICIPANTS: Eighty-nine patients with PD and 83 age-matched healthy controls. MAIN OUTCOME MEASURES: For each subject, three mean measures reflecting activity or immobility during the nocturnal period were calculated. RESULTS: Compared with the healthy elderly subjects, patients with PD have an elevated nocturnal activity level and an increased proportion of time with movement, indicating a more disturbed sleep. The mean duration of nocturnal immobility periods was similar for both groups. This measure, however, did reflect the self-reported disturbed sleep maintenance in both groups. The daily dose of levodopa or the use of dopamine agonists in patients not receiving levodopa, rather than disease severity, proved to be the best predictors of nocturnal activity. CONCLUSIONS: We hypothesize that in mildly to moderately affected patients with PD, levodopa or dopamine agonists cause sleep disruption by their effects on sleep regulation. In more severely affected patients, the beneficial effects of these drugs on nocturnal disabilities that cause sleep disruption in PD prevail.

Effect of biofeedback-assisted relaxation on migraine headache and changes in cerebral blood flow velocity in the middle cerebral artery.

Twenty-three patients with diagnosed migraine headaches were randomly assigned to a biofeedback-assisted relaxation therapy group or to a group who relaxed on their own. The biofeedback trained group decreased pain and medication more than the self relax group. Cerebral blood flow velocity was measured in the middle cerebral artery with transcranial doppler (TCD). The trained group significantly reduced systolic and mean cerebral blood flow velocity on the side with the highest velocity.

Experimental evidence of penile erections during paradoxical sleep in the rat.

We have developed a new technique to chronically monitor penile erections in the rat across behavioural states. This technique, involving chronic erectile tissue pressure monitoring and simultaneous ischiocavernosus and bulbospongiosus (IC-BS) muscle electromyography, demonstrates for the first time that rats exhibit penile erections during paradoxical sleep (PS). No erectile events were observed during slow wave sleep. These PS-related erectile events were similar to visually confirmed, waking state, erections in that they were associated with an increase in baseline erectile tissue pressure and, with IC-BS muscle bursts, dramatic suprasystolic penile pressure peaks often greater than 1000 mmHg. PS-related erections were 11 +/- 7 s in duration and were observed in 28.5% of all PS episodes. This method of chronic penile erection monitoring in the rat provides a new animal model for investigating neural mechanisms of sleep-related erections.

Aging and changes in phasic events during sleep.

Changes in phasic events in the elderly are reviewed. Such phasic events may in part be determined by the macrostructure of sleep (sleep stages). Therefore, a brief description of sleep architecture and EEG morphology in the aged person is given. Second, there is a marked variability among individuals in the number of spindles and K-complexes and more so in older individuals than in younger. However, there is an overall decrease in these events with age. The characteristics of these events (amplitude, frequency content, and distribution) change simultaneously. Third, the number of rapid eye movement occurring during REM sleep decreases with aging, but important gender differences exist, in that women generally maintain a higher REM density. The degree of changes in phasic events might correlate with mental deterioration (sleep cognition theory), but physical factors might also be the underlying reason for the observed changes. Whether these changes are indicative of the individual's ability to maintain sleep remains to be determined.

Nocturnal activity and immobility across aging (50-98 years) in healthy persons.

OBJECTIVE: To measure the influence of age on measures of nocturnal activity and immobility in 100 healthy subjects aged 50 to 98 years. DESIGN: Cross-sectional study. SETTING: Urban population in Leiden. Recordings were performed at home while the subjects maintained their habitual 24-hour pattern of activities. PARTICIPANTS: 100 subjects without a history of major medical disorders and a normal neurological examination and performance-oriented assessment of gait (Tinetti). MEASUREMENTS: Motor activity was recorded during six successive nights with a wrist-worn activity monitor. The occurrence of supra-threshold motor activity was recorded over 15-second epochs. A questionnaire was used to evaluate sleep habits and the occurrence of sleep disturbances. Four mean measures reflecting activity or immobility during the nocturnal period were calculated for each subject. RESULTS: Only one out of four measures, (ie, the nocturnal proportion of time with movement, increased with age for females. For males, no age effects emerged. The mean duration of nocturnal immobility periods was higher in females than in males. Also, for females, the use of hypnotics increased with successive decades. Sex and the use of hypnotics were significantly related to the mean duration of immobility periods. CONCLUSION: If care is taken not to confound aging with illness, measures of nocturnal activity and immobility reveal only marginal effects of aging.

Aging of core and optional sleep.

Two consecutive 24-hr ambulatory recordings of 14 healthy elderly persons (7 women, 7 men, ages 88-102) and of 19 healthy young adults (10 women, 9 men, ages 25-35) were evaluated. In addition to the classical sleep parameter analysis, sleep structure was also analyzed in terms of a proposed distinction between "core" and "optional" sleep (Horne 1989). Core sleep is the essential part of the sleep and is mainly slow wave sleep. This type of sleep is composed of stages 3 and 4 on non-REM sleep (NREM 3-4). Core sleep is obtained during the first three sleep cycles and the remainder of the night sleep is considered optional sleep. Optional sleep is more altered than core sleep. However, in both optional and core sleep, NREM sleep and REM are reduced. There is also an increase in drowsiness and in the time spent awake after sleep onset; however, the extent of these effects are more obvious in elderly men. Aging effects of slow wave sleep probably represent an amplification of the changes as observed in awake electroencephalic (EEG) patterns in healthy seniors. The decrease in slow wave sleep (stages NREM 3-4) is gender related and prevails in elderly men. REM sleep diminishes with increasing age. In the elderly, most REM sleep occurs at the beginning of the night. This contrasts to younger persons where the duration of REM sleep is longer at the end of the night. Furthermore, a decrease in REM sleep latency is particularly obvious in elderly men and probably secondary to the curtailment of slow wave sleep. The ultradian NREM-REM cycle rhythm (as defined by the periodic occurrence of REM sleep) shows a monophasic trend suggesting a diminished adaptive function of aged sleep. The informative value of true, continuous ambulatory recordings in the assessment of sleep-wakefulness patterns in normal and pathological aging is stressed.

Ambulatory monitoring of sleep-wakefulness patterns in healthy elderly males and females (greater than 88 years): the "Senieur" protocol.

OBJECTIVE: The study was designed to investigate sleep-wake patterns in healthy elderly men and women (greater than 88 years) using ambulatory recording techniques. DESIGN: Cross-sectional observations on 2 consecutive days. METHODS: Two consecutive 24-hour recordings were made. Each 30-second period of the recording was scored as characteristic of wakefulness, REM, and non-REM sleep (stages 1-4). SETTING: Interviews and recordings were done in the home of the elderly, not interfering with the habitual routine. PARTICIPANTS: Among eligible members of the "Senieur" protocol, screened for wellness, seven females (88-102 years) and seven males (88-98 years) volunteered to participate. MAIN OUTCOME MEASURES: Organization of sleep, sleep structure, and daytime mapping. RESULTS: There was no difference between the first and second night recording. Important gender differences were observed: males had significantly less total sleep, shorter REM latency, more transitions to wake from REM, less NREM 3 sleep, and virtually no NREM 4. Daytime napping, REM amount, and distribution did not show sex differences. Although the variability in the amount of napping was considerable, it occupied less than 10 percent of the total sleep time in both women and men. Daytime napping was unrelated to sleep characteristics. CONCLUSIONS: Ambulatory sleep-wake recordings allow an objective and critical evaluation of sleep function in normal aging. Interesting findings include a shift of REM sleep to the first part of the sleep period an increased cycle variability, and non-correlation of night-time sleep with daytime napping. In contrast to earlier findings in elderly persons, a polygraphic and subjective first-night effect was lacking.

Effects of zolpidem and flunitrazepam on nocturnal sleep of women subjectively complaining of insomnia.

Eighteen non-pregnant woman complaining about insomnia were polysomnographically investigated for 3 nights with weekly intervals. They received placebo, 2 mg flunitrazepam or 10 mg zolpidem according to a cross-over double blind design. The patients were selected by general practitioners on the basis of subjective complaints. Zolpidem is a recently introduced short-acting imidazopyridine hypnotic, binding to a subunit of the benzodiazepine 1 receptor. Flunitrazepam is a well-known hypnotic, binding to both the benzodiazepine 1 and 2 receptor subtypes. Objective recording did not substantiate the subjective complaint of insomnia. Sleep patterns during placebo differed only little from that expected from age matched healthy persons. Both flunitrazepam and zolpidem significantly shortened sleep onset (5 min of continuous sleep beginning with NREM 1 sleep). The sleep composition following flunitrazepam was characterized by an increase in NREM 2, a prolongation of the time of REM sleep, a reduction of REM sleep and an increase in NREM 3-4 sleep during the first 2 h of sleep. The sleep composition following zolpidem resembled more than seen in persons without sleep complaints. However, as compared to placebo, there was a decrease of the time spent awake during sleep and an increase in NREM 3-4 during the first 2 of sleep.

Long-term EEG monitoring in the early premature: developmental and chronobiological aspects.

Long-term cassette EEG monitoring in the neonatal intensive care unit has established prognostic criteria regarding the developmental outcome by quantifying seizure activity. The clinical significance of the organization of continuous and discontinuous EEG patterns in the early premature is still an open question. This report presents quantified EEG data from repeated 24 h records during the first week of life in premature infants (conceptional age less than 32 weeks) with and without ultrasound evidence of intracerebral hemorrhage. The repartition and evolution of EEG background activity is not a reliable parameter regarding pathology. The continuity index is rather a maturational variable and its ultradian fluctuation is an early expression of the "basic rest activity cycle" (BRAC) rhythm.

Ambulatory first night sleep effect recording in the elderly.

The concept of a first night effect on sleep patterns, specifically in relation to age is a controversial topic in the literature. Our data are obtained during two consecutive 24-h ambulatory home sleep-wake recording in 10 elderly persons with a mean age of 85.5 years. Polysomnographic recordings indicated that a first night effect is present in old age, even using home recording, and that several types of insomnia can be differentiated, stressing that sleep cycle parameters should be taken into account. It is suggested that the first night effect is a 'miniature' replication of a psychophysiological insomnia.

Variability of normal sleep patterns in 40 consecutive ambulatory sleep-wakefulness records.

Sleep-wakefulness (S-W) patterns were recorded continuously for 40 consecutive 24 h using subcutaneous chronic electrodes and an ambulatory cassette recorder in a healthy 57-year-old volunteer. Variability of sleep patterns was assessed in steady-state conditions and in the course of a scientific journey encompassing flights in both west/east and south/north directions. Data were compared with findings from age-matched laboratory control records. Polysomnographic evaluation of our sleep data shows: (1) Stability of the first 3 sleep cycles and variability of the remaining sleep period with respect to both duration and structure. Vulnerability of REM sleep to environmental interference. (2) Stability of the WASO/drowsiness cluster as an intraindividual biological trait independent of social interactions. The clinical relevance of ambulatory serial recording is stressed. (3) The role of the first sleep cycle structure in the chronobiological adaptation process is documented. Apparently travelling in south/north directions may have similar or even more polygraphic implications than west/east transfer.

Measuring sleep (dys)function by polysomnography.

A vigilance state is characterized by a particular activity state of the motorIautonomic and psychiclcognitive functional systems. S-W screening is possible through poly graphic monitoring of physiological variables and signals. Quantification of these signals introduces a set of parameters allowing the characterisation of the sleep (dys)function. There is no consensus regarding the choice or definition of these parameters. A particular cluster is presented and their informative value with respect to clinical practice and research is discussed.