Parental report of sleep problems in Down syndrome.

BACKGROUND: Children with Down syndrome (DS) suffer from sleep problems, including sleep maintenance problems, as well as snoring, and other symptoms of disordered breathing. To examine sleep in DS, we gave parents a questionnaire assessing their child's sleep. MATERIALS AND METHODS: The parents of 35 children with DS (mean age = 12.65 years, range = 7-18 years) completed the 33-item Children's Sleep Habits Questionnaire. RESULTS: Eighty-five per cent of our sample had sleep disturbance scores in the clinical range (mean = 48.63, SD = 7.15, range = 34-64). Our sample also had significantly elevated scores on the Bedtime Resistance, Sleep Anxiety, Night Wakings, Parasomnias, Sleep Disordered Breathing and Daytime Sleepiness subscales. CONCLUSIONS: Children with DS are at risk for developing symptoms of sleep disordered breathing, and may have additional sleep problems that are unrelated to sleep disordered breathing.

Pharyngeal critical pressure in children with mild sleep-disordered breathing.

There is evidence that narrowing or collapse of the pharynx can contribute to obstructive sleep-disordered breathing (SDB) in adults and children. However, studies in children have focused on those with relatively severe SDB who generally were recruited from sleep clinics. It is unclear whether children with mild SDB who primarily have hypopneas, and not frank apnea, also have more collapsible airways. We estimated airway collapsibility in 10 control subjects (9.4 +/- 0.5 yr old; 1.9 +/- 0.2 hypopneas/h) and 7 children with mild SDB (10.6 +/- 0.5 yr old; 11.5 +/- 0.1 hypopneas/h) during stable, non-rapid eye movement sleep. None of the subjects had clinically significant enlargement of the tonsils or adenoids, nor had any undergone previous tonsillectomy or adenoidectomy. Airway collapsibility was measured by brief (2-breath duration) and sudden reductions in pharyngeal pressure by connecting the breathing mask to a negative pressure source. Negative pressure applications ranging from -1 to -20 cmH(2)O were randomly applied in each subject while respiratory airflow and mask pressure were measured. Flow-pressure curves were constructed for each subject, and the x-intercept gave the pressure at zero flow, the so-called critical pressure of the upper airway (Pcrit). Pcrit was significantly higher in children with SDB than in controls (-10.8 +/- 2.8 vs. -15.7 +/- 1.2 cmH(2)O; P < 0.05). There were no significant differences in the slopes of the pressure-flow relations or in baseline airflow resistance. These data support the concept that intrinsic pharyngeal collapsibility contributes to mild SDB in children.

Nonpharmacologic treatment of chronic insomnia. An American Academy of Sleep Medicine review.

This paper reviews the evidence regarding the efficacy of nonpharmacological treatments for primary chronic insomnia. It is based on a review of 48 clinical trials and two meta-analyses conducted by a task force appointed by the American Academy of Sleep Medicine to develop practice parameters on non-drug therapies for the clinical management of insomnia. The findings indicate that nonpharmacological therapies produce reliable and durable changes in several sleep parameters of chronic insomnia sufferers. The data indicate that between 70% and 80% of patients treated with nonpharmacological interventions benefit from treatment. For the typical patient with persistent primary insomnia, treatment is likely to reduce the main target symptoms of sleep onset latency and/or wake time after sleep onset below or near the 30-min criterion initially used to define insomnia severity. Sleep duration is also increased by a modest 30 minutes and sleep quality and patient's satisfaction with sleep patterns are significantly enhanced. Sleep improvements achieved with these behavioral interventions are sustained for at least 6 months after treatment completion. However, there is no clear evidence that improved sleep leads to meaningful changes in daytime well-being or performance. Three treatments meet the American Psychological Association (APA) criteria for empirically-supported psychological treatments for insomnia: Stimulus control, progressive muscle relaxation, and paradoxical intention; and three additional treatments meet APA criteria for probably efficacious treatments: Sleep restriction, biofeedback, and multifaceted cognitive-behavior therapy. Additional outcome research is needed to examine the effectiveness of treatment when it is implemented in clinical settings (primary care, family practice), by non-sleep specialists, and with insomnia patients presenting medical or psychiatric comorbidity.

Patterns of waking EEG spectral power in chemically intolerant individuals during repeated chemical exposures.

Previous studies indicate that low level chemical intolerance (CI) is a symptom of several different controversial conditions with neuropsychiatric features, e.g., chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivity, and "Persian Gulf Syndrome". Prior studies suggest that limbic and/or mesolimbic sensitization may contribute to development of CI. The purpose of this report was to document the waking electroencephalographic (EEG) patterns of individuals with CI during chemical exposures presented over repeated sessions. Three groups of adult subjects who were recruited from the community participated in the study: self-reported CI who had made associated lifestyle changes due to their intolerance (CI/ LSC), self-reported CI who had not made such changes (CI), and normal controls without self-reported CI. Subjects underwent two sessions involving one-minute EEG recordings during exposures to low level chemical odors (a probe for limbic activation). The CI, but not the CI/ LSC, subjects had increased absolute delta power after the chemical exposures during the second, but not the first, session. The findings support the neural sensitization hypothesis for intolerance to low levels of environmental chemicals in vulnerable individuals. As in human studies of stimulant drug sensitization, those with the strongest past history with sensitizing agents may not show-term sensitization to low level exposures in the laboratory.

Psychophysiological insomnia: the behavioural model and a neurocognitive perspective.

A number of paradoxes are apparent in the assessment and treatment of psychophysiological insomnia and sleep state misperception. Three of these paradoxes exist as discrepancies between polysomnographic (PSG) measures and the subjective impressions regarding sleep quality and quantity. The remaining incongruity exists largely within the objective domain. In the case of subjective-objective discrepancies, patients with insomnia: (1) frequently identify themselves as having been awake when awakened from PSG defined sleep; (2) tend to overestimate sleep latency and underestimate total sleep time as compared with PSG measures; (3) appear to derive more benefit from pharmacotherapy that can be explained by objective gains. The remaining paradox pertains to the observation that hypnotic medications, by and large, do not normalize sleep architecture or produce a more 'sleep-like' EEG. In this paper, we review possible explanations for these various paradoxes, introduce a new perspective and suggest possible research avenues. The model introduced is based on the observation that beta and/or gamma activity (which have been found to be associated with cognitive processes) is enhanced in insomnia at or around sleep onset. We propose that this kind of high frequency EEG activity may interfere with the normal establishment of sleep onset-related mesograde amnesia. As a result, the patient with insomnia maintains a level of information and/or memory processing that blurs the phenomenological distinction between sleep and wakefulness and influences retrospective judgments about sleep initiation and duration.

Mesograde amnesia during the sleep onset transition: replication and electrophysiological correlates.

The present study was designed to explore mechanisms of amnesia for meaningful auditory material presented during the sleep onset transition. Thirty undergraduate subjects (17 female, 13 male) were presented with auditory stimuli in an oddball paradigm until sleep onset. Subjects were allowed to accumulate either 30 seconds or 10 minutes of sleep, then awakened and tested on free recall and recognition memory for the meaningful stimuli. After 10 minutes of sleep, but not after 30 seconds of sleep, subjects had profound amnesia on free recall for stimuli presented in the 4-minute window prior to sleep onset. Increased beta electroencephalograph (EEG) power during the sleep period correlated positively with recall of stimuli in the 4-minute presleep window. Event-related potential recordings provided suggestive evidence that subjects continued to process the auditory stimuli to some extent during the sleep onset transition. When allowed to sleep for 10 minutes, subjects evidenced a mixed anterograde and retrograde amnesia for auditory stimuli presented in the 4-minute window prior to sleep onset. The results are discussed in terms of stimulus encoding, consolidation, and retrieval.

Sleep and the menstrual cycle.

To evaluate changes in sleep across the phases of the menstrual cycle, sleep-wake diaries were completed by 32 healthy women twice daily for 2 menstrual cycles. There was a significant increase in sleep onset latency and a significant decrease in sleep efficiency and sleep quality during the luteal phase. This increase in sleep disturbance was observed in the entire sample and was not related to the severity of other premenstrual symptoms. However, women having increased severity of other premenstrual symptoms reported greater luteal increase in daytime sleepiness. Thus, although menstruating women are likely to show increased sleep disturbance during the luteal phase, those with other, more severe premenstrual symptoms are more likely to experience a luteal increase in daytime sleepiness.

Alpha sleep and information processing, perception of sleep, pain, and arousability in fibromyalgia.

This study examined the relationship between alpha sleep and information processing during sleep, perception of sleep, musculoskeletal pain, and arousability in patients with fibromyalgia. Patients (n = 20) were allowed to sleep undisturbed for the first 60 minutes of the study to assess amount of alpha sleep and were classified as high or low alpha generators based on quantitative analyses of alpha activity during this period. The groups were compared for performance on two memory tasks, perceptions of polysomnographically-defined sleep and EEG arousals in response to auditory stimuli. Correlations between symptoms of fibromyalgia and alpha activity were also examined. Alpha activity during sleep in fibromyalgic patients was associated with the perception of shallow sleep and an increased tendency to arouse in relation to auditory stimuli. Alpha activity was not associated with increased memory for auditory stimuli presented during sleep, sleep state misperception, or with myalgia symptoms. Alpha sleep appears to be, electrophysiologically, a shallow form of sleep. Our results suggest that it is perceived as such phenomenologically and that it is also associated with increased arousability.

Time-dependent sensitization of heart rate and blood pressure over multiple laboratory sessions in elderly individuals with chemical odor intolerance.

In this study, we tested the hypothesis that low-level chemical odor intolerance (i.e., "cacosmia") is a manifestation of heightened sensitizability to environmental stimuli. We examined supine heart rate and blood pressure of elderly individuals, who were classified as either having a higher degree of chemical odor intolerance (n = 12) or a lower degree of chemical odor intolerance (n = 13), upon awakening in a sleep research laboratory on 6 different days during an 8-wk protocol. During the 2 initial wk, they consumed a customary baseline diet (including ad lib milk and other dairy products), followed by 3 wk each of nondairy-containing and dairy-containing diets in randomly assigned, counterbalanced order. Measurements were made on 3 pairs of successive days, distributed over a 6-wk period, and on which different diets were consumed. The high-intolerance group had significantly higher mean supine systolic and diastolic blood pressures than did the low-intolerance group. Although subjects consumed milk products during both the initial baseline and subsequent dairy diet periods, the high-intolerance group had significantly higher heart rates and diastolic blood pressures later in the study than at baseline, especially when they were on the dairy diet. In contrast, the cardiovascular measures of the low-intolerance group lowered on average with time. The high-intolerance subjects had an increased mean diastolic blood pressure on the second days versus the first days in the laboratory (averaged across all diets). Collectively, the data suggest that elderly individuals with a high degree of chemical odor intolerance evidence (a) increased sympathetic tone in the cardiovascular system at rest over multiple measurements; and (b) greater sensitizability and/or lesser habituation of heart rate and diastolic blood pressure over time as a function, in part, of repeated environmental stressor exposures (i.e., a novel laboratory contextual setting and/or specific dietary constituents). Consistent with a sensitization model, the findings emphasize the need for two or more identical sessions at least 24 h apart in physiological studies of individuals with a high degree of intolerance for chemical odors versus normal individuals. The results of the blood pressure observations suggest that the possibility of abnormally labile autonomic function and cognitive sequelae in individuals with a high degree of intolerance for chemical odor increases with age.

Subjective and psychophysiologic insomnia: an examination of sleep tendency and personality.

The goal of this study was to compare insomniacs with and without objective verification, on the basis of sleep parameters, personality, and performance. An insomniac complaint group was subclassified as objective insomniac (OI) or subjective insomniac (SI) and compared to a non-complaint group. Groups did not differ on night sleep variables or daytime sleep latency measures; rather, a consistent sleep tendency was revealed for all three groups. The poorer the previous night sleep, the longer the daytime sleep latencies. Groups differed on subjective measures of conscious state during the day. SIs inaccurately estimated sleep/wake state in comparison to objective measures on the MSLT, whereas OIs were accurate in their estimations. Personality scores showed trends that suggested greater neuroticism for SIs and introversion for OIs. Results demonstrated subjective tendencies and related personality types that may help in the understanding of the complaint of insomnia with and without objective findings.

Elevation of plasma beta-endorphin levels of shy elderly in response to novel laboratory experiences.

Heightened psychophysiological reactivity to the novel or unfamiliar is a leading characteristic of sky or behaviorally inhibited individuals. To assess one aspect of the physiological stress response in shyness, the authors compared the morning plasma beta-endorphin levels of 15 extremely sky, healthy elderly individuals with beta-endorphin levels of 15 extremely outgoing persons on three pairs of 2 successive days. The primary finding was that sky participants exhibited significantly higher levels of beta-endorphin on the 1st days of each pair of days, compared with the 2nd days in the laboratory. No main effect for shyness or interaction between shyness and diet on endorphin levels was found. The findings are consistent with a peripheral opioid hyperreactivity to novelty in shy elderly persons. Shyness may constitute a risk factor for panic disorder in younger adults and for nasal allergies and certain cancers in older adults. Experimental design and interpretation of future studies of shy individuals' stress responses may need to consider novelty versus familiarity of the procedures and setting.

A polysomnographic study of sleep disturbance in community elderly with self-reported environmental chemical odor intolerance.

Subjective sleep complaints and food intolerances, especially to milk products, are frequent symptoms of individuals who also report intolerance for low-level odors of various environmental chemicals. The purpose of the present study was to evaluate the objective nature of nocturnal sleep patterns during different diets, using polysomnography in community older adults with self-reported illness from chemical odors. Those high in chemical odor intolerance (n = 15) exhibited significantly lower sleep efficiency (p = .005) and lower rapid-eye-movement (REM) sleep percent (p = .04), with a trend toward longer latency to REM sleep (p = .07), than did those low in chemical intolerance (n = 15), especially on dairy-containing as compared with nondairy (soy) diets. The arousal pattern of the chemical odor intolerant group differed from the polysomnographic features of major depression, classical organophosphate toxicity, and subjective insomnia without objective findings. The findings suggest that community elderly with moderate chemical odor intolerance and minimal sleep complaints exhibit objectively poorer sleep than do their normal peers. Individual differences in underlying brain function may help generate these observations. The data support the need for similar studies in clinical populations with chemical odor intolerance, such as multiple chemical sensitivity patients and perhaps certain veterans with "Persian Gulf Syndrome."

Time-dependent sensitization of plasma beta-endorphin in community elderly with self-reported environmental chemical odor intolerance.

This study examined plasma beta-endorphin as a marker of the physiological stress response in community elderly who were either high (n = 15) or low (n = 15) in self-rated frequency of illness from environmental chemical odors. Individuals who report nonatopic multiple sensitivities to or intolerances for low levels of environmental chemicals also claim high rates of comorbid food sensitivities or intolerances. Subjects gave 9 AM blood samples for plasma beta-endorphin 90 min after ingesting either 1% fat cow's milk or a soy-based nondairy drink, on six different mornings in the laboratory after all-night sleep recordings. The six sessions-were divided into three sets of two successive days each, with each set [involving baseline (ad lib milk), nondairy (soy-based), and dairy diets] separated from the next by 3 weeks. In the chemically tolerant subjects, stably lower beta-endorphin levels suggested that milk may have been a physiologically less stressful beverage than was the soy drink. In contrast, the chemical odor intolerant group exhibited a) increased levels of plasma beta-endorphin averaged over the 6 days (p = .02); and b) marked fluctuations in endorphin from one laboratory day to the next (Group x Diet x Day interaction, p = .005). The findings were consistent with time-dependent, context-dependent sensitization of beta-endorphin in the chemical odor intolerant individuals.

The effects of regularizing sleep-wake schedules on daytime sleepiness.

The present study evaluated the differential effects of two manipulations of sleep-wake schedules on daily subjective ratings of daytime sleepiness of college undergraduate students. Two experimental conditions were compared: a sleep only group and a regularity group. Subjects in both conditions were given a lower limit for total sleep time (7.5 hours). Subjects in the regularity group received an additional instruction to keep a regular sleep schedule. The study was longitudinal and prospective. Following a baseline period (12 days), the experimental conditions were introduced. The experimental phase lasted 4 weeks and overall compliance was good. A follow-up phase (1 week) began 5 weeks past termination of the experimental phase. The findings indicated that when nocturnal sleep is not deprived, regularization of sleep-wake schedules is associated with reduced reported sleepiness. Subjects in the regular schedule condition reported greater and longer lasting improvements in alertness compared with subjects in the sleep only condition and reported improved sleep efficiency.

Slowed reaction time performance on a divided attention task in elderly with environmental chemical odor intolerance.

Previous research has suggested an association between the subjective report of illness from environmental chemical odors and poorer cognitive task performance in persons with industrial levels of xenobiotic exposures. The present study investigated baseline morning performance on a computerized divided attention task in active retired adults without occupational exposures or clinical disorders who nonetheless rated themselves currently high versus low in episodic illness from the odor of certain environmental chemicals. The chemically intolerant group showed slower reaction times in registering both centrally and peripherally placed stimuli, but no difference in making target tracking errors. Measures of negative affect did not account for these findings. Taken together with evidence for heightened neurobehavioral sensitization in this population, the data suggest disturbances in allocation of attention and related cognitive functions.

Sleep onset is associated with retrograde and anterograde amnesia.

The purpose of the present study was to examine explicit and implicit memory for auditory events presented immediately prior to sleep onset. The results of the present study suggest subjects allowed 10 minutes of sleep demonstrate deficient explicit memory for auditory stimuli presented immediately prior to sleep onset. Subjects showed severe free recall deficits for word pairs presented 3 minutes prior to sleep onset and recognition deficits for stimuli from 1 minute prior to sleep onset. Implicit memory for word pairs presented prior to sleep onset seemed intact, and no recency effect was observed. In contrast to the 10-minute condition, subjects allowed 30 seconds of sleep demonstrated no equivalent explicit memory deficits. Memory performance in both delay conditions, however, appeared globally impaired relative to control data from subjects who remained awake. The results are interpreted in terms of elaboration of stimulus encoding, interruption of consolidation and retrograde versus anterograde amnesia.

Nonpharmacologic treatments of insomnia.

Nonpharmacologic treatments that have been evaluated for insomnia are reviewed. These include sleep hygiene techniques, stimulus control instructions, sleep restriction, chronotherapy, bright light therapy, relaxation training, biofeedback, paradoxical intention, and cognitive therapy. Comparative studies of the different treatments indicate considerable overlap in effectiveness. Direct comparisons between treatments have shown stimulus control instructions to be more effective than either relaxation training or paradoxical intention. Further research is needed on the tailoring of treatments to patient needs, as are more detailed comparisons between pharmacologic and nonpharmacologic treatments.

Effects of the 1989 San Francisco earthquake on frequency and content of nightmares.

In a systematic evaluation of the effects of a natural disaster on nightmares, nightmare frequency was found to be about twice as high among 92 San Francisco Bay area college students as among 97 control subjects in Tucson, Arizona, after the 1989 Loma Prieta earthquake. Subjects in California had not only more nightmares in general but substantially more nightmares about earthquakes. Over a 3-week period, about 40% of those in the San Francisco Bay area reported one or more nightmares about an earthquake, as compared with only 5% of those in Arizona. However, nightmares about earthquakes were not more emotionally intense than other nightmares. These findings support the long-held view that the experience of a potentially traumatic event can result in more frequent nightmares, particularly about the event itself, but contradict the common opinion that nightmares about such events are unusually intense.

An evaluation of behavioral treatments for insomnia in the older adult.

Behavioral treatments were evaluated for their effect on the subjective and objective sleep of older adult insomniacs (N = 53) aged 47 to 76 years. Conditions were support and sleep hygiene, support and sleep hygiene plus progressive relaxation, support and sleep hygiene plus stimulus control, or a measurement control group. The results indicated that all groups, including the measurement control group, were effective in improving the sleep diary assessed awakenings, nap time, and feeling refreshed upon awakening. Subjects at 3 weeks felt less depressed and felt that they had more control over their sleep. Stimulus control was most effective in improving sleep at the posttherapy period. A 2-year follow-up showed that the stimulus control subjects most frequently used the treatment instructions and had shorter sleep latencies and highest sleep quality. Behavioral treatments were found to be effective in improving the perception of sleep among older adult insomniacs.