The influence of body mass on long-term cognitive performance of children treated for sleep-disordered breathing.

BACKGROUND: Long-term follow-up of children treated for sleep-disordered breathing (SDB) is limited, as the examination of factors potentially contributing to recovery is also limited. This study aimed to examine whether the recovery of neurocognitive function is achieved at four years post-adenotonsillectomy for SDB in children and whether body mass status influences the outcome. METHODS: This prospective longitudinal study of 3- to 12-year-old children recruited from an otolaryngology clinic compared cognitive performance, sleep, ventilation, and body mass before and at four years post-adenotonsillectomy in children with SDB and compared these parameters to those of untreated healthy controls during the same time points. RESULTS: Children were categorised as normal-weight control (n = 33), normal-weight SDB (n = 18), or overweight/obese SDB (n = 11). Body mass did not significantly differ at four year follow-up compared to the baseline in any subgroup (p > 0.05), and groups were matched on the basis of age and gender. Despite improved sleep and nocturnal ventilation at four years post-adenotonsillectomy, little gain was observed in neurocognitive performance in either nonobese or overweight/obese children with SDB. Overweight/obese children with SDB displayed worse neurocognitive performance than all other children. CONCLUSION: Adenotonsillectomy improves nocturnal ventilation and sleep quality but not neurocognitive performance in the long term. Excess body mass may place children with SDB at increased risk of neurocognitive performance deficits.

Self-reported sleepwalking in Australian senior secondary school students.

BACKGROUND: Few studies have examined self-reported sleepwalking in older adolescents. The aim of this study was to examine the prevalence rates of sleepwalking in a one-month self-report period in Australian adolescents. METHODS: Participants were 532 Australian adolescents in their final two years of secondary school. RESULTS: The prevalence of sleepwalking in the one-month self-report period was 2.9% (95% confidence interval (CI) 1.47-4.33) in this sample-1% reported sleepwalking at least once a week in the previous month. A significant proportion (17.5%) of the participants was unsure if they had sleepwalked. CONCLUSION: The results provide data on the self-reported prevalence rate of sleepwalking in older adolescents. Compared with the population data, this rate falls within the confidence intervals of child and adult prevalence rates of sleepwalking and is consistent with a decline in sleepwalking from childhood and adulthood. Further research is needed to explore how adolescents know they sleepwalk to understand the reliability of self-report measures.

Thermoregulation, scratch, itch and sleep deficits in children with eczema.

Successful sleep onset and maintenance is associated with a reduction in core temperature, facilitated by heat loss at the distal periphery. Problems with initiating and maintaining sleep in children with eczema may relate to impaired thermoregulatory mechanisms, which also contribute to itching and scratching. Our hypothesis was that nocturnal distal skin temperature in eczematous children would be lower than controls, and would also be related to poor sleep quality. We compared overnight polysomnography and distal (finger) and proximal (clavicle) skin temperature in 18 children with eczema and 15 controls (6-16 years). Children with eczema had longer periods of nocturnal wakefulness (mean [SD] = 88.8 [25.8] vs. 44.3 [35.6] min) and lower distal temperatures (34.1 [0.6] °C vs. 34.7 [0.4] °C) than controls, whereas proximal temperature and the distal-proximal gradient were not significantly different. In children with eczema, a higher distal temperature was associated with indicators of poor sleep quality, whereas lower distal temperature was related to more scratching events during sleep. In conclusion, our findings indicate complex interrelationships among eczema, thermoregulation and sleep, and further, that deficits in thermoregulatory mechanisms may contribute to sleep disturbances in children with eczema.

Postnatal depression mediates the relationship between infant and maternal sleep disruption and family dysfunction.

BACKGROUND: Previous research has linked family sleep disruption and dysfunction in children; however, the mechanism is unknown. AIMS: This study examined whether maternal sleep and postnatal depression (PND) mediate the relationship between infant sleep disruption and family dysfunction. STUDY DESIGN AND PARTICIPANTS: Mothers of infants aged 12 months old (N=111; 48% male) completed infant and parent sleep surveys, the Edinburgh Postnatal Depression Scale and the Family Assessment Device. RESULTS: Poor infant sleep was related to poor maternal sleep, which was associated with higher PND and higher level of family dysfunction. CONCLUSIONS: Results are consistent with the proposition that identification of both infant and maternal sleep problems during infancy can be relevant to reduction of PND and improved family functioning.

Parent versus teacher report of daytime behavior in snoring children.

PURPOSE: Problematic behavior is widely reported in children with sleep-disordered breathing (SDB). Daytime behavior is an important component in the evaluation of clinical history in SDB; however, there is a reliance on parental report alone, and it is unclear whether reports by teachers will aid diagnosis. METHODS: We assessed sleep and behavior reported by both parents and teachers in 19 children with SDB and 27 non-snoring controls. All children were screened for prior diagnoses of other medical and/or behavior and learning disorders and underwent polysomnography and both parental and teacher assessment of behavior. RESULTS: Both parents and teachers report greater problematic behavior in SDB children, predominantly of an internalizing nature. Despite this consistency and moderate correlation between informants, the agreement between parent and teacher reports of individual child behavior was poor when assessed using Bland-Altman plots. CONCLUSIONS: Clinicians should be mindful that the behavioral history of a child being evaluated for SDB may vary depending on whether parent or teacher report is being discussed as this may influence clinical decision making.

Psychometric properties of an omnibus sleep problems questionnaire for school-aged children.

OBJECTIVE: There is a paucity of sleep questionnaires that have been psychometrically validated for use in school-aged children. Due to the limitation regarding the psychometric properties and the great variety in question design, there remains a need for a robust omnibus questionnaire that assesses sleep problems in community populations. This study aimed to develop such a questionnaire for school-aged children by assessing the construct validity and reliability of a questionnaire based on a combination of children's sleep domains from two frequently used and validated questionnaires (Habits Questionnaire and Sleep Disorders Scale for Children) and author devised questions. PATIENTS/METHODS: Parents of 1904 children aged 5-10 years (mean 7.7 ± 1.7 years) from 32 elementary schools in Adelaide, South Australia, completed the questionnaire. RESULTS: Principal axis factoring revealed six unique sub-scales--Sleep Routine, Bedtime Anxiety, Morning Tiredness, Night Arousals, Sleep Disordered Breathing, and Restless Sleep--containing a total of 26 items. Internal consistency for sub-scales were moderate to strong (range α = 0.6-0.8) and test-retest reliability was adequate (>0.4). T-score cut-offs were devised for age and sex. CONCLUSION: The new questionnaire provides a robust set of sleep problem sub-scales which can be used for assessment of sleep concerns in a community sample as well as provide for optimal analysis of associations with other measures of childhood daytime functioning such as neurocognition and behaviour.

Snoring and cognitive development in infancy.

OBJECTIVE: This study aimed to assess the influence of snoring and sleep duration on developmental outcomes in 6 month old infants. METHODS: As part of a longitudinal study of snoring in infancy, we identified 16 children (13 males) who commenced snoring shortly after birth and continued to snore frequently (≥ 3 nights/week) at 6 months of age and 88 healthy infant controls who were reported never to snore in the absence of a cold (36 males). Infants were assessed at 6 months of age with the Bayley Scales of Infant and Toddler Development Edition III, and parents completed demographic, sleep, and developmental surveys. RESULTS: Cognitive development was reduced in infants who snored frequently (mean=95.3; SD=4.3) from the first month of life compared to control infants (mean=100.6; SD=3.9) (F [1, 99]=23.8, p<.01; η(p)(2)=.21). CONCLUSION: Snoring during the first 6 months of life was associated with lower cognitive development scores. It is unknown whether these infants will continue to snore through childhood and, if so, whether the associated neurocognitive deficits will become worse with time.

Parental-reported snoring from the first month of life and cognitive development at 12 months of age.

OBJECTIVE: The aim of the present study was to evaluate the effect of persistent snoring in the first year of life on developmental outcomes. METHODS: As part of a longitudinal study of snoring and sleep in infancy, we identified 13 children (10 males) who commenced snoring shortly after birth and continued to snore frequently (≥ 3 nights/week) at 6 and 12 months of age and 78 controls (31 males) who were reported by parents to never snore in the absence of a cold. Infants were assessed with the Bayley Scales of Infant and Toddler Development Edition III and parents completed demographic and sleep questionnaires. RESULTS: Infants reported to snore frequently from the first month of life and who continued to snore frequently until 12 months of age had significantly lower cognitive development scores (mean=94.2; SD=3.9) compared to controls (mean=100.6; SD=3.7) (F (1, 96)=40 6, p<0.001; η(p)(2)=0.32). CONCLUSION: Persistent frequent snoring from the first month of life was associated with lower cognitive development scores at 12 months of age. It is possible that this deficit will become worse with age.

Prevalence of snoring and associated factors in infancy.

INTRODUCTION: In children aged 3-12 years snoring is associated with significant neurocognitive and behavioural deficits; however, there are few studies that have considered both the prevalence of snoring in infants and associated factors that may influence the development of snoring. The goal of the present study was to examine sleep, snoring and associated factors in a community sample of 0-3 month olds. METHODS: Previously validated infant sleep and parent sleep questionnaires were completed by parents of 457 term infants aged 1-13.9 weeks old (mean age=4.6 weeks; SD=2.7; 45% males) during a home-based nurse visit. RESULTS: Approximately 9% of infants were reported to snore habitually (snoring ≥ 3 nights/week). Habitual snoring was significantly associated with exclusive formula feeding (OR: 28.87; p<.01), maternal concern about child's breathing during sleep (OR: 3.91; p=.01) and restless sleep ≥ 3 nights/week (OR: 17.76; p<.001). CONCLUSION: These results show that snoring is as common in infants as it is in older children. Given the known relationships between Sleep Disordered Breathing (SDB) and neurocognitive development, the effect of SDB developing early in childhood may have important consequences on future developmental outcomes.

Central mechanisms of stress-induced headache.

Stress is the most commonly reported trigger of an episode of chronic tension-type headache (CTTH); however, the causal significance has not been experimentally demonstrated to date. Stress may trigger CTTH through hyperalgesic effects on already sensitized pain pathways in CTTH sufferers. This hypothesis could be partially tested by examining pain sensitivity in an experimental model of stress-induced headache in CTTH sufferers. Such examinations have not been reported to date. We measured pericranial muscle tenderness and pain thresholds at the finger, head and shoulder in 23 CTTH sufferers (CTH-S) and 25 healthy control subjects (CNT) exposed to an hour-long stressful mental task, and in 23 CTTH sufferers exposed to an hour-long neutral condition (CTH-N). Headache developed in 91% of CTH-S, 4% of CNT, and 17% of CTH-N subjects. Headache sufferers had increased muscle tenderness and reduced pain thresholds compared with healthy controls. During the task, muscle tenderness increased and pain thresholds decreased in the CTH-S group compared with CTH-N and CNT groups. Pre-task muscle tenderness and reduction in pain threshold during task were predictive of the development and intensity of headache following task. The main findings are that stress induced a headache in CTTH sufferers, and this was associated with pre-task muscle tenderness and stress-induced reduction in pain thresholds. The results support the hypothesis that stress triggers CTTH through hyperalgesic effects on already increased pain sensitivity in CTTH sufferers, reducing the threshold to noxious input from pericranial structures.

Reliability of temporal summation and diffuse noxious inhibitory control.

BACKGROUND: The test-retest reliability of temporal summation (TS) and diffuse noxious inhibitory control (DNIC) has not been reported to date. Establishing such reliability would support the possibility of future experimental studies examining factors affecting TS and DNIC. Similarly, the use of manual algometry to induce TS, or an occlusion cuff to induce DNIC of TS to mechanical stimuli, has not been reported to date. Such devices may offer a simpler method than current techniques for inducing TS and DNIC, affording assessment at more anatomical locations and in more varied research settings. METHOD: The present study assessed the test-retest reliability of TS and DNIC using the above techniques. Sex differences on these measures were also investigated. RESULTS: Repeated measures ANOVA indicated successful induction of TS and DNIC, with no significant differences across test-retest occasions. Sex effects were not significant for any measure or interaction. Intraclass correlations indicated high test-retest reliability for all measures; however, there was large interindividual variation between test and retest measurements. CONCLUSION: The present results indicate acceptable within-session test-retest reliability of TS and DNIC. The results support the possibility of future experimental studies examining factors affecting TS and DNIC.

Sleep-disordered breathing in Prader-Willi syndrome and its association with neurobehavioral abnormalities.

OBJECTIVES: To determine the prevalence and type of sleep-disordered breathing among patients with Prader-Willi syndrome (PWS) and its relationship to such neurobehavioral abnormalities as mental retardation, obsessive-compulsive behavior, and conduct disorders. STUDY DESIGN: Polysomnography (PSG) studies were conducted in 13 unselected subjects with PWS (age 1.5 to 28 years). PSG results were compared with tests of behavior and cognition (Development Behavior Checklist [DBC], Auditory Continuous Performance Test [ACPT], and Wechsler Intelligence Scale appropriate for age). RESULTS: Nine of 13 (69%) subjects had > 10 apneas and hypopneas per hour of sleep. Apart from a 2-year-old subject with normal body weight who demonstrated severe central hypopnea in rapid eye movement sleep, the sleep-breathing disturbance was due to upper airway obstruction. Age-adjusted body mass index was associated with more severe hypoxemia during sleep (min SaO2, r = -.87, P < .005) and more sleep disruption (arousals/hour of sleep, r = .62, P < .05; sleep efficiency, r = -.66, P < .05). Increasing severity of obstructive sleep apnea (OSA) or sleep disturbance was associated with daytime inactivity/sleepiness and autistic-relating behavior (DBC) and with impulsiveness (ACPT). Unexpectedly, sleep hypoxemia appeared to be predictive of increased performance IQ. CONCLUSIONS: OSA is prevalent among subjects with PWS and is associated with increased body mass, daytime inactivity/ sleepiness, and some behavioral disturbances.

Development and validation of a scale to measure work-related fatigue and recovery: the Occupational Fatigue Exhaustion/Recovery Scale (OFER).

OBJECTIVE: Various empirical studies link persistent failure to recover from acute fatigue to the evolution of chronic fatigue. However, existing fatigue measurement scales do not tend to distinguish between acute and chronic fatigue elements well, and none include a measure of effective recovery from fatigue. METHODS: The 15 item Occupational Fatigue Exhaustion Recovery (OFER) scale has been developed and validated in three study populations specifically to measure work-related fatigue. RESULTS: The OFER scale possesses robust, gender-bias free psychometric characteristics. Its three subscales identify and distinguish between chronic work-related fatigue traits, acute end-of-shift states and effective fatigue recovery between shifts. CONCLUSION: These studies confirm the mediating role of intershift-shift recovery in the evolution of adaptive end-of-shift fatigue states to maladaptive persistent fatigue traits. The OFER scale is suggested as a potentially valuable new tool for use in work-related fatigue research.

Are sleep problems under-recognised in general practice?

AIMS: To evaluate the frequency of sleep problems in Australian children aged 4.5-16.5 years, and to determine whether the frequency of sleep problems on questionnaire predicts the reporting of sleep problems at consultation. METHODS: Parents of 361 children (aged 4.5-16.5 years) attending their general practitioner for "sick" visits were asked to assess their child's sleep over the previous six months using the Sleep Disturbance Scale for Children, from which six sleep "disorder" factors and a total sleep problem score were obtained. RESULTS: The percentage of children with a total sleep problem score indicative of clinical significance (T score >70 or >95th centile) was 24.6% (89/361). Despite this high frequency, parents only addressed sleep problems in 4.1% (13/317) of cases and reported that GPs discussed sleep problems in 7.9% (25/317) of cases. Of the 79 children who reported total sleep problem T scores in the clinical range, only 13.9% (11/79) discussed sleep with their general practitioner within the previous 12 months. Regression analyses revealed an age related decrease in problems with sleep-wake transition and sleep related obstructive breathing; sleep hyperhydrosis, initiating and maintaining sleep, and excessive daytime sleepiness did not significantly decrease with age. No significant gender differences were observed. CONCLUSIONS: Results suggest that chronic sleep problems in Australian children are significantly under-reported by parents during general practice consultations despite a relatively high frequency across all age groups. Given the impact on children and families, there is a need for increased awareness of children's sleep problems in the community and for these to be more actively addressed at consultation.

Reduced neurocognition in children who snore.

Obstructive sleep apnea syndrome (OSAS) has been associated with reduced neurocognitive performance in children, but the underlying etiology is unclear. The aim of this study was to evaluate the relationship between hypoxemia, respiratory arousals, and neurocognitive performance in snoring children referred for adenotonsillectomy. Thirteen snoring children who were referred for evaluation regarding the need for adenotonsillectomy to a children's hospital otolaryngology/respiratory department underwent detailed neurocognitive and polysomnographic (PSG) evaluation. PSGs were evaluated for respiratory abnormalities and compared with 13 nonsnoring control children of similar age who were studied in the same manner. The snoring children had an obstructive respiratory disturbance index within normal range (mean obstructive apnea/hypopnea index, 0.6/hr). Despite this, several domains of neurocognitive function were reduced in the snoring group. These included mean verbal IQ scores (snorers 92.6 vs. nonsnorers 110.2, P < 0.001), mean global IQ scores (snorers 96.7 vs. nonsnorers 110.2, P < 0.005), mean selective attention scores (snorers 46.4 vs. nonsnorers 11.8, P < 0.001), mean sustained attention scores (snorers 8.0 vs. nonsnorers 2.2, P = 0.001), and mean memory index (snorers 95.2 vs. nonsnorers 112.1, P = 0.001). There was a direct relationship between number of mild oxygen desaturations of > or = 3%, obstructive hypopneas with > or = 3% oxygen desaturations, and respiratory arousals and severity of neurocognitive deficits, with the greatest effect being on memory scores. The disruption of sleep in snoring children produced by relatively mild changes in oxygen saturation or by increases in respiratory arousals may have a greater effect on neurocognitive function than hitherto appreciated. A possible explanation for these neurocognitive deficits may be the combination of the chronicity of sleep disruption secondary to snoring which is occurring at a time of rapid neurological development in the first decade of life. Future studies need to confirm the reversal of these relatively mild neurocognitive decrements post adenotonsillectomy.

The role of occupational stress in the maladaptive use of alcohol by dentists: a study of South Australian general dental practitioners.

BACKGROUND: It is well recognized that dentistry is a stressful profession. However, there are conflicting views about the extent to which such stress contributes to hazardous drinking among dentists. In addition, the relative contributions of stress and pre-existing vulnerability in predicting alcohol problems among dentists generally (and Australian dentists in particular) have yet to be determined. METHODS: The levels of stress and alcohol consumption of 312 South Australian dentists were measured. Factors known to mediate vulnerability to alcohol disorders were also assessed with appropriate psychometric instruments. RESULTS: High levels of stress/burnout, consistent with other studies of dentists' stress, were recorded. Hazardous levels of alcohol consumption, which were between two and four times higher than the normative South Australian population, were also reported, particularly among males and rural dentists. CONCLUSIONS: To a significant extent, stress and hazardous alcohol consumption are both present among South Australian dentists. However, compared with work stress/burnout, existing personal vulnerability factors are much stronger predictors of such hazardous alcohol consumption. We suggest that professional dental bodies, and state Dental Boards, may play a role in ensuring stress inoculation and guidance on safe limits of alcohol consumption for dentists-in-training; and in creating appropriate mechanisms for assisting dentists who experience alcohol related difficulties.

Extraocular light exposure does not phase shift saliva melatonin rhythms in sleeping subjects.

Preliminary work in humans suggests that extraocular light can shift circadian phase. If confirmed, extraocular light may be of therapeutic benefit in the treatment of circadian-related sleep disorders with the advantage over ocular exposure that it can be administered while subjects are asleep. In sleeping subjects, however, the effect of extraocular light exposure on circadian phase has yet to be fully tested. Likewise, there is limited data on the acute effects of extraocular light on sleep and body temperature that may influence its clinical utility Thirteen subjects [3F, 10M; mean (SD) age = 22.1 (3.0)y] participated in a protocol that totaled 7 nights in the laboratory consisting of a screening phase measurement night followed 1 week later by two counterbalanced experimental sessions each of 3 consecutive nights (habituation, treatment, and posttreatment phase measurement night) separated by 4 days. Saliva was collected for melatonin measurement every half hour from 1800 to 0300 h on the screening night and both the posttreatment phase measurement nights. On the treatment nights, continuous measures of rectal temperature and polysomnographic sleep were collected and overnight urine for measurement of total nocturnal urinary 6-sulphatoxymelatonin excretion. To test for the phase-delaying effects of extraocular light, subjects received either placebo or extraocular light (11,000 lux) behind the right knee from 0100 to 0400 h. Treatment had no significant effect on the onset of saliva melatonin secretion, phase of nocturnal core body temperature, or urinary 6-sulfatoxymelatonin excretion, but a small increase was observed in wakefulness over the light administration period. In summary, extraocular light was not shown to delay circadian phase but was shown to increase wakefulness. The authors suggest that the present protocol has limited application as a treatment for circadian-related sleep disorders.

Cognitive and behavioural performance in children with sleep-related obstructive breathing disorders.

Sleep-related obstructive breathing disorders (SROBD) are common in children. While the sequelae of cor pulmonae, and growth and developmental impairment have been well documented, neurocognitive deficits have been less well studied. There is emerging evidence that children with SROBD show reduced neurocognitive functioning especially in the inter-related areas of attentional capacity, memory and cognitive function. In addition, these children show increased problematic behaviour and reduced school performance. Early reports suggest that some of these deficits may be reversible with treatment. The genesis of the defects is unclear but may include hypoxaemia and subtle changes in sleep architecture. The natural history of SROBD and long-term effects on neurocognitive functioning and behaviour remain to be fully examined.

Behavior and neurocognitive performance in children aged 5-10 years who snore compared to controls.

Sleep disordered breathing in children is a common but largely underdiagnosed problem. It ranges in severity from primary snoring to obstructive sleep apnea syndrome (OSAS). Preliminary evidence suggests that children with severe OSAS show reduced neurocognitive performance, however, less is known about children who snore but do not have severe upper airway obstruction. Participants included 16 children referred to the Ear, Nose and Throat/Respiratory departments of a Children's Hospital for evaluation of snoring and 16 non-snoring controls aged 5-10 years. Overnight polysomnography (PSG) was carried out in 13 children who snored and 13 controls. The PSG confirmed the presence of primary snoring in seven and very mild OSAS (as evidenced by chest wall paradox) in eight children referred for snoring while controls showed a normal sleep pattern. To test for group differences in neurocognitive functioning and behavior, children underwent one day of testing during which measures of intelligence, memory, attention, social competency, and problematic behavior were collected. Compared to controls, children who snored showed significantly impaired attention and, although within the normal range, lower memory and intelligence scores. No significant group differences were observed for social competency and problematic behavior. These findings suggest that neurocognitive performance is reduced in children who snore but are otherwise healthy and who do not have severe OSAS. They further imply that the impact of mild sleep disordered breathing on daytime functioning may be more significant than previously realized with subsequent implications for successful academic and developmental progress.

Core body temperature is elevated during constant wakefulness in elderly poor sleepers.

STUDY OBJECTIVES: The aim of this study was to test for heightened physiological activity in elderly poor sleeepers compared to good sleepers under ad lib sleep and constant wakeful conditions. DESIGN AND SETTING: Subjects participated in a five-day protocol consisting of four nights of polysomnographic (PSG) and rectal temperature monitoring followed by 26 hours of continuous rectal temperature monitoring under controlled constant wakefulness. PARTICIPANTS: Participants were 16 self-reported sleep maintenance insomniacs and 16 self-reported good sleeping controls over 55 years of age. INTERVENTIONS: NA. MEASUREMENT AND RESULTS: Subjects were grouped according to (1) subjective sleep status and (2) into quartiles according to amount of PSG determined wake after sleep onset (WASO). Significant group differences in temperature were observed when subjects were classified according to PSG but not subjective criteria. In the former case, subjects with the lowest (bottom quartile) compared to the highest (top quartile) amount of PSG determined WASO showed lower sleep and nighttime constant wakeful core body temperatures. CONCLUSIONS: In the elderly, elevated core body temperature is associated with increased nocturnal wakefulness suggesting that physiological activation may underlie sleep maintenance insomnia. This was clearly significant when subjects were compared using objective criteria and temperature was collected under constant wakeful conditions.