Mark Kohler

Adenotonsillectomy and neurocognitive deficits in children with Sleep Disordered Breathing.

Background Sleep Disordered Breathing (SDB) is a common childhood disorder that encompasses a range of sleep-related upper airway obstruction. Children with SDB demonstrate significant neurocognitive deficits. Adenotonsillectomy is the first line of treatment for SDB and whilst this improves respiratory disturbance, it remains to be established whether neurocognitive gains also result. Methods A total of 44 healthy snoring children aged 3–12 years awaiting adenotonsillectomy (SDB group), and 48 age and gender matched non-snoring controls from the general community, completed the study. All children underwent polysomnography and neurocognitive assessment at baseline and after a 6-month follow-up (after surgery in the snoring group). Our primary aim was to determine whether neurocognitive deficits in snoring children were significantly improved following adenotonsillectomy. Results Wide ranging neurocognitive deficits were found at baseline in SDB children compared to controls, most notably a 10 point IQ difference (P<.001) and similar deficits in language and executive function. Whilst adenotonsillectomy improved respiratory parameters and snoring frequency at 6 months post surgery, neurocognitive performance did not improve relative to controls. Conclusion Adenotonsillectomy successfully treated the respiratory effects of SDB in children. However, neurocognitive deficits did not improve 6-months post-operatively.

Sleep Spindle Activity and Cognitive Performance in Healthy Children

STUDY OBJECTIVES To investigate the association between indices of sleep spindle activity and cognitive performance in a sample of healthy children. DESIGN Correlational. Intelligence (Stanford-Binet) and neurocognitive functioning (NEPSY) were assessed, with sleep variables being measured during overnight polysomnography. SETTING Hospital sleep laboratory. PARTICIPANTS Twenty-seven healthy children (mean age 8.19 y; 14 female, 13 male). INTERVENTIONS N/A. MEASUREMENTS AND RESULTS Participants underwent a single night of overnight polysomnography after completing measures of intelligence and neurocognitive functioning. Sleep spindles were visually identified by an experienced sleep scoring technician and separated algorithmically into fast (> 13 Hz) and slow spindle (< 13 Hz) categories. The number of fast spindles was significantly correlated with narrative memory (r(s) = 0.38) and sensorimotor functioning (-0.43). Mean central frequency of spindles was also significantly correlated with sensorimotor functioning (-0.41), planning ability (-0.41), and working memory (-0.54). CONCLUSIONS Basal sleep spindle activity is associated with different aspects of cognitive performance in children. To the extent that these associations in a pediatric population are different from what is known in adult sleep may play an important role in development.

The effects of chewing versus caffeine on alertness, cognitive performance and cardiac autonomic activity during sleep deprivation

Chewing has been shown to alleviate feelings of sleepiness and improve cognitive performance during the day. This study investigated the effect of chewing on alertness and cognitive performance across one night without sleep as well as the possible mediating role of cardiac autonomic activity. Fourteen adults participated in a randomized, counterbalanced protocol employing a chewing, placebo and caffeine condition. Participants completed tasks assessing psychomotor vigilance, tracking, grammatical reasoning, alertness and sleepiness each hour across the night. All participants received either placebo or caffeine (200 mg), while the chewing condition also chewed on a tasteless and odorless substance for 15 min each hour. Heart rate (HR), root mean square of the successive differences in R‐R intervals on the ECG (RMSSD), and preejection period (PEP) were simultaneously recorded. Alertness and cognitive performance amongst the chewing condition did not differ or were in fact worse when compared with placebo. Similarly, measures of HR and RMSSD remained the same between these two conditions; however, PEP was reduced in the later part of the night in the chewing condition compared with a relative increase for placebo. Caffeine led to improved speed and accuracy on cognitive tasks and increased alertness when compared with chewing. Relative increases in RMSSD and reductions in HR were demonstrated following caffeine; however, no change in PEP was seen. Strong associations between cardiac parasympathetic activity and complex cognitive tasks, as well as between subjective alertness and simpler cognitive tasks, suggest a differential process mediating complex versus simple cognitive performance during sleep deprivation.

Emoticons in mind: An event-related potential study

It is now common practice, in digital communication, to use the character combination “:-)”, known as an emoticon, to indicate a smiling face. Although emoticons are readily interpreted as smiling faces, it is unclear whether emoticons trigger face-specific mechanisms or whether separate systems are utilized. A hallmark of face perception is the utilization of regions in the occipitotemporal cortex, which are sensitive to configural processing. We recorded the N170 event-related potential to investigate the way in which emoticons are perceived. Inverting faces produces a larger and later N170 while inverting objects which are perceived featurally rather than configurally reduces the amplitude of the N170. We presented 20 participants with images of upright and inverted faces, emoticons and meaningless strings of characters. Emoticons showed a large amplitude N170 when upright and a decrease in amplitude when inverted, the opposite pattern to that shown by faces. This indicates that when upright, emoticons are processed in occipitotemporal sites similarly to faces due to their familiar configuration. However, the characters which indicate the physiognomic features of emoticons are not recognized by the more laterally placed facial feature detection systems used in processing inverted faces.

Cerebrovascular Function in Aging and Dementia: A Systematic Review of Transcranial Doppler Studies

Background/Aim: The contribution of cerebrovascular dysfunction to the manifestation of dementia and cognitive decline in late life is gaining increased attention. We aimed to systematically review evidence for associations between dementia or aging and cerebrovascular function as measured using transcranial Doppler (TCD) examination. Methods: A total of 1,172 articles were retrieved from PsychInfo and PubMed searches, and 34 relevant articles were identified using a variety of TCD methods. Results: The pulsatility index (vessel resistance), spontaneous emboli and cerebrovascular reactivity to hyper-/hypocapnia appeared good discriminators of dementia. Aging was associated with a slowing in blood flow velocity. Conclusion: TCD ultrasonography is inexpensive, portable and well tolerated by aged and demented subjects. The technique stands to make a valuable contribution to the knowledge regarding the underlying functional biology of age-related cognitive change and dementia.

Neurocognitive performance and behavior before and after treatment for sleep-disordered breathing in children

Neurocognitive and behavioral problems are increasingly reported in children with sleep-disordered breathing (SDB). The impact of treatment for SDB on neurocognition and behavior is, therefore, an issue of increasing importance. To date, there has been little consideration given to the quality of studies when reviewing associated neurocognitive and behavioral problems in children with SDB, and furthermore, there has been little systematic review of treatment outcomes. The aim of this review was to provide an up-to-date and critical review of the current literature. Findings indicate a specific pattern of neurocognitive problems in children with SDB; however, the pattern of behavioral problems is less clear. Very few studies were found to provide a rigorous investigation of posttreatment neurocognitive and behavior outcomes. Despite this, relatively consistent improvements in global intelligence, attention, and visual spatial ability are shown; however, persistent deficits in other domains are also evident. For behavior, problems of hyperactivity, aggression or conduct problems, and somatic complaints improve following treatment. In contrast, symptoms of anxiety and social problems less consistently improve. These findings should aid in the development of more targeted investigations and well-designed studies exploring both the causative mechanisms and the treatment response for neurocognitive and behavior problems in children with SDB.

Risk factors and treatment for obstructive sleep apnea amongst obese children and adults

Purpose of reviewThe purpose of this review is to summarize the evidence for the association between obesity and obstructive sleep apnea (OSA), as well as predisposing risk factors and treatment strategies for OSA amongst obese patients. Recent findingsRecent findings highlight a number of factors including sex, age, upper airway structure and ethnicity, which may predispose patients to OSA when obese. Both invasive and noninvasive weight-reduction strategies also show positive signs of being an effective means to reduce or remediate OSA amongst obese adults and children. SummaryIn view of recent findings, a direct association between body mass and upper airway obstruction should be viewed with caution. Obesity may play a more significant role in the predisposition to OSA amongst particular subgroups of the population, such as adults, and those with particular craniofacial and upper airway morphology. Healthcare prioritization and requirements may be more substantial for such groups. Further, commonly used treatment methods for OSA (such as adenotonsillectomy for children and continuous positive airway pressure for adults) may be less effective for obese individuals. Weight-reduction strategies appear important for an optimal outcome, and such strategies may be more or less invasive depending on the severity of obesity, OSA or both, and other patient complications.

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.

The role of NREM sleep instability in child cognitive performance.

STUDY OBJECTIVES Based on recent reports of the involvement of cyclic alternating pattern (CAP) in cognitive functioning in adults, we investigated the association between CAP parameters and cognitive performance in healthy children. DESIGN Polysomnographic assessment and standardized neurocognitive testing in healthy children. SETTINGS Sleep laboratory. PARTICIPANTS Forty-two children aged 7.6 ± 2.7 years, with an even distribution of body mass percentile (58.5 ± 25.5) and SES reflective of national norms. MEASUREMENTS Analysis of sleep macrostructure following the R&K criteria and of cyclic alternating pattern (CAP). The neurocognitive tests were the Stanford Binet Intelligence Scale (5(th) edition) and a Neuropsychological Developmental Assessment (NEPSY) RESULTS: Fluid reasoning ability was positively associated with CAP rate, particularly during SWS and with A1 total index and A1 index in SWS. Regression analysis, controlling for age and SES, showed that CAP rate in SWS and A1 index in SWS were significant predictors of nonverbal fluid reasoning, explaining 24% and 22% of the variance in test scores, respectively. CONCLUSION This study shows that CAP analysis provides important insights on the role of EEG slow oscillations (CAP A1) in cognitive performance. Children with higher cognitive efficiency showed an increase of phase A1 in total sleep and in SWS.

Altered cardio-respiratory response to spontaneous cortical arousals in children with upper airway obstruction

OBJECTIVE Upper airway obstruction (UAO) during childhood is associated with cardiovascular morbidity. The aim of this study was to investigate the cardio-respiratory response to cortical arousal during sleep in children with UAO. METHODS Standard paediatric overnight polysomnography (PSG) was conducted in 40 children with UAO (25M, 7.5±2.7yrs) prior to and 6 months following adenotonsillectomy. For comparison a control group of 40 normal, sex and age matched children (21M, 7.5±2.6yrs) underwent two PSGs without intervention at the same time points. RESULTS Heart rate and respiratory rate were measured during spontaneous and respiratory arousals in stage 2 and REM sleep 15s prior to and 15s immediately following cortical arousal onset. Cortical arousal was associated with a significant increase in heart and respiratory rate in both groups of children. UAO children, however, showed a significantly higher heart rate response in stage 2 sleep (-17.5±6.0 vs. -14.4±4.8%; p<0.05), a lower pre-arousal baseline respiratory rate (stage 2: 17.1±1.4 vs. 18.2±1.7 BPM; p<0.01) and a prolonged increase in respiratory rate compared to control children. Cardiac and respiratory arousal responses were not significantly different from controls following adenotonsillectomy in the UAO children. CONCLUSIONS UAO in children is associated with an altered cardiorespiratory response to spontaneous arousal from sleep, which may indicate early signs of autonomic dysfunction. Surgical treatment of UAO appears to reverse these outcomes.