OSA In Children Found To Impair Cognition, Behavior, And Academic Performance

Boca Raton, FL - May 8, 2002

A new study finds that obstructive sleep apnea may have a significant and deleterious impact on a child's cognition, school performance, and behavior. The examination of children with this disorder, before and after treatment, reveals that a tonsillectomy/adenoidectomy (T&A) results in improved quality of life in these young patients.

Obstructive sleep apnea syndrome (OSAS), a common sleep disorder in adults, has gained recognition as a significant sleep problem in children. Of school age children, 10-30 percent are reported to snore and 4.9-8.5 percent are habitual snorers with the incidence of OSAS in children estimated at one to three percent.

Previous research has found major differences between OSAS in children and in adults. They are: (1) a peak incidence in children between two and six years vs. an increasing occurrence in adults with age; (2) an approximately equal male to female ratio in school age children vs. male predominance in adults; (3) a normal weight or failure to thrive in children with OSAS vs. more frequent obesity in adults; (4) the occurrence of snoring as the most common presenting symptom and a reduced complaint of excessive daytime sleepiness in childhood OSAS (shortened sleep latencies occur in children with OSAS, but excessive daytime sleepiness is infrequent and tends to develop among more severe OSAS and/or obese children); (5) the usual association of adenotonsillar hypertrophy in childhood with the potential for "cure" with surgery.

The complications of childhood OSAS include cognitive and behavioral dysfunction and in some, a profile similar to that of attention deficit hyperactivity disorder. An association between daytime sleepiness, behavior problems, and sleep disturbances due to snoring alone with improvement following surgical treatment has been reported. However, the impact of the nocturnal sleep disturbance and diurnal behavioral and cognitive complications of OSAS on children's educational and social development may be considerable, but has not been well defined.

Additionally, there is scant information regarding the severity, persistence, and variability of disruption of life activities in these children. For children with OSAS, it is unclear to what degree relief of sleep related airway obstruction (with a tonsillectomy/adenoidectomy) improves daytime performance and quality of life, and whether this is due to decreasing sleep fragmentation and/or by decreasing apnea/hypopnea and oxygen desaturation.

The absence of widely accepted guidelines for the diagnosis and determination of the severity of childhood OSAS led researchers to investigate the disorder's impact on the functional status and quality of life of children. The authors of "Obstructive Sleep Apnea in Children: Impact on Cognition, Behavior, And Quality of Life" are Daniel G. Glaze MD, Marilyn Bautista, MPH, Karen Evankovich, PhD, M. Lynn Chapieski PhD, Ellen Friedman MD, Michael G. Stewart MD, Merrill Wise MD, Marianna Sockrider MD PhD, O'Brian Smith PhD, all from the Baylor College of Medicine, Houston, TX. This study was funded and supported by the National Institutes of Health, National Heart, Lung, and Blood Institute, grant # 62404. Their findings will be presented May 13, 2002, at the Annual Meeting of the American Society of Pediatric Otolaryngology at the Boca Raton Resort & Club, Boca Raton, FL.

Methodology

Eligible subjects were boys and girls, ages 5.5 to 13 years with breathing difficulties during sleep. Subjects were required to be English speaking to allow completion of the neuropsychological test battery and QOL questionnaires. Children with previous T&A, syndromes (e.g. Down's, craniofacial, etc), neurological and/or neuromuscular disorders, significant medical problems, and/or asthma requiring treatment were excluded from the study.

Prior to T&A each subject underwent (1) an eight to 12 hour full attended overnight polysomnography (PSG), i.e. sleep study, PSG that included continuous monitoring of electroencephalogram, eye movements, electromyogram, electrocardiogram, airflow (nasal pressure transducer and oral thermocouples), effort (chest and abdominal strain gauges), oxygen saturation (SaO2; pulse oximeter), end tidal carbon dioxide (ETpCO2; nasal catheter), snoring (microphone) and extremity movements (accelerometers; and (2) a neuropsychological evaluation to determine intellectual function, verbal and non-verbal memory, sustained, and impulsive attention), academic development, adaptive behavior, and fine motor skills; and (3) the parent of each subject was asked to complete two validated pediatric Quality of Life instruments, global and disease specific questionnaires. The same questionnaires were administered six months after the T&A.

Correlations were determined for the parameters derived from the PSG and the neuropsychological battery including intelligence, memory, attention and impulsivity, and academic performance. Differences in respect to the neuropsychological test battery were established. Comparison of the scores of the subscales of the QOL instruments, before and after T&A, was determined with a Wilcoxin Test.

Results

The study examined 23 children (15 males; mean age 8.2 years, range 5.7-12.9 years). Ethnic background was as follows: eight Hispanics; seven whites; six African Americans; and three Asians. All subjects snored during sleep. The mean IQ was 104 (range 82-130).

Significant correlations of the severity of OSAS with five domains of cognition and behavior were observed. These included intelligence, memory, academic performance, attention/impulsivity, and adaptive behavior. The impact of sleep disordered breathing on intelligence was not solely explained by attention/impulsivity deficits. The findings raise concerns that while behavior problems may reverse or improve following treatment (T&A) of OSAS, cognitive deficits, especially in the context of long standing sleep disordered breathing, may only partially improve following intervention.

Other findings indicate significant improvement in both global and disease specific measures of quality of life following T&A. These findings suggest that OSAS negatively impacts on the QOL of children. However, other factors, such as chronic illness secondary to recurrent bouts of tonsillitis and consequent school absences, may also contribute to these findings.

Conclusion

This study suggests the degree of impairment and quality of life should be considered in determining OSAS severity and the decision for intervention, i.e. T&A. Evaluation of the effectiveness of T&A for OSAS in children should consider resolution or improvement in cognition, behavior and day-to-day living.