Neuropsychological Consequences of Sleep-Disordered Breathing

Abstract

Pediatric sleep disorders have been gaining awareness among practitioners due to their potential for cognitive, behavioral, and somatic effects (Gozal 2008; Moore et al. 2006). Sleep-disordered breathing (SDB) is commonly seen in children and encompasses a range of disorders, in primary snoring to obstructive sleep apnea (Marcus 2000). Sleep-disordered breathing is characterized by partial or complete upper airway obstruction during sleep due to collapse or narrowing of the pharynx. This can result in sleep fragmentation due to brief arousals during the night, as well as disruption or cessation of airflow (Blunden and Beebe 2006; Halbower and Mahone 2006). This chapter describes the neuropsychological and behavioral consequences of SDB, comorbid disorders, and effects of treatment. Sleep-disordered breathing is considered a spectrum of airflow limitation, from mild to severe. For instance, primary snoring (PS), defined as snoring without oxygen desaturation or sleep arousals, is at the mild end of the spectrum. Upper airway resistance syndrome (UARS), in the middle of the spectrum, is characterized by increased negative intrathoracic pressure with sleep arousals and sleep fragmentation but no oxygen desaturations (Bao and Guilleminault 2004; Garetz 2008; Lumeng and Chervin 2008). In obstructive sleep apnea (OSA), at the severe end of the spectrum, there are repeated episodes of blockage of the airway with changes in oxygenation. Obstructive sleep apnea results from a combination of factors, including anatomical obstruction from adenoids, tonsils, or a narrow pharynx, and decreased neuromuscular tone required to maintain airway patency (Arens and Marcus 2004). An overnight polysomnogram (PSG) completed in a sleep laboratory and measuring sleep–wake states, respiration, movement, blood levels of oxygen and carbon dioxide, and cardiac activity, is considered the “gold standard” for the diagnosis of OSA (American Academy of Pediatrics 2002). The PSG is used to diagnose respiratory events, cardiac changes, and arousals from different sleep states. Respiratory events include obstructive apneas and hypopneas. Obstructive apnea events are episodes of complete airway obstruction, while hypopneas are partial obstructions or airflow limitations (Garetz 2008; Redline et al. 2007).