Neurocognitive consequences of OSA include daytime sleepiness, loss of alertness, memory deficit, reduced vigilance, impaired executive function, psychomotor speed deficits, increased risk for automobile and occupational accidents and decreased quality of life. This impairment in cognitive functions in OSA patients has been found to be associated with reductions in gray matter volume of left hippocampus and right frontal gyrus. There was a significant improvement in gray matter of these areas following treatment with CPAP for 3 months.[103,104] Attention deficits in OSA include a decline in vigilance, sustained attention and selective attention. Psychomotor speed deficit has also been observed in moderate-to-severe OSA. Studies have demonstrated a decline in memory and learning abilities. Executive functions that are found to be impaired are mental flexibility, planning, analysis, synthesis and organizational skills.[108,109] There are semantic language deficits in OSAS.[110,111] CPAP treatment is found to be effective in improving some cognitive functions (memory and psychomotor speed). High executive functions and verbal fluency may not improve following treatment with CPAP. Though CPAP use has not been shown to improve many of these deficits in adults, significant improvement in neurobehavioral function after 3 months of CPAP therapy has been reported in children.[112,114,115]
Expert Rev Resp Med. 2012;6(5):557-566. © 2012 Expert Reviews Ltd.