Thursday, July 10, 2014
In children, OSAS may cause attention-deficit hyperactivity disorder in addition to behavioral problems and learning disabilities. Risk factors for cognitive impairment include increasing age, male sex, apolipoprotein E ε4 allele positivity, current cigarette smoking, obesity, hypertension, diabetes mellitus, metabolic syndrome, Down syndrome, hypothyroidism, significant alcohol consumption, stroke, and the use of psychoactive medications. At a cellular level, OSAS likely causes cognitive impairment through intermittent hypoxia, hormonal imbalance, and/or systemic inflammation, either independently or via the resultant endothelial dysfunction that occurs. Excessive daytime sleepiness should be measured and minimized in all studies of neurocognitive impairment.
Recent studies have used functional and structural neuroimaging to delineate the brain areas affected in patients with OSAS with neurocognitive dysfunction. A common finding in several of these studies is decreased hippocampal volume. Other affected brain areas include the frontal and parietal lobes of the brain, which show focal reductions in gray matter. These changes can be reversed at least partially with the use of CPAP, which highlights the importance of early recognition and treatment of OSAS. The currently available data in this field are quite limited, and more research is needed.