Cognitive complaints in patients with untreated obstructive sleep apnea versus patients with neurological and respiratory diseases: prevalence, severity and risk factors.

PURPOSE: Little is known about cognitive complaints (self-reported problems in cognitive functioning) in patients with Obstructive Sleep Apnea (OSA). We compared the prevalence and severity of cognitive complaints in patients with untreated OSA to patients with neurological and respiratory diseases. We also studied risk factors for cognitive complaints across these diseases, including OSA. METHODS: We used a convenience sample to compare untreated OSA patients (N = 86) to patients with stroke (N = 166), primary brain tumor (N = 197) and chronic obstructive pulmonary disease (COPD, N = 204) on cognitive complaints (Cognitive Failure Questionnaire, CFQ), anxiety and depression (Hospital Anxiety and Depression Scale, HADS) and cognitive impairments using neuropsychological tests. We combined all patient groups (OSA, stroke, brain tumor and COPD) and studied potential risk factors (demographic variables, anxiety, depression and cognitive impairments) for cognitive complaints across all patient groups using regression analysis. RESULTS: The prevalence of cognitive complaints was higher in OSA patients and complaints of forgetfulness and distractibility were more severe compared to stroke and primary brain tumor patients, but similar to or lower than COPD patients. Regression analysis for the combined sample of all patient groups showed that cognitive complaints were most strongly associated with symptoms of anxiety and depression. CONCLUSION: A high rate of OSA reported clinically significant cognitive complaints, comparable to other respiratory and neurological patients. Symptoms of anxiety and depression are important risk factors for cognitive complaints in patients with various neurological and respiratory diseases. Future studies should examine the relation between anxiety, depression and cognitive complaints in patients with OSA.

Cognitive complaints in obstructive sleep apnea.

Obstructive sleep apnea (OSA) is associated with impairments in cognitive functioning. Although cognitive complaints are related to quality of life, work productivity and health care expenditures, most research and all reviews have focused exclusively on objective cognitive functioning so far. In this systematic review, we assessed the available literature on subjective measures of cognition in adult OSA patients. Concentration complaints were consistently found to be more severe in untreated OSA patients as compared to primary snorers and healthy controls. The same seems to be true for memory and executive function problems, but firm conclusions cannot be made as of yet, due to methodological limitations of the available studies. Cognitive complaints appear to be at least partially related to subjective sleepiness. Importantly, they are not necessarily a sign of objective cognitive impairment. Additional research is needed to explore the relation between cognitive complaints, sleepiness and mood problems using validated and norm-referenced questionnaires for cognitive complaints. In addition, the impact of continuous positive airway pressure (CPAP) treatment on cognitive complaints in OSA warrants further study.