Dados do Trabalho

Título

Association between sleep parameters and cognitive functioning in individuals with obstructive sleep apnea

Introdução

Cognitive functioning, apolipoprotein ε4 allele (APOE4) polymorphism are controversial in individuals with obstructive sleep apnea (OSA) and the lack of information about the presence of the allele APOE4 makes it difficult to determine to what extent this genetic factor can influence cognitive functioning and have a detrimental effect in the setting of OSA.

Objetivo

Explore the association between sleep parameters and cognitive functioning taking into account the APOE4 polymorphism in OSA.

Métodos

A total of 55 sedentary individuals (age=51±6), with no major comorbidities were recruited to undergo the polysomnography, genotyping and cognitive evaluation. Attention and executive functioning were evaluated using Stroop Color Word Test (SCWT) and Frontal Assessment Battery, Trail Making Test - Parts A and B, Digit Symbol Test, Forward Digits, Backward Digits. Episodic declarative memory was assessed using Rey Auditory Verbal Learning Test (RAVLT) with immediate, delayed recall, and learning abilities. The Short Cognitive Performance Test-Syndrom-Kurztest (SKT) and Mini-mental State Examination (MMSE) were also evaluated.

Resultados

Thirteen individuals had apnea hypopnea index (AHI) <15 events/h of sleep (control group, APOE4=1) and 42 individuals with AHI≥15 events/h of sleep (OSA group, APOE=9). AHI and arousal index were higher and the minimum O2 saturation was lower in the OSA group (P<0.05), regardless of the APOE4. In regard to cognitive performance, OSA group showed worse values for Digit Symbol test, SCWT part 2, SCWT part 3, SKT total score compared with control group (P<0.05). Excluding individuals with APOE4 from groups, executive functioning (SCWT part 2) and attention/memory (SKT total score) remained with a significant difference between groups (P<0.05). A multiple linear regression analysis in OSA group without APOE4 found that the AHI explain 61% of the results in SCWT part 2 (P<0.008). The correlation between AHI and SCWT part 2 was significant (β=0.610, 95%CI 0.035—0.214, P=0.008).

Conclusões

AHI and arousal index were higher and the minimum O2 saturation was lower in OSA group, regardless of the APOE4. AHI predicted executive functioning measured by SCWT in OSA group. Thus, interventions to improve OSA severity should be considered to prevent the risk of decline in executive functioning in patients with moderate to severe OSA.

Palavras-chave

apnea, executive functioning, apolipoprotein ε4