The APOE genotype was examined in 123 patients with OSA and in 121 controls, together with a series of neuropsychological tests.
OSA and control subjects had similar APOE genotype and allele distribution, but when neuropsychological tests were considered, OSA patients showed significantly lower values for verbal long-term (delayed free recall at the Rey auditory-verbal learning test) and working memory (bisyllabic words). Moreover, spatial span was found to be lower in OSA ε4 allele carriers than in non-carriers; this difference was not observed in controls.
This study confirms the presence of a verbal memory impairment in OSA patients and provides evidence for a significant interaction of APOE ε4 allele and OSA on frontal lobe function in adults, possibly mediated by the presence of specific frontal lobe neuroanatomical changes in these patients.