Autobiographical memory impairment in obstructive sleep apnea patients with and without depressive symptoms

V Vien Lee, John Trinder, Melinda L. Jackson

Obstructive sleep apnoea is associated with memory impairments, and higher rates of depressive symptoms and major depressive disorder compared with community estimates. Autobiographical memory overgenerality, a behaviour characterized by difficulty recalling specific memories from one's own life, is recognized as a marker of depression. Previous studies have demonstrated the predictive quality of specific autobiographical memory recall on the course of depression in patients with obstructive sleep apnoea. However, it remains unclear whether impaired autobiographical memory is simply a feature of depression, or whether it is also impaired in patients with obstructive sleep apnoea without depression. This study aimed to investigate whether autobiographical memory impairments can be observed in patients with obstructive sleep apnoea, independent of the severity of depressive symptoms. Twenty-one patients with obstructive sleep apnoea symptomatic for depressive symptoms (mean age = 43.43 years, SD = 9.97), 17 patients with obstructive sleep apnoea asymptomatic for depressive symptoms (mean age = 40.65 years, SD = 9.39), and 20 healthy controls without sleep-disordered breathing (mean age = 32.80 years, SD = 6.69) completed an Autobiographical Memory Test. Patients with obstructive sleep apnoea symptomatic for depressive symptoms recalled significantly fewer specific memories when compared with healthy controls (P = 0.010). No difference in the recall of specific autobiographical memory was observed between symptomatic and asymptomatic patients with obstructive sleep apnoea. With regard to valence, symptomatic patients with obstructive sleep apnoea recalled significantly fewer negative specific memories when compared with controls (P = 0.010). Impairment in specific autobiographical memory recall can be observed in patients with obstructive sleep apnoea, regardless of the severity of depressive symptoms; however, this effect may not be as prominent in younger patients with obstructive sleep apnoea.