| Abstract: | 阻塞性睡眠呼吸中止（obstructive sleep apnea, OSA）是一種最常見的睡眠呼吸障礙，影響約2%至4%的成年人，OSA會引起一連串的生理變化，並常與高血壓、心血管疾病、糖尿病、及中風等多種疾病共病，認知功能缺損也可能是OSA的相關症狀。過去研究以睡眠呼吸障礙（sleep-disordered breathing, SDB）之程度來定義OSA的嚴重程度，然而，OSA可能通過慢性間歇性低血氧（intermittent hypoxemia, IH）和睡眠片段化（sleep fragmentation, SF）影響認知功能，過去研究對於OSA患者的IH、SF與認知功能的關係仍未有充分討論。本研究之目的為（1）探討OSA患者的認知缺損型態；（2）釐清相對於SDB，IH和SF對OSA患者認知功能的影響。研究邀請20名OSA患者（呼吸中止淺呼吸指數(apnea hypopnea index, AHI) > 5）和20名無睡眠困擾之認知功能正常對照組，並進行神經心理評估，包括一般認知功能、記憶、注意力和工作記憶、執行功能、精神運動速度與協調的比較。研究結果顯示，與對照組相比，OSA患者在再認記憶、執行功能、及精神運動速度與協調表現明顯缺損，然而，本研究中OSA患者認知表現存在高度異質性，這可能可歸因於患者人口學變項（即教育程度和性別）和睡眠期間生理功能的差異。在排除人口學和生理功能差異的影響後，IH和SF仍與精神運動速度與協調和執行功能相關，而SDB所造成的認知影響可能可由人口學與生理功能差異解釋。本研究初步揭示OSA患者認知缺損的本質，並對於過去研究報告OSA患者認知缺損表現的不一致性提出可能解釋。IH和SF在評估OSA早期認知效果方面可能比SDB更重要，IH和SF可能能夠用於促進認知障礙的早期發現和評估早期介入的有效性。
Obstructive sleep apnea (OSA) is one of the most common sleep-disordered breathing (SDB) conditions, affecting about 2% to 4% of adults. OSA causes a series of physiological changes and is a common comorbid of hypertension, cardiovascular disease, diabetes, stroke and other metabolic diseases. Cognitive impairment may also be a symptom associated with OSA. Previous researchers defined the severity of OSA using the levels of SDB. However, OSA may affect cognitive function through chronic intermittent hypoxemia (IH) and sleep fragmentation (SF). The relationships between IH and cognitive functions and the relationship between SF and cognitive functions among patients with OSA remain poorly appreciated. The purposes of the present study were (1) to investigated the cognitive profiles of patients with OSA; and (2) to clarified the impacts on cognitive functions of IH and SF as compared to those of SDB among patients with OSA. Twenty patients with OSA (AHI > 5) and 20 cognitively normal individuals without sleep disturbance were recruited in this study and undertook a neuropsychological assessment including evaluations of general cognitive function, memory, attention/working memory, executive function, psychomotor speed and coordination. The results showed that compared with the control group, OSA patients had significantly cognitive impairments in recognition memory, executive function, and psychomotor speed and coordination. However, high extents of heterogeneity in the cognitive profiles among the patients with OSA were observed, which may be attributable to differences in demographic variables (i.e., educational levels and gender) and physiological functions during sleep among the patients. After excluding the effects of differences in demographics and physiological functions, IH and SF, but not SDB, still correlated with psychomotor speed and coordination and executive functions. The preliminary study shed light into the nature of cognitive deficits among patients with OSA and reconciled the inconsistency in the cognitive effects of OSA reported in previous studies. IH and SF might be more important in evaluating early cognitive effects in OSA than SDB. IH and SF might be able to be used to indicators facilitating the early detection of cognitive impairment and evaluation of the effectiveness of early intervention. |
