# Sleep-Disordered Breathing Risk with Comorbid Insomnia Is Associated with Mild Cognitive Impairment
[PERSON]  
1 Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; [EMAIL_ADDRESS] (A.R.R. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (S.K. ); [EMAIL_ADDRESS] (D.E.D.P. ); [EMAIL_ADDRESS] (J.M.K. ); [EMAIL_ADDRESS] (D.M.W.) [PERSON]  
1 Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; [EMAIL_ADDRESS] (A.R.R. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (S.K. ); [EMAIL_ADDRESS] (D.E.D.P. ); [EMAIL_ADDRESS] (J.M.K. ); [EMAIL_ADDRESS] (D.M.W.) [PERSON]  
1 Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; [EMAIL_ADDRESS] (A.R.R. ); [EMAIL_ADDRESS] (J.M.K. ); [EMAIL_ADDRESS] (D.E.D.P. ); [EMAIL_ADDRESS] (J.M.K. ); [EMAIL_ADDRESS] (D.M.W.) [PERSON]  
1 Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; [EMAIL_ADDRESS] (A.R.R. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (S.K. ); [EMAIL_ADDRESS] (D.E.D.P. ); [EMAIL_ADDRESS] (J.M.K. ); [EMAIL_ADDRESS] (D.M.W.) [PERSON]  
1 Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; [EMAIL_ADDRESS] (A.R. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (S.K. ); [EMAIL_ADDRESS] (D.E.D.P. ); [EMAIL_ADDRESS] (J.M.K. ); [EMAIL_ADDRESS] (D.M.W.) [PERSON]  
1 Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; [EMAIL_ADDRESS] (A.R. ); [EMAIL_ADDRESS] (X.S. ); [EMAIL_ADDRESS] (S.K. ); [EMAIL_ADDRESS] (D.E.D.P. ); [EMAIL_ADDRESS] (J.  
which, together, may convey more severe cognitive consequences. In a meta-analysis of 18 prospective studies examining sleep disturbances (i.e., insomnia, SDB, and other sleep problems) and the risk of dementia [2], only three studies assessed both SDB and insomnia, yet none of their analyses accounted for SDB with comorbid insomnia [4; 5; 6]. In the general adult population, the prevalence of insomnia is 10-40% [7; 8], while the prevalence of SDB ranges between 9 and 38% [9]. Estimates of the prevalence of SDB with comorbid insomnia vary depending on the population studied. Among adults presenting to sleep clinics with SDB symptoms, 39-58% also report insomnia symptoms. In contrast, among those presenting with insomnia complaints, 29-67% have at least mild SDB [10]. That is, SDB with comorbid insomnia occurs together more frequently than expected based on prevalence estimates of each sleep disorder alone. SDB with comorbid insomnia has been hypothesized as a bidirectionally related entity [11]. Obstructive respiratory events occurring during the initial wake-to-sleep transition may contribute to difficulties with sleep onset, while worsening sleep-disordered breathing during REM sleep may trigger premature early awakenings. One study showed that 90% of awakenings among participants with insomnia were preceded by an obstructive respiratory event, although participants attributed the awakenings to psychological (stress, ruminations, anxiety) or physiological (nocuria, discomfort, temperature) causes [12]. Baseline SDB has also been shown to predict incident insomnia symptoms at 7.5-year follow-up in a longitudinal observational study (OR = 1.83; 95% CI = 0.94-3.54; \(p\) = 0.074) [13]. Though treating SDB with positive airway pressure (PAP) therapy has been shown to improve some insomnia complaints (i.e., middle insomnia), it can fail to improve others (early and late insomnia) [14; 15; 16; 17; 18; 19]. Conversely, a smaller body of research has demonstrated that insomnia may be a risk factor for SDB. Experimentally induced sleep fragmentation, sleep restriction, and sleep deprivation (all features of insomnia) have been shown to exacerbate respiratory disturbances during sleep among those with and without SDB [20; 21; 22; 23; 24; 25; 26]. Treatment of insomnia with cognitive behavioral therapy for insomnia in patients with SDB with comorbid insomnia resulted in a reduction in SDB severity [27].