Insomnia as an expression of obstructive sleep apnea syndrome--the effect of treatment with nocturnal ventilatory support

Comorbid Insomnia and Obstructive Sleep Apnea (COMISA): Current Concepts of Patient Management

Obstructive sleep apnea (OSA) and insomnia are the two most common sleep disorders among the general population, and they may often coexist in patients with sleep-disordered breathing (SDB). The higher prevalence of insomnia symptoms in patients with OSA (40–60%) compared to that observed in the general population has thus led researchers to identify a new disorder named comorbid insomnia and OSA (COMISA), whose true burden has been so far largely underestimated. The combined treatment of COMISA patients with positive-airway pressure ventilation (PAP) with cognitive behavioral therapy for insomnia (CBTi) has shown a better patient outcome compared to that obtained with a single treatment. Furthermore, recent evidence has shown that an innovative patient-centered approach taking into consideration patient characteristics, treatment preferences and accessibility to treatment is recommended to optimize clinical management of COMISA patients. However, in this complex mosaic, many other sleep disorders may overlap with COMISA, so there is an urgent need for further research to fully understand the impact of these therapies on outcomes for OSA patients with comorbidity. In light of this need, this review focuses on the major sleep disorders comorbid with OSA and the recent advances in the management of these insomniac patients.

Brain mechanisms of insomnia: new perspectives on causes and consequences

While insomnia is the second most common mental disorder, progress in our understanding of underlying neurobiological mechanisms has been limited. The present review addresses the definition and prevalence of insomnia and explores its subjective and objective characteristics across the 24-hour day. Subsequently, the review extensively addresses how the vulnerability to develop insomnia is affected by genetic variants, early life stress, major life events, and brain structure and function. Further supported by the clear mental health risks conveyed by insomnia, the integrated findings suggest that the vulnerability to develop insomnia could rather be found in brain circuits regulating emotion and arousal than in circuits involved in circadian and homeostatic sleep regulation. Finally, a testable model is presented. The model proposes that in people with a vulnerability to develop insomnia, the locus coeruleus is more sensitive to-or receives more input from-the salience network and related circuits, even during rapid eye movement sleep, when it should normally be sound asleep. This vulnerability may ignite a downward spiral of insufficient overnight adaptation to distress, resulting in accumulating hyperarousal, which, in turn, impedes restful sleep and moreover increases the risk of other mental health adversity. Sensitized brain circuits are likely to be subjectively experienced as "sleeping with one eye open". The proposed model opens up the possibility for novel intervention studies and animal studies, thus accelerating the ignition of a neuroscience of insomnia, which is direly needed for better treatment.

Men and women with chronic insomnia disorder and OSAS: Different responses to CPAP

Objective

To evaluate the response to CPAP in patients with chronic insomnia disorder (CID) with OSAS in an unselected patient population including all OSAS severity groups. As a secondary objective, we also wanted to evaluate the differences between patients that improve insomnia symptoms with CPAP and patients that do not improve, specifically evaluating possible gender differences.

Methods

Retrospective study of patients with a diagnosis of OSAS treated with CPAP and CID at the first clinical visit, selected from a database of an outpatient sleep clinic of University Hospital.

Results

From a database of total of 827 patient, 90 patients were identified with OSAS and CID (53.3% women). Middle / moderate OSAS was diagnosed in 68.9% and severe OSA in 31.1%. Most patients (61.1%) improved insomnia symptoms after CPAP therapy. In the responders group, 58.2% had initial insomnia, 63.6% middle insomnia and 12.7% late insomnia. Responders to CPAP were more frequently women (women 61.8%, men 38.2%, p = 0.035) and there was no other difference between responders and non-responders. On subgroup analysis, this difference was significant only in severe OSAS (women 88.9%, men 31.6%, p = 0.013).

Conclusion

In most patients with CID and OSA, there is a consistent reduction of insomnia symptoms with the CPAP use. This factor emphasizes the importance of performing PSG in CID. Insomnia in men with severe OSAS responds less frequently to CPAP suggesting that in these cases the insomnia phenotype is less dependent on the respiratory symptoms.