Excessive daytime sleepiness which still remains after an effective treatment with nocturnal ventilotherapy or with other specific treatments (positional therapy, oro-mandibular devices) in patients with obstructive sleep apnea syndrome has a prevalence of 55% of treated cases, representing a notable theme of clinical and research interest.

In recent years there have been several studies on the use of wakefulness-promoting drugs generally prescribed in patients with narcolepsy, in this disorder with promising results. Right in consideration of the forthcoming approval of these drugs, it is important to find biomarkers able to predict which patients will develop daytime sleepiness resistant to ventilatory treatment. Several studies have highlighted the association between obstructive sleep apnea syndrome and the increase of cerebral amyloid beta deposits, concluding that apnoic disorder can be considered a risk factor for the development of cognitive impairment and Alzheimer';s disease.

In this scenario, it would be useful to identify biological markers able to underline which clinical phenotypes of sleep apnea syndrome are more associated with residual excessive daytime sleepiness and/or cognitive impairment. In recent years several kits for the assay of biomarkers of neurodegeneration have been developed not only in CSF, but also in human serum. Among them, the most important are light chain neurofilaments (NFL), amyloid isoforms 40 and 42 (Ab40 and Ab42). Other biomarkers found in neurodegenerative diseases associated with excessive daytime sleepiness are orexin A (OXA) and histamine (HA).

In this view, the aim of this study is to evaluate the role of biomarkers of neurodegeneration in characterizing disease severity and response to treatment of obstructive sleep apnea syndrome with residual excessive daytime sleepiness.

Inclusion Criteria:

• Mild or moderate-severe obstructive sleep apnea
• Written informed consent

Exclusion Criteria:

• Other sleep disorders
• Pregnancy or breastfeeding
• Cerebral diseases or neuropsychiatric deficits
• Psychiatric disorders
• Impossibility to provide informed consent

Patients with sleep apnea syndrome with excessive daytime sleepiness