Abstract |
The main focus of the present thesis was to evaluate a pupillometric test (the 5 minute Pupillary Alertness Test - 5-min PAT) as an objective measure of subjective daytime sleepiness (EDS). For this reason, we examined its sensitivity to modafinil, an alertness promoting drug which is commonly prescribed for the treatment of EDS. We also compared the 5-min PAT test with the gold standard MSLT in patients with obstructive sleep apnea (OSA). We showed that the test is sensitive to physiologic circadian rhythms, it distinguishes apneic patients from healthy controls, it is sensitive to OSA severity and to the alertness promoting effects of modafinil, while it correlates well with ΜSLT. The 5-min PAT test seems to reflect different aspects of arousal in comparison with MSLT, it is easily repeatable and it is a simple, low cost, easy and quick to administer and score. For these reasons, the 5-min PAT test is a promising clinical tool for the assessment of daytime sleepiness and its severity, and perhaps for the monitoring of the course of OSA after CPAP treatment, something that is important to be determined in future research.
We also compared for the first time the levels of alexithymia in a non-depressed, non-mentally ill sample of OSA patients with that of a control group which was one-to-one matched for age, gender, education and subjective depressive symptomatology. We found higher alexithymia levels in our OSA group even after the exclusion of all patient-control pairs at the high end of subjective depressive symptomatology (as measured with the Beck Depression Inventory - BDI-21). Additionally, as OSA is expected to impair vigilance and executive functioning owing to the sensitivity of the prefrontal cortex to the effects of sleep fragmentation and intermittent hypoxia, we examined the pattern of cognitive dysfunction using 3
Περίληψη 413
separate neuropsychological tests based on prefrontal cortical function. We found deficits in working memory, planning for emotional decision making and planning for problem solving. Finally, we evaluated several neurobiologically founded and heritable personality dimensions in OSA patients but found no difference compared to matched controls, when we excluded those with the higher scores in subjective depressive symptomatology with the exception of higher “Harm Avoidance” . These original findings have important implications for diagnosis, clinical assessment and treatment plan as well as in disease and treatment monitoring.
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