The Assessment of Hypersomnolence: A Clinical Experience

Introduction: Excessive Daytime Somnolence (EDS) is a common complaint amongst patients presenting to a Sleep Clinic. Sleep deprivation is a major cause of EDS and therefore its accurate assessment is essential. Methods: All patients referred for a Diagnostic Sleep Study (DSS) and Multiple Sleep Latency Test (MSLT) for the investigation of EDS were invited to participate in the study. Patients wore an actigraph armband and completed a sleep diary for at least 7 days. Patients had blood tests excluding medical reasons for fatigue and completed questionnaires: Functional Outcome of Sleep Questionnaire, Depression Anxiety Stress Scales and Short Form Fatigue Questionnaire. Results: 64 patients were referred for the investigation of EDS during the study period; 33 patients were unsuitable due to co-morbidities, 4 declined and 27 consented. 3 patients were further excluded because of co-morbidities not known at time of consent. 7/24 patients were excluded due to the presence of obstructive sleep apnoea and/or iron deficiency, or reduced total sleep time (<300minutes) on polysomnography. 10/17 patients had a Mean Sleep Latency < 8minutes. 1/10 patients who slept more 7hours per night (on actigraphy) with a Mean Sleep Latency of 5.8minutes could be labelled with Idiopathic hypersomnolence, using ICSD-3 criteria. Conclusion: The use of actigraphy, blood work up, and questionnaires provides a more accurate assessment of EDS, as it allows the exclusion of patients with a possible medical and/or psychiatric etiology for fatigue and/or those patients who are sleep deprived.