∙ Study participants:

• Subjective complaints of Excessive daytime sleepiness (EDS) and/or Hypersomnia (H) as defined above

• EDS and/or H present daily or almost daily for at least 1 month prior to the consultation

• Ability and consent to undergo electrophysiological routine assessment

• Ability to give informed consent

∙ Healthy controls:

• Age and gender matched healthy subjects

• Including blood related relatives of study participants

• Ability and consent to undergo electrophysiological routine assessment

• Ability to give informed consent

∙ Controls with Sleep disordered breathing (SDB):

• Subjective complaints of EDS with Epworth Sleepiness Scale (ESS) \> 10 (adults) and/or H due to SDB: Presence of clinically significant and untreated obstructive sleep apnea (OSA) as determined by the investigator with an apnea-hypopnea-index \>30/h

• Multiple sleep-latency test (MSLT) mean sleep latency ≤ 8min

• Subjective and objective improvement of EDS and/or H within 3 months after treatment with

• Positive airway pressure (PAP) therapy with documented

‣ Reduction of apnea-hypopnea index below \<10/h

⁃ Reduction of ESS by ≥ 25%

⁃ MSLT mean Sleep Latency \> 12min

• Ability and consent to undergo electrophysiological routine assessment

• Ability to give informed consent