eTABLE 2. Definition of terms for sleep-related symptoms and related terms.

Term	Definition	Burden on the patient
Sleep disturbance	Disturbed sleep in the narrower sense	Insomnia; consequent daytime tiredness or unusual behavior (sleepwalking) leading to symptoms.
Daytime sleepiness	Reduced central nervous activation; patient feels urgent need to sleep and may actually fall asleep; also called narcolepsy; can be measured using vigilance tests	Daytime sleepiness can reduce patients‘ ability to live life actively, and can impair the ability to drive.
Daytime tiredness	General term describing stress-related reduction in mental and physical performance	Daytime tiredness is a normal experience for everyone, so long as it does not restrict everyday living. If it does lead to restrictions, or if compensating mechanisms are no longer effective, it can be pathological.
Fatigue	Subjective sense of physical and/or mental exhaustion. It occurs in the absence of stress or out of proportion to the amount of stress undergone.	Fatigue reduces patients‘ ability to live life actively, and their ability to perceive active living as enjoyable rather than a burden.

Source: „S3-Leitlinie Palliativmedizin für Patienten mit einer nicht-heilbaren Krebserkrankung“ (2)