Characteristics (statistical and phenomenological) of patients with CFS
| Sleep phenotype | Central differential features | Associated diagnostic features | How this may present subjectively |
|---|---|---|---|
| 1 | Long Sleep Onset Latency, Long REM Latency, High amounts of Slow Wave Sleep and low amounts of REM | Low amounts of stage 2 sleep | Problems in getting off to sleep but when asleep few awakenings. The sleep that is obtained is of normal quality |
| 2 | High number of arousals per hour and high amounts of stage 2 sleep | No difficulties in getting off to sleep and few awakenings but feelings or evidence of a ‘restless’ night sleep | |
| 3 | High Total Sleep Time, low amounts of time awake during the night and low number of wake periods during the night | High amounts of REM Sleep, Short Sleep Onset Latency, Low number of Awakenings, Short REM Latencies and low amounts of stage 1 sleep | No difficulties in getting off to sleep and few awakenings but feelings of being unrefreshed on waking despite a significant amount of time in bed asleep |
| 4 | Highest number of wake periods during the night and highest amounts of time awake during the night | Low Total Sleep Time, Low number of arousals per hour during the night and Low amounts of Slow Wave Sleep | Short sleep duration and although no difficulties getting off to sleep lots of awakenings for significant periods of time. Also increased feelings of daytime sleepiness |
CFS,chronic fatigue syndrome; REM,Rapid Eye Movement.