First-night effect in the chronic fatigue syndrome

Area of Science:

• Sleep Medicine
• Neuroscience
• Clinical Research

Background:

• The first-night effect, or habituation phenomenon, can influence polysomnography (PSG) results.
• Previous studies suggest variability in the first-night effect in chronic fatigue syndrome (CFS).
• Optimal recording methodology necessitates evaluating habituation in specific patient populations.

Purpose of the Study:

• To investigate the presence and magnitude of the first-night effect in patients with chronic fatigue syndrome.
• To determine if recording methodology influences key sleep parameters in CFS patients.
• To assess the impact of psychiatric comorbidities on the first-night effect in CFS.

Main Methods:

• Two-night polysomnography was conducted in a hospital sleep unit for a large group of CFS patients without primary sleep disorders.
• Key sleep parameters including Total Sleep Time, Sleep Efficiency, Sleep Onset Latency, and REM sleep metrics were analyzed.
• Bland and Altman plots and factorial analysis were used to assess differences between nights and identify influencing factors.

Main Results:

• A significant first-night effect was observed in CFS patients, influencing multiple sleep parameters.
• Systematic bias related to recording order (first-night effect) was confirmed using Bland and Altman plots.
• No significant differences in the first-night effect were found between patients with and without generalized anxiety comorbidity.

Conclusions:

• Chronic fatigue syndrome is identified as a condition with a clinically significant habituation effect.
• The findings underscore the importance of considering the first-night effect in PSG for CFS patients.
• Standardized recording protocols may be necessary to account for habituation in CFS sleep studies.