Sleep microstructure in patients with systemic sclerosis: A cyclic alternating pattern analysis study

Area of Science:

• Sleep Medicine
• Rheumatology
• Neurophysiology

Background:

• Cyclic alternating pattern (CAP) is a marker of non-REM sleep instability.
• Systemic sclerosis (SSc) is associated with various sleep disturbances.
• Understanding sleep microstructure in SSc is crucial for comprehensive patient care.

Purpose of the Study:

• To investigate the expression of cyclic alternating pattern (CAP) in non-REM sleep of patients with systemic sclerosis (SSc).
• To compare CAP findings in SSc patients with a matched control group.
• To determine if CAP analysis reveals sleep microstructure alterations in SSc.

Main Methods:

• Polysomnography was used to record sleep in 31 SSc patients and matched controls.
• Conventional sleep scoring and detailed CAP analysis were performed by certified somnologists.
• Key sleep parameters including sleep efficiency, stages, latency, and oxygen saturation were compared.

Main Results:

• SSc patients showed higher arousal and periodic limb movement indices compared to controls.
• CAP analysis revealed significantly higher CAP numbers, A2 index, and A3 duration in SSc patients.
• SSc patients had a lower A1 duration, indicating altered sleep microstructure despite similar overall sleep macrostructure.

Conclusions:

• Systemic sclerosis patients exhibit increased sleep instability, evidenced by elevated CAP during non-REM sleep.
• CAP analysis provides valuable insights into sleep microstructure disturbances in SSc that are missed by conventional sleep scoring.
• Microstructure analysis using CAP is essential for a complete understanding of sleep abnormalities in SSc.