Søvnstruktur og oppvåkningsterskel hos pasienter med forsinket søvnfasesyndrom


Forskere fra NTNU, St. Olavs Hospital og Universitetet i Bergen har i denne studien sammenlignet 20 pasienter med forsinket søvnfasesyndrom med 16 kontroller for blant annet å identifisere og sammenligne oppvåkningsterskel. For å stimulere til oppvåkning ble det benyttet en alarmklokke med lydintensitet som gikk fra 72 db til 104 db. Resultatene viser blant annet at gjennomsnittlig oppvåkningsterskel var høyere hos pasienter med forsinket søvnfasesyndrom sammenlignet med kontroller.

Sleep structure and awakening threshold in delayed sleep-wake phase disorder patients compared to healthy sleepers

Studien er publisert i Sleep Medicine

Solheim B, Langsrud K, Kallestad H, Engstrøm M, Bjorvatn B, Sand T.

STUDY OBJECTIVES:

Difficult early morning awakening is a primary symptom of delayed sleep-wake phase disorder (DSWPD), however, it remains poorly investigated. Our main objective was to quantify the awakening threshold in DSWPD-patients and healthy controls as well as investigate a possible relationship with sleep stages. A secondary objective was to compare habitual sleep measured by polysomnography and actigraphy between patients and controls.

METHODS:

Twenty DSWPD patients and 16 controls had two polysomnographic recordings at a sleep laboratory. Participants followed their habitual sleep-wake schedule on the first night and a forced sleep-wake schedule (00:00-07:00 h) on the second night. We used a custom-made alarm clock was for the forced-night awakening, starting at 72 dB sound intensity which increased up to 104 dB.

RESULTS:

Mean awakening threshold in dB was higher in patients compared to controls; 75.5 vs. 72.6, p = 0.01, and the difference could not be explained statistically by sleep-time. Patients who were in REM sleep upon attempted awakening had a higher awakening threshold compared to patients who were in NREM sleep; 80.0 vs 74.7, F = 6.4, p = 0.02. Patients had increased sleep onset latency both at home with actigraphy and by PSG during the first laboratory night (20.6 vs 12.1 min, p = 0.004), however no further differences between the groups were observed regarding sleep structure.

CONCLUSIONS:

A high early-morning forced awakening threshold in DSWPD was related to REM sleep. Sleep onset problems, even with habitual bedtimes, may also be an integral feature of DSWPD.