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An alternative measure of sleep fragmentation in clinical practice: the sleep fragmentation index
José Haba-Rubio1, Vicente Ibanez, Emilia Sforza
1Sleep Laboratory, Department of Psychiatry, University Hospital, Geneva, Switzerland.
Background And Purpose:
Micro-arousals (MA) are commonly considered as sleep components reflecting sleep fragmentation. However, their elucidation is time-consuming, with considerable inter-observer variability. The aim of our study was to investigate the usefulness of a sleep fragmentation index (SFI) to detect sleep disruption in a large sample of patients.
Patients And Methods:
Five-hundred ninety-eight polysomnographic studies made in controls and patients were examined. The SFI was calculated as the total number of awakenings and sleep stage shifts divided by total sleep time.
Results:
In the whole group a significant correlation was found between the SFI and the MA index (MAI) (P<0.001) with good agreement across a wide range of values. When patients were stratified according to final diagnosis a significant relation was noted for patients with insomnia (P<0.001), parasomnia (P<0.001), circadian schedule disorders (P<0.001) and sleep related breathing disorders (P< 0.001). Lower values were found in controls (P<0.01) and in patients with periodic limb movement disorder and/or restless legs syndrome (P<0.05). In 111 patients having two consecutive recording nights, a good reproducibility was present with no differences between nights (P=ns) and with significant correlation (P<0.001).
Conclusions:
The SFI seems to be an accurate, reproducible and easy method to detect sleep fragmentation in patients with sleep disorders. Further studies are needed to validate the usefulness of this tool in clinical practice.
Insights
The Sleep Fragmentation Index (SFI) accurately detects sleep disruption by correlating with micro-arousals (MA). This easy method is reproducible and useful for diagnosing sleep disorders.
Area of Science:
- Sleep Medicine
- Neuroscience
- Clinical Research
Background:
- Micro-arousals (MA) are indicators of sleep fragmentation but are difficult and time-consuming to quantify.
- Significant inter-observer variability exists in the manual scoring of micro-arousals.
Purpose of the Study:
- To evaluate the utility of a novel Sleep Fragmentation Index (SFI) for detecting sleep disruption.
- To assess the SFI's effectiveness in a large patient cohort.
Main Methods:
- Calculated SFI as the ratio of awakenings and sleep stage shifts to total sleep time.
- Analyzed 598 polysomnographic studies from controls and patients with various sleep disorders.
Main Results:
- A significant correlation was observed between the SFI and the Micro-Arousal Index (MAI).
- The SFI showed significant associations with insomnia, parasomnia, circadian rhythm disorders, and sleep-related breathing disorders.
- The SFI demonstrated good reproducibility across two consecutive nights of polysomnography.
Conclusions:
- The SFI is a reliable, reproducible, and user-friendly tool for assessing sleep fragmentation.
- Further research is recommended to validate the SFI's clinical application in sleep disorder management.
