REM sleep as a potential indicator of hyperarousal in psychophysiological and paradoxical insomnia sufferers.

STUDY OBJECTIVES

The objective was to study REM sleep macrostructure and microstructure as potential indicators of hyperarousal in insomnia by comparing good sleepers (GS) and insomnia sufferers (INS) (subdivided into psychophysiological "PSY-I" and paradoxical "PARA-I").

DESIGN

Cross-sectional comparisons of GS, PSY-I and PARA-I.

SETTING

Participants slept for 4 consecutive nights in the laboratory where PSG was recorded. Nights 2 and 3 were combined to compare REM sleep between groups.

PARTICIPANTS

Thirty-nine PSY-I, 27 PARA-I and 47 GS completed the study, comprising home questionnaires, clinical interviews and night PSG recordings. All participants were aged between 25 and 55 and met inclusion criteria for either PSY-I, PARA-I or GS.

INTERVENTIONS N/A MEASUREMENTS AND RESULTS: Results showed no between group differences on REM sleep macrostructure. As for REM sleep microstructure, PSY-I had an increased number of wake intrusions compared to PARA-I (p=.03). Subjective SE, TST and TWT were significantly correlated with the duration of REM sleep (REMD; p≤.002) and with the proportion of REM sleep for PARA-I (p≤.06).

CONCLUSIONS

REM sleep macrostructure does not seem to be an adequate indicator of hyperarousal in insomnia. However, the number of wake intrusions in REM could be used to differentiate PSY-I from PARA-I and could reflect the heightened arousal of the former group. Relationships between REM sleep duration and proportion could be linked to dream imagery activity, especially in PARA-I. Further investigations are needed to identify variables that could reflect hyperarousal and differentiate insomnia types.