Experimental Sleep Restriction Facilitates Pain and Electrically Induced Cortical Responses.

STUDY

OBJECTIVES

Sleep restriction (SR) has been hypothesized to sensitize the pain system. The current study determined whether experimental sleep restriction had an effect on experimentally induced pain and pain-elicited electroencephalographic (EEG) responses.

DESIGN

A paired crossover study.

INTERVENTION: Pain testing was performed after 2 nights of 50% SR and after 2 nights with habitual sleep (HS).

SETTING

Laboratory experiment at research center.

PARTICIPANTS

Self-reported healthy volunteers (n = 21, age range: 18-31 y).

MEASUREMENTS AND

RESULTS

Brief high-density electrical stimuli to the forearm skin produced pinprick-like pain. Subjective pain ratings increased after SR, but only in response to the highest stimulus intensity (P = 0.018). SR increased the magnitude of the pain-elicited EEG response analyzed in the time-frequency domain (P = 0.021). Habituation across blocks did not differ between HS and SR. Event-related desynchronization (ERD) was reduced after SR (P = 0.039). Pressure pain threshold of the trapezius muscle region also decreased after SR (P = 0.017).

CONCLUSION

Sleep restriction (SR) increased the sensitivity to pressure pain and to electrically induced pain of moderate, but not low, intensity. The increased electrical pain could not be explained by a difference in habituation. Increased response magnitude is possibly related to reduced processing within the somatosensory cortex after partial SR.