Date of Graduation

2017

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Psychology

Committee Chair

Hawley E Montgomery-Downs

Committee Co-Chair

Orfeu M Buxton

Committee Member

Kevin T Larkin

Committee Member

James W Lewis

Committee Member

Daniel W McNeil

Abstract

Purpose: Pain is amplified following partial sleep deprivation. Pain has not been evaluated after sleep interruption, when total sleep time is preserved. Sleep interruption, also called sleep fragmentation, is ecologically relevant because it is caused by common sleep disorders such as Obstructive Sleep Apnea [OSA], Upper Airway Resistance Syndrome [UARS] and Periodic Limb Movements Disorder [PLMD]. The Sleep Continuity Hypothesis posits that the restorative effects of sleep are related to sleep quality in addition to quantity. With this study, my goal was to evaluate whether sleep fragmentation affected pain threshold and/or tolerance by systematically fragmenting the sleep of otherwise healthy adults.;Methods: Twelve adult female participants without chronic pain or evidence of a sleep disorder underwent a 14-day protocol. Sleep was monitored using actigraphy throughout the study. Participants completed daily morning and evening reaction time tasks to evaluate changes in attention. To measure changes in pain threshold (when a stimulus becomes painful) and tolerance (when a stimulus is no longer tolerable), a pressure-pain task was administered in-lab by a researcher. This test occurred a total of eight times, morning and evening. Participants spent the eighth, ninth and 13th nights in-lab. Night eight was for acclimatization to the research facility [BASE]. To compare pain after experimental sleep fragmentation (every five minutes; [FRAG]) with pain after sham [SHAM], these conditions were assigned pseudo-randomly to nights nine and 13. Three nights of recovery sleep outside the lab occurred between SHAM and FRAG nights.;Results: Sleep interruptions were induced at a rate of 5.2 times per hour, on average, without changing participants' total sleep time. Stage two sleep proportion was higher on fragmentation night. Lapses in vigilance were lower after BASE than other nights. The slowest 10% of reaction times were slower after SHAM than BASE. Overall, reaction time did not reliably differ as a result of fragmentation. Neither pain threshold nor pain tolerance differed as a function of experimental condition.;Conclusions: Systematic sleep fragmentation, particularly of stage two sleep, did not affect reaction time (a measure of sustained attention) or pressure pain (threshold or tolerance). Reaction time was not related to individual-level changes in fragmentation or pain. Future work should aim to establish the minimal fragmentation that engenders a clinical effect (without concomitant hypoxemia) to inform clinical definitions of fragmentation severity.

Download

Share

COinS