Psychomotor Vigilance Impairment During Total Sleep Deprivation Is Exacerbated in Sleep-Onset Insomnia

Abstract

Purpose

Individuals with primary insomnia frequently report cognitive impairment as a next-day consequence of disrupted sleep. Studies attempting to quantify daytime impairment objectively in individuals with insomnia have yielded mixed results, with evidence suggesting impairments in aspects of executive functioning but not psychomotor vigilance. It has been suggested that persons with insomnia may have latent performance deficits for which they would be able to compensate effectively under normal daytime circumstances – suggesting that any such deficits may be exposed through perturbation. In this context, we used a laboratory-based total sleep deprivation (TSD) paradigm to investigate psychomotor vigilance performance in individuals with chronic sleep-onset insomnia as compared to healthy normal controls.

Participants and methods

Fourteen participants, seven individuals with chronic sleep-onset insomnia (ages 24–40y) and seven age-matched, healthy normal sleepers completed a highly controlled in-laboratory study involving 38 h of TSD. A 10 min and a 3 min version of the psychomotor vigilance test (PVT) were administered every 3 h during TSD.

Results

In both the individuals with sleep-onset insomnia and the age-matched normal sleepers, lapses of attention and false starts on the PVT were relatively infrequent during the first 16 h of the TSD period, but increased significantly when wakefulness was extended beyond 16 h. However, the effects of TSD on PVT performance were considerably exacerbated in the sleep-onset insomnia group, which showed about twice as many lapses of attention, more than twice as many false starts, and approximately twice as big a time-on-task effect on the 10 min PVT as the age-matched normal sleepers group, with similar findings on the 3 min PVT.

Conclusion

These findings indicate that daytime impairment reported by individuals with sleep-onset insomnia has an objective performance component that is exposed during TSD. Thus, persons with sleep-onset insomnia could be at increased risk of performance impairment in settings that involve extended wakefulness. This underscores the importance of treating insomnia and suggests that laboratory sleep deprivation studies could serve to document the effectiveness of treatment approaches.

Keywords:

• bedtime-specific hyperarousal
• chronic insomnia
• cognitive performance
• extended wakefulness
• primary insomnia
• vulnerability to sleep loss

Acknowledgments

We thank the study volunteers for their participation, and the staff of the Human Sleep and Cognition Laboratory in the Sleep and Performance Research Center at Washington State University for their assistance in data collection. This study was supported by Office of Naval Research grant N00014-13-C-0063 through Pulsar Informatics, Inc. The smartphone-based PVTs used in the study were on loan from Pulsar Informatics, Inc. This company was not involved in study design and execution, data analyses, and manuscript writing.

Disclosure

The authors report no conflicts of interest in this work.