Unihemispheric Sleep

Last updated: November 27, 2018

What Does Unihemispheric Sleep Mean?

Unihemispheric sleep is a homeostatic function that involves one side of the brain remaining half-awake during circadian rhythm cycles. Medical evidence suggests the left cortex is more acute to external stimuli in contrast with the right hemisphere that is dormant during sleep stage cycles including non-rapid eye movement (NREM) and rapid eye movement (REM). Electroencephalography (EEG) and auxiliary testing methods monitor and track brainwave activity where unihemispheric sleep is a common sleep pattern deviation.


WorkplaceTesting Explains Unihemispheric Sleep

Sleep contributes to the maintenance of intracellular health of the brain where cognition, memory retention, and motor coordination are important physiological functions. EEG test findings provide comparative analysis highlighting the simultaneous interplay between wakefulness and sleep in the corresponding left (wake) and right (sleep) hemispheres of the brain. The first night effect (FNE) is an epiphenomenon of unihemispheric sleep that occurs when an individual is exposed to a different environment, triggering perceptual awareness on one side of the brain to stay alert.

Although sleep experts suspect unihemispheric sleep serves as an innate human response to environmental cues, consistent episodes of first night effects can induce sleep deprivation. Individuals who travel regularly or who occupy commercial driving positions have erratic sleep schedules that interfere with normal biorhythms influencing their job performance skills. Because of the disparity of unihemispheric sleep patterns, the medical community recognizes it as a sleep disturbance in which individuals are susceptible to chronic fatigue.

Consequently, federal laws regulate working hours, especially in safety-sensitive occupations that require operating heavy machinery, given the prevalence of sleep deprivation. Slow wave activity (SWA), or deep sleep, devices are available to temper the wakeful side of the brain with artificial sounds designed to normalize biorhythms for people with unihemispheric sleep patterns.


Share this Term

  • Facebook
  • LinkedIn
  • Twitter

Related Reading


WellnessErgonomicsFit for Work TestingHealth and SafetyWorkplace HealthLab TestEmploymentSleep

Trending Articles

Go back to top