Oculomotor responses during partial and total sleep deprivation.
BACKGROUND
Oculomotor responses related to the pupil light reflex (PLR) and saccadic velocity may be sensitive to the effects of sleepiness and therefore could be used to evaluate an individual's fitness for duty.


METHODS
There were 12 normal subjects who completed an 8-d study. They were allowed 8 h in bed on the first three nights, 4 h in bed on the fourth night, and then were sleep deprived for the following 64 h. Approximately every 3 h, subjects performed a battery of tests which included a 45-s automated oculomotor test and a 40-min PC-based driving simulator task. Sleepiness was evaluated with a self-assessment instrument. Subjects were allowed 10 h of recovery sleep following sleep deprivation.


RESULTS
Oculomotor results for nine subjects showed a significant increase in latency to pupil constriction and a significant decrease in saccadic velocity with total, but not partial, sleep deprivation. The most robust changes during sleep deprivation occurred for saccadic velocity. A night of recovery sleep reversed the effects of total sleep deprivation on latency to pupil constriction and saccadic velocity. Subjective sleepiness and off-road accidents were found to significantly increase over the sleep deprivation period. A significant positive correlation between increasing latency to pupil constriction and increasing sleepiness and driving accidents, and a significant negative correlation between decreasing saccadic velocity and increasing sleepiness and driving accidents during sleep deprivation were found.


CONCLUSIONS
These findings suggest that oculomotor functions, particularly saccadic velocity, are feasible for assessing neurophysiological changes associated with and predictive of sleep deprivation-induced operational performance degradation.
Rowland
Laura M
LM
Walter Reed Army Institute of Research, Silver Spring, MD, USA. lrowland@mprc.umaryland.edu
Thomas
Maria L
ML
Thorne
David R
DR
Sing
Helen C
HC
Krichmar
Jeffrey L
JL
Davis
H Quigg
HQ
Balwinski
Sharon M
SM
Peters
Robert D
RD
Kloeppel-Wagner
Esther
E
Redmond
Daniel P
DP
Alicandri
Elizabeth
E
Belenky
Gregory
G
D000328:Adult; D001334:Automobile Driving; D001921:Brain / Q000502:physiology; D005260:Female; D006801:Humans; D009801:Oculomotor Muscles / Q000503:physiopathology*; D017286:Polysomnography; D012025:Reflex, Pupillary / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D012890:Sleep / Q000502:physiology; D012892:Sleep Deprivation / Q000503:physiopathology*; D013647:Task Performance and Analysis