Visual search performance across 40 h of continuous wakefulness: Measures of speed and accuracy and relation with oculomotor performance

L De Gennaro, M Ferrara, G Curcio, M Bertini
Physiology & Behavior 2001 September 1, 74 (1): 197-204
The aim of the study was to estimate the sensitivity of a brief self-paced visual search task to increased levels of sleepiness as a consequence of 40 h of sleep deprivation. Time-of-day effects on this task, on subjective sleepiness and on oculomotor performance changes, were also assessed. Eight normal subjects slept for three nights in the laboratory (adaptation, baseline, recovery). Baseline and recovery nights were separated by a period of 40 h of continuous wakefulness, during which subjects were tested every 2 h from 10:00 to 22:00 h on both days preceding and following the sleep deprivation night, as well as from 24:00 to 08:00 h during the deprivation period. At the same time, subjects filled in a visual analogue sleepiness scale and the Stanford Sleepiness Scale (SSS). As regards cognitive performance, significant effects were found on speed measures, while accuracy was not affected. The number of explored rows was higher after the baseline night than after the sleepless night, and showed a consistent time-of-day trend. Omissions ratio (OR), false positives ratio (FPR) and hits ratio (HR) did not show any significant effect. Subjective ratings of sleepiness varied according to speed measures, being affected by sleep deprivation and time of day. Since similar effects were found with an oculomotor task, detrended functions for all variables across the 40 h of continuous wakefulness were calculated. A circadian effect was found, in which speed measures seem to be more affected than accuracy ones in both visual search and oculomotor tasks. It is concluded that 40 h of prolonged wakefulness significantly impairs performance in a brief cognitive visual search task. Such a performance worsening is evident on speed, but not on accuracy indices, and is strictly related to the deterioration of oculomotor performance, indicating a clear circadian effect.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"