Sleep deprivation does not mimic alcohol intoxication on field sobriety testing

Area of Science:

• Forensic Psychology
• Neuroscience
• Traffic Safety

Background:

• Sleep deprivation (SD) can cause cognitive impairment comparable to alcohol intoxication.
• Some studies suggest SD may also impair motor skills, potentially mimicking alcohol's effects.
• SD is sometimes used as a defense in driving under the influence (DUI) cases.

Purpose of the Study:

• To investigate whether sleep deprivation alone affects motor skills assessed by standard field sobriety tests (FSTs).
• To determine if sleep deprivation can be mistaken for alcohol intoxication during roadside assessments.
• To differentiate the effects of sleep deprivation from alcohol intoxication on driving impairment indicators.

Main Methods:

• Twenty-nine adult subjects underwent two test sessions: one after normal sleep and one after at least 24 hours of wakefulness.
• Subjects consumed controlled amounts of alcohol during both sessions.
• Law enforcement officers administered standardized field sobriety tests, and researchers measured visual function and vital signs.

Main Results:

• The number of validated impairment clues on FSTs increased with rising blood alcohol concentration.
• Sleep deprivation alone did not increase the number of impairment clues on FSTs.
• SD did not produce motor skill deficits that would lead officers to suspect intoxication in the absence of alcohol.

Conclusions:

• Sleep deprivation does not independently cause observable motor skill deficits on field sobriety tests that mimic alcohol intoxication.
• The findings suggest that SD alone is unlikely to lead law enforcement to falsely conclude a driver is intoxicated.
• Impairment observed during FSTs is primarily attributable to alcohol consumption, not solely to sleep deprivation.