WEDNESDAY, April 14, 2004 (HealthDayNews) -- Even after a person's motor performance returns to normal, alcohol-related damage to cognitive functioning lingers, says a Canadian study in the April issue of Alcoholism: Clinical & Experimental Research.
That means that, even though they're no longer drunk, someone driving a car the morning after a night of drinking may still be a danger on the road.
"Given that most tasks require some information processing and that alcohol is one of the most commonly used recreational drugs, we felt that a more thorough examination of how alcohol disrupts the stream of information processing was warranted," study author Tom A. Schweizer, a postdoctoral fellow at the Rotman Research Institute in Toronto, said in a prepared statement.
"What is not clear from earlier studies is whether this disruption is attributable to a specific slowing of one stage -- that is, perceptual, cognitive or motor -- or a slowing of all stages within the information-processing stream," Schweizer said.
"Also, few studies have looked specifically at the differential effects of alcohol on cognitive functioning during rising and declining blood alcohol concentrations (BACs). One of the goals of this research was to address whether or not cognitive functioning behaves like motor functioning during rising and declining BACs," he said.
The study included 34 male social drinkers. Half received a placebo and half received a moderately high dose of alcohol. They were then given specially designed tasks. Their reaction times and errors were recorded.
Compared to their baseline results, the men in the alcohol group made many more errors as their BAC levels increased and also as their BAC levels decreased. The men who consumed alcohol also had longer reaction times during rising BACs. Those reaction times returned to baseline levels when the men's BAC levels were declining.
Schweizer warned that people need to be extra cautious when trying to assess their recovery after being drunk.
"The mismatch between motor and cognitive recovery creates special hazards that may have implications for accident risks. A drinker who is about to drive a vehicle immediately after recovering from a drinking episode may be more dangerous than while actively drinking because they mistakenly assume they're OK," Schweizer said.
More information
The American Medical Association has more about alcohol and driving.
