Acquisition of tolerance to alcohol-induced memory deficits in humans

Acute and chronic alcohol tolerance in humans: effects of dose and consecutive days of exposure

Male social drinkers received doses of either 0.75 or 1.0 g/kg body weight of alcohol over 5 consecutive days. The beverage was divided into three equal drinks, and subjects performed an eye-hand coordination motor task after each drink. The breath alcohol concentration (BAC) was assessed at each performance measurement period. Performance was also assessed when the BAC level on the descending limb of the BAC curve was similar to each of the three BAC measurements on the ascending curve. Each group developed chronic tolerance (comparing the daily postalcohol performance with the daily prealcohol performance) by the 4th day of exposure. The development of a degree of acute tolerance (assessed by comparing the performance on the ascending and descending limbs of the BAC curve) was not observed consistently in the 1.0 g/kg dose group, but was seen in more than half of the subjects in the 0.75 g/kg dose group by the 4th and 5th day of exposure.

Activation, attention, and visuospatial learning in adults with and without a family history of alcoholism

While recent evidence shows visuospatial information processing deficits to be present in chronic alcoholics, it remains unclear whether such deficits are present prior to alcohol abuse in persons at risk for developing alcoholism. If present, it is also unclear whether the information processing mechanisms underlying these deficits are the same in alcoholics and persons at risk for alcoholism. This study investigated visuospatial information processing psychophysiological activation in adults with and without a family history of alcoholism. Thirty matched nonalcoholics served as participants. Fifteen persons were from families in which at least one biologic parent and one other relative had a history of alcoholism. Another group of 15 persons had no family history of alcoholism. In addition to displaying atypical patterns of learning-contingent physiological activation, participants with a family history of alcoholism displayed visuospatial learning that was significantly poorer than persons with no family history of alcoholism. The learning and physiological activation displayed by the participants with a family history of alcoholism were similar to those displayed by previously studied alcoholics using a similar learning task. The data suggest that visuospatial learning deficits may reflect an antecedent to, rather than a consequence of, chronic alcohol abuse.

Spatial learning of visual 'nonsense figures' during experimental ethanol intoxication

The interaction of alcohol and visuospatial learning was evaluated during two experimental sessions. During one session, participants were experimentally intoxicated to obtain a blood alcohol concentration of at least 0.10%. During another session, a nonalcohol placebo was administered. The learning task consisted of a paired-associate paradigm requiring participants to learn the distinct spatial positions of 6 visually presented "nonsense shapes." The visuospatial learning of participants in the placebo condition was generally superior to their learning while intoxicated. However, intercorrelations of performance measures indicated that the relation between alcohol ingestion and performance differences across conditions was not linear.

Effects of practice and alcohol on performance of a perceptual-motor task

Practice may modify the effects of alcohol on perceptual-motor performance in at least three different ways: (1) alcohol may affect learning—that is, the rate at which performance of a skill improves with practice; (2) alcohol may have a greater effect on performance when the skill is unfamiliar than when it is practised; and (3) practice with alcohol may allow adaptation to its effects. These were investigated using a simple computer game in which subjects attempted to destroy a tank by pressing a key to release a bomb from a plane horizontally traversing the screen above it. The results demonstrated that (1) performance improved with practice; (2) with alcohol (0.8 mg/kg body weight), subjects were more variable and less accurate; (3) improvement with alcohol was greater than without alcohol, but as performance was impaired by alcohol, there was greater scope for improvement; (4) those who practised with alcohol still improved when switched to no alcohol late in practice; and (5) alcohol had the same effect early and late in practice. It is therefore concluded that there is no evidence to support any of the three suggestions outlined above.

Gender differences in acute psychomotor, cognitive, and pharmacokinetic response to alcohol

This study investigated gender differences in acute response to alcohol. After practicing several cognitive and psychomotor tasks while sober, male (n = 11) and female (n = 13) social drinkers were administered a 0.65 g/kg dose of ethanol. Subjects were tested on both the ascending and descending limbs of the blood alcohol curve on measures of divided attention, short-term memory, body sway, pursuit tracking ability, and subjective level of intoxication. Blood alcohol level (BAL) was sampled frequently throughout the procedure. Females achieved consistently higher BALs than did males throughout, due mainly to higher BALs among women in the middle stage of the menstrual cycle. Women not using birth control medications also attained higher BALs than did males. When gender differences in BALs were controlled statistically, only memory functioning distinguished the groups: males recorded memory functioning more quickly on the descending limb of the blood alcohol curve than did females. Stage of menstrual cycle or use of birth control medications did not influence psychomotor or cognitive performance while women were intoxicated.

Use of regression residuals to quantify individual differences in acute sensitivity and tolerance to alcohol

Due to the problem of correlation of errors inherent in the difference or ratio scores typically used to quantify individual differences in acute sensitivity and tolerance to alcohol, it is recommended that residual scores from regression analyses be used instead for such quantification. Conceptualizations of acute sensitivity and tolerance and problems with the reliability of change scores are also discussed.