Effects of dexamphetamine with and without alcohol on simulated driving.

RATIONALE: In party circuits dexamphetamine is frequently used in combination with alcohol. It is hypothesized that co-administration of dexamphetamine to alcohol might reduce the sedative effects of alcohol, but may potentiate risk-taking behaviour. OBJECTIVES: The study was aimed at assessing the effects of alcohol, dexamphetamine and the combination of both on simulated driving and cognitive performance. METHOD: Eighteen subjects participated in a randomized, crossover, placebo-controlled study employing four conditions: 10 mg dexamphetamine, 0.8 g/kg alcohol, 10 mg dexamphetamine + 0.8 g/kg alcohol, and placebo. Fundamental driving skills and risk-taking behaviour were assessed in a driving simulator. Subjects also completed vigilance and divided attention tasks, and subjective ratings. RESULTS: Mean BAC levels during simulated driving were between 0.91‰ and 0.64‰. Subjects using alcohol showed a significantly larger mean standard deviation of lateral position and shorter accepted gap time and distance. Use of alcohol or dexamphetamine + alcohol was associated with a higher frequency of red light running and collisions than the dexamphetamine or placebo conditions. Performance of vigilance and divided attention tasks was significantly impaired in the alcohol condition and, to a lesser degree, in the dexamphetamine + alcohol condition. CONCLUSION: Single doses of 0.8 g/kg alcohol increased risk-taking behaviours and impaired tracking, attention and reaction time during a 3-h period after drinking when BACs declined from 0.9 to 0.2 mg/ml. The stimulatory effects of co-administration of dexamphetamine 10 mg were not sufficient to overcome the impairing effects of alcohol on skills related to driving.

Self-reported and measured weight, height and body mass index (BMI) in Italy, the Netherlands and North America.

BACKGROUND: Self-reported values of height and weight are used increasingly despite warnings that these data-and derived body mass index (BMI) values-might be biased. The present study investigates whether differences between self-reported and measured values are the same for populations from different regions, and the influences of gender and age. METHODS: Differences between self-reported and measured weights, heights and resulting BMIs are compared for representative samples of the adult population of Italy, the Netherlands and North America. RESULTS: We observed that weight is under-reported (1.1 ± 2.6 kg for females and 0.4 ± 3.1 kg for males) and height over-reported (1.1 ± 2.2 cm for females and 1.7 ± 2.1 cm for males), in accordance with the literature. This leads to an overall underestimation of BMI values (0.7 ± 1.2 kg/m(2) or 2.8% for females and 0.6 ± 1.1 kg/m(2) or 2.3% for males). When BMI values are assigned to four categories (from 'underweight' to 'obesity'), 11.2% of the females and 12.0% of the males are categorized too low when self-reported weights and heights are used, with an extreme of 17.2% for Italian females. Older people tend to relatively over-report height and under-report weight, but the magnitude differs between countries and gender. CONCLUSION: We conclude that, apart from a general overestimation of height and underestimation of weight resulting in an underestimation of BMI, substantial differences are observed between countries, between females and males and between age groups.

Task specificity of finger dexterity tests.

Finger dexterity tests are generally used to assess performance decrease due to gloves, cold and pathology. It is generally assumed that the O'Connor and Purdue Pegboard test yield similar results. In this experiment we compared these two tests for dry conditions without gloves, and for dry and wet conditions with two types of Nytril gloves. In line with previous observations, wearing gloves caused a decrease in performance of about 12% for the O'Connor test and 9% for the Purdue test. Wetting the gloves prior to the test had no effect on the Purdue score. However, wetting the gloves increased the O'Connor performance significantly by 11%. The results show that the O'Connor and Purdue tests do not yield similar results and should be used selectively for specific tasks.

Malaria prophylaxis for aircrew: safety of atovaquone/proguanil in healthy volunteers under aircraft cabin pressure conditions.

BACKGROUND: Because malaria in endemic areas presents a serious threat to the health of aircrew, optimal prevention is important. An effective and safe prophylactic antimalarial drug is needed. The combination of 250 mg atovaquone with 100 mg proguanil HCl (atovaquone/proguanil, or A/P) has shown good prophylactic efficacy and tolerance for prevention of falciparum malaria. However, medication for use by aircrew on duty is subject to approval by national and international aviation authorities, who require convincing evidence that the treatment has no negative effects on the flight performance of crews. The purpose of the present study was to evaluate the risk of detrimental effects of atovaquone/proguanil on flight-related performance and alertness in healthy subjects under conditions of aircraft cabin pressure. METHODS: A randomized, double-blind crossover study was conducted in which 24 subjects were enrolled to use A/P and placebo, each in a 14-day prophylactic dosing regimen with a 21-day washout phase. Vigilance, alertness, complex information processing, and sleepiness were assessed in a hypobaric chamber at 75.2 kPa, which equals the lower limit of commercial aircraft cabin pressure. Furthermore, duration and quality of sleep at home were recorded during the 14 days of drug administration. RESULTS: Twenty-two subjects completed the study. No significant differences were found between the effects of placebo and A/P on vigilance, alertness, complex information processing, sleep duration and quality, and the occurrence of adverse effects. CONCLUSIONS: In-flight performance and alertness of aircrew will not be affected by the prophylactic use of A/P during a period of 14 days.