Dose-related effects of alcohol on cognitive functioning

We assessed the suitability of six applied tests of cognitive functioning to provide a single marker for dose-related alcohol intoxication. Numerous studies have demonstrated that alcohol has a deleterious effect on specific areas of cognitive processing but few have compared the effects of alcohol across a wide range of different cognitive processes. Adult participants (N = 56, 32 males, 24 females aged 18–45 years) were randomized to control or alcohol treatments within a mixed design experiment involving multiple-dosages at approximately one hour intervals (attained mean blood alcohol concentrations (BACs) of 0.00, 0.048, 0.082 and 0.10%), employing a battery of six psychometric tests; the Useful Field of View test (UFOV; processing speed together with directed attention); the Self-Ordered Pointing Task (SOPT; working memory); Inspection Time (IT; speed of processing independent from motor responding); the Traveling Salesperson Problem (TSP; strategic optimization); the Sustained Attention to Response Task (SART; vigilance, response inhibition and psychomotor function); and the Trail-Making Test(TMT; cognitive flexibility and psychomotor function). Results demonstrated that impairment is not uniform across different domains of cognitive processing and that both the size of the alcohol effect and the magnitude of effect change across different dose levels are quantitatively different for different cognitive processes. Only IT met the criteria for a marker for wide-spread application: reliable dose-related decline in a basic process as a function of rising BAC level and easy to use non-invasive task properties.Mathew J. Dry, Nicholas R. Burns, Ted Nettelbeck, Aaron L. Farquharson and Jason M. Whit

Evaluation of discomfort glare in the 50+ elderly: experimental study

Objectives: The aim of the study was to analyze discomfort glare sensation in subjects aged 50 years and more in comparison with younger subjects (i.e. younger than 35 years of age). Material and Methods: The experiments were performed on a computer workstation placed in controlled lighting environment where 2 discomfort glare conditions were modeled. Each participant performed for about 1 h specially designed visual tasks, including the tests with Landolt's rings presented on the screen by a computer program. The glare evaluation method consisted of subjective evaluation of discomfort glare on the semantic glare rating scale, tests of mesopic contrast and glare sensitivity, subjective assessment of lighting quality and asthenopic symptoms. The time needed to perform the task and the number of mistakes were also recorded. The subjective evaluation of glare was compared with the Unified Glare Rating (UGR) index calculated by the DIALux simulation program. Results: A higher percentage of the younger group subjects assessed glare after the experimental session as uncomfortable and intolerable than in the 50+ group, who more often assessed glare as acceptable. The assessment of discomfort glare in the younger group corresponded to higher UGR value compared to UGR value calculated by DIALux. In the 50+ group, such correlation was found only for lower discomfort glare (UGR = 19). The results showed that younger participants more frequently suffered from visual fatigue and assessed lighting as less comfortable. However, the mesopic glare sensitivity increased significantly after the experiments only in the 50+ group under both glare conditions. Conclusions: The obtained results showed that discomfort glare sensation changes with age. The younger population seems to be more sensitive and demanding than the older one in relation to discomfort glare limiting, in spite of the lack of significant objective measures of fatigue. The exposure of the elderly to bigger discomfort glare could adversely affect the objective measures of fatigue like mesopic glare sensitivity and visual performance