Salivary levels of alpha-amylase are associated with neurobehavioral alertness during extended wakefulness, but not simulated night-shift work.

Sleep loss is one of the most common causes of accidents and errors in operational environments. Currently, no single method satisfies all of the requisite criteria of an effective system for assessing the risk of injury prior to safety being compromised. Research has concentrated towards the development of a biomarker for individualized assessment of sleepiness-related deficits in neurobehavioral alertness, with salivary alpha-amylase (sAA) recently reported as a potential biomarker during acute total sleep deprivation. The present study extends on previous research by investigating the association between sAA and neurobehavioral alertness during simulated night-shift work, during individuals are required to work at night when biological processes are strongly promoting sleep and sleep during the day when endogenous processes are promoting wakefulness. In a laboratory-controlled environment, 10 healthy non-shift working males aged 24.7 ±â€¯5.3 years (mean ±â€¯SD) underwent four consecutive nights of simulated night-shift work. Between 17:30-04:30 h participants provided saliva samples and completed a 3 min psychomotor vigilance test (PVT-B), 40 min simulated driving task, and 3 min digit symbol substitution test (DSST). Higher sAA levels were associated with faster response speed on the PVT-B, reduced lane variability on the simulated driving task, and improved information processing speed on the DSST during the first night-shift. There were no associations between sAA levels and performance outcomes during subsequent night-shifts. Findings indicate that the usability of sAA to assess the risk of neurobehavioral deficits during shift-work operations is limited. However, the robust circadian rhythm exhibited by sAA during the protocol of circadian misalignment suggests that sAA could serve as a potential circadian marker.

Comparison of environmental chemical results for split samples analyzed in different laboratories.

Data comparisons were made for split or co-located samples analyzed in contract laboratories and quality assurance (QA) laboratories during environmental studies directed by the U.S. Army Corps of Engineers. Archived results were analyzed statistically as concentration ratios (contract laboratory/QA laboratory). Concentration ratios were found to be lognormally distributed, and this was the model used for comparisons. For metals in soils and volatile organic compounds (VOCs) in groundwater, 10.2% of metal ratios in soils and 5.6% of VOC ratios in groundwater exceeded limits of 0.40-2.50. Considering that both methods are multianalyte, we find that only 4.0% of the metal samples and 2.0% of the VOC samples had more than one outlier ratio per sample. More recent data produced very similar results. For VOCs, total petroleum hydrocarbons (TPHs), and explosives in soils, limits of 0.25-4.00 are suggested with the understanding that large improvements are badly needed. Even with these wide limits, approximately 42% of VOCs, 14% of TPHs, and 11% of explosives contract laboratory/QA laboratory ratios were outside these limits. Here, too, the most recent data yielded very comparable results. Sampling and preparation procedures for VOCs in soils requires immediate attention, but all methods can and should be capable of producing improved agreement between laboratories.

Text-contingent color aftereffects: a reexamination.

Five experiments reexamined color aftereffects contingent on the semantic properties of text (Allan, Siegel, Collins, & MacQueen, 1989). The influence of different assessment techniques and the effect of eye movements and overlapping contour information on the induction of color aftereffects by word and nonword letter strings were determined. Experiment 1 showed that no aftereffect was found when a traditional method of assessing color aftereffects was used. Experiments 2 and 4 demonstrated color aftereffects for both words and nonwords, but only when subjects fixated the same locus during induction and testing and only when assessed with the technique described by Allan et al. (1989). If, however, eye movements were made during induction, no color aftereffect was obtained (Experiment 3). Induction to nontext patterns with properties similar to those of text but with fewer overlapping contours resulted in a strong color aftereffect (Experiment 5). These results suggest that the color aftereffect contingent on text is very weak and is not dependent on semantic factors, but that it is a product of induction to local color and orientation information.

Workplace surveillance for carpal tunnel syndrome using hand diagrams.

Four hundred and eleven workers from 4 different companies participated in a worksite screening program designed, in part, to estimate the prevalence of carpal tunnel syndrome (CTS). Each worker completed a discomfort survey and underwent limited nerve conduction testing of the median and ulnar sensory nerves in both wrists. The discomfort survey included a hand diagram which allowed subjects to shade in area(s) affected by numbness, burning, tingling, or pain. The discomfort survey also asked each worker to indicate whether she or he had experienced neuropathic symptoms (i.e., numbness, burning, tingling, or pain) in the wrist, hand or fingers of each hand, without regard to localization (i.e., median versus ulnar versus radial distribution), and also nocturnal occurrence of symptoms. Analyses involved comparing hand diagram scores and non localized wrist/hand/finger symptoms with electrodiagnostic test results. All configurations of hand diagram scores of the dominant hands had a statistically significant association with electrophysiologically determined median nerve dysfunction, but so did non localized symptom reports. The sensitivity, specificity, and positive predicted values of hand diagrams were poorer than those reported previously. While some test performance characteristics of hand diagrams were better than those for non localized distal extremity symptoms consistent with CTS, some were worse. Overall, our data suggest that hand diagrams are no better than using a questionnaire to determine if workers have experienced symptoms consistent with CTS in their wrists, hands or fingers without regard to localization. The choice of screening tool would depend on the goal of screening, in particular, whether it is more desirable to have slightly higher sensitivity or positive predictive value.

Adolescent attitudes toward body image and anorexic behavior.

This study explored the relationship between anorexic behavior and selected dimensions of body image. Anorexic behavior was assessed by two scales, the Eating Attitudes Test (EAT 26) (Garner, Olmstead, Bohr, & Garfinkel, 1982) and the Eating Disorders Inventory (EDI) (Garner, Olmstead, & Polivy, 1983). Predictor variables, selected dimensions of body image, physical attractiveness, self-esteem, and physical effectiveness, were measured by scales adapted by Lerner and Karabenick (1974) and Lerner, Orlos, and Knapp (1976). Multiple regression techniques were used to determine how much of the tendency toward anorexic behavior can be predicted by selected dimensions of body image. The major focus of the analysis was to explore the contributions of each of the dimensions of body image to predicting tendencies toward anorexic behavior in adolescents. The research sample consisted of 169 high school students, aged 15 to 18, who were enrolled in health, physical education, or psychology classes in the spring of 1983. Results indicated that the dimension of self-esteem was the major factor in the prediction of anorexic behaviors as measured by the Eating Disorders Inventory.