Performance Evaluation Tests for Environmental Research (PETER): evaluation of 114 measures

Factor Analysis and Predictive Validity of Microcomputer-Based Tests ,

11 tests were selected from two microcomputer-based performance test batteries because previously these tests exhibited rapid stability (<10 min. of practice) and high retest reliability efficiencies (r>0.707 for each 3 min. of testing). The battery was administered three times to each of 108 college students (48 men and 60 women) and a factor analysis was performed. Two of the three identified factors appear to be related to information processing (“encoding” and “throughput/ decoding”), and the third named an “output/speed” factor. The spatial, memory, and verbal tests loaded on the “encoding” factor and included Grammatical Reasoning, Pattern Comparison, Continuous Recall, and Matrix Rotation. The “throughput/ decoding” tests included perceptual/numerical tests like Math Processing, Code Substitution, and Pattern Comparison. The output speed factor was identified by Tapping and Reaction Time tests. The Wonderlic Personnel Test was group administered before the first and after the last administration of the performance tests. The multiple Rs in the total sample between combined Wonderlic as a criterion and less than 5 min. of microcomputer testing on Grammatical Reasoning and Math Processing as predictors ranged between 0.41 and 0.52 on the three test administrations. Based on these results, the authors recommend a core battery which, if time permits, would consist of two tests from each factor. Such a battery is now known to permit stable, reliable, and efficient assessment.

Development of Postural Equilibrium Tests for Examining Environmental Effects

The postural balance of 18 college students was measured with a modified version of the Fregly-Graybiel Battery of ataxia tests. The intention was to improve the stability of the tests and to ascertain which produced the most reliable results. Four tests of walking and standing were administered twice a day over five days. Subjects performed the tests in an erect position with their arms crossed and their eyes closed. Performance gradually increased with practice. Factor analysis implied three factors account for most of the variance of the four tests. The Stand-on-nonpreferred Leg (SONL) test was the most reliable and is recommended for the most economical assessment of highly transitory postural effects due to environmental factors, e.g., toxic materials.

Robust Testing and Evaluation (T&E) of Systems

Using “robust” testing and evaluation (T&E) components will ensure system T&E success despite unanticipated resource and schedule shocks. Selected tools for building robust T&E plans, methods, and analysis components are described. These robust tools provide a beginning framework that the practitioner can build upon to achieve successful T&Es.

The Crucial Role of Working Memory in Intellectual Functioning

Cognitive psychology offers an important contribution to the understanding of the mechanisms underlying intelligence. In this paper, we synthesize the research showing that, among the different cognitive mechanisms associated with intelligence, working memory has a particularly high explanatory power, especially when considered in its active component involving not only the maintenance (as in short-term memory) but also the manipulation of information. The paper considers two main implications of this finding for the applied and clinical fields. For a start, we examine how intelligence tests take into consideration working memory. Secondly, we consider the highly debated literature on the effects of working memory training on intellectual performance. Theoretical and applied implications for the relationship between working memory and intelligence are discussed.

The Temporal Stability of the Effects Induced by the Cued Reaction Time Task

The temporal stability of the effects induced by the Cued Reaction Time Task (CRTT) on the orienting of attention was assessed across four weekly sessions. Benefits, costs, and validity effects were computed for each session, and the correlation coefficients between each session were calculated (interindividual stability index). Intraindividual stability indices, the percentage of individuals showing both costs and benefits or the validity effect, were also calculated. The results (based on 41 participants) show a low stability for the effects in which the neutral trials were involved (benefits and costs) but an acceptable reliability for the validity effect, especially when evaluated using the intraindividual index. To maximize the reliability of the data collected using the CRTT, the validity effect seems to be a better probe of spatial orienting of attention.

Acute neuropsychological effects of MDMA and ethanol (co-)administration in healthy volunteers

RATIONALE

In Western societies, a considerable percentage of young people expose themselves to 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy"). Commonly, ecstasy is used in combination with other substances, in particular alcohol (ethanol). MDMA induces both arousing as well as hallucinogenic effects, whereas ethanol is a general central nervous system depressant.

OBJECTIVE

The aim of the present study is to assess the acute effects of single and co-administration of MDMA and ethanol on executive, memory, psychomotor, visuomotor, visuospatial and attention function, as well as on subjective experience.

MATERIALS AND METHODS

We performed a four-way, double-blind, randomised, crossover, placebo-controlled study in 16 healthy volunteers (nine male, seven female) between the ages of 18-29. MDMA was given orally (100 mg) and blood alcohol concentration was maintained at 0.6 per thousand by an ethanol infusion regime.

RESULTS

Co-administration of MDMA and ethanol was well tolerated and did not show greater impairment of performance compared to the single-drug conditions. Impaired memory function was consistently observed after all drug conditions, whereas impairment of psychomotor function and attention was less consistent across drug conditions.

CONCLUSIONS

Co-administration of MDMA and ethanol did not exacerbate the effects of either drug alone. Although the impairment of performance by all drug conditions was relatively moderate, all induced significant impairment of cognitive function.

Acute effects of the ampakine farampator on memory and information processing in healthy elderly volunteers

Ampakines act as positive allosteric modulators of AMPA-type glutamate receptors and facilitate hippocampal long-term potentiation (LTP), a mechanism associated with memory storage and consolidation. The present study investigated the acute effects of farampator, 1-(benzofurazan-5-ylcarbonyl) piperidine, on memory and information processes in healthy elderly volunteers. A double-blind, placebo-controlled, randomized, cross-over study was performed in 16 healthy, elderly volunteers (eight male, eight female; mean age 66.1, SD 4.5 years). All subjects received farampator (500 mg) and placebo. Testing took place 1 h after drug intake, which was around Tmax for farampator. Subjects performed tasks assessing episodic memory (wordlist learning and picture memory), working and short-term memory (N-back, symbol recall) and motor learning (maze task, pursuit rotor). Information processing was assessed with a tangled lines task, the symbol digit substitution test (SDST) and the continuous trail making test (CTMT). Farampator (500 mg) unequivocally improved short-term memory but appeared to impair episodic memory. Furthermore, it tended to decrease the number of switching errors in the CTMT. Drug-induced side effects (SEs) included headache, somnolence and nausea. Subjects with SEs had significantly higher plasma levels of farampator than subjects without SEs. Additional analyses revealed that in the farampator condition the group without SEs showed a significantly superior memory performance relative to the group with SEs. The positive results on short-term memory and the favorable trends in the trail making test (CTMT) are interesting in view of the development of ampakines in the treatment of Alzheimer's disease and schizophrenia.

Prescript-Assist probiotic-prebiotic treatment for irritable bowel syndrome: a methodologically oriented, 2-week, randomized, placebo-controlled, double-blind clinical study

BACKGROUND

The symptomatic efficacy of Prescript-Assist (Safer Medical, Inc., Fort Benton, Montana), a treatment combining probiotic and prebiotic components, has previously been evaluated clinically only in an open-label study in patients with various gastrointestinal conditions, including irritable bowel syndrome (IBS).

OBJECTIVES

This study was conducted primarily to compare the effects of Prescript-Assist with placebo in patients with a diagnosis of IBS. Toward this objective, a secondary methodologic goal was to determine the number and nature of symptom clusters ("subsyndromic factors") that characterize IBS.

METHODS

This was a double-blind, placebo-controlled clinical study in which patients were randomly assigned to receive either Prescript-Assist one 500-mg capsule BID or 1 placebo capsule BID for 2 weeks. Thirteen IBS symptoms identified from the clinical literature were embedded in a larger research instrument. Using a scale from 0 to 5, patients rated the intensity of these symptoms for the 7-day period immediately before the start of treatment, at the end of each study week, and after each of the 2 subsequent weeks (during which all patients received open-label Prescript-Assist as part of a larger study evaluating methodologic approaches to enhancing assessments of medication efficacy/safety). The symptom-intensity data were subjected to maximum likelihood factor analysis with varimax rotation to identify any IBS subsyndromic factors, and the effect of treatment on each of the identified factors was evaluated using analyses of covariance with appropriate baseline-week assessments as covariate controls.

RESULTS

The study included 25 patients with IBS (23 women, 2 men; age range, 20-70 years). Three subsyndromic factors were identified that together accounted for 60.2% of total IBS symptom variance: factor 1, general ill feelings/nausea; factor 2, indigestion/flatulence; and factor 3, colitis. Treatment with Prescript-Assist was associated with significant reductions in each of the subsyndromic factors. Factor 1 was significantly reduced by 0.345 standard score units (F(1,46) = 4.26; P = 0.042), factor 2 by 0.544 standard score units (F(1,46) = 7.83; P = 0.008), and factor 3 by 0.826 standard score units (F(1,46) = 10.20; P = 0.003).

CONCLUSIONS

This study identified 3 subsyndromic factors of IBS: general ill feelings/nausea, indigestion/flatulence, and colitis. In this methodologically oriented double-blind study in patients with IBS, combined probiotic-prebiotic treatment with Prescript-Assist was associated with significant reductions in these factors.

Modulation of memory and visuospatial processes by biperiden and rivastigmine in elderly healthy subjects

RATIONALE

The central cholinergic system is implicated in cognitive functioning. The dysfunction of this system is expressed in many diseases like Alzheimer's disease, dementia of Lewy body, Parkinson's disease and vascular dementia. In recent animal studies, it was found that selective cholinergic modulation affects visuospatial processes even more than memory function.

OBJECTIVE

In the current study, we tried to replicate those findings. In order to investigate the acute effects of cholinergic drugs on memory and visuospatial functions, a selective anticholinergic drug, biperiden, was compared to a selective acetylcholinesterase-inhibiting drug, rivastigmine, in healthy elderly subjects.

METHODS

A double-blind, placebo-controlled, randomised, cross-over study was performed in 16 healthy, elderly volunteers (eight men, eight women; mean age 66.1, SD 4.46 years). All subjects received biperiden (2 mg), rivastigmine (3 mg) and placebo with an interval of 7 days between them. Testing took place 1 h after drug intake (which was around Tmax for both drugs). Subjects were presented with tests for episodic memory (wordlist and picture memory), working memory tasks (N-back, symbol recall) and motor learning (maze task, pursuit rotor). Visuospatial abilities were assessed by tests with high visual scanning components (tangled lines and Symbol Digit Substitution Test).

RESULTS

Episodic memory was impaired by biperiden. Rivastigmine impaired recognition parts of the episodic memory performance. Working memory was non-significantly impaired by biperiden and not affected by rivastigmine. Motor learning as well as visuospatial processes were impaired by biperiden and improved by rivastigmine.

CONCLUSIONS

These results implicate acetylcholine as a modulator not only of memory but also of visuospatial abilities.

Test-retest reliability and factor stability of the behavioral evaluation for epidemiology studies test battery

The Behavioral Evaluation for Epidemiology Studies test battery uses touch-screen technology and novel methodologies to enhance neurobehavioral assessment. Scores generally show differential stability from the first trial with individual test reliabilities at or above .80 when normalized to a 3-min. administration. Six highly reliable (r > or = .87) factors were identified that cover functions known to be sensitive to neurotoxicants and physical exposures. These results strongly support recommendation of the new test battery for use in repeated-measures epidemiologic studies where first trial stability is desired.

Elevation-dependent symptom, mood, and performance changes produced by exposure to hypobaric hypoxia

Altitude exposures above 3,000 m produce changes in symptoms, moods, and cognitive/motor performance of unacclimatized individuals and should produce graded effects on these parameters as elevation and duration are increased. This study examined effects on these parameters as a function of altitude level and duration of exposure by administering standardized tests from 1 to 3 times to 23 males in an altitude chamber during 4.5-hour exposures to 3 levels of hypobaric hypoxia: 500 m, 4,200 m, and 4,700 m. Exposure to altitude significantly affected symptoms, moods, and performance in an elevation-dependent fashion. Adverse changes increased with higher altitudes (all measures were affected at 4,700 m, whereas only some were at 4,200 m) and usually with longer durations. Therefore, specific aspects of symptoms, moods, and performance are significantly degraded after only a few hours of exposure to hypobaric hypoxia, and the severity of the effects dramatically increases when testing is conducted at 4,700 m compared to 4,200 m.

Individual differences in performance on elementary cognitive tasks (ECTs): lawful vs. problematic parameters

Over the past 2 decades, the cognitive-correlates approach has dominated investigations into the nature of intelligence. This research program relies on a number of processing speed parameters (apart from "average performance"). These measures include the slope, intercept, and intraindividual variability of both decision time and movement time. By correlating these measures with established markers of intelligence, researchers postulate theoretical models underlying these information-processing constructs. However, there is a lack of substantive evidence that these phenomena are as robust within the individual as has been proposed. The authors tested the properties of intraindividual parameters by asking participants (N = 179) to perform 10 elementary cognitive tasks (ECTs). Detailed analyses revealed that average performance parameters, extracted from these ECTs, behaved lawfully. However, up to 40% of participants failed to provide acceptable indices of intraindividual model fit. Similarly, intraindividual variability measures appeared less valid than previously suggested. The implications of these findings for cognitive and biological models of intelligence are discussed.

Goal difficulty, anxiety and performance

This study reports a detailed investigation of the interaction between goal setting, anxiety and perceptuo-motor performance. Forty-four subjects completed familiarization, control and treatment conditions in which they were required to perform a series of perceptual speed trials. In the control condition, subjects were assigned a vague, general goal of 'do your best', whilst in the treatment condition, increasingly difficult, specific goals were assigned. During each condition, subjective goal difficulty, goal acceptance, performance, cognitive anxiety, somatic anxiety and self-confidence were examined. The results suggested that the manipulation of the control and treatment conditions were successful. In the treatment condition, an increase in cognitive anxiety and a reduction in self-confidence accompanied increasing goal difficulty but these remained stable in the control condition. Performance was greater when 'do your best' as opposed to 'very easy' goals were assigned, but this situation was reversed when 'very hard' goals were assigned. The results of these laboratory-based findings are discussed with particular reference to the implications for practitioners in applied settings.

Analyzing multivariate neurobehavioral outcomes in occupational studies: a comparison of approaches

Neurobehavioral studies often employ test batteries and confront issues of multiple testing and comparability between batteries. We have organized our battery of 12 tests into areas of neurobehavioral function to reduce the number of reported results, provide greater statistical power, and improve interpretability of the results. We explored several different organizational and statistical methods of creating summary scores including a priori groupings based upon clinical experience and factor analysis. We compared the sensitivity of these summary scores to performance changes associated with exposure to styrene in the manufacture of reinforced plastics. Our results demonstrated dramatic increases in power to detect exposure related changes compared to using individual test scores. Furthermore, the various methods provided generally compatible and comparable results. We encourage other neurobehavioral investigators to pursue and refine this approach.

Performance tests

This paper discusses the use of psychological performance tests to assess the effects of environmental stressors. The large number and the variety of performance tests are illustrated, and the differences between performance tests and other psychological tests are described in terms of their design, construction, use, and purpose. The stressor emphasis is on the effects of drugs since that is where most performance tests have found their main application, although other stressors, e.g., fatigue, toxic chemicals, are mentioned where appropriate. Diazepam is used as an example. There is no particular performance emphasis since the tests are intended to have wide applicability. However, vehicle-driving performance is discussed because it has been the subject of a great deal of research and is probably one of the most important areas of application. Performance tests are discussed in terms of the four main underlying models--factor analysis, general information processing, multiple resource and strategy models, and processing-stage models--and in terms of their psychometric properties--sensitivity, reliability, and content, criterion, construct, and face validity. Some test taxonomies are presented. Standardization is also discussed with reference to the reaction time, mathematical processing, memory search, spatial processing, unstable tracking, verbal processing, and dual task tests used in the AGARD STRES battery. Some comments on measurement strengths and appropriate study designs and methods are included.

Performance and brain electrical activity during prolonged confinement

A subset of the AGARD-STRES battery including memory search, unstable tracking, and a combination of both tasks (dual-task), was applied repeatedly to the four chamber crew members before, during, and after the 60-day isolation period of EXEMSI. Five ground control group members served as a control group. A subjective state questionnaire was also included. The results were subjected to a quantitative single-subject analysis. Electroencephalograms (EEG) were recorded to permit correlation of changes in task performance with changes in the physiological state. Evaluation of the EEG focused on spectral parameters of spontaneous EEG waves. No physiological data were collected from the control group. Significant decrements in tracking ability were observed in the chamber crew. The time course of these effects followed a triphasic pattern with initial deterioration, intermediate recovery to pre-isolation baseline scores after the first half of the isolation period, and a second deterioration towards the end. None of the control group subjects displayed such an effect. Memory search (speed and accuracy) was only occasionally impaired during isolation, but the control group displayed a similar pattern of changes. It is suggested that a state of decreased alertness causes tracking deterioration, which leads to a reduced efficiency of sustained cue utilization. The assumption of low alertness was further substantiated by higher fatigue ratings by the chamber crew compared to those of the control group. Analysis of the continuous EEG recordings revealed that only two subjects produced reliable alpha wave activity (8-12 Hz) over Pz and, to a much smaller extent, Fz-theta wave activity (5-7 Hz) during task performance. In both subjects Pz-alpha power decreased consistently under task conditions involving single-task and dual-task tracking. Fz-theta activity was increased more by single-task and dual-task memory search than by single-task tracking. The alpha attenuation appears to be associated with an increasing demand on perceptual cue utilization required by the tracking performance. In one subject marked attenuation of alpha power occurred during the first half of the confinement period, where he also scored the highest fatigue ratings. A striking increase in fronto-central theta activity was observed in the same subject after six weeks of isolation. The change was associated with an efficient rather than a degraded task performance, and a high rating of the item "concentrated" and a low rating of the item "fatigued." This finding supports the hypothesis that the activation state associated with increased fronto-central theta activity accompanies efficient performance of demanding mental tasks. The usefulness of standardized laboratory tasks as monitoring instruments is demonstrated by the direct comparability with results of studies obtained from other relevant research applications using the same tasks. The feasibility of a self-administered integrated psychophysiological assessment of the individual state was illustrated by the nearly complete collection of data. The large number of individual data collected over the entire period permitted application of quantitative single-subject analysis, allowing reliable determination of changes in the individual state in the course of time. It thus appears that this assessment technique can be adapted for in-flight monitoring of astronauts during prolonged spaceflights. Parallel EEG recording can provide relevant supplementary information for diagnosing the individual activation state associated with task performance. The existence of large individual differences in the generation of task-sensitive EEG rhythms forms an important issue for further studies.

Dual-task performance in space: results from a single-case study during a short-term space mission

During spaceflights, astronauts are exposed to many stressors (e.g., microgravity, confinement) that may impair human information-processing capabilities. In order to analyze the possible effects of the space environment on human time-sharing efficiency, a single-case experiment was conducted in which the time course of dual-task performance (unstable tracking with concurrent memory search) of one space crew member was monitored repeatedly (13 times) throughout an 8-day space mission. Tasks were taken from the Advisory Group for Aerospace Research and Development battery of Standardized Tests for Research with Environmental Stressors. Comparisons of in-flight, preflight, and postflight performance revealed no decrements in single-task memory search performance but did reveal clear impairments in single-task tracking and dual-task performance. From these results we conclude that psychomotor processes and higher attentional functions are particularly prone to disturbance effects in space.

Effects of graded dosages of alcohol on nine computerized repeated-measures tests

We report a controlled laboratory validation experiment to provide an empirical sequel to the general background of the development of the Automated Performance Test System (APTS) that was presented in Turnage et al. (1992). The purpose of this study was to index performance deficit against various Blood Alcohol Concentrations (BACs) of small (0.05% BAC), medium (0.10% BAC), and large (0.15% BAC) dosages as well as a placebo (0.00 BAC) condition. Blood alcohol concentrations, measured in four different ways, were highly reliable and the method with the highest intercorrelation was whole blood. When taken singly, eight of the nine tests produced significant (p < 0.001) relationships with the disparate blood alcohol levels, which were essentially monotonic. A multiple regression analysis suggested that most of the tests were behaving similarly and that two or three tests accounted for 52 to 54% of the variance attributable to alcohol that was explained by the longer battery. While all tests appear valid, some of them appeared more sensitive than others (viz., code substitution, manikin, and choice reaction time). From the standpoint of these tests, greater changes occurred in cognitive function between the placebo and 0.05 level than between the 0.05 and 0.10 levels. However, the greatest reduction in performance occurred between 0.10 and 0.15, and the relatively abrupt nature of this change implies that sharp decrements in cognitive performance occur at that point. There were individual differences in resistance to alcohol, and there is strong inference that these differences would be reliable if they were tested again. We believe that further development and study of such techniques is warranted for use in fitness-for-duty testing and development of a dose equivalency index.

Action profiles of smoking and caffeine: Stroop effect, EEG, and peripheral physiology

Twenty female regular cigarette smokers and coffee drinkers performed a numerical Stroop task in a 2 x 2 (caffeine x smoking) prepost crossover design. In the easier of the two different versions, caffeine and smoking reduced the reaction times (RT's) when given alone, but there was no additive effect. The Stroop effect itself (difference between RT's to numbers and RT's to symbols) was reduced by the two treatments only in the more difficult version, but the combination did not differ from the placebo condition. The physiological reactions to both treatments were additive, although the two reaction profiles were different. Smoking increased heart rate, blood pressure, finger vasoconstriction, respiratory frequency, EEG dominant alpha-frequency, and beta power and reduced respiratory amplitude, EEG delta and theta power. Caffeine increased blood pressure, finger vasoconstriction, motor activity, frontal EMG, and EEG theta power and decreased heart rate and EEG beta power.

Computerized assessment in neuropsychology: a review of tests and test batteries

This article contains detailed reviews of 13 computerized neuropsychological and performance test batteries and six stand-alone computer tests. Tasks found on these instruments are described and tables illustrate which batteries employ which measures. In addition to issues of reliability and validity, special considerations apply to computerized assessment. These issues are discussed and readers are provided information to help them assess computerized tests in relation to their particular clinical and research needs. Since many computerized tests were developed as performance assessment tools, the relationship between performance and neuropsychological assessment is examined.

Relationships between multidimensional competitive state anxiety and cognitive and motor subcomponents of performance

This study examined the relationship between multidimensional competitive state anxiety and cognitive (i.e. digit span) and motor (i.e. perceptuo-motor speed) subcomponents of performance in an experimental group of hockey players during the period leading up to an important hockey match, and also in a control group of hockey players before a routine training session. Using a 'time-to-event' experimental paradigm, an increase in somatic anxiety 20 min before the hockey match was accompanied by improved perceptuo-motor speed performance. Stepwise multiple regression analyses showed that somatic anxiety was negatively related to digit span performance, whilst somatic anxiety and self-confidence were positively related to perceptuo-motor speed performance. These findings suggest that somatic anxiety may be an important source of performance variance.

Factor analysis and predictive validity of microcomputer-based tests

11 tests were selected from two microcomputer-based performance test batteries because previously these tests exhibited rapid stability (less than 10 min, of practice) and high retest reliability efficiencies (r greater than 0.707 for each 3 min. of testing). The battery was administered three times to each of 108 college students (48 men and 60 women) and a factor analysis was performed. Two of the three identified factors appear to be related to information processing ("encoding" and "throughput/decoding"), and the third named an "output/speed" factor. The spatial, memory, and verbal tests loaded on the "encoding" factor and included Grammatical Reasoning, Pattern Comparison, Continuous Recall, and Matrix Rotation. The "throughput/decoding" tests included perceptual/numerical tests like Math Processing, Code Substitution, and Pattern Comparison. The output speed factor was identified by Tapping and Reaction Time tests. The Wonderlic Personnel Test was group administered before the first and after the last administration of the performance tests. The multiple Rs in the total sample between combined Wonderlic as a criterion and less than 5 min. of microcomputer testing on Grammatical Reasoning and Math Processing as predictors ranged between 0.41 and 0.52 on the three test administrations. Based on these results, the authors recommend a core battery which, if time permits, would consist of two tests from each factor. Such a battery is now known to permit stable, reliable, and efficient assessment.

Psychology of computer use: IX. A menu of self-administered microcomputer-based neurotoxicology tests

This study examined the feasibility of repeated self-administration of a newly developed battery of mental acuity tests which may have application in screening for fitness-for-duty or for persons who may be exposed to environmental stress, toxic agents, or disease. 16 subjects self-administered 18 microcomputer-based tests (13 new, 5 "core"), without proctors, over 10 sessions. The hardware performed well throughout the study and the tests appeared to be easily self-administered. Stabilities and reliabilities of the tests from the "core" battery were comparable to those obtained previously under more controlled experimental conditions. Eight of the new tests exceeded minimum criteria for metric and practical requirements and can be recommended as additions to the menu. Although the average retest reliability was high, cross-correlations between tests were low, implying factorial diversity. The menu can be used to form batteries with flexible total testing time which are likely to tap different mental processes and functions.

Motor and cognitive testing of bone marrow transplant patients after chemoradiotherapy

Assessment of cognitive and motor performance of bone marrow transplant patients prior to, during, and following intensive toxic chemoradiotherapy may provide an important adjunct to measures of physiological and medical status. The present study is an attempt to assess whether, as side-effects, these aggressive treatments result in cognitive performance deficits, and if so, whether such changes recover posttreatment. Measurement of cognitive ability in this situation presents special problems not encountered with one-time tests intended for healthy adults. Such tests must be sensitive to changes within a single individual, which emphasizes the crucial importance of high reliability, stability across repeated-measures, and resistance to confounding factors such as motivation and fatigue. The present research makes use of a microbased portable test battery developed to have reliable and sensitive tests which were adapted to study the special requirements of transplant patients who may suffer cognitive deficits as a result of treatment. The results showed slight but significant changes in neuropsychological capacity when compared to baseline levels and controls, particularly near the beginning of treatment. The sensitivity of the battery in detecting such subtle temporary changes is discussed in terms of past research showing effects of other stressors, such as stimulated high altitude and ingestion of alcohol, on these measures.

Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans

Acutely stressful situations can disrupt behavior and deplete brain norepinephrine and dopamine, catecholaminergic neurotransmitters. In animals, administration of tyrosine, a food constituent and precursor of the catecholamines, reduces these behavioral and neurochemical deficits. Using a double-blind, placebo-controlled crossover design we investigated whether tyrosine (100 mg/kg) would protect humans from some of the adverse consequences of a 4.5 hour exposure to cold and hypoxia. Tyrosine significantly decreased symptoms, adverse moods, and performance impairments in subjects who exhibited average or greater responses to these environmental conditions. These results suggest that tyrosine should be evaluated in a variety of acutely stressful situations.

Time-course of effects of oral cinnarizine and hyoscine on task performance

Investigations into antimotion sickness drugs fall into two main categories: efficacy ('benefits') and side-effects ('costs'). This study was of the second type. Oral cinnarizine (30 mg: normal dose; and 75 mg: 2.5 x normal dose) and placebo, were investigated using a battery of automated mental, motor, physiological and other tests in twelve young healthy male volunteers. The higher cinnarizine dose level was chosen to exaggerate effects and make it easier to track them. Oral hyoscine (1.2 mg: 2 x normal dose) was employed as a positive internal control. Side-effects were almost exclusively due to hyoscine whereas cinnarizine was almost free of significant effects even at the higher dose of 75 mg. Hyoscine impaired performance 1-3 hours postdrug, whereas the effects of cinnarizine occurred approximately 5-7 hours postdrug. This paralleled the slower time-course for the protective action of cinnarizine against motion sickness noted in earlier studies. These results, taken in conjunction with previous trials, suggest that oral cinnarizine would seem less likely than hyoscine to produce unwanted decrements in performance.

Neurobehavioral and psychosocial functioning of women exposed to high altitude in mountaineering

The effects of chronic hypoxemia upon cognition and behavior were studied in women exposed to high altitude in mountaineering. Neuropsychological tests and psychosocial and physiological questionnaires were given to eight women before, during, and immediately after a Himalayan climb to 20,500 feet. Cognitive functioning remained relatively intact with only two significant decrements, complex abstract reasoning and word-finding ability. Significant changes were found on all psychosocial and physiological questionnaires. Feelings of acceptance of others and anxiety declined significantly. Physical symptoms were greatest during the first five days of ascent. Subjects' self-ratings of mental functioning were significantly better after the expedition than either before or during the climb. Self-assessments were correlated with emotions and physical symptoms, not with actual performances on the test battery. It is suggested that complex cognitive tasks and psychosocial functioning be studied in more detail as these were more influenced by exposure to high altitude in mountaineering.

Development of an automated performance test system for environmental and behavioral toxicology studies

In developing a menu of computerized performance tests for repeated-measures applications the metric properties of selected tests have been examined. Factors of chief concern have been stability and reliability, as well as the practical issue of the length of time it takes to achieve high levels of both. In this study, these factors, as well as predictive validity, are examined. 25 subjects were tested repeatedly (10 sessions) with 11 tests previously identified as "good" candidates for repeated-measures research in paper-and-pencil (marker test) versions. The 11 tests were administered concurrently in their traditional paper-and-pencil modes and newly implemented microcomputer-based versions, along with the Wechsler Adult Intelligence Scale (WAIS). Nine of the 11 microcomputer-based tests achieved stability. Reliabilities were generally high, with r greater than or equal to .77 for 3 min. of testing. Cross-correlations of microbased tests with traditional paper-and-pencil versions suggest equivalency between the test constructs in the different media. Correlations between six of the microbased subtests and the WAIS identified common variance, and these might comprise an efficient short (6 min.) battery of tests.