Cognitive and psychomotor performance tests and experiment design in multiple chemical sensitivity

People suffering from multiple chemical sensitivity (MCS) complain of a variety of symptoms that could impair cognitive and psychomotor function either directly or indirectly. This paper discusses the use of cognitive and psychomotor performance tests together with some experiment designs that could be considered for use to assess fitness of MCS sufferers for work or the efficacy of diagnostic, preventative, or therapeutic measures. The tests could also contribute to the body of objective information on MCS and help sway the opinion of those who are dubious of its authenticity. The credentials of cognitive and psychomotor performance tests are derived from their successful use in studying the effects of drugs, and the types of tests are illustrated by describing those used by the United Kingdom Defence Evaluation and Research Agency Chemical and Biological Defence Human Studies Group, which has been involved in the assessment of drugs and chemicals on work performance for many years. The tests include mathematical, verbal and spatial processing, tracking, reaction time, attention and vigilance, and memory tests. The discussion of experiment designs includes both repeated measures and parallel groups designs together with their advantages and disadvantages and some suggested modifications to accommodate the particular problems posed by MCS.

The assessment of neurobehavioral toxicity: SGOMSEC joint report

Exposure to neurobehavioral toxicants is a problem of international scope. Although many different procedures are available for the assessment of human behavioral function, performance tests are displacing traditional diagnostic tests for ascertaining the consequences of exposure to neurotoxic chemicals. Performance testing includes variables such as attention and concentration, sensory function, motor control, spatial relations, visuomotor coordination, memory, and affect. Special tests have also been devised for evaluating child development. One of the salient needs in these efforts is the construction of databases allowing access to normative data.

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.

Effects of physostigmine on stimulus encoding in a memory-scanning task

Previous studies of the effects of physostigmine on memory have involved other drugs, a memory that has already been impaired, or both, often with contradictory results. Also, traditional memory tests do not differentiate memory from other task components such as perception and response, and drug effects on these could be mistaken for effects on memory. The present study was designed to investigate the effects of physostigmine alone on normal memory using Sternberg's additive-factor, memory-scanning task, with additional variables to isolate effects on stimulus encoding and response stages. Sixteen volunteers participated, the design was between-groups, and physostigmine or normal saline was given, double-blind, by intravenous infusion for 70 min. The drug had no effect on the memory component of the task, but significantly improved stimulus encoding (P < 0.001). Thus, it is possible that physostigmine improves performance on memory tests by improving perception as well as, or instead of, memory.