Evaluation of the French version of EUROQUEST: a questionnaire for neurotoxic symptoms.

Background: EUROQUEST was designed to explore various neuropsychiatric symptoms caused by neurotoxic agents in occupational epidemiological studies. This paper was aimed at assessing (i) the internal consistency of the French version of EUROQUEST, (ii) its sensitivity to age, educational level and exposure, (iii) and its convergent validity by examining relationships between declared symptoms and results from psychometric tests on the same mental functions.

Design: Data from four cross-sectional studies were selected: 180 workers exposed to toluene, mixed solvents or anaesthetic gas, and 588 non-exposed ones. The internal consistency of the questionnaire was assessed by computing Cronbach's alphas. Sensitivity to age, educational level and exposure were assessed with multiple linear regression models. Relationships between EUROQUEST scores and correspondent neuropsychological tests were assessed with Pearson's correlation coefficients. The relationships between EUROQUEST domain specific scores, age and educational level were evaluated for men and women from the Reference group. Most of the analyses were performed in men and women separately.

Results: The results of the Cronbach's alphas computed for each EUROQUEST domain, showed a reasonable internal consistency for the questionnaire. For both women and men, memory problems and sleep disorders increased significantly with age. A significant association between EUROQUEST scores and exposure to neurotoxic agents was found for workers exposed to anaesthetic gas only. In addition, EUROQUEST memory symptoms from the Reference population were found to be correlated with two memory neuropsychological tests, both for men and women.

Conclusion: Our results showed a high internal consistency and a good convergent validity on assessed domains. Moreover, they showed a significant sensitivity to age, educational level and highlighted sensitivity to anaesthetic gas exposure.