Assessment of Subtle Neurological Deficits

Objectives-This project was conducted to examine whether the computerised analysis of psychomotor responses available from Cognitive Drug Research is appropriate for measuring an effect oflow level exposure to mercury in dentists. Methods-A computerised battery of psychomotor tests was given to two groups of dentists (older dentists and trainees) and to two age matched control groups. As well as the psychomotor tests, volunteers were required to complete a questionnaire to identify potential influences on psychomotor performance and to provide a sample for analysis of urinary mercury. Results-Statistical analysis of the results showed that the older dentists had slightly higher concentrations of urinary mercury although most were around background levels and they were all within occupational limits. Five of the psychomotor tests showed no differences between the performance of the four groups. The older dentists showed significantly better performance on the simple reaction time test and significantly poorer performance in the immediate word recall and delayed word recall tests. Conclusions-Poorer performance in memory recall tests confirms previously reported studies. This together with the confirmation that this test system is a practical tool in the occupational setting suggests that a larger study of the effects ofmercury exposure on dentists would be appropriate. (Occup Environ Med 1995;52:813-817)