Neurobehavioral effects of formaldehyde and solvents on histology technicians: repeated testing across time.

Neurobehavioral functions were studied by periodic testing of 318 histology technicians and by a single session testing 494 of such technicians from 1982 through 1986. Tests included immediate recall of stories, of drawings, and of number series from the Wechsler Memory Scale, block designs from the Wechsler Adult Intelligence Scale (WAIS), slotted pegboard, trail making A and B, embedded figures, number writing on the fingers, visual simple and two-choice reaction times, balance (speed of body sway), and the profile of mood state (POMS) score. Mean test scores of four initial "first test" groups were not different from 1982 to 1986. Immediate recall of stories and drawings improved on the first retest as did the block design score. Other test scores showed insignificant variation over the 4 years, including memory for numbers forward and backward, trails A and B, number writing on fingers, radius of body sway, and choice reaction time. Only placing of pegs in the pegboard took longer. POMS score was lower in the second year in naive subjects and decreased from 39 to 13 in those retested. Variations in results of neurobehavioral tests given at intervals across 4 years were small. No cumulative effects of occupational exposures or of aging were found. However, small decreases may have been offset by increases due to test familiarity or learning.