Predictors of improvement in P300 latency in solvent-exposed adults

Persons with a history of exposure to organic solvents have been shown to h ave cognitive and personality changes, as well as abnormalities on measures of neurophysiology (e.g., delays in P300 latency). Studies assessing long- term sequelae in exposed persons have been limited, especially those using neurophysiologic measures. This study assessed cognitive event-related pote ntials (ERPs) in 16 persons with a history of organic solvent exposure at t wo testings, separated, on average, by 1.5 years. The sample was divided in to persons who showed improvement on P300 latency (e.g., reduction in laten cy of 1.5 SD of control group) and those who did not. Sixty-three percent s howed no improvement, whereas 37% showed significant improvement. Recency o f exposure and the interaction of exposure duration and history of peak exp osure significantly predicted group membership. That is, persons with short er duration of exposure coupled with no peak exposures and longer time from exposure to test were more Likely to fall in the improved group. Substitut ing age for duration of exposure in the interaction term improved classific ation of the two groups. The results support previous findings that most ex posed persons do not show significant improvements over time. The results f urther suggest that there is a need to assess factors, such as aging, which may make one more vulnerable to the neurotoxic effects of solvents.