Methodology of forensic neurotoxicity evaluation: PCB case.

Many scientists and doctors are not aware that the level of certainty for litigation purposes differs from that usually associated with scientific studies. Although the 0.05 probability level is commonly used in scientific studies ("beyond a reasonable doubt"), in U.S. civil litigation the diagnostic criteria is "more probable than not" (greater than 0.50 or chance probability level). The following case of PCB neurotoxicity will be discussed within the context of a forensic evaluation. A number of workers were employed by a metal salvage company to strip copper coils from used electrical transformers. Symptoms of neurotoxicity developed in the men, which were evaluated by questionnaire, interview and psychological examination. Neuropsychological and nerve conduction tests were administered. Results showed deficits in nervous system function related to PCB exposure. An individual case is described in detail.