[1] Univ Med & Dent New Jersey, New Jersey Med Sch, Dept Neurosci, Newark, NJ 07103 USA
[2] Univ Med & Dent New Jersey, Robert Wood Johnson Med Sch, Ctr Childhood Exposure & Assessment, Piscataway, NJ 08854 USA
[3] Cent Middlesex Hosp, Dept Neurol, Peripheral Nerve & Auton Unit, London NW10 7NS, England
[4] Univ Med & Dent New Jersey, Sch Publ Hlth, Dept Prevent Med, Newark, NJ 07103 USA
[5] Kennedy Krieger Inst, Dept Neurol & Dev Med, Baltimore, MD 21205 USA