Brainstem auditory evoked potentials (BAEPs) study in chronic arsenic poisoning patients.

OBJECTIVES: To explore the possible neurotoxicity of arsenic to auditory sensory pathways and evaluate roles of BAEPs in the detection of early brain damage resulting from arsenic exposure. DESIGN: Cross-sectional analytic study. MATERIAL AND METHOD: Twenty nine females with skin lesions consistent with arsenical dermatoses and 27 controls who met the inclusion criteria were investigatetd by Auditory Evoked Potentials (AEPs). Case findings resulted from a house-to-house survey in village 12, Ronphibun subdistrict and village 5, Saothong subdistrict, Nakhon Si Thammarat Province, southern Thailand in 1995. RESULTS: Differences between the arsenic-exposed population and the referent group regarding BAEP parameters, BAEP latencies and interpeak latencies were not found. CONCLUSION: Evidence of the abnormalities of the auditory sensory pathways was not found among female patients with arsenical dermtoses in Ronphibun. The role of BAEPs in the detection of brain damage resulting from arsenic exposure could not be demonstrated.

Nerve conduction studies in chronic arsenic poisoning patients.

OBJECTIVE: To assess the nerve conduction functions among female patients with arsenical dermatoses compared with the controls. DESIGN: Cross-sectional analytic study SUBJECTS AND METHOD: Thirty females with skin lesions consistent with arsenical dermatoses and 27 controls who met the inclusion criteria were investigated by nerve conduction functions. Case findings resulted from a house-to-house survey in village 12, Ronphibun subdistrict and village 5, Saothong subdistrict, Nakhon Si Thammarat Province, southern Thailand in 1995. RESULTS: Differences between the arsenic-exposed population and the reference group regarding nerve conduction velocities (NCVs), proximal and distal latencies and amplitudes of sensory and motor nerve action potentials were not found except for the absent response to the sural nerve stimulation in three subjects of the exposed group. CONCLUSION: The effects of arsenic toxicity on the peripheral nerves in the form of slow nerve conduction velocities were not found among female patients with arsenical dermatoses in Ronphibun. Some patients might have experienced arsenic neuropathy to some degree in the past (before 1987) but they had recovered to some degree at the time of the present investigation (1996) as most of the patients with chronic arsenic poisoning in the present study changed their sources of drinking water from arsenic-contaminated shallow-well water to other sources such as rainwater, tap water or commercial bottled water.