ID 369 – The effects of chronic arsenic exposure on somatosensory pathway

Abstract

Objective From 1920 to 1962, a mining company at a small mountainous village called Toroku in Japan intermittently produced arsenic trioxide. Although many patients had severe whole-body surface and deep sensory disturbances, previous studies reported only slight axonal degeneration based on nerve conduction studies or sural nerve biopsy. Methods Subjects were six patients with chronic arsenic exposure in Toroku. All patients had moderate to severe whole-body surface and deep sensory impairments without any motor disturbances. Peripheral nerve conduction study and bilateral median nerve somatosensory evoked potentials were performed in all patients. Results In nerve conduction study, two patients showed mild decrease of sensory nerve action potentials. In somatosensory evoked potentials, the N9 was delayed in two patients. The N11 was not detected in any patients, while the P13/14 was detected only in two patients. The N20 was detected in all patients. Patients with chronic arsenic poisoning had a significantly longer central sensory conduction time (latency between N9 and N20) compared to normal subjects (p Conclusions Sensory disturbances in patients with chronic arsenic poisoning are related to not only peripheral neuropathy but also central nervous system impairment. Key message Chronic arsenic exposure may affect the central nervous system.