Bioelectrical activity of the central nervous system among populations in a rare earth element area.

Auditory brainstem electric response (ABR) and somatosensory evoked potential (SEP) of 21 subjects (41 ears) among villagers in a rare earth element (REE) area in Gan County, Jiangxi, China, were studied. No difference in ABR between the subjects from the REE area and the control group was noted. However, the conduction detected by SEP from the median nerve to the thalamus (P15) was shortened (P < 0.05), especially to the first-grade primary somatosensory responsive region (S1) (P < 0.01) and the amplitude of S1 decreased (P < 0.05), indicating that REE was difficult to accumulate in the brainstem, but it was susceptible to cerebral cortex, thus causing sub-clinical damage. This condition was confirmed in the animal experiment. It was suggested that the toxicity through long-term intake of small doses of REE might not be negligible, and the hazard of REE environments should be investigated.