Takaoka, S.; Fujino, T.; Shigeoka, S.-I.; Yorifuji, T. Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury. Toxics2023, 11, 1023.
Takaoka, S.; Fujino, T.; Shigeoka, S.-I.; Yorifuji, T. Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury. Toxics 2023, 11, 1023.
Takaoka, S.; Fujino, T.; Shigeoka, S.-I.; Yorifuji, T. Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury. Toxics2023, 11, 1023.
Takaoka, S.; Fujino, T.; Shigeoka, S.-I.; Yorifuji, T. Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury. Toxics 2023, 11, 1023.
Abstract
Hundreds of thousands of people living along the Yatsushiro Sea coast have been exposed to methylmercury from the contaminated water of the Chisso factory in Minamata. Methylmercury causes neurological deficits in the cerebrum and cerebellum, with symptoms of ataxia, dysarthria, and visual field constriction in severe cases, but the most common symptom of a milder disorder is somatosensory disturbance due to parietal lobe damage. We investigated the characteristics of the somatosensory disturbances in detail by studying subjective complaints, neurological findings, and quantitative sensory tests in 197 residents (63.2 ± 10.7 years old) from contaminated areas exposed to methylmercury from seafood and 130 residents (63.7 ± 9.3 years old) from control areas. The most commonly affected sensory modalities were superficial peripheral touch and pain in the extremities, followed by two-point discrimination and deep senses, and in the most severe cases, full-body sensory dysfunction and impairment of all sensory submodalities. Although the severity of the sensory submodalities correlated with each other, there was almost no correlation between the severity of these submodalities and indices of peripheral nerve conduction studies, suggesting that the primary cause of the sensory deficits was damage to the central nervous system. The health effects of chronic methylmercury toxicosis can be elucidated by a detailed examination of sensory deficits.
Keywords
methylmercury; long term exposure; symptoms; neurological findings; somatosensory submodalities; quantitative sensory examination; nerve conduction study
Subject
Public Health and Healthcare, Public, Environmental and Occupational Health
Copyright:
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