Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury
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. The most common neurological disorder caused by methylmercury is somatosensory disturbance, but very few studies have been conducted...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-12-01
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| Series: | Toxics |
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| Online Access: | https://www.mdpi.com/2305-6304/11/12/1023 |
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| author | Shigeru Takaoka Tadashi Fujino Shin-ichi Shigeoka Takashi Yorifuji |
| author_facet | Shigeru Takaoka Tadashi Fujino Shin-ichi Shigeoka Takashi Yorifuji |
| author_sort | Shigeru Takaoka |
| collection | DOAJ |
| description | 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. The most common neurological disorder caused by methylmercury is somatosensory disturbance, but very few studies have been conducted in the world to determine its pathophysiology and origin, including the Japanese cases, which have produced numerous intoxicated individuals. We have already shown in previous studies the body part where the disorder occurs and that its cause is not peripheral nerve damage but damage to the parietal lobes of the cerebrum. We reanalyzed the results of subjective symptoms, neurological findings, and quantitative sensory measurements 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 same subjects as in previous studies, to determine the characteristics of somatosensory disturbance in detail. 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. The severity of sensory submodalities correlated with each other but not with peripheral nerve conduction test indices, further confirming the correctness of our assertion about the responsible foci of sensory disturbance. The health effects of chronic methylmercury toxicosis can be elucidated by a detailed examination of sensory deficits. |
| first_indexed | 2024-03-08T20:19:04Z |
| format | Article |
| id | doaj.art-5a7d7456651849b7902f7b494ce6816b |
| institution | Directory Open Access Journal |
| issn | 2305-6304 |
| language | English |
| last_indexed | 2024-03-08T20:19:04Z |
| publishDate | 2023-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Toxics |
| spelling | doaj.art-5a7d7456651849b7902f7b494ce6816b2023-12-22T14:46:10ZengMDPI AGToxics2305-63042023-12-011112102310.3390/toxics11121023Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to MethylmercuryShigeru Takaoka0Tadashi Fujino1Shin-ichi Shigeoka2Takashi Yorifuji3Kyoritsu Neurology and Rehabilitation Clinic, 2-2-28 Sakurai-cho, Minamata 867-0045, JapanMinamata Kyoritsu Hospital, 2-2-12 Sakurai-cho, Minamata 867-0045, JapanMinamata Kyoritsu Hospital, 2-2-12 Sakurai-cho, Minamata 867-0045, JapanDepartment of Human Ecology, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, JapanHundreds 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. The most common neurological disorder caused by methylmercury is somatosensory disturbance, but very few studies have been conducted in the world to determine its pathophysiology and origin, including the Japanese cases, which have produced numerous intoxicated individuals. We have already shown in previous studies the body part where the disorder occurs and that its cause is not peripheral nerve damage but damage to the parietal lobes of the cerebrum. We reanalyzed the results of subjective symptoms, neurological findings, and quantitative sensory measurements 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 same subjects as in previous studies, to determine the characteristics of somatosensory disturbance in detail. 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. The severity of sensory submodalities correlated with each other but not with peripheral nerve conduction test indices, further confirming the correctness of our assertion about the responsible foci of sensory disturbance. The health effects of chronic methylmercury toxicosis can be elucidated by a detailed examination of sensory deficits.https://www.mdpi.com/2305-6304/11/12/1023methylmercurysomatosensory disturbancesomatosensory submodalitiessomatosensory quantificationnerve conduction study |
| spellingShingle | Shigeru Takaoka Tadashi Fujino Shin-ichi Shigeoka Takashi Yorifuji Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury Toxics methylmercury somatosensory disturbance somatosensory submodalities somatosensory quantification nerve conduction study |
| title | Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury |
| title_full | Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury |
| title_fullStr | Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury |
| title_full_unstemmed | Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury |
| title_short | Characteristics of Abnormalities in Somatosensory Submodalities Observed in Residents Exposed to Methylmercury |
| title_sort | characteristics of abnormalities in somatosensory submodalities observed in residents exposed to methylmercury |
| topic | methylmercury somatosensory disturbance somatosensory submodalities somatosensory quantification nerve conduction study |
| url | https://www.mdpi.com/2305-6304/11/12/1023 |
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