Effect of occupational exposure to elemental mercury on short term memory.

Abstract

the STM capacity should also be adversely affected by exposure to mercury. This study was conducted to test this prediction and to provide converging evidence that one locus of the neurotoxic effect of mercury is short term memory.Two alternative measures of STM capacity were evaluated under field study conditions. The first, the Wechsler digit span forward,6 was included because it is the test of STM span that has traditionally been used in behavioural toxicology studies.7A second, more extensive test of STM span was also evaluated because it has been suggested that the Wechsler digit span test taken alone "is not sufficiently discriminating to detect significant differences in intellectual (that is, retention) functioning."8 This second test entails estimating an individual's 50% threshold for serial recall-that is, the number of digits that can be correctly recalled 50% of the time, in serial order.The reliability and precision of these two tests were assessed within the context of evaluating the effects of chronic exposure to elemental mercury on STM. This provided an opportunity to study the performance of a heterogeneous population (mercury cell chlor-alkali workers) and to illustrate the usefulness of precise behavioural measures in assessing the neurotoxic effects of chronic exposure to elemental mercury. 413

Neuropsychological effects associated with exposure to mercury vapor among former chloralkali workers

“…It could therefore be a random finding. Still, several studies on cussently exposed populations have reported reduced performance on memory tests (9,10,14,18), and the possibility cannot be excluded that the observed poorer performance on the word pairs test among the workers with the highest exposure intensity was real.…”

“…Several studies have reported neurobehavioral effects related to motor and cognitive functions (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) in humans during ongoing exposure to mercury vapors. Contrary to the large number of studies on currently exposed workers, few epidemiologic studies have focused on the long-term effects on workers who are no longer exposed.…”

“…Neurobehavioral effects of occupational exposure have been described as falling into the 3 major groups of alterations in emotional state, effects on cognitive functions, and effects on motor functions (1,2). Ongoing exposure to lower concentrations of mercury vapors has been associated with increased hand or finger tremor, subclinical changes in coordination, neuromuscular functions, and deficits in memory and attention (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Magos (21) suggested that it may be a mistake to relate defects to exposure estimates valid at a time when the possibility of higher exposure in the past cannot be excluded.…”

Does Inorganic Mercury Play a Role in Alzheimer's Disease? A Systematic Review and an Integrated Molecular Mechanism

“…Studies on current exposure of workers to mercury [57][58][59][60][61][62][63][64][65][66][67][68][69] were mostly conducted on workers in industry (chlorine-alkaline factories, thermometer factories, mercury extraction plants), and in one case on gold miners in the Philippines who use large amounts of mercury without any protection [59]. Correlations between the amount of Hg excreted in urine and measures of cognitive abilities (memory tests, attention span) were always significant and negative, i.e., the more mercury excreted the worse the test results.…”

A aplicação da neuropsicologia na pesquisa experimental: o exemplo da intoxicação por vapor de mercúrio

“…Achados de estudos observacionais com trabalhadores industriais (produção de lâm-padas fl uorescentes, termômetros ou cloro-álcalis) comparados com controles mostraram défi cit de memória operativa (Smith, Langolf, & Goldberg, 1983), memória verbal de curto prazo (Soleo, Urbano, Petrera, & Ambrosi, 1990), atenção concentrada, habilidade para cálculos (Liang, Sunn, Chen, & Li,1993), lentidão psicomotora (Lucchini et al, 2003, Piikivi, Hanninen, Martelin, & Mantere, 1984, tempo de reação diminuído e incoordenação motora (Lucchini et al, 2003). Foram encontradas correlações entre índice de exposição ao vapor de mercúrio (concentração urinária do metal) e défi cits de atenção e memória visual de curto prazo (Ellingsen et al, 2001), funções executivas e memória (Piikivi et al, 1984), além de lentidão psicomotora (Ellingsen et al, 2001).…”