Neuropsychological function and past exposure to metallic mercury in female dental workers

The aim of this study was to see if dental personnel with previous exposure to metallic mercury have later developed disturbances in cognitive function. Ninety-one female participants who had been selected from a previous health survey of dental personnel were investigated neuropsychologically within the following domains: motor function, short-term memory, working memory, executive function, mental flexibility, and visual and verbal long-term memory. The scores were mainly within normal ranges. Relationships between an exposure score, the duration of employment before 1990, and previously measured mercury in urine as independent variables and the neuropsychological findings as dependent variables, were analyzed by multiple linear regression controlling for age, general ability, length of education, alcohol consumption, and previous head injuries. The only relationship that was statistically significant in the hypothesized direction was between the previously measured urine mercury values and visual long-term memory, where the urine values explained 30% of the variability. As the study had a low statistical power and also some other methodological limitations, the results have to be interpreted with caution. Even so, we think it is right to conclude that neuropsychological findings indicative of subsequent cognitive injuries are difficult to find in groups of otherwise healthy dental personnel with previous occupational exposure to mercury.     

The effect of age on decision making according to the Iowa gambling task

Aging has been associated with several brain changes that often affect the cognitive functioning of adults, but changes in executive functions, particularly in the field of decision making, have not been fully investigated. The Iowa Gambling Task (IGT) is a widely used tool to evaluate decision making, but little is known about the effect of age on its results. This study used the IGT and compared healthy young (n = 40) and elderly (n = 40) adults to evaluate their decision making processes. There were significant differences in the learning curve of the two age groups, but no difference in overall IGT performance. The results for the first IGT block were different from those of the rest of the task, and the group of elderly adults had a better performance in this block. Elderly adults also showed a preference for deck A, the one that resulted in greater losses. Findings confirmed the results of other studies, which reported that the IGT block score is the variable with the greatest sensitivity to age in this instrument.     

Retrieval independence in successive recognition tasks

In three experiments participants studied AB word pairs and completed two recognition tests. In the first recognition test, which was included in all three experiments, the B word had to be discriminated from two distractors that did not appear on the study list. In Experiment 1, in the second recognition test, an AB target was compared with distractors composed of words not on the study list. In Experiment 2, in the second recognition test, an AB target had to be discriminated from two other pairs that were created by randomly re-pairing A and B words that appeared on the study list. In Experiment 3, on the second recognition test, words from the study list were systematically re-paired to form distractors that contained either the same A term or the same B term as the target pair. Recognition of the B word on the first test was always at least partly independent of recognition of the AB pair on the second test. Even when recognition judgements were restricted to those for which the participants were most confident, all experiments demonstrated significant retrieval independence between the two tests.     

Concurrent and retroactive interference effects in memory of movement patterns

Three experiments examined memory for enacted and observed movement patterns. The effect of visuo-spatial tracing tasks requiring overt motor movements, comparable to those required by the to-be-recalled movement pattern task when enacted, were compared with the effects of non-motor interference tasks, such as articulatory suppression and counting backwards. None of the experiments was able to detect indices of motor mechanisms in memory of movement patterns. The results are discussed in terms of theories of action memory and working memory and of a problem-solving account.     

Autobiographical Memory and Suicide Attempts in Schizophrenia

According to the cry of pain model of suicidal behavior, an over‐general autobiographical memory function is often found in suicide attempters. The model has received empirical support in several studies, mainly of depressed patients. The present study investigated whether deficits in autobiographical memory may be associated with an increased frequency of suicide attempts in patients with schizophrenia. We found support for our hypothesis that patients with schizophrenia and previous suicide attempts have an over‐generalized autobiographical memory compared to patients with schizophrenia without previous suicide attempts. Adjustment for sociodemographic and clinical variables did not change the results.