Use of semantic context by patients with Alzheimer's disease

In this study we used semantic-priming procedures to examine limitations in the use of semantic context by patients with Alzheimer's disease. We also tried to determine whether any such contextual effects were mediated solely through automatic processes or whether attentional processes were also involved. Three tasks were applied to examine the effect of semantic context on the performance of 18 normal elderly and 18 normal young subjects, and on 18 patients with Alzheimer's disease. When normal and demented subjects were asked to decide whether a given item was a member of a certain category, results showed that their response times were equally affected by the item's dominance in the category. The time that demented patients took to recognize a word was actually affected more by the semantic context provided by a priming sentence than was that of normal subjects. When asked to generate the final word of an incomplete sentence, demented subjects performed very poorly unless potential responses were highly constrained by sentence context.     

The Relation of White Matter Hyperintensities to Cognitive Performance in the Normal Old: Education Matters

ABSTRACT

This study examined whether the severity of cerebral white matter abnormalities (evident on MR images as white matter hyperintensities (WMH)) was related to the cognitive performance of 141 high-functioning older adults. The elderly showed the typical age decrement on measures of processing speed, working memory, and inhibition; however WMH severity was significantly related only to processing speed. The strength of this relationship was, however, influenced by the educational level of the participants, such that processing speed was more associated with WMH severity in less-educated than in well-educated participants. This is consistent with recent concepts of cognitive reserve, but does raise a question as to the underlying source of the cognitive decrement found in the sort of well-educated elders typically used in cognitive-aging studies.     

Memory Impairment in Elderly Individuals With a Mildly Elevated Serum TSH: The Role of Processing Resources,Depression and Cerebrovascular Disease

This study examined whether a mild elevation in serum Thyroid Stimulating Hormone (TSH) in normal older individuals was associated with a cognitive impairment. Participants consisted of 15 individuals with a high- TSH level and 82 with a normal TSH. The high-TSH group performed significantly worse than the normal- TSH group on tests of immediate and delayed verbal recall and on the Mini-Mental State Exam. This decrement was not due to group differences in processing resources nor was it explained by comorbid cerebrovascular disease, depression or anticholinergic drug usage. These results suggest that undetected mild thyroid dysfunction may contribute to the cognitive decrements found in older adults.     

Book reviews

Institutions represent both the conscious and unconscious aspects of the interacting members. Psychotherapists need to address their unconscious position in the institution as well as the conscious aspects of their work. This paper describes the possible relevance that psychotherapy may have at the unconscious level. The notion of the ‘social defence system’ is extremely useful in finding one's way in the engulfing emotional attitudes, and for tolerating the often dismaying sense of irrelevance that psychotherapy appears to attract. The social defence system of a prison and a mental hospital are considered in this light and some thought are devoted to the changing state of the National Health Service at present.     

The relation of white matter hyperintensities to cognitive performance in the normal old: education matters

This study examined whether the severity of cerebral white matter abnormalities (evident on MR images as white matter hyperintensities (WMH)) was related to the cognitive performance of 141 high-functioning older adults. The elderly showed the typical age decrement on measures of processing speed, working memory, and inhibition; however WMH severity was significantly related only to processing speed. The strength of this relationship was, however, influenced by the educational level of the participants, such that processing speed was more associated with WMH severity in less-educated than in well-educated participants. This is consistent with recent concepts of cognitive reserve, but does raise a question as to the underlying source of the cognitive decrement found in the sort of well-educated elders typically used in cognitive-aging studies.     

A positron emission tomography (PET) study of autobiographical memory retrieval

Memory for the experiences of one's life, autobiographical memory (AM), is one of the most human types of memory, yet comparatively little is known of its neurobiology. A positron emission tomography (PET) study of AM retrieval revealed that the left frontal cortex was significantly active during retrieval (compared to memory control tasks), together with activation in the inferior temporal and occipital lobes in the left hemisphere. We propose that this left frontal lobe activation reflects the operation of control processes that modulate the construction of AMs in posterior neocortical networks.     

The Hypothesis Of Ether And Reid's Interpretation Of Newton's First Rule Of Philosophizing

My object is to question a recurrent claim made to the point that Thomas Reid (1710–1796) was hostile to ether theories and that this hostility had its source in his distinctive interpretation of the first of Newton's regulæ philosophandi. Against this view I will argue that Reid did not have any quarrel at all with unobservable or theoretical entities as such, and that his objections against actual theories concerning ether were scientific rather than philosophical, even when based on Newton's first rule. I argue further that Reid's insistence on Newton's rule concerns, not direct observation, but rather the notion of explanation itself.     

Favourite objects of autistic children

Favourite objects (FOs) of autistic children were compared with the FOs of healthy preschool and school children as well as mentally handicapped children. Three clusters of objects were obtained for normal children (comprising primary transitional objects and their forerunners, secondary transitional objects, and non-cuddly toys). When autistic children and mentally handicapped children were included, a fourth cluster of deviant objects was found. Frequency distributions of the two handicapped groups in the clusters were similar. Similarities between the two handicapped groups were also found within each cluster. The occurrence of secondary transitional objects was rare in the handicapped groups. The characteristics of "autistic" FOs reported in earlier case studies (e.g. being hard, often having an exciting effect, not being used in their adequate functions) were typical only of objects in the fourth cluster.     

Some aspects on behavioral teratology research

A compelling question in teratology research is whether the experimental model used allows for extrapolation from laboratory animals to man. Our thesis is that behaviors that are biologically relevant for the animal are more likely to reveal the relationship between the behavior and its substrate than are non-specific behaviors. Applying this reasoning to the study of the ontogenesis of the behavior, we plead for including the use of species-typical behaviors in testing for teratogenic effects. Our further discussion is focussed upon the different levels at which an analysis of teratogenic effects may be carried out. At one level, the analysis is directed towards the behavioral effects of a given treatment; at another level to specify the function that is impaired by the treatment.