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Biomedical subjects

A D Baddeley

Publications and source records attributed to A D Baddeley.

11 recordsLinked to original sources
PubMed1992

Memory impairment in schizophrenia: its extent, affiliations and neuropsychological character.

In a sample of 60 schizophrenic patients encompassing all grades of severity and chronicity memory impairment was found to be prevalent, often substantial, and disproportionate to the overall level of intellectual impairment. The deficits were not easily attributable to poor cooperation, attention or motivation; nor were they related to neuroleptic or anticholinergic medication. Memory impairment was significantly associated with severity and chronicity of illness and also with negative symptoms and formal thought disorder. There was evidence from the sample as a whole, and from a more detailed examination of five patients with relatively isolated deficits, that schizophrenic memory impairment conformed to the pattern seen in the classical amnesic syndrome. Additionally, there was preliminary evidence for a marked deficit in semantic memory.

Adult↗
PubMed1992

Autobiographical fluency: a method for the study of personal memory.

Fifty-five subjects recalled autobiographical episodes or personal facts such as names of friends and teachers, from different lifetime periods. In each case, subjects were given 90 sec in which to retrieve as many items as possible. Also tested was subjects' fluency in generating items from semantic categories (animals, vegetables, British prime ministers, and U.S. presidents). Results of cluster analysis on the fluency tasks showed a dissociation between subjects' ability to retrieve personal episodes, personal semantic information, and nonpersonal semantic information. The dissociations observed in the fluency tasks are interpreted in terms of the different retrieval strategies required for the different types of information sought.

Adult↗
PubMed1991

Long-term recency effects and phonological short-term memory. A neuropsychological case study.

Long-term recency effects were investigated in a left brain-damaged patient, PV, who had a pathologically low auditory-verbal span and a lack of the normal recency effects in immediate free recall of auditorily presented lists of words, attributed to the abnormally reduced capacity of the phonological short-term store component of memory (Vallar and Papagno, 1986). In a task requiring the delayed free recall of a list of anagram solutions the patient showed both a recall performance level and a long-term recency effect comparable to the control group. These findings dissociate long and short-term recency phenomena, which would reflect the operation of different memory components. A collateral finding was PV's difficulty in anagram solving, which may be traced back to the defective function of her phonological short-term store.

Adult↗
PubMed1991

The decline of working memory in Alzheimer's disease. A longitudinal study.

A previous study (Baddeley et al., 1986) explored the hypothesis that patients suffering from dementia of the Alzheimer type (AD) are particularly impaired in the functioning of the central executive component of working memory. It showed that, when patients are required to perform 2 concurrent tasks simultaneously, the AD patients are particularly impaired, even when level of performance on the individual tasks is equated with that of age-matched controls. Although the results were clear, interpretation was still complicated by 2 issues: first, the question of comparability of performance on the separate tests between AD and control patients; secondly, the question of whether our results could be interpreted simply in terms of a limited general processing capacity being more taxed by more difficult dual tasks than by the individual tasks performed alone. The present study followed up the AD and control patients after 6 and 12 mths. We were able to allow for the problem of comparability of performance by using patients as their own control. Under these conditions, there is a very clear tendency for dual task performance to deteriorate while single task performance is maintained. A second experiment varied difficulty within a single task in which patients and controls were required to categorize words as belonging to 1, 2 or 4 semantic categories. There was a clear effect of number of categories on performance and a systematic decline in performance over time. There was, however, no interaction between task difficulty as measured by number of alternatives and rate of deterioration, suggesting that the progressive deterioration in performance shown by AD patients is a function of whether single or dual task performance is required, and is not dependent on simple level of task difficulty. Implications for the analysis of the central executive component of working memory are discussed.

Aged↗
PubMed1990

Interference with visual short-term memory.

Working memory (Baddeley and Hitch 1974) incorporates the notion of a visuo-spatial sketch pad; a mechanism thought to be specialized for short-term storage of visuo-spatial material. However, the nature and characteristics of this hypothesized mechanism are as yet unclear. Two experiments are reported which examined selective interference in short-term visual memory. Experiment 1 contrasted recognition memory span for visual matrix patterns with that for visually presented letter sequences. These two span tasks were combined with concurrent arithmetic or a concurrent task which involved manipulation of visuo-spatial material. Results suggested that although there was a small, significant disruption by concurrent arithmetic of span for the matrix patterns, there was a substantially larger disruption of the letter span task. The converse was true for the secondary visuo-spatial task. Experiment 2 combined the span tasks with two established tasks developed by Brooks (1967). Span for matrix patterns was disrupted by a visuo-spatial task but not by a secondary verbal task. The converse was true for letter span. These results suggest that the impairment in short-term visual memory resulting from secondary arithmetic reflects a small general processing load, but that the selective interference due to mode of processing is by far the stronger effect. Results are interpreted as being entirely consistent with the notion of a specialized visuo-spatial mechanism in working memory.

Adult↗
PubMed1990

Emotional factors in forgetting.

Levinger & Clarke (1961) found that subjects tended to forget more word associations to emotional rather than neutral words. Kline (1981) regarded this study as providing 'irrefutable evidence for the Freudian concept of repression'. On the other hand, results from Kleinsmith & Kaplan (1964) suggested that this effect may reverse after a delay. The present study attempted to replicate Levinger & Clark's result using stimulus words balanced for concreteness and frequency. In addition, recall was tested immediately and after a delay. Associations to emotional material were more poorly recalled immediately than associations to material which was low in emotional valence, but tended to be better recalled a month later. There were no differences in recall of pleasant versus unpleasant material. Results do not support the repression hypothesis, in that emotional material becomes more memorable over time. Moreover, repression should differentially apply to unpleasant rather than pleasant material but no such differences were found.

Attention↗
PubMed1990

Amnesic syndrome in schizophrenia.

Memory impairment is not usually considered to form part of the clinical picture of schizophrenia, except perhaps in severely deteriorated patients. In a survey of 60 patients encompassing all grades of severity and chronicity poor memory performance was found to be common, sometimes substantial, and disproportionately pronounced compared to the degree of general intellectual impairment. Although associated with severity and chronicity of illness, impaired memory was by no means confined to old, institutionalized, or markedly deteriorated patients. The pattern of deficit appeared to resemble that of the classic amnesic syndrome rather than that seen in Alzheimer-type dementia.

Adolescent↗
PubMed1989

How do old dogs learn new tricks: teaching a technological skill to brain injured people.

Little is known about the way people learn technological skills. This investigation was carried out to see how 100 brain injured, 50 controls and two amnesic patients performed on a task requiring them to learn a six-step programme for an electronic memory aid. Performance was correlated with other measures of memory to determine whether the technological skill was similar to a procedural learning task, a spatial memory task, a visual task, a verbal task or an amalgam of these. All controls but only 59 percent of the patients learned the task within three trials. The two amnesic patients also failed to learn the new skill. There was a high correlation between overall performance on a standardized test of everyday memory (the Rivermead Behavioural Memory Test) but little evidence that the technological skill was similar to a procedural learning task; nor was it specifically related to visual, verbal or spatial memory. It is concluded that a combination of skills is required to learn the technological task. Implications for the concept of procedural learning are discussed.

Adolescent↗
PubMed1977

When face recognition fails.

Two studies investigated recognition of pictures of faces, focusing on the effects of changes in appearance of the face from presentation to test and type of processing or encoding. Experiment 1 demonstrated that (a) previously seen faces changed in pose and facial expression were discriminated from "new" faces essentially as well as pictures identical at presentation and test; (b) major changes in the appearance of a face ("disguises") reduced recognition almost to the level of chance; and (c) subjects encoding faces in terms of personality characteristics showed better recognition performance than subjects whose processing was based on physical, facial features. Experiment 2 expanded on result (b), utilizing photographs with systematic variations in pose and in the presence/absence of glasses, wig, and beard. The design required subjects to learn names for target faces and then to identify those targets in a series of test photographs. The manipulation of pose and disguising features produced effects on probability of identification that were orderly and dramatic in magnitude. Simple changes in appearance can effectively interfere with recognition of faces.

Attention↗