Biomedical subjects

B Ska

Publications and source records attributed to B Ska.

18 recordsLinked to original sources

PubMed2000

Conceptual apraxia and semantic memory deficit in Alzheimer's disease: two sides of the same coin?

This study was designed to examine the patterns of apraxic disturbances and the relationships between action knowledge and other measures of semantic knowledge about objects in 10 well-characterized Alzheimer's disease (AD) patients. Five tasks were used to assess components of action knowledge (action-tool relationships, pantomime recognition, and sequential organization of action) and praxis execution (actual use, pantomiming) according to the cognitive model of praxis. Three tasks (verbal comprehension, naming, and a visual semantic matching task) were used to assess verbal-visual semantics. Considering patterns of apraxia first, conceptual apraxia was found in 9 out of the 10 AD patients, suggesting that it is a common feature even in the early stages of AD. Second, we found partly parallel deficits in tests of action-semantic and verbal-visual semantic knowledge in 9 AD patients. Impaired action knowledge was found only in patients with a semantic language deficit. These findings provide no evidence that "action semantics" may be separated from other semantic information. Our results support the view of a unitary semantic system, given that the representations of action-semantic and other semantic knowledge of objects are often simultaneously disrupted in AD.

Aged↗

PubMed2000

[Plurality of patterns of cognitive impairment in normal aging and in dementia].

Normal aging, as well as most of the degenerative diseases of the central nervous system characterizing old age, have an impact on cognitive abilities which are obvious as well as increasingly understood. Cognitive changes in normal ageing realize a plurality of possible patterns of cognitive disabilities. Dementias are also well known to be characterized by a plurality of cognitive impairments patterns. The different cognitive patterns are likely to be due to distinct levels of impairments of different domains of cognition, or of different components within one given domain of cognition. These differences are such that in some cases they can even realize double dissociations. The plurality of cognitive impairments patterns in normal aging and in dementia will be discussed as well as the different factors that could contribute to such a plurality. Some of these factors relate to pre-morbid characteristics of the individuals known to influence the functional organization of the brain for cognition. Others--of major importance--are related to the nature and the distribution of the pathophysiological processes underlying normal ageing or a given degenerative disease. It is also reminded that some or many of these factors can interact with more general cognitive factors, such as speed of execution. It is however suggested that, despite of their presence, these general factors partly contribute to the cognitive impairments in neurodegenerative dementia. In this case, the impact of different disease-related factors over a general cognitive factor is probably much greater than in the case of normal aging.

Aged↗

PubMed1999

Cognitive processing of drawing abilities.

This critical review examines constructional apraxia from a cognitive neuropsychological perspective. To our knowledge, van Sommers (1989) is the only researcher to present a global cognitive model of drawing abilities. He organizes it into two hierarchical systems: Marr's model of visual perception and a graphic production system. The latter comprises four hierarchically organized components: depiction decisions, production strategy, contingent planning, and articulatory and economic constraints. Van Sommers' model will be discussed in light of other models and on the basis of empirical neuropsychological studies (Farah, 1984; Kosslyn & Koenig, 1992; Roncato, Sartori, Masterson, & Rumiati, 1987; van Sommers, 1989). We find that: (1) the Kosslyn and Koenig visual perception model describes more accurately the perceptual components underlying copying than the visual perception system of van Sommers' drawing model, (2) Van Sommers' arguments in favor of a depiction processing as opposed to visual imagery are not convincing, (3) Van Sommers' assumption that a production strategy is a component is unclear, and (4) articulatory and economic constraints are not cognitive components, but constraints imposed during action programming. This literature review leads to a discussion of future research topics and the specificity of constructional apraxia.

Apraxias↗

PubMed1996

Comparative study of oral and written picture description in patients with Alzheimer's disease.

Oral and written picture descriptions were compared in 22 patients with Alzheimer's disease (AD) and 24 healthy elderly subjects. AD patients had a significant reduction of all word categories, which, similarly to controls, was more pronounced in written than in oral texts. They also reported fewer information units than controls, but without task difference. At the syntactic level, written descriptions of AD subjects were characterized by a diminution of subordinate clauses and a reduction of functors. More grammatical errors were present in written descriptions by AD and control subjects. AD and control groups produced an equivalent number of semantic errors in both tasks. However, in oral description, AD patients had more word-finding difficulties. In sum, AD descriptions were always shorter and less informative than control texts. Additionally, written descriptions of AD patients appeared shorter and more syntactically simplified than, but as informative as oral descriptions. Whereas no phonemic paraphasias were observed in either group, AD patients produced many more graphemic paragraphias than controls produced. Furthermore, written descriptions had more irrelevant semantic intrusions. Thus, as compared to oral descriptions, written texts appeared to be a more reliable test of semantic and linguistics difficulties in AD.

Aged↗

PubMed1996

Development of the Quebec User Evaluation of Satisfaction with assistive Technology (QUEST).

This study's purpose was to develop a clinical instrument designed to evaluate user satisfaction with assistive technology devices. This paper describes the methodology used to develop the instrument entitled the Quebec User Evaluation of Satisfaction with assistive Technology (QUEST). Based on the theoretical and practical foundations of assistive technology as well as on the concept of satisfaction, preliminary versions of the instrument were created and examined by a panel of team participants. After the panel's recommendations were incorporated, a pretest of the revised instrument was conducted and the final French version of QUEST emerged. The originality of QUEST lies in its inter-activeness and user-directed approach to assessing satisfaction with assistive technology. From a set of 27 variables, the user is asked to indicate the degree of importance he/she attributes to each of the satisfaction variables and then to rate his/her degree of satisfaction with each of the variables considered (quite or very) important. While QUEST remains a clinical instrument undergoing pilot testing, it holds much promise in our quest for a reliable and valid means of assessing assistive technology outcome from the user's perspective.

Humans↗

PubMed1995

[Adequate neuropsychological evaluation of dementia].

The authors discuss the protocol of the Optimal Neuropsychological Evaluation of Dementias of Montreal and its possible application in Brazil. This protocol is important for evaluation in neuropsychological evolution of dementia of the Alzheimer type and for bringing to the fore distinct affected cognitive profiles as much on a transversal base as longitudinal. The authors believe that its application would contribute to the progress of research in neurology, as in the clear distinction between normal aging and pathological aging.

Alzheimer Disease↗

PubMed1995

[Cognitive heterogeneity in Alzheimer's disease].

The authors describe and discuss neuropsychological aspects related to the functional organization of the brain connected to cognition in 81 Alzheimer's disease patients in the Laboratoire Théophile-Alajouanine du Centre de Recherche du Centre hospitalier Côte-des-Neiges in the University of Montreal. They confront the clinical of homogeneity against the heterogeneity within functional organization of the brain. The criteria used for diagnosis were those of the NINCDS-ADRDA. All of the patients were in the beginning of the evolution, in stages 3 and 4 of Reiberg (Functional Assessment Staging, FAST). The conclusion shows that there are two cognitive profiles: a non-recurrent profile, made up by the majority of the patients, and the heterogeneity depends on the genetic background of each individual; a recurrent profile, made up by a small group of patients that show changes in the heterogeneity of clinical, nosological, pathological and normal aging forms.

Alzheimer Disease↗

PubMed1994

Is there a decline in picture naming with advancing age?

This review of 25 studies of the picture-naming accuracy of normal aging individuals shows that an age-related decline in picture naming is an inconsistent finding. Naming performance of older adults varied throughout the studies reviewed in this paper. This variability is attributed to the research methods used and to subject characteristics. To date, there are no studies that have considered all "nuisance factors" (e.g., health status, medication) in such a way that would allow support for a decrease in picture-naming accuracy associated with primary aging.

Adolescent↗

PubMed1993

[Aging and cerebral representation of language].

Some characteristics of acquired aphasias during adulthood--frequency, severity, type of aphasia--would change with aging. In particular, Wernicke's aphasia patients are repeatedly reported to be older than Broca's. Several hypotheses are proposed to account for these age-related changes. One of the explanations puts forward hypothetical changes in the neural substrate with aging. A second hypothesis refers to the involvement of cognitive and behavioral changes occurring in elderly. A third one claims that changes in functional distribution of language in brain (between hemispheres and within left hemisphere) may occur with aging.

Aged↗

PubMed1992

Interaction between verbal and gestural language in progressive aphasia: a longitudinal case study.

The objective of this longitudinal study is to investigate the on-line interaction between praxis and linguistic abilities in a progressive aphasia case. During 3 years of evolution, procedural discourse of a progressive aphasic patient was videotaped five times, allowing us to analyze the progression of both language and gestural production as well as the interaction between these two. We anticipated that, in the absence of apraxia, the patient would compensate for her speech deficit by producing progressively more and more meaningful gestures. Our compensatory hypothesis was confirmed but the compensation was not as efficient as one would expect given the absence of apraxia. With the progression of the speech deficit, the patient could not replace some verbs by pantomimes that were otherwise accompanying her discourse in the preceding testing sessions. We suggest that such a compensatory ability may constitute one important characteristic of the progressive aphasia syndrome.

Aphasia↗

PubMed1990

Discourse analysis in neuropsychology: comment on Chapman and Ulatowska.

This paper discusses a recent article by Chapman and Ulatowska (1989, Brain and Language, 36, 651-658) on discourse analysis in aphasia. As such, the research in this area is interdisciplinary drawing from neuropsychology, as well as cognitive psychology, and, in part, aging. We illustrate problems that can arise when theoretical constructs and methodological considerations in this interdisciplinary approach are not rigorously observed. It is argued that definitive conclusions regarding the functional organization of the brain and discourse can be offered only when discourse analysis uses the state of the art from neuropsychology and cognitive psychology.

Adult↗

PubMed1990

Heterogeneity in the cognitive profile of normal elderly.

An increasing number of studies point to the fact that distinct cognitive subgroups may be identified among subjects with dementia of the Alzheimer type (DAT). Although such heterogeneity could be the expression of neuropsychological, genetic, or epidemiological factors, the identification of neuropsychological subtypes in DAT could also reflect the existence of cognitive subgroups in a normal aged population. In the present study, the existence of neuropsychological subgroups was sought from among 81 volunteers aged between 55 and 84 years. Subjects were given a neuropsychological battery addressing various aspects of cognitive functioning. Results show that six subgroups could be identified among this population. Subgroups differ primarily in their overall degree of performance. Qualitative differences in cognitive performance are also present, mostly when subgroups which exhibit poor overall performance are considered. Consequently, the presence of such heterogeneity in normal elderly should be taken into account in any attempt to identify neuropsychologically based subgroups in early dementia of the Alzheimer type.

Aged↗

PubMed1990

Line orientation judgment in normal elderly and subjects with dementia of Alzheimer's type.

Ninety-five normal controls divided into three subgroups (55-64 yrs, 65-74 yrs, and 75-84 yrs) and 11 subjects with early dementia of Alzheimer's type (DAT) were given a line orientation judgment task (Benton, Varney, & Hamsher, 1978). No difference appeared between the three control subgroups in global score but the difference between controls and DAT subjects was significant. However, some DAT subjects had a global score overlapping the scores of controls. Error types were also analyzed. Results of this analysis showed that some errors appeared in all subjects, normal and DAT, while others were specific to DAT subjects. It was speculated that these error types were a manifestation of a deeper visuospatial deficit, revealing a major problem of the DAT in spatial organization. Thus, this study suggests that an analysis of the error types observed in the line orientation judgment task may be helpful in differentiating normal elderly from early DAT.

Aged↗

PubMed1988

Agrammatism in sentence production without comprehension deficits: reduced availability of syntactic structures and/or of grammatical morphemes? A case study.

A French-speaking patient with Broca's aphasia--following a left-hemisphere lesion involving the sylvian region but sparing Broca's area--is presented. Like G. Miceli, A. Mazzuchi, L. Menn, and H. Goodglass's (1983, Brain and Language, 19, 65-97) case 2, this patient produces agrammatic speech in the absence of any comprehension deficit. Unlike Miceli's patient, though, agrammatic speech can be observed in all sentence production tasks (from spontaneous speech to repetition, oral reading, and writing) whereas production of individual words--be they open class or closed class--is almost always intact. On the basis of extensive (psycho)linguistic testing, it is argued that this patient's deficit is not central and not crucially syntactic (at least) at the level of knowledge but seems to disrupt specifically those (automatic?) processes responsible for both retrieval and production of free-standing grammatical morphemes whenever they have to be inserted into phrases and sentences.

Aphasia↗

PubMed1987

Pantomimes and aging.

The goal of this study was to verify the evolution of pantomiming in normal aged subjects in comparison to normal younger adults. Ninety-six subjects participated in this study: 30 between the ages of 20 and 30; 30 between the ages of 40 and 50; and 36 between the ages of 60 and 82. The subjects were required to execute 42 pantomimes on verbal command. The executed gestures were divided into two categories and analyzed separately: (a) the static constituents which refer to the shape the subject gave to the body part(s) involved; and (b) the dynamic constituents which refer to the executed action and to the relations established between several static constituents during the execution. The results showed that the aged subjects' performance was different from the younger subjects' performance principally in the static constituents of self-oriented one-hand gestures where the aged subjects used a part of their body to serve as the absent object.

Adult↗

PubMed1986

Informative content of narrative discourse in right-brain-damaged right-handers.

Thirty-six right-brain-damaged (RBD) right-handers and 20 controls (C) were submitted to a narrative production task using the pictorial representation of a trivial story. Each subject's narrative was analyzed, using a "propositional analysis," in order to study amount as well as nature of informative content. Results show that RBD subjects' narratives contain a smaller amount of information that did not appear to be related to a smaller amount of verbal output or to the presence of a visual neglect, that the information contained in RBD subjects' narratives appears to be a subset of that contained in C subjects' narratives, and that these results do not pertain to all C or RBD subjects, since both groups are nonhomogeneous. Even though these results are not linked to the presence of some visual neglect or visual agnosia per se, they could be, at least in part, the expression of some degree of perceptive difficulties of the iconography. However, they are also interpreted as expressing a problem with the organization of narrative discourse at levels of cognitive processing which may not be exclusive to language, but which are nonetheless essential for discourse organization.

Brain Damage, Chronic↗

PubMedDate not supplied

Pantomime recognition impairment in Alzheimer's disease.

This study was designed to examine whether 10 AD patients with diffuse lesions and an early semantic deficit could comprehend the meaning of pantomimes and symbolic gestures. We especially wanted to determine the relationship between pantomime recognition and production. The tasks involved naming or showing an understanding (e.g., circumlocutions) of the pantomimes executed by the examiner and producing pantomimes to verbal command or to imitation. The results showed no significant relationship between pantomime comprehension and pantomime production. However, 60% of AD patients performed poorly compared to controls on the Gesture Recognition task. Gesture comprehension was highly correlated with a measure of global cognitive impairment (3MS). The data are consistent with the proposed separation of comprehension and action production systems in a cognitive model of praxis. Gesture comprehension may be diffusely distributed and thus preserved in the early stages of AD as in circumscribed lesions of the left parietal lobe.

Aged↗

PubMedDate not supplied

[Heterogeneity of cognitive profiles in dementias of the Alzheimer type: theoretical aspects and clinical consequences].

Presently, Alzheimer's disease can only be diagnosed with the coexistence of clinical symptoms and the presence of neuropathological alterations. Thus, in the absence of pre mortem biological markers, cognitive deficits form the starting point and the basis of inclusion criteria on which the clinician relies in order to make a putative diagnose of dementia of the Alzheimer type (DTA). Cognitive deficits should thus be accurately described through neuropsychological testing since it is essential to identify the cognitive deterioration patterns of the patients--in terms of selective impairment of cognitive functions--as well as the evolution of these patterns. Regarding this issue, the classical teaching of the Geneva school has proposed a homogeneous deterioration of the aphasic-apraxicagnosic syndrome into four stages. However, recent work does not support this hypothesis. On the contrary, these studies tend to show the presence of heterogeneity in neuropsychological manifestations of the disease. The aim of the present paper is to provide a critical review of this topic through a brief survey of the classical work and research that have recently been conducted. An analysis of the possible candidates responsible for the existence of this heterogeneity of cognitive profiles is presented. Finally, theoretical implications and clinical repercussions are discussed.

Age Factors↗