Biomedical subjects

M Laiacona

Publications and source records attributed to M Laiacona.

At least 37 records · Page 2Linked to original sources

PubMed1996

Performance consistency in picture naming: a study of the rehabilitation effect on two aphasic patients.

We describe the effect of language rehabilitation on the naming deficits of 2 patients affected by longstanding amnestic aphasia. In particular, our aim was to study the evolution of the rate of inconsistent naming (i.e., performance with stimuli that were named sometimes correctly and sometimes incorrectly when the test was repeated at close intervals) by means of a stochastic model based on Markov chains (Faglioni & Botti, 1993). From a quantitative point of view, both patients showed a significant improvement that was still present several months after treatment. However, at baseline these patients showed different degrees of consistency which revealed a basic difference in the way their language functions. One case presented with low consistency, delayed responses, and self-corrections: A clear effect of rehabilitation was improvement in consistency and reduction of delays. In the other case, at baseline consistency was greater, but naming of pictures did not improve even after delay or self-correction; after rehabilitation more stimuli were named correctly, but only after delay and self-correction. The relevance of consistency and its relationship with delayed naming and self-corrections is discussed. It is suggested that consistency analysis based on stochastic models would make a useful contribution to the description and interpretation of naming deficits in aphasic patients.

Adult↗

PubMed1996

Naming deficit in herpes simplex encephalitis.

OBJECTIVES: The preferential involvement of living categories in naming impairment is well recognised in Herpes Simplex Encephalitis (HSE). In this paper we describe naming, neuropsychological and neuroradiological findings with seven fresh HSE cases. MATERIAL & METHODS: Patients were given a picture naming task that included 60 items belonging to 6 different categories (three living, i.e. fruits, vegetables and animals and three non-living, i.e. furniture, vehicles and tools). In the statistical analysis several possible sources of bias as the frequency of the target word, the familiarity with the objects to name, the image complexity and other parameters were taken into account. RESULTS: Four out of seven patients were significantly more impaired with living things. We describe their general cognitive profile and discuss the anatomo-functional aspects of category dissociation. CONCLUSION: Language impairment, disproportionately severe for the naming of living exemplars, is frequently observed in HSE, is clinically relevant and should be specifically investigated.

Adolescent↗

PubMed1996

Group aggregates and individual reliability: the case of verbal short-term memory.

Two experiments examined the generalizability of the effects of word length and phonological similarity with visual and auditory presentation in immediate verbal serial ordered recall. In Experiment 1, data were collected from 251 adult volunteers drawn from a broad cross-section of the normal population. Word length and phonological similarity in both presentation modes significantly influenced the group means. However, 43% of the subjects failed to show at least one of the effects, and the likelihood that effects appeared was highly correlated with verbal memory span. In Experiment 2, 40 subjects of the original sample were retested, 20 of whom had failed to show one or more effects in Experiment 1. Whether or not an effect had appeared for individual subjects on the first test session was a poor predictor of whether the effect would appear on retest. Finally, an analysis of subject reports demonstrated that the patterns of experimental data could be accounted for in part by the strategies that subjects reported using, and the effect of strategy was independent of the effect of span. The implications of these findings for theories of verbal short-term memory are discussed.

Acoustic Stimulation↗

PubMed1995

Poppelreuter-Ghent's Overlapping Figures Test: its sensitivity to age, and its clinical use.

This study aims to identify the cognitive variables involved in a task of visual recognition of meaningful and meaningless two-dimensional line-drawings of shapes; the Poppelreuter-Ghent Overlapping Figures Test. It was found that the performance of healthy controls was influenced by age and education, but not sex. Age and education adjusted norms are set forth. Meaningful patterns were better recognised than meaningless ones. Number of overlapping patterns, direction, and degree of rotation were among the other variables considered. Only the latter variable significantly influenced the difficulty of the task. The clinical use of this test was verified on clinical populations of patients affected by Alzheimer's disease and right or left hemisphere damage. Left hemisphere damaged patients did not show deficits. Alzheimer and right hemisphere damaged patients were impaired and the degree of rotation significantly influenced their performance. In conclusion, the Poppelreuter-Ghent's Test is a multicomponential task, the visuo-spatial components of which were shown to be the most important.

Journal Article↗

PubMed1994

Living and non-living categories. Is there a "normal" asymmetry?

A picture naming task and a semantic memory verbal questionnaire were given to normal subjects to assess the possible asymmetry between knowledge for non-living and living things. We first examined 60 elderly subjects with low education. Asymmetry between non-living and living things was found in the semantic knowledge questionnaire and living things fared worse. This difference was not explained by discrepancy in item frequency, familiarity or prototypicality. Using the same questionnaire, we analysed difficulty judgements given by younger, better-educated subjects: questions about living things were slightly, but significantly more difficult than questions regarding non-living things. In order to check for a possible sample bias, we submitted another verbal questionnaire with an analogous structure to different judges and replicated the previous results. These findings are discussed with regard to the selective semantic memory deficit for living things observed in patients. We suggest that the cognitive pattern presented by these cases may be linked to, but not fully explained by the greater difficulty living things present for normal subjects.

Aged↗

PubMed1993

Progressive neuropsychological and extrapyramidal deterioration resembling progressive supranuclear palsy: is aphasia relevant for correct diagnosis?

We describe the case of a woman presenting with a clinical syndrome closely resembling progressive supranuclear palsy, who also showed some progressive neuropsychological defects (aphasia and apraxia) not consistent with a simple loss of timing and activation as is generally postulated in this pathology. The case is discussed with regard to the definition of subcortical dementia and the possible alternative diagnosis of corticobasal degeneration.

Aged↗

PubMed1993

Autobiographical recollection and frontal damage.

A neuropsychological experiment on autobiographical retrieval of incidental past events, checked by means of a standardized enquiry, was carried out on a series of 16 patients with CT-assessed frontal lobe lesions. Of 16 patients, six were impaired on autobiographical retrieval. Moreover, eight were impaired on supraspan verbal learning. Impairment on both resulted in three patients, whereas in five there was no impairment on either test. Concordance between autobiographical and learning impairment was far from significant. Poor autobiographical retrieval correlated significantly with "executive" test performances and with the CT-verified bilaterality of the frontal damage. Poor learning of new information did not correlate significantly with "executive" performances, nor did it appear to be related to the hemispheric side or to the bilaterality of the frontal lesion. We propose that the relationship between the attentional system of retrieving from remote memory and of learning new information is qualitatively different.

Aged↗

PubMed1993

Perceptual and associative knowledge in category specific impairment of semantic memory: a study of two cases.

We report two head-injured patients whose knowledge of living things was selectively disrupted. Their semantic knowledge was tested with naming and verbal comprehension tasks and a verbal questionnaire. In all of them there was consistent evidence that knowledge of living things was impaired and that of non-living things was relatively preserved. The living things deficit emerged irrespective of whether the question tapped associative or perceptual knowledge or required visual or non visual information. In all tasks the category effect was still significant after the influence on the performance of the following variables was partialled out: word frequency, concept familiarity, prototypicality, name agreement, image agreement and visual complexity. In the verbal questionnaire dissociations were still significant even after adjustment for the difficulty of questions for normals, that had proven greater for living things. Besides diffuse brain damage, both patients presented with a left posterior temporo-parietal lesion.

Adult↗

PubMed1992

A cancellation test: its reliability in assessing attentional deficits in Alzheimer's disease.

The aim of the study is to provide (i) a standardized procedure for a Cancellation Test of Digits, designed to assess in the visual modality selective attention deficits in patients with Alzheimer's disease, and (ii) a detailed analysis of how patients cope with it. Age-, education-, and sex-adjusted normative scores earned by 352 healthy controls are set forth, as well as data yielded by the Digit Cancellation Test in 74 Alzheimer patients, in 26 patients with a CT-assessed frontal lobe lesion and in a group of 24 healthy subjects urged to perform the task with a shortened time-constraint. Findings include discriminant power of Alzheimer patients versus healthy controls, sensitivity to cognitive evolution of the dementing process and analysis of errors. Attention data failed to supply psychometric support for the posterior-to-anterior algorithm of progressive cortical encroachment of Alzheimer's disease suggested by PET-findings. Emphasis is put on methodological aspects of neuropsychological research on Alzheimer patients and on the analysis of processing components of the tests employed. Results are discussed in the light of the relationships between psychometric assessments and related functions, and underlying neuronal degeneration.

Adult↗

PubMed1991

Sex differences in spatial memory: a reanalysis of block tapping long-term memory according to the short-term memory level.

This paper analyzes the spatial memory performance of 495 subjects. Both short-term and long-term memory have been analyzed by means of the Corsi block-tapping test. We provide separate norms for the learning of a supra-span sequence according to the level of spatial short-term memory. The long-term memory of males and females was compared in groups matched for spatial short-term memory, and the gender effect was never found to be significant. This finding is discussed in relation to the nature of sex differences in spatial abilities.

Educational Status↗

PubMed1991

Generative associative naming in dementia of Alzheimer's type.

Forty-eight patients with mild to moderate dementia of Alzheimer's type (DAT) were tested with a generative associative naming task, a task that combines the aspects of fluency and of word association tests. The variables taken into consideration were the number of adequate and inadequate responses, conventionality, word frequency and lexical-semantic relation to the target. DAT patients' performances were compared to those of a group of control subjects matched for sex, age and educational level. As a group, the patients gave fewer adequate responses, more idiosyncratic responses and perseverations, while there was no difference in the qualitative variables. However, the analyses of the performance profiles suggest that, irrespective of the severity of the disease, two major subgroups of DAT patients may be identified: (1) a first subgroup of subjects produced words with a lower conventionality rate and these were mostly in propositional relationship to the target; they also produced a higher rate of idiosyncratic responses and perseverations. (2) A second subgroup of subjects gave more conventional responses, mostly in the hierarchical-categorical relationship. The disorders of the former subgroup seem to correspond to a disrupted access to some relatively spared semantic abilities, whereas those of the latter to a semantic breakdown.

Aged↗

PubMed1990

Aphasia in left-handers. Comparison of aphasia profiles and language recovery in non-right-handed and matched right-handed patients.

The present retrospective analysis reports two studies. In Study 1, clinical aspects of aphasia are compared in right-handed (RH) and non-right-handed (NRH) patients; in Study 2, recovery from aphasia is compared in RH and NRH aphasic patients with a minimum of 5 months of daily language rehabilitation. From a continuous series of 1200 brain-damaged subjects, 24 NRH patients with a vascular lesion documented by computerized tomography were selected. In 19 cases the lesion was in the left hemisphere and in 5 cases in the right hemisphere. For 14 NRH patients, a RH subject with similar lesion, matched for age, education, length of illness, etiology (ischemic vs. hemorrhagic), and, when possible, sex was found. Presence and type of aphasia were compared in the two patients of the same pair and were found similar except for Pair 14; the RH subject had global aphasia and the NRH had conduction-like aphasia. Fifteen NRH patients were rehabilitated and reexamined at least 5 months after the first examination. Recovery of the 12 patients with a left-hemisphere lesion was compared with recovery of a group of RH subjects and no significant differences were found. Recovery of the three patients with right-hemisphere lesions is described. It is concluded that differences in type of aphasia and recovery between RHs and NRHs have been overemphasized in the past and must be reconsidered.

Adult↗

PubMed1989

Neuropsychological follow-up of patients operated for aneurysms of anterior communicating artery.

The neuropsychological outcome of 43 patients operated for ACoA aneurysms was assessed with a battery of 15 tests, tapping a wide spectrum of cognitive abilities. As a group ACoA aneurysms patients were impaired on 8 tests, including the three assessing memory. When however, patients falling below the cut-off point determined in normal controls were considered, 42% of the sample was unimpaired and only 35% fell on two or more tests. The analysis of single cases showed that memory was often affected, but short-term memory even more than long-term memory. In addition to the well known memory disorder, the patients showed a wide range of neuropsychological defects, including language and space functions. The hypotheses that could account for this broad-based neuropsychological impairment are discussed.

Follow-Up Studies↗

PubMed1989

Neuropsychological follow-up of patients operated for aneurysms of the middle cerebral artery and posterior communicating artery.

This study assessed with a neuropsychological battery the outcome of 27 patients operated on for an aneurysm of the Middle Cerebral Artery a mean of 35 months before, and of 27 patients operated for aneurysms of the Posterior Communicating Artery, a mean of 47 months before. Both groups showed a defective pattern of performance that was related to the hemispheric side of the aneurysm with left-sided patients impaired on naming, verbal fluency and verbal short-term memory and right sided patients on both short-term and long-term spatial memory and discrimination of line orientation. In single cases, the scope of neuropsychological impairment was sometimes wider than that expected only on the basis of the competence of the affected hemisphere.

Follow-Up Studies↗

PubMed1989

Neuropsychological outcome of patients operated upon for an intracranial aneurysm: analysis of general prognostic factors and of the effects of the location of the aneurysm.

One hundred and fourteen patients operated on for an intracranial aneurysm were followed up in order to investigate their neuropsychological outcome and to detect if there were any clinical features assessed around the time of operation that had prognostic significance. The neuropsychological examination evaluated language, apraxia, memory, intelligence and spatial ability. In the statistical analysis the overall severity of neuropsychological disorder was studied. "Late surgery timing" had a negative influence upon the neuropsychological outcome. There was not a difference between different aneurysm sites. Several patients with an apparently good clinical outcome showed neuropsychological deficits. Neuropsychological assessment is important in the evaluation of outcome after subarachnoid haemorrhage.

Adolescent↗

PubMed1988

Progressive language impairment without dementia: a case with isolated category specific semantic defect.

A patient is described with a 5 year progressive defect of naming and auditory verbal comprehension, the pathological nature of which was presumably degenerative. The auditory comprehension defect unevenly affected different semantic categories, and was particularly severe for the names of animals, fruits and vegetables. The patients showed loss of the verbal knowledge of the physical attributes of the concepts corresponding to the words he was unable to understand, and sparing of the verbal knowledge of the functional attributes. His performance was defective also on the colour-figure and sound-picture matching test.

Aged↗

PubMed1987

Verbal and spatial immediate memory span: normative data from 1355 adults and 1112 children.

Norms are provided for verbal and visuo-spatial immediate memory span, two tasks widely used in the clinical assessment of short-term memory and its neurological disorders. Data have been collected from 1355 male and female adult subjects, with various educational backgrounds and a 20-99 years age range. Span shows a major decrement after the late sixties and is affected by educational level. Male subjects score better on the spatial task. Data collected from 1112 male and female children, 4-to-10 year-old, show that span increases with age and boys score better on the spatial test.

Adult↗

PubMed1987

Problem solving ability in aging and dementia: normative data on a non-verbal test.

A non-verbal problem solving task, viz. a simplified version of Shallice's London Towers Test, was given to 131 normal subjects to obtain normative data relating to age, education and sex. The test was built up in its easiest possible feature in order to be administrable also to demented patients, therefore possibly becoming part of the neuropsychological diagnostic procedures of the demential syndromes. Although this version of the test proved to be very easy and therefore likely to yield a statistically treatable wide distribution of scores in demented patients, the age-related decline of performance in normals was apparent. Education and sex showed no significant influence on the test-performance. With correction of the raw scores for age and with knowledge of the distribution of scores in the normal population, this test is now ready to assess the normality of the scores of a new subject according to his age, giving information on this otherwise still uncovered sector of cognitive abilities.

Adult↗