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Biomedical subjects

L Cipolotti

Publications and source records attributed to L Cipolotti.

At least 55 records · Page 3Linked to original sources
PubMed1996

Short-term memory impairment and arithmetical ability.

We document the dissociation of preserved calculation skills in a patient with impaired auditory short-term memory. The patient (MRF) had a memory span of three digits. Furthermore, he showed rapid decrement in performance of single digits and letters with both auditory and visual presentation in the Brown-Peterson forgetting task. Analysis of his calculation skills revealed a normal ability to solve auditorily presented multidigit addition and subtraction problems such as 173 + 68 and to execute the Paced Auditory Serial Addition Task (Sampson, 1956, 1958; Gronwall, 1977). In addition, his performance on other tests, including arithmetic manipulation of natural numbers, decimals and fractions, approximation, magnitude, ratio, and percentage, appeared to be normal (Hitch, 1978b). It is argued that these findings require a revision of Baddeley and Hitch's (1974) concept of the function of working memory.

Amnesia↗
PubMed1996

Word comprehension. The distinction between refractory and storage impairments.

We report a series of experiments in which we compare the residual word comprehension skills of patients with cortical degenerative conditions and those with an "access' dysphasia. Using word-picture matching tasks it was shown that (i) the presentation rate (the response-stimulus interval) affected the word comprehension performance of the patients with an access dysphasia but not of the patients with degenerative conditions; (ii) the semantic relatedness of the stimulus arrays had a greater influence in the performance of the access dysphasic patients than with a degenerative condition; (iii) word frequency was a strong determinant of the performance of patients with degenerative conditions but not those with an access dysphasia; and (iv) response inconsistency was a characteristic of the patients with an access dysphasia, whereas this was not observed in those with a degenerative condition. These four effects clearly differentiate the word comprehension performance of these two types of patients. Thus, two types of word comprehension impairment have been identified. A unitary account of the pattern of performance in the access patients in terms of refractoriness has previously been proposed and it is reiterated here. Similarly, a unitary account of the patients with degenerative conditions in terms of storage deficit is advanced. It is speculated that these two types of deficit, refractoriness and storage, reflect two sources of damage to the stored representations underpinning a word, rather than a dichotomy between deficits affecting the procedures of accessing semantic representations and the stored representations themselves. The implications for neurological diagnosis and therapeutic intervention are discussed.

Aged↗
PubMed1995

The isolation of calculation skills.

The unusual preservation of calculation skills in a patient with severe global aphasia is described. The implications for the relationship between numerical and language abilities are discussed.

Aphasia↗
PubMed1995

Selective impairment for simple division.

We report the case of a patient, C.B., with a calculation impairment. His performance on simple division problems was severely impaired while his performance on simple and complex addition, subtraction and multiplication problems was largely spared. The patient was also found to be impaired in solving simple arithmetical problems such as Nx? = M. The implications of these findings for the organization of arithmetical facts are discussed.

Brain Damage, Chronic↗
PubMed1995

Selective impairment in manipulating Arabic numerals.

This paper describes an acalculic patient (B.A.L.) with an unusual selective deficit in manipulating arabic numerals. The patient was unimpaired in reading aloud letters, words and written number names but unable to read aloud single arabic numerals. Furthermore, his ability to produce the next number in the sequence and his ability to produce answers to simple addition and subtraction was relatively spared when the stimuli were presented as number names but impaired when the stimuli were presented as arabic numerals. Using magnitude comparison tasks it was demonstrated that his knowledge of cardinal values of arabic numerals was preserved. His impairment in manipulating arabic numerals was interpreted in terms of a deficit in the connection between format specific number codes and the verbal numeral production system.

Agraphia↗
PubMed1995

Semantic memory and reading abilities: a case report.

We document the unexpected dissociation of preserved reading skills in a patient with severely impaired semantic memory. The common co-occurrence between impairment of word meaning and surface dyslexia has not been observed. The patient (hereafter called DRN) had marked naming and word comprehension difficulties. A strong word frequency effect was observed on tests of word comprehension but was absent in a test of word reading. DRN's ability to read both regular and exception words that he failed to comprehend was remarkably well preserved. We will argue that these findings provide further support for the independence of semantic and phonological processing.

Aged↗
PubMed1994

The accessibility of proper names.

In this paper we describe a patient with a severe global dysphasia who provides an example of a category specific access impairment. Using matching to sample techniques it was possible to demonstrate the selective preservation of her ability to comprehend proper nouns coupled with impaired comprehension of common nouns. It was found that for the object names category M.E.D. performed better on the first presentation of an item than she did on subsequent presentations. Her performance was also found to be affected by presentation rate and an analysis of her responses showed marked inconsistency when the same stimuli were administered more than once. This category specific access impairment suggests the relative independence of the cognitive mechanisms responsible for the access of different semantic categories.

Auditory Perception↗
PubMed1994

From "one thousand nine hundred and forty-five" to 1000,945.

A patient, D.M., with spared number reading and number comprehension was found to show a transient selective syntactic impairment in writing numbers to dictation. For example, when he heard "One thousand nine hundred and forty-five", he wrote 1000,945. These errors are explained in terms of a dissociation between the concatenation and overwriting rules in the model proposed by Power and Dal Martello (Lang. Cognit. Processes 5, 237-254, 1990).

Agraphia↗
PubMed1993

Attentional dyslexia: a single case study.

A single case study of an attentional dyslexic is reported. The patient B.A.L. was able to read single letters and single words presented in isolation without difficulty. However, his reading of prose was very disrupted and his ability to read rows of letters and words was significantly impaired. A "flanking" procedure, in which there was a single target item, flanked by other stimuli, was used in a series of experiments to analyse his dyslexic impairment. First it was established that his attentional deficit was specific to reading in so far as the patient did not have comparable difficulties with pictorial material. His performance in the flanking experiments was consistently impaired; and furthermore was unaffected by speed of presentation, the number of flanking stimuli, and the spatial arrangement of the flanking stimuli. The important exception was when the flanking stimuli were of a different category. There was no decrement in performance when target letters were flanked by words or when words were flanked by letters. This study both corroborates and extends the original account of attentional dyslexia (Shallice and Warrnington, Neuropsychologia 15, 31-41, 1977) in terms of a damaged "filter" mechanism controlling the transition from a parallel to a serial stage of reading processing. The categorical effects reported here indicate that such a filter must be post lexical and suggest further that there are multiple filters in the reading system.

Attention↗
PubMed1993

Spared written naming of proper nouns: a case report.

In this study we describe an investigation into the residual written word retrieval skills of M.E.D., a patient with a severe aphasia. M.E.D.'s performance on written naming and writing to dictation tasks showed a distinctive pattern of performance across semantic categories. The patient's ability to write the names of countries and famous people was consistently superior to her ability to write the names of objects. These results could be considered as indicative of a double dissociation in the proper nouns category, as there are already patients on record who have a selective deficit in retrieving proper nouns.

Anomia↗
PubMed1993

Evidence of multiple memory systems in the human brain. A [18F]FDG PET metabolic study.

Patients with global amnesia of different aetiologies (n = 11), and patients with probable Alzheimer's disease of recent onset and mild to moderate severity (n = 18) underwent extensive neuropsychological examination, which included the evaluation of multiple components of memory, and a measurement of regional cerebral glucose metabolism with [18F]fluoro-deoxyglucose ([18F]FDG) and PET. In the neuropsychological tests, both global amnesia and Alzheimer's disease patients had impaired episodic long-term memory, while deficits of short-term, semantic and implicit memory were present only in Alzheimer's disease. When local metabolic rates for glucose were compared with values from age- and education-matched normal controls, a common pattern of bilateral hypometabolism was present in the hippocampus, cingulate and frontal basal cortex of both global amnesia and Alzheimer's disease patients. On the other hand, significant hypometabolism was found in the thalamus in only global amnesia, and in the frontal, parietal and temporal associative cortex in only Alzheimer's disease. The results of a multivariate regression analysis of test scores with metabolic data indicated that different clusters of cerebral areas were associated with each of the main components of memory function. These data are in agreement with 'neural network' models of the neural basis of cognition, according to which complex functions are subserved by multiple interconnected cortical and subcortical structures.

Aged↗
PubMed1992

Reading aloud in jargonaphasia: an unusual dissociation in speech output.

A patient is described who showed several dissociations between oral and written language processing after bilateral retrorolandic vascular lesion. Dissociation was firstly between abolished auditory comprehension and preserved written comprehension and then involved confrontation naming, clearly superior in the written modality. The third striking dissociation involved oral output; spontaneous speech, although fluent and well articulated, consisted of neologistic jargon, while reading aloud was clearly superior though not perfect. Data are discussed with reference to a cognitive model of word processing. The pattern of dissociation in word production may be due to a failure in retrieving the phonological word form from the semantic system.

Aged↗
PubMed1991

A specific deficit for numbers in a case of dense acalculia.

In this study we investigated the acalculic condition of a patient, C.G., with the classical signs of Gerstmann's Syndrome: finger agnosia; right-left disorientation; a profound agraphia (but with an equally profound alexia) and a remarkably dense acalculia. Using a series of number processing and number knowledge tasks, a selective impairment for numbers was demonstrated. Within the category of numbers C.G. showed a largely preserved ability to deal with numbers below 4, in all tasks and in all modalities, while she was totally unable to deal with numbers above 4. The consistency of responses and the ineffectiveness of cueing indicated that numbers above 4 were lost, rather than hard to access. Further testing showed that this impairment did not result from a more general semantic memory problem, a difficulty in understanding quantities or a deficit in reasoning abilities thought to underlie the concept of numbers. Difficulty with some other ordinal structures was also present, but appeared unrelated to those affecting numbers.

Female↗
PubMed1990

Autobiographical memory loss and confabulation in Korsakoff's syndrome: a case report.

A patient with Korsakoff's syndrome is presented, who showed a selective loss of Autobiographical Memory along with a preserved Semantic Memory. Confabulations were a prominent feature. They only involved Autobiographical Memory and were persistent in time and consistent in content. The implications of these findings for understanding the nature of Autobiographical Memory impairment are discussed.

Alcohol Amnestic Disorder↗
PubMed1990

An unusual case of perseveration sparing body-related tasks.

A patient who, following left occipital and posterior callosal lesion, showed a massive pattern of perseveration with sparing of body related tasks is described. It is thought that such dissociation would reflect independence of body related tasks at the level of internal representation.

Aged↗
PubMed1989

When a patient can write but not copy: report of a single case.

A dissociation between spared spontaneous and impaired writing on copy is described in a patient with severe limb and constructional apraxia. Visual-perceptual abilities were normal as well as oral language and reading. The findings are discussed in the light of an information processing model of writing.

Aged↗
PubMed1989

Impairment in processing meaningless verbal material in several modalities: the relationship between short-term memory and phonological skills.

Phonological processing abilities were studied in a patient who, following focal brain damage, showed selective impairment in non-word reading, writing, and repetition and also a severe short-term memory (STM) deficit specific for auditorily presented verbal material. The patient could execute tasks involving phonemic manipulation and awareness perfectly. Our data, in contrast with earlier observations in a case of developmental phonological dyslexia, show that acquired impairment in non-word reading, writing, repetition, and immediate memory may occur despite good phonological processing abilities. The role of STM in processing meaningless verbal material is discussed.

Adult↗