Cognitive profile in dementia associated with vitamin B12 deficiency due to pernicious anaemia.
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Aged↗
Biomedical subjects
L Cipolotti
Publications and source records attributed to L Cipolotti.
Selective sparing of verb naming in a case of severe Alzheimer's disease.
A patient with severe Alzheimer's disease (AD) presented with a severe impairment in naming nouns but selective sparing of the naming of verbs. Her impairment in naming nouns was presented across a wide range of categories investigated. To our knowledge, this is the first case documenting the selective preservation of verb naming in a patient with AD. The implications for the notion of an intrinsic vulnerability of verb naming in AD and for the current knowledge of anatomical correlates of noun/verb processing are discussed.
Aged↗
Fractionation of visual memory: evidence from a case with multiple neurodevelopmental impairments.
It is known that the adult visual memory system is fractionable into functionally independent cognitive subsystems, selectively susceptible to brain damage. However, it is unclear whether these cognitive subsystems can fractionate developmentally. The present study describes an investigation of visual memory of a patient (PE) with multiple developmental disorders. PE was congenitally deaf, had Gilles de la Tourette syndrome and autism, with non-verbal ability in the normal range. The patient presented with a recognition memory impairment for unknown human faces. This contrasted with his superior recognition memory for unknown buildings, landscapes and outdoor scenes. PE's memory impairment for faces could not be explained by a general deficit in face processing. Interestingly, PE also showed a recognition memory impairment for animals. These findings indicate that different domains of the visual memory system can be fractionated developmentally. In particular, it demonstrates that topographical memory can develop independently from other aspects of visual memory.
Adult↗
Dynamic aphasia: an inability to select between competing verbal responses?
In this study we report a patient (A.N.G.) who, following a malignant left frontal meningioma impinging upon Brodmann area 45, presented a 'pure' dynamic aphasia. Her spontaneous speech was markedly reduced in the absence of any syntactical impairment. Her naming, repetition and reading skills were completely normal. Two experimental investigations were carried out. The first investigation found that A.N.G. had a profound impairment in phrase and sentence generation tasks given a verbal context. However, her verbal generative skills were normal when she was asked to describe pictorial scenes and complex actions. Moreover, it was found that A.N.G. had no difficulty ordering the constituent words of a sentence. Thus, it was concluded that her verbal planning skills were intact. The second investigation tested a hypothesis that dynamic aphasia is due to an inability to select a verbal response option whenever the stimulus activates many competing verbal responses. Predictions based upon this hypothesis were confirmed on three different verbal generation tasks. It was found that our patient's grave verbal generative impairment was present for tasks involving stimuli which activate many potential responses. However, it was absent for tasks involving stimuli which activate few or only a single 'prepotent' response. The findings are discussed with reference to traditional interpretations of dynamic aphasia and more general interpretations of prefrontal cortex functioning. On the basis of a computational model of prefrontal cortex functioning, we propose that pure dynamic aphasia may be caused by damage to a 'context' module containing units responsible for selection of verbal response options. Moreover, it is suggested that our findings support the view that Brodmann area 45 is involved in verbal response generation to stimuli which activate many potential response options.
Aphasia↗
Selective sparing of topographical memory.
The case of a 61 year old patient with Pick's disease involving predominantly the left temporal lobe, who has been studied over a 5 year period, is reported. She presented with a grave impairment of both verbal and non-verbal memory functions. Her non-verbal memory deficits included profound impairments on the recognition of unfamiliar faces and the recall of abstract designs. Remarkably, her visual recognition memory performance for unknown buildings, landscapes, and outdoor scenes was preserved. Strikingly, her ability to recall familiar routes and learn new ones through a complex virtual reality town was also entirely normal. This seems to be the first case documenting the selective preservation of topographical memory in the context of severe non-verbal and verbal memory impairments. These findings imply that topographical memory and non-verbal memory are subserved by separable neural systems.
Brain↗
Does recognizing orally spelled words depend on reading? An investigation into a case of better written than oral spelling.
In this study we describe an investigation into the residual spelling skills of a patient (BRK) with a deep dysgraphia. His written spelling was significantly superior to his oral spelling and he had grave difficulties in recognizing orally spelled words. In addition, his impairment in recognizing orally spelled words was qualitatively very similar to his difficulties in oral spelling. In contrast, he could read and repeat the stimuli he could no longer spell. It seems therefore that, recognizing orally spelled words is dependent on the same procedures used in spelling rather than in reading. It is argued that BRK's discrepancy between oral and written spelling reflects a deficit in accessing a letter name code which translates abstract graphemic representations into letter names. In addition, it is suggested that the letter name code has an additional synthesizing function that is involved both in checking self-generated oral spellings and in recognizing orally spelled words.
Aphasia, Wernicke↗
Topographical disorientation: selective impairment of locomotor space?
We report a single-case study of a patient who suddenly lost her ability to orient herself in her neighbourhood. On formal testing she demonstrated remarkably selective deficits in episodic and semantic memory of topographical items and rouse. Her general intellectual abilities were unaffected as were basic perceptual processes and episodic and semantic memory other than topography. We interpret her deficit as a further example of category-specific processing impairment affecting knowledge acquired through selective channels-in this case visuo-locomotor information.
Brain↗
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↗
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↗
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↗
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↗
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↗
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↗
Neuropsychological assessment.
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Brain Damage, Chronic↗
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↗
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↗
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↗
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↗