[Semeiologie aspects of acalculias. Considerations on a case of mixed acalculia].
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Aged↗
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[A case showing agraphia and acalculia with mild finger agnosia and right-left disorientation. With special reference to the acalculia in convalescence (author's transl)].
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Agnosia↗
Spontaneous recovery from acalculia.
A topic much considered in research on acalculia was its relationship with aphasia. Far less attention has been given to the natural course of acalculia. In this retrospective study, we examined the relationship between aphasia and acalculia in an unselected series of 98 left-brain-damaged patients and the spontaneous recovery from acalculia in 92 acalculic patients with follow-up. There was a significant association between aphasia and acalculia although 19 participants exhibited aphasia with no acalculia and six acalculia with no aphasia. We observed significant improvement between a first examination carried out between 1 and 5 months post-onset and a second examination carried out between 3 and 11 months later (mean: 5 months). The mechanisms of spontaneous recovery are discussed.
Adult↗
[Acalculia. Neurological bases, evaluation and disorders].
OBJECTIVE: To make a review of the literature on alterations in mathematical ability secondary to structural cerebral lesions. DEVELOPMENT AND CONCLUSIONS: We refer to the initial classification of acalculia of Berger (secondary acalculia when this is due to broader neuropsychological deficits and primary acalculia when it occurs alone) to the classical division of Hecaen (alexia and numerical agraphia with or without alterations in reading and writing of letters and words, visuo-spatial acalculia due to alterations in the spatial organization of multi-digit figures and the partial results of arithmetical operations, anarithmetia or primary failure in mathematical ability) and the most recent classifications based on neurocognitive models, which subdivide the acalculias into those secondary to changes in the system for processing numbers and those due to changes in the cognitive system for mathematics (McCloskey and Caramazza). Similarly, we review the correlations between the clinical changes in mathematics and the cerebral localization of the causative lesions (left parieto-temporal, right and including frontal and subcortical associative areas) together with the association of acalculia and other neuropsychological deficits. Finally we review the neuropsychological instruments available for the evaluation of acalculias, with particular reference to the tools validated and scaled for our language and sociocultural setting.
Agraphia↗
Pure global acalculia following a left subangular lesion.
We describe the case of a right-handed patient who presented a severe acalculia in the context of a pure Gerstmann syndrome following a subangular lesion that spared the left inferior parietal lobule (IPL). The patient showed impairments in Arabic and verbal codes, in number production and comprehension, as well as in numerical facts and problem solving. By using the EC301 calculation battery, semantic and syntactic tasks in Arabic and verbal codes, we tested the different hypotheses raised by the cognitive neuropsychological models of acalculia. The patients' difficulties, which were not associated with a general intellectual deterioration, and those affecting number processing as a particular semantic class, were indicative of a "global acalculia". This deficit, which exceeded the anarithmetia usually described in Gerstmann syndrome following left IPL lesion, suggested that the isolation of this area may constitute a sufficient condition for producing such a global acalculia. These results are discussed in terms of a disorder in the manipulation of mental images of spatially related objects.
Brain↗
[Diagnosis of disorders in dealing with numbers (acalculia)].
Disturbances in numeric skills (acalculia) often occur in adults following CNS damage. We present an examination procedure which assesses number-processing abilities as well as basic skills in calculation. Results of an investigation based on a unselected sample of brain-damaged adults (N = 52) show that numeric skills can be impaired in a variety of different ways. With our acalculia examination procedure it is possible to distinguish secondary forms of acalculia, which can only occur in combination with other neuropsychological disturbances, and primary acalculia, which cannot be explained as resulting from accompanying disturbances.
Adolescent↗
[Acalculia].
Acalculia is an acquired disturbance of calculation that has several clinical expressions. Disturbances cna be aphasic and nonaphasic. Further division is into alexia and agraphia for numbers, anarithmetria and spatial acalculia. In addition to these manifestations due to focal cerebral lesions also diffuse lesions can produce disturbance of calculia. Acalculia is also encountered as a developmental disturbance. Testing of acalculia has to encroach both oral and written calculations with clinical and standardized neuropsychological tests.
Aphasia↗
Isolated acalculia due to left parietal lesion.
OBJECTIVE: To clarify the characteristics and the localization of isolated calculation disturbances due to left parietal lesions. DESIGN: Case series. SETTING: Tertiary care hospital. PATIENTS AND OTHER PARTICIPANTS: Three referred patients with isolated calculation disturbances due to stroke in the left parietal region. Sixteen volunteers for age and education constituted the control group. OUTCOME MEASURES: Neuropsychological tests, including a battery of tests for acalculia and the Wechsler Adult Intelligence Scale, and magnetic resonance imaging were performed. RESULTS: Three patients made calculation errors in the process where a number of steps were carried out simultaneously. The patients showed no aphasic components in number operations. They understood the basic processes of calculation. They showed little difficulty in the retrieval of table values. The patients had no impairment in aligning arithmetic problems or in assigning and maintaining place-holding values. They did not show any deficit of immediate memory for calculation problems. Overlapping lesions were located along the left intraparietal sulcus. CONCLUSION: The area lying along the left intraparietal sulcus is critical for isolated parietal acalculia. The profile of isolated acalculia suggests that it results from the disruption of the working memory for calculation.
Brain Diseases↗
[Number processing and acalculia in dementia].
In this review, studies on number processing and calculation in demented patients are summarized. Single cases, group studies and our own examinations all show that acalculia is a frequent symptom of dementia and correlates with severity of dementia. While calculation and numeral transcoding deficits are often prominent in early courses of the disease, deficits in semantic processing and basic number processing are less severe. Still, single cases demonstrate that very specific dysfunctions in number processing and calculation can occur in dementia. In number transcoding, a characteristic error type occurs in demented patients that has not (or rarely) been described in other brain damaged people so far. In these "shift errors" or "intrusion errors" the wrong number code is used or the number codes are mixed (e.g. patients write "2hindert11" instead of zweihundertelf (two hundred eleven)). Due to the frequent occurence of acalculia in dementia and its specific features, it is suggested that acalculia should be integrated into the criteria for dementia and that number processing and calculation tests are used in the diagnosis of dementia.
Aged↗
Acalculia: historical development and current significance.
Acalculia is a loss of calculating abilities occurring as a result of cerebral damage. This paper reviews the development of the notion of acalculia from an expected concomitant of aphasia or dementia to that of a sometimes autonomous disorder. Current evidence indicates that acalculia tends to occur particularly in lesions of the left posterior hemispheric areas.
Aphasia↗
Integrated versus modular theories of number skills and acalculia.
This paper contrasts two views of the cognitive architecture underlying numerical skills and acalculia. According to the abstract-modular theory (e.g., McCloskey, Caramazza, & Basili, 1985), number processing is comprised of independent comprehension, calculation, and production subsystems that communicate via a single type of abstract quantity code. The alternative, specific-integrated theory (e.g., Campbell & Clark, 1988), proposes that visuospatial, verbal, and other modality-specific number codes are associatively connected as an encoding complex and that different facets of number processing generally involve common, rather than independent, processes. The hypothesis of specific number codes is supported by conceptual inadequacies of abstract codes, format-specific phenomena in calculation, the diversity of acalculias and individual differences in number processing, lateralization issues, and the role of format-specific codes in working memory. The integrated, associative view of number processing is supported by the dependence of modular views on abstract codes and other conceptual inadequacies, evidence for integrated associative networks in calculation tasks, acalculia phenomena, shortcomings in modular architectures for number-processing dissociations, close ties between semantic and verbal aspects of numbers, and continuities between number and nonnumber processing. These numerous logical and empirical considerations challenge the abstract-modular theory and support the encoding-complex view that number processing is effected by integrated associative networks of modality-specific number codes.
Humans↗
Acalculia and dyscalculia.
Even though it is generally recognized that calculation ability represents a most important type of cognition, there is a significant paucity in the study of acalculia. In this paper the historical evolution of calculation abilities in humankind and the appearance of numerical concepts in child development are reviewed. Developmental calculation disturbances (developmental dyscalculia) are analyzed. It is proposed that calculation ability represents a multifactor skill, including verbal, spatial, memory, body knowledge, and executive function abilities. A general distinction between primary and secondary acalculias is presented, and different types of acquired calculation disturbances are analyzed. The association between acalculia and aphasia, apraxia and dementia is further considered, and special mention to the so-called Gerstmann syndrome is made. A model for the neuropsychological assessment of numerical abilities is proposed, and some general guidelines for the rehabilitation of calculation disturbances are presented.
Animals↗
[Acalculia: its classification, aetiology and clinical management].
AIM: To carry out a review of the literature on the different neurological mechanisms involved in processing calculations, the injuries to brain structure that can result in acalculia and the clinical management of these patients. Development and conclusions. Acalculia is defined as the disorder affecting the ability to calculate that is acquired as the result of a brain injury. Despite being a frequent symptom and its association to numerous systemic and neurological diseases, no clear study protocol exists due to the fact that, first, it is usually accompanied by other, more important neurological symptoms and, second, it occurs in a very heterogeneous population, where clear differences can be seen according to the sociocultural level of the patient. Acalculia has been associated both to general alterations of the central nervous system and to others affecting local structures. Perhaps the most striking example of the former is the case of dementias, where it has even been suggested that it could be an early sign of Alzheimer's disease. With respect to the latter, the most notable are those affecting the left parietal lobe. In this article the following are discussed: 1) the different classifications that have been developed for the loss of the ability to calculate; 2) the involvement of the different structures of the nervous system in numeric processing, based on the associated structural lesions and on studies that have been conducted using functional tests and brain imaging; and 3) the different neuropsychological instruments that are available to study this capacity.
Brain↗
The natural course of acalculia in left-brain-damaged patients.
Acalculia is a frequent disorder in left-brain-damaged patients but nothing is known about its natural course. We report a study on 51 vascular acalculic patients examined at least twice. Our results indicate that recovery from acalculia is possible in the first months post-stroke, that initial severity does not significantly influence recovery, and that it correlates with recovery of auditory comprehension.
Adult↗
Acalculia: an historical review of localization.
This article reviews the brain localization of calculation disorders (acalculia) beginning with Gall's claim in the early 19th century for a "center" of calculation. A renewed interest in the subject arose around the time of Henschen during the first quarter of the 20th century. A summary of the cases of acalculia since Henschen leads to the conclusion that regardless of the functional modular nature of calculation ability, there is neither a localized region nor a specific hemisphere uniquely underlying the disorder.
Brain↗
Acalculia: an fMRI study with implications with respect to brain plasticity.
We report the case of a 44-year-old right-handed man with severe acalculia and 4 normal age-matched controls. The acalculia patient had magnetic resonance findings of a wedge shaped defect in the left posterior temporal-parietal cortex, involving the angular gyrus, and a lacunar infarct of the right thalamus. Functional magnetic resonance exams were performed utilizing four tasks consisting of serial subtracting by sevens, basic calculation, complex calculation, and abstract calculation. Both patient and controls showed specific task-related activation with some differences that may indicate brain plasticity, even though no significant recovery in calculations abilities was observed in the patient.
Adult↗
Agraphia and acalculia after a left prefrontal (F1, F2) infarction.
A patient presented with agraphia and acalculia associated with a left frontal (F1, F2) infarction. He made mainly phonological but also lexical errors in writing (syllabograms), but his ability to write kanji (morphograms) was relatively preserved. Although he could add and subtract numbers, he could neither multiply nor divide them because of a difficulty in retrieving the multiplication tables and calculation procedures. Positron emission tomography showed decreased cerebral blood flow and metabolism limited to the infarct site. These findings suggest that agraphia and acalculia may occur associated with a left prefrontal lesion, and that the retrieval of arithmetic processes is modality specific.
Agraphia↗
[The problem of acalculia: a study of a case].
1)The Authors describe a case of acalculia and emphasize some peculiar aspects, the study of which was facilitated by being the patient a mathematics teacher. 2) The patient was unable to perform arithmetic operations (addition and subtraction) but was able to carry our more complex and algebric operations. The acalculia was associated with constructional apraxia. 3) These findings are discussed and the hypothesis is suggested that simple mental arithmetic calculations need spatial operations which are not required for more complex mathematical reasoning and that the ability for calculation may decline by the very same progression, one level after the other, as the language.
Brain Diseases↗