Acalculia

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Brian Butterworth - One of the best experts on this subject based on the ideXlab platform.

  • Dexterity with Numbers: rTMS Over Left Angular Gyrus Disrupts Finger Gnosis and Number Processing
    Neuropsychologia, 2005
    Co-Authors: Brian Butterworth
    Abstract:

    Since the original description of Gerstmann's syndrome with its four cardinal symptoms, among which are finger agnosia and Acalculia, the neuro-cognitive relationship between fingers and calculation has been debated. We asked our participants to perform four different tasks, two of which involved fingers and the other two involving numbers, during repetitive transcranial magnetic stimulation (rTMS) over the posterior parietal lobe of either hemisphere. In the finger tasks, they were required to transform a tactile stimulus randomly delivered on one of their fingers into a speeded key-press response either with the same or with the homologous finger on the opposite hand. In the numerical tasks, they were asked to perform a magnitude or a parity matching on pairs of single digits, in the context of arithmetically related or unrelated numerical primes. In accordance with the original anatomical hypothesis put forward by Gerstmann [Gerstmann, J. (1924). Fingeragnosie: eine umschriebene Stoerung der Orienterung am eigenen Koerper. Wiener clinische Wochenschrift, 37, 1010?12], we found that rTMS over the left angular gyrus disrupted tasks requiring access to the finger schema and number magnitude processing in the same group of participants. In addition to the numerous studies which have employed special populations such as neurological patients and children, our data confirm the presence of a relationship between numbers and body knowledge in skilled adults who no longer use their fingers for solving simple arithmetical tasks. Since the original description of Gerstmann's syndrome with its four cardinal symptoms, among which are finger agnosia and Acalculia, the neuro-cognitive relationship between fingers and calculation has been debated. We asked our participants to perform four different tasks, two of which involved fingers and the other two involving numbers, during repetitive transcranial magnetic stimulation (rTMS) over the posterior parietal lobe of either hemisphere. In the finger tasks, they were required to transform a tactile stimulus randomly delivered on one of their fingers into a speeded key-press response either with the same or with the homologous finger on the opposite hand. In the numerical tasks, they were asked to perform a magnitude or a parity matching on pairs of single digits, in the context of arithmetically related or unrelated numerical primes. In accordance with the original anatomical hypothesis put forward by Gerstmann [Gerstmann, J. (1924). Fingeragnosie: eine umschriebene Stoerung der Orienterung am eigenen Koerper. Wiener clinische Wochenschrift, 37, 1010?12], we found that rTMS over the left angular gyrus disrupted tasks requiring access to the finger schema and number magnitude processing in the same group of participants. In addition to the numerous studies which have employed special populations such as neurological patients and children, our data confirm the presence of a relationship between numbers and body knowledge in skilled adults who no longer use their fingers for solving simple arithmetical tasks.

  • dexterity with numbers rtms over left angular gyrus disrupts finger gnosis and number processing
    Neuropsychologia, 2005
    Co-Authors: Elena Rusconi, Vincent Walsh, Brian Butterworth
    Abstract:

    Since the original description of Gerstmann's syndrome with its four cardinal symptoms, among which are finger agnosia and Acalculia, the neuro-cognitive relationship between fingers and calculation has been debated. We asked our participants to perform four different tasks, two of which involved fingers and the other two involving numbers, during repetitive transcranial magnetic stimulation (rTMS) over the posterior parietal lobe of either hemisphere. In the finger tasks, they were required to transform a tactile stimulus randomly delivered on one of their fingers into a speeded key-press response either with the same or with the homologous finger on the opposite hand. In the numerical tasks, they were asked to perform a magnitude or a parity matching on pairs of single digits, in the context of arithmetically related or unrelated numerical primes. In accordance with the original anatomical hypothesis put forward by Gerstmann [Gerstmann, J. (1924). Fingeragnosie: eine umschriebene Stoerung der Orienterung am eigenen Koerper. Wiener clinische Wochenschrift, 37, 1010–12], we found that rTMS over the left angular gyrus disrupted tasks requiring access to the finger schema and number magnitude processing in the same group of participants. In addition to the numerous studies which have employed special populations such as neurological patients and children, our data confirm the presence of a relationship between numbers and body knowledge in skilled adults who no longer use their fingers for solving simple arithmetical tasks.

  • dexterity with numbers rtms over left angular gyrus disrupts finger gnosis and number processing
    PERGAMON-ELSEVIER SCIENCE LTD (2005), 2005
    Co-Authors: Elena Rusconi, Brian Butterworth
    Abstract:

    Since the original description of Gerstmann's syndrome with its four cardinal symptoms, among which are finger agnosia and Acalculia, the neuro-cognitive relationship between fingers and calculation has been debated. We asked our participants to perform four different tasks, two of which involved fingers and the other two involving numbers, during repetitive transcranial magnetic stimulation (rTMS) over the posterior parietal lobe of either hemisphere. In the finger tasks, they were required to transform a tactile stimulus randomly delivered on one of their fingers into a speeded key-press response either with the same or with the homologous finger on the opposite hand. In the numerical tasks, they were asked to perform a magnitude or a parity matching on pairs of single digits, in the context of arithmetically related or unrelated numerical primes. In accordance with the original anatomical hypothesis put forward by Gerstmann [Gerstmann, J. (1924). Fingeragnosie: eine urnschriebene Stoerung der Orienterung am eigenen Koerper. Wiener clinische Wochenschrift, 37, 1010-12], we found that rTMS over the left angular gyrus disrupted tasks requiring access to the finger schema and number magnitude processing in the same group of participants. In addition to the numerous studies which have employed special populations such as neurological patients and children, our data confirm the presence of a relationship between numbers and body knowledge in skilled adults who no longer use their fingers for solving simple arithmetical tasks. (c) 2005 Elsevier Ltd. All rights reserved.

  • A SPECIFIC DEFICIT FOR NUMBERS IN A CASE OF DENSE Acalculia
    Brain, 1991
    Co-Authors: Lisa Cipolotti, Brian Butterworth, Gianfranco Denes
    Abstract:

    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.

Kyoung Min Lee - One of the best experts on this subject based on the ideXlab platform.

Alessandra Caporali - One of the best experts on this subject based on the ideXlab platform.

  • Spontaneous recovery from Acalculia.
    Journal of The International Neuropsychological Society, 2005
    Co-Authors: Anna Basso, Alessandra Caporali, P. Faglioni
    Abstract:

    : 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.

  • the natural course of Acalculia in left brain damaged patients
    Neurological Sciences, 2000
    Co-Authors: Alessandra Caporali, F Burgio, Anna Basso
    Abstract:

    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.

  • Acalculia aphasia and spatial disorders in left and right brain damaged patients
    Cortex, 2000
    Co-Authors: Anna Basso, F Burgio, Alessandra Caporali
    Abstract:

    The paper reports the performance of 50 left- and 26 vascular right-brain-damaged (LBD, RBD) patients in the EC301 Calculation Battery, which explores different aspects of number and calculation processing. All patients underwent a comprehensive neuropsychological testing that also included evaluation for the presence and type of aphasia in LBD patients, and of spatial disorders in RBD patients. LBD were subdivided in three groups: non-aphasic (NA), Broca and Wernicke aphasics. Results indicate that language and calculation disorders can dissociate. The relationship between spatial and calculation disorders in RBD patients is less clear. No significant difference was found between Broca and Wernicke aphasics, nor between NA and RBD patients. In the transcoding tasks (reading or writing to dictation numbers and number words, for instance) syntactic errors were the most frequent type of errors in all groups. They were also present when neither the input nor the required response was in the Arabic code, and a word-by-word strategy could have been used to read the number word or write a spoken number in the orthographic code.

Jamie I D Campbell - One of the best experts on this subject based on the ideXlab platform.

  • operand operator compatibility in cognitive arithmetic
    Canadian Journal of Experimental Psychology, 2012
    Co-Authors: Jamie I D Campbell, Jill Hrenyk
    Abstract:

    Adults' simple addition performance (e.g., 3 + 4 = ?) is faster, more accurate, and more often based on direct memory retrieval (rather than a procedural method, such as counting) when problems are presented in digit format (3 + 4) than written-word format (three + four). A possible explanation is that the mathematical symbol + is more compatible to memory retrieval with Arabic numerals than word numerals. To investigate this, two groups of 42 participants received eight blocks of 72 simple addition problems. For one group, operand format (digits or words) switched across trials within each block and operator (the symbol + or the word plus) alternated between blocks. For the other group, operator switched across trials, whereas operand format alternated between blocks. In the switch-format condition, compatible formats (e.g., 3 + 4, three plus four) were solved by direct memory retrieval more often than were incompatible formats (3 plus 4, three + four). There was no compatibility effect on use of direct memory retrieval when operand format was fixed within blocks and operator format switched across trials. There was also a reaction time (RT) advantage only for digit operands with + relative to plus when format switched, but + facilitated only word problems when operand format was blocked. The results indicate that operand- operator compatibility and format switching had previously unsuspected effects that qualify previous research examining format effects in arithmetic. Keywords: simple arithmetic, strategy choice, operand format This experiment investigated effects of numeral format (e.g., 3 + 4 vs. three + four) on adults' simple addition performance. Much research has demonstrated that adults' simple arithmetic with writtenword operands is substantially slower, more error prone, and relies more on procedural strategies (e.g., counting) than digit-format problems (see Campbell & Epp, 2005, for a review). Furthermore, these effects are often exaggerated for larger, more-difficult problems (e.g., 7 + 9) relative to small problems (3 + 2; e.g., Campbell & Alberts, 2009). The source of these effects has been the focus of considerable debate. Some researchers argue that format effects in arithmetic arise only during problem encoding or response stages (e.g., McCloskey & Macaruso, 1995; Noel, Fias, 8c Brysbaert, 1997; Sokol, McCloskey, Cohen & Aliminosa, 1991), whereas others propose format can directly affect retrieval or calculation processes (e.g., Bernardo, 2001; Blankenberger & Vorberg, 1997; Campbell, 1994; Campbell & Alberts, 2009; Campbell, Parker, & Doetzel, 2004). The majority of experiments that have compared simple arithmetic performance with digit and written-word operands have used a mathematical symbol (+, -, X, +) to identify arithmetic operation. As a result, the difficulty of the word-format condition might owe to the fact that it mixes two formats: The operands are in written-verbal format whereas the operator is a pictorial symbol (e.g., four + five). In contrast, the constituents of Arabic problems are all pictorial symbols (4 + 5). The performance advantage typically observed for the digit format might occur because the operands and operator are compatible and cohere as a compound retrieval cue, whereas a combination of written-words and symbol may be difficult to encode. Indeed, using compatible stimuli (e.g., 4X6, four times six), Sokol et al. (1991) found no difference between digit and word formats in the simple multiplication performance of two acalculic subjects. Another reason to suspect that operand- operator compatibility is potentially important is that solving simple arithmetic problems in spoken-word format is no more difficult than digit format when digits are presented sequentially to match spoken format (LeFevre, Lei, Smith-Chant, & Mullins, 2001; Metcalfe & Campbell, 2008). With spoken-word problems, the operands and operator are encoded phonologically and therefore do not involve inconsistent formats. …

  • integrated versus modular theories of number skills and Acalculia
    Brain and Cognition, 1991
    Co-Authors: James M Clark, Jamie I D Campbell
    Abstract:

    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.

Carlo Semenza - One of the best experts on this subject based on the ideXlab platform.

  • re assessing Acalculia distinguishing spatial and purely arithmetical deficits in right hemisphere damaged patients
    Cortex, 2017
    Co-Authors: Silvia Benavidesvarela, F Burgio, Laura Passarini, Francesca Meneghello, D Piva, Giuseppe Rolma, Carlo Semenza
    Abstract:

    Arithmetical deficits in right-hemisphere damaged patients have been traditionally considered secondary to visuo-spatial impairments, although the exact relationship between the two deficits has rarely been assessed. The present study implemented a voxelwise lesion analysis among 30 right-hemisphere damaged patients and a controlled, matched-sample, cross-sectional analysis with 35 cognitively normal controls regressing three composite cognitive measures on standardized numerical measures. The results showed that patients and controls significantly differ in Number comprehension, Transcoding, and Written operations, particularly subtractions and multiplications. The percentage of patients performing below the cutoffs ranged between 27% and 47% across these tasks. Spatial errors were associated with extensive lesions in fronto-temporo-parietal regions -which frequently lead to neglect- whereas pure arithmetical errors appeared related to more confined lesions in the right angular gyrus and its proximity. Stepwise regression models consistently revealed that spatial errors were primarily predicted by composite measures of visuo-spatial attention/neglect and representational abilities. Conversely, specific errors of arithmetic nature linked to representational abilities only. Crucially, the proportion of arithmetical errors (ranging from 65% to 100% across tasks) was higher than that of spatial ones. These findings thus suggest that unilateral right hemisphere lesions can directly affect core numerical/arithmetical processes, and that right-hemisphere Acalculia is not only ascribable to visuo-spatial deficits as traditionally thought.

  • right hemisphere spatial Acalculia and the influence of neglect
    Frontiers in Human Neuroscience, 2014
    Co-Authors: Silvia Benavidesvarela, Marco Pitteri, Konstantinos Priftis, Laura Passarini, Francesca Meneghello, Carlo Semenza
    Abstract:

    The present study aimed at exploring basic number and calculation abilities in right-hemisphere damaged patients (RHD), focusing primarily on one-digit orally presented tasks, which do not require explicit visuo-spatial abilities. Twenty-four non mentally-deteriorated RHD patients (12 with clinical neglect (RHDN+), 12 without clinical neglect (RHDN-)), and 12 healthy controls were included in the study. Participants were administered an ad hoc numerical battery assessing abilities such as counting, number magnitude comparison, writing and reading Arabic numerals and mental calculation, among others. Significant differences emerged among healthy controls and both the RHDN+ group and the RHDN- group, suggesting that the mathematical impairment of RHD patients does not necessarily correspond to the presence of left-neglect. A detailed analysis of the sub-tests of the battery evidenced expected differences among RHDN+ patients, RHDN- patients, and controls in writing and reading Arabic numerals. Crucially, differences between RHDN+ patients and controls were also found in tasks such as mental subtraction and mental multiplication. The present findings thus suggest that unilateral right hemisphere lesions may produce specific representational deficits that affect simple mental calculation, and not only the spatial arrangement of multi-digit written numbers as previously thought.

  • Acalculia from a right hemisphere lesion dealing with where in multiplication procedures
    Neuropsychologia, 2006
    Co-Authors: Alessia Grana, Riccardo Hofer, Carlo Semenza
    Abstract:

    The present study describes in detail, for the first time, a case of failure with multiplication procedures in a right hemisphere damaged patient (PN). A careful, step-by-step, error analysis made possible to show that an important portion of PN's errors could be better explained as spatial in nature and specifically related to the demands of a multi-digit multiplication. These errors can be distinguished from other types of errors, including those, expected after a right hemisphere lesion, determined by a generic inability to deal with spatial material, or from other deficits, like neglect, affecting cognitive capacities across the board. The best explanation for PN's problems is that he might have difficulties in relying on a visuo-spatial store containing a layout representation specific to multiplication. As a consequence, while knowing what, when and how to carry out the various steps, PN does not know where. What he may thus lack is a spatial schema of multiplication. Such schema is thought to help normal calculators in overcoming working memory demands of complex calculation by representing the information of where exactly each sub-step should be placed.