Language Disorder in a Child with Early Left Thalamic Lesion

The present paper describes two patients, AB and FS, whose deficit in transcoding verbal to Arabic numerals was greatly affected by the format of the input. Despite intact comprehension of written verbal numerals and otherwise intact production of Arabic numerals they both transcode inefficiently the former into the latter. Yet, their ability to write the same Arabic numerals on dictation was fully preserved. Moreover, in both patients’ performance, a systematic error pattern emerged reflecting the influence of the lexico-syntactic structure of the input numerals in the transcoding processes. Current models of number transcoding may not easily account for this pattern of dissociation without postulating different code-dependent pathways for verbal to Arabic transcoding. Within a more parsimonious approach, it is tentatively suggested that spoken and written verbal codes activate with different efficiency the same transcoding algorithm.     

Writing and rewriting arabic numerals: dissociated processing pathways?

The present paper describes two patients, AB and FS, whose deficit in transcoding verbal to Arabic numerals was greatly affected by the format of the input. Despite intact comprehension of written verbal numerals and otherwise intact production of Arabic numerals they both transcode inefficiently the former into the latter. Yet, their ability to write the same Arabic numerals on dictation was fully preserved. Moreover, in both patients' performance, a systematic error pattern emerged reflecting the influence of the lexico-syntactic structure of the input numerals in the transcoding processes. Current models of number transcoding may not easily account for this pattern of dissociation without postulating different code-dependent pathways for verbal to Arabic transcoding. Within a more parsimonious approach, it is tentatively suggested that spoken and written verbal codes activate with different efficiency the same transcoding algorithm.     

Dissociating Arabic Numeral Reading and Basic Calculation: A Case Study

This study is about JS, a patient who suffered from anomia, phonological dyslexia and severe writing problems following a left hemispheric stroke. He showed good arabic numeral comprehension as evidenced in number-comparison tasks, but impairment in transcoding arabic numerals into verbal numbers and verbal numbers into arabic numerals. Although JS had several operand reading errors, the four arithmetic operations were not affected. In calculations with arabic numerals, he produced the correct results both in oral and written responses. For instance, when presented with the multiplication “7×3”, JS read the operation as “four times five”, but provided the correct response orally “twenty one” and written “21”. This behavior goes against those hypotheses which posit that multiplication facts are verbally-based, and those which establish the same route for verbal number production in calculation and arabic numeral reading.     

Dissociating arabic numeral reading and basic calculation: a case study

This study is about JS, a patient who suffered from anomia, phonological dyslexia and severe writing problems following a left hemispheric stroke. He showed good arabic numeral comprehension as evidenced in number-comparison tasks, but impairment in transcoding arabic numerals into verbal numbers and verbal numbers into arabic numerals. Although JS had several operand reading errors, the four arithmetic operations were not affected. In calculations with arabic numerals, he produced the correct results both in oral and written responses. For instance, when presented with the multiplication "7 x 3", JS read the operation as "four times five", but provided the correct response orally "twenty one" and written "21". This behavior goes against those hypotheses which posit that multiplication facts are verbally-based, and those which establish the same route for verbal number production in calculation and arabic numeral reading.     

Treating number transcoding difficulties in a chronic aphasic patient

Background : Number transcoding comprises the ability to read and write Arabic numerals and number words. Although number transcoding and counting are frequently impaired in aphasic patients, little attention has been given to the development of specific treatment methods and the evaluation of their efficiency. We report the treatment of the chronic aphasic patient PK who had severe difficulties in reading Arabic numerals. Number words could only be produced with an automatic counting strategy, always beginning with one. Aims : The therapy study was aimed at examining whether PK's numeral transcoding abilities could be improved by an intensive remediation programme that comprised tasks in which Arabic numerals had to be transcoded into number words. Methods & Procedures : Treatment consisted of specific training blocks of gradually increasing complexity. Therapy started with reading one-digit Arabic numerals, followed by teens, decades, and two- to five-digit numerals, which were divided into different subgroups according to complexity. Outcomes & Results : After an 8-week therapy period significant improvement in the processing of one- to five-digit numbers was observed. PK was able to read 49.4% of the Arabic numerals as compared to 2.2% before treatment. Performance was influenced significantly by number length and number word structure. Transcoding abilities improved remarkably for two- and three-digit numbers containing a zero or ending with two zeros. Stability of the treatment effects was assessed in a follow-up study 6 months after termination of the treatment programme. PK was still able to read 48.3% of the Arabic numerals successfully. Conclusions : In a single-case study of patient PK, suffering from chronic severe aphasia that was also characterised by severe transcoding and calculation impairments it could be demonstrated that these transcoding problems could be remedied to a substantial degree when employing a carefully graded intensive retraining programme for Arabic number naming.     

Remediation of arabic numeral processing in a case of developmental dyscalculia

In this case study we investigated numeral transcoding in CM, a young man with developmental dyscalculia. Our initial assessment revealed that CM's difficulties in numeral transcoding occurred mainly on tasks requiring the production of Arabic numerals. His errors on these tasks were most often syntactically ill-formed strings in which the basic lexical elements are retained, but the overall structure is incorrect (e.g. nine hundred two thousand seventy → 92,70). We then implemented a training programme designed to overcome CM's syntactic impairment. Pre-training/post-training comparisons revealed significant improvement on the trained written-verbal-to-Arabic task as well as on an untrained spoken-verbal-to-Arabic task presumed to share the same Arabic numeral production process. A comparison of CM's numeral transcoding performance with control children showed that CM's performance improved from a third-grade level to approximately a fourthgrade level (i.e. the grade in which most children begin to display proficient number transcoding skills). Further analyses revealed that the syntactic errors produced by CM and the control subjects were inconsistent in terms of length, a finding that contrasts with the results of previous studies of numeral transcoding in children. In the general discussion we mention possible reasons for the discrepant outcomes across studies.     

The neural origin of the priming distance effect: Distance‐dependent recovery of parietal activation using symbolic magnitudes

Numerical magnitudes are known to be processed in areas around the intraparietal sulci of the brain. We used an fMRI‐adaptation paradigm to investigate how they are actually coded at the neural level. In a number identification task, we manipulated the numerical distance between prime and target numbers (same, close, and far pairs) and their symbolic notation (Arabic and verbal numerals). We show that bilateral parietal activations present a distance‐dependent recovery of activation positively correlated with the distance between primes and targets: the larger the prime‐target distance, the higher the recovery of activation. Importantly, this effect is only present for trials where an Arabic numeral precedes a verbal numeral and not the reverse. Together, these findings reveal the neural origin of the behavioral priming distance effect and demonstrate that the relative importance of the semantic and nonsemantic pathways in a dual‐route model of number processing is modulated by symbolic notation. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.     

Intrusion errors in numerical transcoding by Alzheimer patients

The errors made by brain-damaged patients when they attempt numerical transcoding tasks have recently been considered as a possible aid to early diagnosis of the disease. The transcoding errors of 20 Alzheimer's disease patients are described, and the incidence of each kind of error compared with norms from healthy subjects. Tegnér and Nyb?ck (Tegnér R, Nyb?ck H. "To hundred and twenty4our": a study of transcoding in dementia. Acta Neurologica Scandinavia 1990; 81: 177-178) reported that Alzheimer patients often express numerical information in a mixture of verbal and digital codes and Kessler and Kalbe (Kessler J, Kalbe E. Written numerical transcoding in patients with Alzheimer's disease. Cortex 1996; 32: 755-761) suggested that such intrusions of the source code into the target code may not only be largely absent from the responses of the healthy population, but also from the transcoding operations of patients with other kinds of brain damage, such as aphasia. It was found that intrusion errors occurred much more frequently in the transcoding protocols of some of the Alzheimer patients than they do in those of healthy subjects. On the other hand, they were entirely absent from the protocols of other Alzheimer patients. The implications of the findings for the early diagnosis of Alzheimer's disease are discussed, and the phenomenon of intrusion errors is considered in terms of some of the models of arithmetical processing that have been proposed.     

Number representation deficit: a bilingual case of failure to access written verbal numeral representations

This study reports the case of a Greek–German bilingual patient (S.V.) with specific deficit in Arabic number production from written German number words. S.V. was able to successfully complete the reverse task, i.e. to convert Arabic numerals into written or oral German number words. She also showed preserved ability to produce both German and Greek numbers and to accurately make oral magnitude judgments in both languages. However, when transcoding two-digit numbers from German written numerals to Arabic numbers she consistently reversed the digits. A series of in-house tasks were used to test her general abilities of number processing, i.e. number synesthesia and calculation. Moreover, a number magnitude comparison task was developed specifically for pairs of numbers with reverse digits and we found that out of pairs of numbers with reverse digits with magnitude less than 100, there exist 19 pair combinations for which distance and relative distance are not concordant. The results suggest that S.V.’s performance was significantly worse as the absolute distance between the numbers in the number pairs increased. These investigations are discussed in analogy with a grammatical rule problem related to absolute and relative distance effects.     

Cerebral networks for number processing: Evidence from a case of posterior callosal lesion

Abstract

We report a study of number processing in a patient with a lesion selectively destroying the posterior half of her corpus callosum. This case provided an opportunity to study the cerebral distribution of numerical abilities across hemispheres, and their interhemispheric communication pathways. Tasks of interhemispheric same-different judgement with digits and sets of dots showed that exact digit identity could not be transferred between hemispheres, but that some approximate magnitude information could. With arabic numerals presented in the left visual field, reading aloud and arithmetic were severely impaired. In contrast, larger-smaller magnitude comparison was spared. With right-visual-field stimuli, the patient's performance was essentially normal in reading aloud, arithmetic and number comparison. These findings lend support to the hypothesis that both hemispheres are capable of identifying arabic digits, and of accessing and comparing the corresponding magnitudes. However, the verbal abilities which underlie overt naming and arithmetic computations are available only to the left hemisphere.     

Assessment of calculation and number processing using the EC301 battery: cross-cultural normative data and application to left- and right-brain damaged patients.

To provide referential normative data on simple tasks dealing with number processing and calculation which could be used in clinical investigations, 551 normal volunteers aged between 18 and 69 years from France and Belgium (n = 180). Italy (n = 212) and Germany (n = 159). performed the 31 tasks which constitute the EC301 calculation and number processing battery. Differences between countries were significant for 16 tasks and a Gender x Education interaction was observed for some tasks, with men performing better than women among subjects with low education only. To present an overview of preserved and impaired calculation and number processing abilities in left-brain damaged (LBD) aphasic patients and right-brain damaged (RBD) nonaphasic patients, the 31 subtests of the EC301 battery were proposed to 80 patients with cerebrovascular accident, 56 left and 24 right, for most cases in the territory of the middle cerebral artery. LBD aphasic patients showed low performance on oral and alphabetical spoken verbal and written verbal counting, transcoding when a written code was involved, and mental or written calculation; but relatively good performance at finding the number of elements in small sets, comparing numbers written in the Arabic digital code and placing correctly numbers on an analogue number line. The lowest performances of RBD patients were observed for estimation tasks and for placing a number on a scale. Results and their implications for further research are discussed according to the present information processing and anatomofunctional models of calculation and number processing.     

Characteristics of number transcoding errors of Chinese- versus English-speaking Alzheimer's disease patients

ABSTRACT

Number processing disorder is an acquired deficit in mathematical skills commonly observed in Alzheimer’s disease (AD), usually as a consequence of neurological dysfunction. Common impairments include syntactic errors (800012 instead of 8012) and intrusion errors (8 thousand and 12 instead of eight thousand and twelve) in number transcoding tasks. This study aimed to understand the characterization of AD-related number processing disorder within an alphabetic language (English) and ideographical language (Chinese), and to investigate the differences between alphabetic and ideographic language processing. Chinese-speaking AD patients were hypothesized to make significantly more intrusion errors than English-speaking ones, due to the ideographical nature of both Chinese characters and Arabic numbers. A simplified number transcoding test derived from EC301 battery was administered to AD patients. Chinese-speaking AD patients made significantly more intrusion errors (p = 0.001) than English speakers. This demonstrates that number processing in an alphabetic language such as English does not function in the same manner as in Chinese. The impaired inhibition capability likely contributes to such observations due to its competitive lexical representation in brain for Chinese speakers.     

The role of the temporal lobe semantic system in number knowledge: evidence from late-stage semantic dementia

Previous reports have demonstrated that many aspects of number knowledge remain unimpaired in semantic dementia, despite severe comprehension problems in other domains. It is argued that this advantage for numbers arises because the disease spares the parietal lobe magnitude system thought to be critical for number processing. Models of numerical cognition that favour a separation between verbal and magnitude representations of number might, however, predict a restricted impairment of the verbal number code in this condition. We obtained support for this hypothesis in a patient with late-stage semantic dementia. She was impaired at a variety of tasks tapping the verbal number code; for example, reading and writing Arabic numerals, naming and word-picture matching with dot pictures, reading aloud number words, digit span and magnitude comparison/serial ordering tasks with number words. In contrast, she demonstrated good understanding of the magnitude and serial order of numbers when tested with Arabic numerals and non-symbolic representations. These findings suggest that although the magnitude meaning of numbers is isolated from the temporal lobe semantic system, the anterior infero-temporal lobe may play a critical role in binding English number words to their non-symbolic magnitude meaning.     

Number processing in pure alexia: The effect of hemispheric asymmetries and task demands

Abstract

The relative sparing of arabic numerals, in patients who fail to read words or even letters, is a classical feature of pure alexia originally observed by Dejerine (Comptes Rendus des Seances de la Societé de Biologie 1892; 4: 61–90). We report a study of number processing abilities in two patients suffering from typical pure alexia. Our main finding was that number identification performance varied considerably with task demands. Both patients could name pairs of digits, when they were engaged in a simple naming task or for the purpose of magnitude comparison. In contrast, they frequently misidentified the very same digits when treating them as the components of multidigit numerals, or as the operands of addition problems. With two-digit numerals, a similar dissociation was shown between excellent comparison and severely impaired reading aloud. Finally, the variation of performance with task demands was shown not to prevail with spelled-out numerals. These findings confirm that some patients with pure alexia are able to process up to a semantic level symbolic stimuli that they cannot read aloud. We speculate that both hemispheres possess effective digit identification abilities, which are differentially called on depending on the task.     

"Progressive acalculia": a variety of focal degenerative atrophy affecting number processing

A 72-year-old man experienced increasing difficulties in calculating and processing numbers. He made many syntactic errors when he read and wrote numbers, both in arabic and number-word forms. Transcoding between arabic numerals and number-words was severely impaired. His calculation abilities were grossly impaired. He could not perform even simple multiplications, but additions and subtractions were preserved. He was unable to recite multiplication tables or the alphabet. In contrast, numerosity judgment, magnitude comparisons,and semantic evaluation of numbers were intact. The patient's deficit could be summarized as an Impairment in all tasks involving numbers in a verbal format, corresponding to the so-called "verbal anarithmetia'." It was noteworthy that verification of operations, including multiplications, was accurately performed. For example, the patient could not solve a multiplication like 8 x 9, but could estimate that 9 x 2=1 1 was closer to the exact result than 9 X 2=17, or could state that 8 x 2=16 was exact even though, at the same time, he expressed verbally the terms of the corresponding addition "eight plus two is ten." Other cognitive deficits were detected by neuropsychological tests which demonstrated mainly anomic aphasia, dysorthographic agraphia without alexia, impairment of short term and episodic memory, digital agnosia. However, the patient could not be considered to have demon-eti due to preserved self-sufficiency, except for tasks requiring calculation abilities. During the two years of follow-up, the impairment in processing numbers and calculation remained predominant over other deficits. Cerebral MRI showed an atrophy of the left temporal and parietal lobes, and SPECT study showed a reduction of regional cerebral blood flow of the left hemisphere. This original clinical presentation of a cerebral degenerative disease could be described as "primary progressive acalculia" whatever the underlying primary pathological process.     

Encoding, memory, and transcoding deficits in Childhood Apraxia of Speech

A central question in Childhood Apraxia of Speech (CAS) is whether the core phenotype is limited to transcoding (planning/programming) deficits or if speakers with CAS also have deficits in auditory-perceptual encoding (representational) and/or memory (storage and retrieval of representations) processes. We addressed this and other questions using responses to the Syllable Repetition Task (SRT) [Shriberg, L. D., Lohmeier, H. L., Campbell, T. F., Dollaghan, C. A., Green, J. R., & Moore, C. A. (2009). A nonword repetition task for speakers with misarticulations: The syllable repetition task (SRT). Journal of Speech, Language, and Hearing Research, 52, 1189-1212]. The SRT was administered to 369 individuals in four groups: (a) typical speech-language (119), (b) speech delay-typical language (140), (c) speech delay-language impairment (70), and (d) idiopathic or neurogenetic CAS (40). CAS participants had significantly lower SRT competence, encoding, memory, and transcoding scores than controls. They were 8.3 times more likely than controls to have SRT transcoding scores below 80%. We conclude that speakers with CAS have speech processing deficits in encoding, memory, and transcoding. The SRT currently has moderate diagnostic accuracy to identify transcoding deficits, the signature feature of CAS.     

Rehabilitation of number processing and calculation skills

The main purpose of this article is to present the research that has been done on the rehabilitation of number and calculation disorders. It is argued that theoretically based rehabilitation of arithmetical processing requires the formulation of a detailed functional diagnosis based on a theoretically driven evaluation of numerical processing and calculation skills. Up to now, the strategies that have been adopted in this rehabilitation field have mainly consisted in attempts to re-teach lost knowledge via extensive practice. These therapeutic programmes are described in two domains: the transcoding of numerals and the retrieval of arithmetical facts. Finally, the authors underline the necessity to develop in the near future programmes of rehabilitation adopting a more ecological perspective.     

Encoding,memory, and transcoding deficits in Childhood Apraxia of Speech

A central question in Childhood Apraxia of Speech (CAS) is whether the core phenotype is limited to transcoding (planning/programming) deficits or if speakers with CAS also have deficits in auditory-perceptual encoding (representational) and/or memory (storage and retrieval of representations) processes. We addressed this and other questions using responses to the Syllable Repetition Task (SRT) [Shriberg, L. D., Lohmeier, H. L., Campbell, T. F., Dollaghan, C. A., Green, J. R., & Moore, C. A. (2009). A nonword repetition task for speakers with misarticulations: The syllable repetition task (SRT). Journal of Speech, Language, and Hearing Research, 52, 1189–1212]. The SRT was administered to 369 individuals in four groups: (a) typical speech–language (119), (b) speech delay–typical language (140), (c) speech delay–language impairment (70), and (d) idiopathic or neurogenetic CAS (40). CAS participants had significantly lower SRT competence, encoding, memory, and transcoding scores than controls. They were 8.3 times more likely than controls to have SRT transcoding scores below 80%. We conclude that speakers with CAS have speech processing deficits in encoding, memory, and transcoding. The SRT currently has moderate diagnostic accuracy to identify transcoding deficits, the signature feature of CAS.     

Transcoding and calculation in aphasia

Aphasia may have deteriorating effects on several numerical skills, such as counting, reading numerals aloud, or writing them to dictation, as these abilities rely on intact language. However, aphasia also seems to have specific effects on the calculation system. Group studies, as well as single-case studies, point to the fact that language-impaired patients have particular difficulties in completing multiplication tasks, while other operations are less impaired. From a theoretical point of view, there is still a debate as to whether this association reflects a general psycholinguistic problem, the effect of aphasia on numerical cognition, or a deficit in non-specific resources underlying both number and language domains. In studies on number transcoding multi-route models have been proposed which parallel semantic and asemantic routes in alphabetical processing. Yet, the review of the empirical evidence suggests that these models still lack relevant theoretical specification.     

Severe degenerative cortical and cerebellar atrophy and progressive dementia in a young adult

Abstract

A 32-year-old patient is described who presented with severe cognitive deficits and major cortical and cerebellar atrophy. Investigations included numerous clinical laboratory tests, magnetic resonance imaging, [¹⁸F]2-fluoro-2-deoxy-D-glucose positron emission tomography and detailed neuropsychological examinations. Tests covered mood, intelligence, attention and concentration, language, verbal fluency, various memory abilities, and cognitive flexibility. Furthermore, some experimental testing procedures were applied, such as drawing objects, and transcoding verbal and Arabic numerals. Laboratory findings failed to give any indication for viral, bacterial, genetic or metabolic diseases, or for chronic intoxication. In particular, no presenilin genes were found. Neuroradiology revealed very severe cortical and less severe cerebellar degeneration. In most neuropsychological tests, the patient was greatly impaired. In spite of some inconsistencies at the anatomical and cognitive levels, it is concluded that, in spite of his young age, the patient suffered from an unusual from of Alzheimer's disease.