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.     

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.     

Selective impairment for reading numbers and number words: a single case study

The article reports the case of a patient who showed a selective inability in reading multi-digit numbers following recovery from aphasic disorders. Although his ability to read words, non-words, syntagms and sentences was almost preserved, he made errors with Arabic numerals and number words. Different types of errors with alphabetic material were also observed: he made only rare phonological substitutions with linguistic stimuli, whereas errors were almost always lexical in reading number words. A series of experiments showed that his ability to access number semantics was intact. In contrast, he selectively failed in all production tasks (including calculation), but only when the required response was in the oral output modality. This pattern was interpreted in terms of a selective deficit to the spoken number name production system. Furthermore, the different types of errors made with alphabetic materials belonging to the two classes of stimuli (numerical versus non-numerical) further support the hypothesis of a categorical organisation in the lexical-semantic system.     

Deafness for the meanings of number words

We describe the performance of an aphasic individual who showed a selective impairment affecting his comprehension of auditorily presented number words and not other word categories. His difficulty in number word comprehension was restricted to the auditory modality, given that with visual stimuli (written words, Arabic numerals and pictures) his comprehension of number and non-number words was intact. While there have been previous reports of selective difficulty or sparing of number words at the semantic and post-semantic levels, this is the first reported case of a pre-semantic deficit that is specific to the category of number words. This constitutes evidence that lexical semantic distinctions are respected by modality-specific neural mechanisms responsible for providing access to the meanings of words.     

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.     

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.     

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.     

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.     

The writing of arabic numerals,kanji, and kana in brain-damaged patients

This study investigated the neural mechanisms involved in the writing of Arabic numerals, kanji, and kana. Tasks involving writing numerals in Arabic, kanji, and, kana were administered to four patients with Gerstmann's syndrome and to five Wernicke aphasics. The results indicated that the ability to write Arabic numerals was well preserved in the Wernicke aphasics despite their serious phonological disturbances. The patients with Gerstmann's syndrome, who have a deficit with the concept of number, could write kanji numerals better than Arabic and kana numerals. Unlike Arabic numerals (ideogram) and kana (syllabogram), kanji (morphogram) have both semantic and phonetic values. The results suggested that Arabic numerals may be somesthetic and linked directly to the concept of number bypassing phonological analysis.     

Code-dependent pathways for number transcoding: evidence from a case of selective impairment in written verbal numeral to arabic transcoding

This article presents a brain-damaged patient (RR) suffering from cognitive deficits following neurological insults, who showed a selective impairment in number transcoding. Except for written verbal numeral to arabic transcoding, his ability to transcode numerals, including writing arabic numerals to dictation, is largely preserved. Other number processing skills, including numeral recognition, numeral comprehension, and calculation, were unimpaired. Semantic and asemantic models of number processing cannot easily account for the patient's performance and it is suggested that the number transcoding system should include different code-dependent pathways for arabic transcoding from spoken verbal numerals and from written verbal numerals. Since the errors produced in the impaired transcoding rely upon the syntactical structure of numeral stimuli, it is also proposed that transcoding code-dependent pathways should reflect the structure of the verbal numeral system, especially the difference between sum and product relationships.     

Door but not four and 4 a category specific transcoding deficit in a pure acalculic patient

We report a left parietal damaged, acalculic, non aphasic patient who showed a specific deficit in reading Arabic and spelled-out numerals. Word reading was flawless, while he showed a severe impairment in reading meaningless strings of phonemes (phonological alexia). He also showed a dissociation between the preserved ability to retrieve knowledge about general facts and the impairment in retrieving cardinal, personal and non-personal numerical facts. These findings point to a separate organization in the brain of the numerical domain.     

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.     

Acalculia, aphasia and spatial disorders in left and right brain-damaged patients

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.     

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.     

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.     

Wernicke's and global aphasia without alexia.

It has been proposed that the comprehension of written language requires transcoding from the visual (grapheme) to the auditory (phoneme). It has also been proposed that visual word images can be comprehended without grapheme-phoneme transcoding. We describe three aphasic patients with left hemisphere impairment who had poor speech comprehension but could comprehend written language. One of these patients had a subsequent right hemisphere lesion and lost his ability to read. We propose that the right hemisphere in some individuals may be capable of extracting semantic information from iconic images (ideogram) without phonological processing.     

Genetics and mathematics: evidence from Prader-Willi syndrome

Mathematical abilities were tested in people with Prader-Willi syndrome (PWS), using a series of basic mathematical tasks for which normative data are available. The difference between the deletion and the disomy variants of this condition was explored. While a wide phenotypic variation was found, some basic findings emerge clearly. As expected from previous literature, deletion and disomy participants were found to differ in their degree of impairment, with disomy being overall the most spared condition. However, the tasks selectively spared in the disomy condition are not necessarily the easiest ones and those that discriminate less the PWS group from controls. It rather seems that disomy patients are spared, with respect to deletion, in tasks entailing transcoding and comparison of numbers in the Arabic code. Overall a particular difficulty was detected in reliably performing parity judgments. This task has been shown to be very frequently spared after a brain injury, even in severe aphasic conditions. The most interesting result is the sparing in analog number scale, whereby PWS seem, overall, to outperform controls. This finding may help in understanding previously reported, surprising results about cognitive skills in PWS. Elevated performances in PWS may result from life-long hyper-reliance on one visuo-spatial system in presence of underdevelopment of the other.     

Word and number reading in the brain: Evidence from a Voxel-based Lesion-symptom Mapping study

The high incidence of number transcoding deficits in aphasic subjects suggests there is a strong similarity between language and number domains. However, recent single case studies of subjects who showed a dissociation between word and number word transcoding led us to hypothesize that the two types of stimuli are represented independently in the cognitive system.Moreover, it is still unclear whether word and number word reading rely on different brain areas.The present study was designed to investigate this issue in a group of 20 left hemispheric stroke patients who were all tested on Arabic number, number word and word reading (all stimuli were matched for frequency and length). To identify which brain lesions affected performance on the three tasks, we analyzed patients’ lesions and behavioural performances using Voxel-based Lesion-symptom Mapping. With this technique, several t-tests can be performed at each voxel to compare behavioural performances of patients with and without a lesion affecting that voxel.Results showed that Arabic number and number word reading involve the same damaged structures, primarily located in the temporo-parietal regions, whereas word reading relies on a frontal network that includes the superior part of Broca's area and the premotor cortex. These data complement the existing neuropsychological literature by suggesting that the already reported dissociations between word and number word reading are supported by distinct cortical networks.     

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.