Christine M. Temple

Procedural Dyscalculia and Number Fact Dyscalculia: Double Dissociation in Developmental Dyscalculia

Abstract Traditional developmental models describe a series of sequenced stages and interpret developmental disorders in terms of arrested development. Two different cases of developmental dyscalculia are described which cannot both be explained against the same stage model of the development of arithmetical skill. In both cases accurate number processing skills have developed. SW has also acquired accurate number facts and tables but has selective difficulty with the procedures of calculation. HM shows the reverse pattern with normal mastery of calculation procedures but selective difficulty in the mastery of arithmetical tables. The arithmetical modules involved in tables and procedures develop in a semi-independent fashion, neither being an essential precursor of the other. This study demonstrates that there are individual differences in the developmental dyscalculias consistent with individual differences in the developmental pathways to the adult calculation system. It also-demonstrates that the deve...

Reading in callosal agenesis

It has been suggested that deficits in explicit phonological processing are causal in developmental dyslexia. Deficits in such skills have been reported in developmental phonological dyslexia, though not in developmental surface dyslexia. The reading performance of two children with callosal agenesis, who have been previously shown to have impairments on rhyming tasks, are reported. Neither child is dyslexic in the traditional sense, since word reading levels are appropriate for age. However, both children have impaired development of the phonological reading route despite normal lexical skills. The pattern of their reading is therefore comparable to developmental phonological dyslexia. Problems in explicit phonological processing may be causal in the failure to establish an efficient phonological reading route but this is insufficient to create difficulty with word recognition itself. The corpus callosum may be essential for the normal development of a phonological reading route.

Digit dyslexia: a category-specific disorder in development dyscalculia

Abstract A case study of developmental dyscalculia is presented in which there is impairment of number processing. When reading and writing arabic numbers the syntactic component of the number is processed accurately but lexical processing results in incorrect digit selection. When reading arabic numbers the allocation of lexical items into syntactic frames is particularly poor for digits in the units position. Lexical allocation is unaffected by stimulus length. Despite poor short term memory, word reading is not impaired except for the reading of numeral words for which there is a category specific deficit. Reading errors to numeral words are more frequent than to arabic numbers but the nature of the errors is comparable. This reading deficit coexists with good phonological reading skills. The results are discussed in relation to models derived from studies of the acquired dyscalculias.

Ten pen men: rhyming skills in two children with callosal agenesis.

Cases of callosal agenesis provide unique opportunities to investigate the normal role of the corpus callosum in the development of cognitive functions, including language. The only language impairment which has been consistently observed in three acallosal patients is on the retrieval of words from rhyming cues. Two new cases of callosal agenesis in children of normal intelligence are presented. Their performance on a variety of rhyming tasks involving both production and recognition of rhyme is reported. Both children display deficits and possible explanations are discussed.

Red is read but eye is blue: A case study of developmental dyslexia and follow-up report

Recently, analogies have been drawn between the developmental and acquired dyslexias, but there has been no unequivocal report of developmental deep dyslexia. The case is reported here of a 9-year-old child whose reading performance resembles deep dyslexia in several ways. The incidence of errors with a semantic component is shown to be significantly above chance. The pattern of errors is discussed in relation to recent data on error patterns in normal beginning readers. Text reading, spelling, naming, and repetition are described. In contrast to previous case reports, follow-up data are presented which chart the qualitative changes in performance over time despite relatively little quantitative change. The child described has several specific handicaps. Developmental deep dyslexia may not be a prevalent subtype because the multiple impairments necessary to produce the disorder seldom co-occur and may tend to preclude reading development altogether.

Foop is Still Floop: A Six Year Follow-Up of Phonological Dyslexia and Dysgraphia"

A six year follow-up of a previously documented case of developmental phonological dyslexia, is reported. Overal reading and spelling levels have risen significantly, but the qualitative nature of the performance has remained unchanged: impaired non-word reading; morphological and visuo-semantic paralexias; and function word substitutions in text. Rhyming skills also remain impaired. A higher proportion of errors are paralexias and within these a higher proportion are visuo-semantic or morphological. The error pattern of phonological dylexia is thus more pronounced than before. In spelling, only a minority of errors are phonologically plausible. There is no evidence of the mastery of the alphabetic “stage” of reading or the alphabetic “stage” of spelling. It is argued that A.H. is reading orthographically not logographically and that current reading models, which require passage through an alphabetic “stage” before attaining an orthographic stage, do not adequately account for individual variation in the acquisition of literacy skills.

Developmental Dyslexia and Dysgraphia Persistence in Middle Age.

J.R. is a middle-aged man whose developmental dyslexia and dysgraphia have persisted in a problematic fashion for the 30 years since he left school. He is a phonological dyslexic. Whereas surface dyslexics operate on reading units that are too small, Mr. R operates on units that are too large. Spelling exhibits both regularity and lexicality effects. These seemingly contradictory results are consistent with a two-route model of spelling in which each route is functioning with approximately 50% efficiency. Performance on paralinguistic rhyming tasks is poor and shows no recovery in comparison to younger developmental phonological dyslexics. Difficulties with higher-order sound segmentation, analysis, or organization may underly the lifelong literacy problems.

Auditory and reading comprehension in hyperlexia: Semantic and syntactic skills

In contrast to dyslexia, in hyperlexia, there is precocious development of reading in the absence of other precocious skills, thus reading is significantly above expectation on the basis of prediction from age and intelligence. A psycholinguistic investigation is reported, of a 10 year old, non-autistic hyperlexic, on tasks of both written and auditory presentation of single words, sentences and text. M.S. shows good development of both phonological and lexical reading mechanisms. He does not display a pattern of reading performance which resembles any selective reading disorder and there is no evidence that the nature of his reading development, in relation to accuracy, is abnormal in style. However, reading accuracy is significantly better than both reading comprehension and auditory comprehension. The comprehension deficit does not affect language in an undifferentiated way. Semantic comprehension is normal for age but syntactic comprehension is significantly impaired. Thus, although there are no unusual dissociations in relation to reading accuracy, there is a significant dissociation between reading accuracy and reading comprehension, and also between semantic and syntactic comprehension of both written and auditory material which argues for modularity in the development of these subsystems.