Visual motor ability in normal and disabled readers

A group of 42 third graders were grouped equally into sequentially deficient, simultaneously deficient, and normal readers based on their performance on Boder Reading and Spelling Pattern Test and Gates-Macginitie Reading Test. The subjects were then administered Bender Visual-motor Gestalt Test. There were significant differences among the three groups; the simultaneous-deficient group committed the most errors on the Bender test. The results were related to reading.     

Development of phonetic memory in disabled and normal readers

The development of phonetic codes in memory of 141 pairs of normal and disabled readers from 7.8 to 16.8 years of age was tested with a task adapted from L. S. Mark, D. Shankweiler, I. Y. Liberman, and C. A. Fowler (Memory & Cognition, 1977, 5, 623–629) that measured false-positive errors in recognition memory for foil words which rhymed with words in the memory list versus foil words that did not rhyme. Our younger subjects replicated Mark et al., showing a larger difference between rhyming and nonrhyming false-positive errors for the normal readers. The older disabled readers' phonetic effect was comparable to that of the younger normal readers, suggesting a developmental lag in their use of phonetic coding in memory. Surprisingly, the normal readers' phonetic effect declined with age in the recognition task, but they maintained a significant advantage across age in the auditory WISC-R digit span recall test, and a test of phonological nonword decoding. The normals' decline with age in rhyming confusion may be due to an increase in the precision of their phonetic codes.     

Event-related brain potentials differentiate normal and disabled readers

Auditory event-related potentials (AERPs) recorded to irrelevant tone pairs while subjects performed visual, reading-related cognitive tasks differed significantly between normal and disabled readers. Disabled readers as compared with normal readers showed significantly lower amplitude right hemisphere AERP responses during tasks that involved visual-phonemic transfer of information and simple pattern recognition. Disabled readers as compared with normal readers also showed significantly higher amplitude left hemisphere responses during the visual-phonemic task. In both experimental conditions the reading-disabled subjects showed significantly lower amplitude right than left hemisphere AERP responses. Task-related strategies did not differ between groups. The pattern of AERP amplitude asymmetry found for disabled readers, which was opposite to that found for normal readers, suggests that the same reading-related tasks activated different cerebral processes in the two groups studied.     

Processing of identity and position information in normal and disabled readers

Processing of identity and position information was investigated in normal and disabled readers at two grade levels (third/fourth grade and sixth grade). Two partial-report tasks were used. The identity task consisted of visual presentation of a five-letter array, followed by a probe letter. Subjects responded yes for a match and no for a mismatch (identity response). The identity + position task was identical except that an additional response was required on correct yes trials: subjects reported the position of the probe letter in the array (position response). Both grade level and reading ability differences were found on the identity response measure, but not on the position response measure. Results were inconsistent with the hypothesis that disabled readers have difficulties in processing order information. Reader ability differences in identity processing attenuated somewhat with age. Serial position functions for both identity and position responses suggested the presence of a left-to-right scanning operation in both age and ability groups. Reader ability differences in processing letter identities were discussed in the context of current theories of reading acquisition.     

Performance of disabled and normal readers on the continuous performance test

Twelve-year-old reading-disabled children of normal intelligence were compared on the Continuous Performance Test with two control groups of normal intelligence and reading ability either of the same age or of the same reading age as the reading-disabled group. Signal-detection analysis showed that the reading-disabled were more conservative than chronological-age controls in their willingness to identify the target letter sequence. Although this conservative performance was shared by the reading-age controls, the readingdisabled suffered an additional handicap of relatively frequent anticipatory errors. Groups also differed on a sensitivity measure, suggesting a deficit in working memory in the reading-disabled children.This research was supported by the New Zealand Neurological Foundation. We thank the children and school staff for their willing cooperation. We are indebted to the research students who found the subjects and helped collect the data.     

Purdue pegboard performance of disabled and normal readers: Unimanual versus bimanual differences

Differences between dyslexics and controls in the unimanual and bimanual conditions of the peg placement section of the Purdue Pegboard Test were examined. Twenty-three disabled and twenty-three normal readers were studied. The groups were carefully screened on a neuropsychological battery. The disabled readers were comprised of a relatively homogeneous language-disordered subgroup exhibiting deficits in naming. Significant Group X Condition interactions were obtained for both raw and percentile scores and indicated that disabled readers performed worse than controls in the unimanual compared to bimanual conditions. The dyslexics performed particularly poorly compared with controls on the left hand condition. The implications of these data for hypotheses which argue for left hemisphere dysfunction, as well as those which posit interhemispheric transfer deficits in reading disabled children, are discussed.     

Semantic and visual memory codes in learning disabled readers

Two experiments investigated whether learning disabled readers' impaired recall is due to multiple coding deficiencies. In Experiment 1, learning disabled and skilled readers viewed nonsense pictures without names or with either relevant or irrelevant names with respect to the distinctive characteristics of the picture. Both types of names improved recall of nondisabled readers, while learning disabled readers exhibited better recall for unnamed pictures. No significant difference in recall was found between name training (relevant, irrelevant) conditions within reading groups. In Experiment 2, both reading groups participated in recall training for complex visual forms labeled with unrelated words, hierarchically related words, or without labels. A subsequent reproduction transfer task showed a facilitation in performance in skilled readers due to labeling, with learning disabled readers exhibiting better reproduction for unnamed pictures. Measures of output organization (clustering) indicated that recall is related to the development of superordinate categories. The results suggest that learning disabled children's reading difficulties are due to an inability to activate a semantic representation that interconnects visual and verbal codes.     

Functional cerebral lateralization in subtypes of disabled readers

This study investigated the functional cortical organization of reading-disabled boys and age-matched normal readers. Subjects were initially classified according to E. Boder's (1971a. In B. Bateman (Ed.), Learning disorders. Seattle: Special Child Publications. Vol. 4.) distinction between dysphonetic children (who make nonphonetic, bizarre spelling errors), dyseidetic children (who make phonetically acceptable errors, but do not respond to some words as “wholes”), and children who display normal error patterns (who make phonetically acceptable errors and respond to words as “wholes”). It was hypothesized that different types of reading disability would be associated with different patterns of lateralized brain function. This proposal was examined by testing subjects on three experimental neuropsychological measures—hemispheric time-sharing, conjugate lateral eye movements, and tactile directional perception. Conjugate lateral eye movements were disregarded as the control subjects failed to show predicted asymmetries on this measure. The two other measures were considered valid and demonstrated atypical lateralization in the reading-disabled groups. Lateralization of verbal and/or spatial functiosn differed among the reading-disabled groups and an attempt was made to relate these atypical patterns to the type of reading difficulties presented.     

Sentential structure and the perceptual spans of two samples of disabled readers

The constructs of accuracy and speed were adopted as performance criteria against which to define two clinical samples of disabled readers. Accuracy-disabled subjects had failed to achieve reliable age-appropriate word recognition skills. Rate-disabled readers were age-appropriate in word recognition accuracy but deficient on measures of contextual accuracy and reading speed. When their eye-voice spans were measured under different text manipulations, accuracy-disabled and rate-disabled children differed in the magnitude of their perceptual spans during the act of reading. The two samples did not differ in the extent to which they availed themselves of contextual constraints to extend their spans in the reading of connected text. Both samples of disabled readers appeared able to use syntactic information as an independent source of sentential information in reading, even the sample whose reading disability was associated with oral syntax deficits. Comparisons with a previous sample of normal beginning readers suggested both types of disabled readers to be reading with perceptual spans of reduced dimensions.This research was supported by operating funds from the Medical Research Council of Canada, the Ontario Mental Health Foundation/COMSOC Provincial Lottery Grants Program, and The Hospital for Sick Children Foundation. The author gratefully acknowledges the generous contributions of Terry Smialy and Judy Millington in assisting with all phases of data collection and data analysis. Special thanks are due Judy Millington for her skill in computing and analyzing the phrase boundary and pseudoboundary counts. Identification of the present rate-disabled subjects was made possible through the assistance of Andrew Biemiller, Donald G. Doehring, and Roger T. Lennon, who made previously unpublished normative data on reading speed available for use in this research project. The generosity of these individuals is very gratefully acknowledged. This paper was presented in part to the annual meeting of the American Psychological Association, Anaheim, California, August 1983.     

Selected linguistic and perceptual abilities of empirically derived subgroups of learning disabled readers

A battery of eight linguistic and perceptual tests chosen because of their use in previous research and in the public schools was administered to 100 school-verified verified learning disabled readers (LDR) and 50 normal readers (NR) matched for age and IQ. Standard scores, derived from a comparison of each LDR child's score with the NR group's performance on each diagnostic measure, were cluster analyzed to identify subgroups within the LDR group. Six LDR subgroups were found. Multivariate analysis of variance and discriminant analysis indicated that all LDR subgroups were significantly different from one another as well as significantly different from the NR group's performance on the diagnostic battery. In addition, significant differences were found among the six LDR subgroups on measures of oral reading, reading comprehension, and spelling skills. However, the six groups did not differ with respect to family history variables and the attainment of developmental milestones. These results were compared with those of previous studies and were examined for their implications for a more precise match between LDR learner characteristics and type of teaching method and/or materials.     

Semantic priming effects in normal versus poor readers

The authors studied sensitivity to semantic priming, as distinct from semantic judgment, in poor readers. Association strength (high vs. low semantic association) was manipulated factorially with semantic association type (categoric vs. thematic association). Participants were 11-year-old poor readers (n = 15) who were matched with a group of chronological-age controls (n = 13), and also matched with a group of reading-age controls (n = 15). Three priming conditions were used: related, unrelated, and neutral prime. Neutral primes consisted of a row of hash marks. Related primes elicited shorter decision latencies than did unrelated primes. Neutral primes elicited the slowest responses in all groups. Poor readers showed an additional delay in the neutral prime condition. No effects of association type (categorical vs. thematic) or association strength (high vs. low) were found, nor were any relationship with reading ability found. The delayed performance of the poor readers on neutral primes is explained in terms of orthographic processing and dependency on grapheme phoneme relationships. The findings are discussed with reference to F. R. Vellutino, D. M. Scanlon, and D. Spearing's (1995) work on semantic processing and reading ability.     

Processing syntactic functions of words in normal and dyslexic readers

Readers with dyslexia were compared with normal readers for the ability to identify the grammatical function of words in the course of sentence processing by means of electrophysiological measures along with behavior measures. Participants were 18 dyslexic and 18 normally reading, native Hebrew-speaking male university students, aged 18 to 27 years. Obtained results confirmed the hypothesis (Leikin & Breznitz, 1999) that Hebrew readers used lexical-morphological properties of words to identify their grammatical roles. However, the morphologically based strategy acquired full expression only in the presence of the verb, which in the Hebrew sentence fulfills the central role. Seemingly, readers use a few different procedures to identify the grammatical roles of words. Selection of a particular strategy seems to be influenced by diverse factors, including syntactic and lexical-morphological characteristics of the stimuli and level of reading skills. In addition, the results showed significant differences in sentence processing between normal and dyslexic readers, as reflected by ERP measures. These results are in line with the hypothesis, suggesting the existence of a syntactic processing weakness in readers with dyslexia.