An argument for administering WISC-R Digit Span

An argument is presented in favor of always administering the optional Digit Span subtest of the WISC-R. Use of Digit Span in conjunction with other subtests in a subtest grouping schemata--according to factor loadings--will substantially increase the usefulness of the WISC-R. Data show that often the Digit Span is not being given.     

WISC-R subtest but no overall VIQ-PIQ difference in Dutch children with PDD-NOS

VIQ-PIQ differences have been studied in children with autism and Asperger syndrome but have not been studied in a separate group of children with PDD-NO, although, PDD-NOS has a much higher prevalence rate than autism and deficits in communication and social interaction are severe. The Wechsler Intelligence Scale for Children-Revised (WISC-R) was administered to 100 children, aged 6-12 years, with PDD-NOS (n = 76), autism (n = 13), and Asperger syndrome (n = 11). PDD-NOS was diagnosed using explicit research criteria. No overall differences between VIQ and PIQ were found in PDD-NOS and autism. Peaks in the subtest scores on Information, Similarities, Picture Arrangement, and Mazes, and troughs in the subtest scores on Comprehension, Digit Span, and Coding were demonstrated in children with PDD-NOS. Their score on the Freedom from Distractibility factor was lower than the scores on the Verbal Comprehension factor and the Perceptual Organization factor. Children with PDD-NOS seemed to have a similar VIQ-PIQ profile as children with autism, and on the subtest level children with PDD-NOS showed some similarities to children with Asperger syndrome or autism. It was not possible to distinguish PDD-NOS from autism or Asperger syndrome by using IQ scores.     

WISC-R Subtest But No Overall VIQ–PIQ Difference in Dutch Children with PDD-NOS

VIQ–PIQ differences have been studied in children with autism and Asperger syndrome but have not been studied in a separate group of children with PDD-NO, although, PDD-NOS has a much higher prevalence rate than autism and deficits in communication and social interaction are severe. The Wechsler Intelligence Scale for Children-Revised (WISC-R) was administered to 100 children, aged 6–12 years, with PDD-NOS (n = 76), autism (n = 13), and Asperger syndrome (n = 11). PDD-NOS was diagnosed using explicit research criteria. No overall differences between VIQ and PIQ were found in PDD-NOS and autism. Peaks in the subtest scores on Information, Similarities, Picture Arrangement, and Mazes, and troughs in the subtest scores on Comprehension, Digit Span, and Coding were demonstrated in children with PDD-NOS. Their score on the Freedom from Distractibility factor was lower than the scores on the Verbal Comprehension factor and the Perceptual Organization factor. Children with PDD-NOS seemed to have a similar VIQ–PIQ profile as children with autism, and on the subtest level children with PDD-NOS showed some similarities to children with Asperger syndrome or autism. It was not possible to distinguish PDD-NOS from autism or Asperger syndrome by using IQ scores.     

On the use of the WISC-R supplementary subtests as alternates

If a regularly administered WISC-R subtest cannot be administered properly or is invalidated, the manual suggests that a supplementary subtest, either Digit Span or Mazes, can serve as a substitute, but perhaps prorating the sum of scaled scores on the remaining subtests would be better. Data from the WISC-R standardization sample were analyzed to investigate the psychometric properties of these two variants of the standard procedure. Proration consistently resulted in higher validities (i.e., correlations between scores on the variant Verbal, Performance, or Full Scale and scores on the corresponding original scale), whereas substitution almost as consistently resulted in higher reliabilities, but in both cases the differences were small. Examiners may decide for themselves whether or not to use the supplementary subtests as alternates.     

The mediating effect of age on the relationship between child behavior checklist hyperactivity scores and neuropsychological test performance

The relationship between hyperactivity and neuropsychological test performance at different age levels was examined. It was found that for young children (6 to 8 years of age, n=90), there was no significant association between hyperactivity/attentional problems (as measured by the Hyperactivity scale of the Child Behavior Checklist) and performance on neuropsychological tasks thought to contain an attentional component (WISC-R Coding, Arithmetic, and Digit Span; WRAT Arithmetic; and the Benton Visual Retention Test). However, for older children (9 to 12 years of age, n=92), there were significant and large negative correlations between CBC Hyperactivity scores and Coding, WRAT Arithmetic, and Benton VRT scores. Multiple regression analyses supported the above results (for Coding and WRAT Arithmetic), indicating that hyperactivity/inattention has a particularly deleterious effect on test performance (relative to sameage peers) as age increases.Aspects of the research reported in this article were presented at the 1987 meeting of the International Neuropsychological Society in Washington, D.C. The authors gratefully acknowledge the assistance of William Ingram and Lisa Rosa in the data collection.     

Verbal Learning in Boys With P-Type Dyslexia,L-Type Dyslexia,and Boys Without Learning Disabilities: Differences in Learning Curves and in Serial Position Curves

Twenty-five boys with P-dyslexia, 23 with L-dyslexia, and 26 boys without reading disabilities were administered the Digit Span (Forward and Backward) and the Dutch version of the Rey Auditory-Verbal Learning Test. Compared to normal boys, dyslexic boys exhibited reduced scores on Digits Backward and recalled fewer words during the five learning trials. Nonlinear modeling of the data for the five learning trials revealed that dyslexic boys showed smaller learning parameters than did normal boys and that L-dyslexic boys exhibited more loss of information during learning than did P-dyslexic boys. In dyslexic boys, the word-list primacy effect was strongly reduced. In normal boys, but not in dyslexic boys, Digits Backward correlated moderately with the primacy measure. The results suggest that reduced word-list learning in dyslexics is a consequence of a temporal ordering deficit rather than a rehearsal deficit.     

The backward span of the Corsi Block-Tapping Task and its association with the WAIS-III Digit Span

The Corsi Block-Tapping Task measures visuospatial short-term and working memory, but a standardized backward condition is lacking. The authors present a standardized backward procedure that was examined in 246 healthy older adults (ages 50 to 92), comparing the results with the Digit Span subtest of the Wechsler Adult Intelligence Scale--Third Edition. Principal component analysis resulted in a two-factor model, dissociating a verbal and a spatial working-memory factor. Also the Corsi backward is not more difficult than the Corsi forward, in contrast to the Digit Span backward that is more difficult than the Digit Span forward. This may suggest that the Corsi Block-Tapping Task backward task relies on processing within working-memory's slave systems, whereas the Digit Span backward also relies on the central executive component of working memory. Finally, regression-based normative data and cutoff scores for older adults are presented for use in clinical practice.     

Three-year stability of WISC-R factor scores for black and white, female and male children classified as learning-disabled

Wechsler Intelligence Scale for Children-Revised (WISC-R) test and retest scores for a homogeneous sample (N=322) of approximately equal numbers of black and white, female and male learning-disabled children were compared over 3 years for factor structure and factor structure stability. These analyses were also conducted with a subsample (N=229) of the total sample for whom Digit Span scores were available. The socioeconomic status of children in the sample was determined by parents' occupation. The results suggested that WISC-R factor structure was stable over 3 years. Two-and three-factor solutions were found for the total group; three factors were found when Digit Span was included in the analysis. Coefficients of congruence indicated factorial similarity between groups of black and white, female and male children classified as learning-disabled.     

A multivariate comparison of the intellectual performance of black and white children matched on four demographic variables

This study investigated the performance of 285 matched pairs of Black and White children from the standardization sample on the 12 subtests and 3 IQ scales of the Wechsler Intelligence Scale for Children—Revised (WISC-R). The children were matched on four demographic variables found in a previous (Reynolds and Gutkin, 1979) study to be significantly related to WISC-R performance: sex, socioeconomic status as determined by the occupation of the head of household, region of residence in the U.S. and urban vs rural residence. Multivariate analysis of variance comparing performance across race on the 15 dependent variables revealed that Whites exceeded Blacks on all tasks except Digit Span—a test of rote memory. Results were also related to the evaluation of the Spearman hypothesis.     

Psychometric validity of proration and Digit Span substitution for estimating WISC--R verbal and Full Scale IQs

This study investigated the merits of substituting the Digit Span subtest for an invalid Verbal Scale subtest versus a proration method in calculating WISC--R Verbal and Full Scale IQ. Subjects were 93 child and adolescent psychiatric patients (67 boys and 26 girls) who ranged in age from 8 to 16 yr. Analysis indicated that the use of Digit Span as a substitute for the regularly administered Verbal subtests was inferior to the use of the comparable proration method. Although relatively few cases of misclassification occurred for either method in relation to Full Scale IQ, the rate of Verbal IQ misclassification by the Digit Span substitution method was significantly greater than with use of its proration. When faced with a choice, clinicians should attach greater validity to prorated estimates of a child's WISC--R Verbal IQ.     

Reliable digit span is unaffected by laboratory-induced pain: implications for clinical use

Reliable Digit Span (RDS) is an indicator used to assess the validity of cognitive test performance. Scores of 7 or lower suggest poor effort or negative response bias. The possibility that RDS scores are also affected by pain has not been addressed thus potentially threatening RDS specificity. The current study used cold pressor-induced pain to investigate the effect of pain on RDS scores. Sixty undergraduate volunteers randomly assigned to one of three conditions (control, simulator, pain) completed the Digit Span subtest from the Wechsler Adult Intelligence Scale-III from which the RDS is derived. No differences in RDS scores were found between the control and pain groups, and neither group scored below 8. Sixty-five percent of the simulator group scored 7 or below. These results suggest that RDS is not affected by pain, and scores of 7 or less in persons with pain can be more confidently attributed to negative response bias.     

A comparison of word recognition processes in dyslexic and normal readers at two reading-age levels

This study addressed the question of whether dyslexic children use qualitatively different word identification processes as compared to normal readers at the same stage of reading acquisition. Fifty-two dyslexic children and reading-age matched normal readers were required to pronounce words and pseudowords designed to tap several word recognition and decoding processes. Performance profiles were compared for the two reading groups at two reading ages. Although an invariant acquisition sequence was observed across reading groups, differences in level of performance between dyslexics and reading-age controls varied as a function of reading age. The performance of the more advanced dyslexics was virtually indistinguishable from normal readers on all measures. In contrast, the younger reading age dyslexics differed from normal readers on several measures of spelling-sound correspondences. However, no reading group differences were observed on measures of word recognition. The results indicated that dyslexics and normal readers at the same reading age use essentially the same processes to recognize words, but may differ in knowledge of correspondence rules.     

Multifactorial assessment of reading disability: identifying the best predictors

A multifactorial diagnostic assessment battery was evaluated using data obtained from 105 reading-disabled children and their matched controls (total N = 210). A stepwise discriminant function analysis selected five nonreading measures from among 16 as the best diagnostic predictors of reading disability. These measures included WISC-R Information and Digit Span, self-reported family histories of reading problems, and tests of symbol-processing speed and letter fluency.     

Spanish developmental dyslexia: Prevalence, cognitive profile, and home literacy experiences

This study was designed to examine the prevalence, cognitive profile, and home literacy experiences in subtypes of Spanish developmental dyslexia. The subtyping procedure used comparison with chronological-age-matched and reading-level controls on reaction times and accuracy responses to high-frequency words and pseudowords. Using regression-based procedures, 8 phonological dyslexics and 16 surface dyslexics were identified from a sample of 35 dyslexic fourth graders by comparing them with chronological-age-matched controls on reaction times to high-frequency word and pseudoword reading. However, when the dyslexic subtypes were defined by reference to reading-level controls, 12 phonological dyslexics were defined but only 5 surface dyslexics were identified. Both dyslexic subtypes showed a deficit in phonological awareness, but children with surface dyslexia also showed a deficit in orthographical processing assessed by a homophone comprehension task. This deficit was associated with poor home literacy experiences, with the group of parents with children matched in reading age, in comparison with the group of parents with children with surface dyslexia, reporting more literacy home experiences.     

Flicker masking and developmental dyslexia

Recent studies have provided evidence that dyslexic children tend to show longer visual persistence than control children when presented with low-spatial-frequency grating stimuli. The possibility that this phenomenon might reflect an impairment of inhibitory Y-cell activity in the visual system of dyslexics has been investigated. A flicker masking technique was used to mask Y-cell activity selectively in a group of dyslexic boys and a group of age-matched controls. There were no overall differences in reaction times to the offsets of grating patterns of various spatial frequencies between the groups, and no differences between subgroups defined by age, degree of reading impairment, or any other criterion. The results show no evidence of abnormal Y-cell function in developmental dyslexia.     

Dyslexia: the articulatory hypothesis revisited

Articulatory disorders have been associated with developmental phonological dyslexia in the literature. However, very few information is available about the articulatory movements involved in speech production in dyslexic children. This study uses aerodynamic/acoustic data to explore how dyslexic children produce bilabial stops in French (/b, p/) within a sentence where they occurred in two positions and in three vowel environments. Average durations of articulatory closure and release were calculated in 10 phonological dyslexic children and two groups of age-matched and reading age-matched controls. Moreover, deviation from a standard pronunciation of the same material was evaluated separately by blind examiners. Our results reveal differences in the timing of the articulatory movements between dyslexics and normal controls, as well as more deviations from the target consonant for the dyslexics than for the controls. These observations are consistent with recent findings pointing to a general deficit in fine motor control in dyslexia.     

Performance of dyslexic children on speech perception tests

Several researchers who have compared the performance of dyslexic and normal-reading children on a variety of different tasks have suggested that dyslexic children may have subtle deficits in the phonemic analysis of spoken as well as written language. Thus it is of interest to know how children who have extraordinary difficulty learning to read can perform explicity auditory-phonetic tasks. Seventeen dyslexic children (10 years of age) and a group of 17 controls were administered tests of identification and discrimination of synthesized voiced stop consonants differing in place of articulation. These were tests of the type used to study categorical perception in adults, adapted for use with young children. Significant differences between dyslexics and controls were found in both kinds of tasks; the pattern of identification and discrimination differences suggests an inconsistency in the dyslexics' phonetic classification of auditory cues. A significant relationship was found between reading level and speech discrimination.     

Are there qualitative differences in reading behavior between dyslexics and normal readers?

This study asked whether the reading behavior of dyslexics differs qualitatively from that of normal children. Thirty-seven children who had been identified is dyslexic (mean age 11 years, 9 months) were matched with 37 normal readers (mean age 8,6) on ability to read regular words. The dyslexics' and normals' levels of performance on nonsense words and exception words were strikingly close. Also, patterns of individual differences were similar for the two groups. The results suggest that these dyslexics are delayed in the development of both spelling-sound rules and word specific associations. They do not support the view that dyslexics have a specific deficit in the use of spelling-sound rules, or that dyslexics show more extreme individual differences than do normal readers.     

Italian developmental dyslexic and proficient readers: where are the differences?

Italian dyslexic children are characterized by a pervasive reading speed deficit, with relatively preserved accuracy. This pattern has been associated with predominant use of the nonlexical reading procedure. However, there is no evidence of a deficit in the lexical route of Italian dyslexics. We investigated both lexical and nonlexical reading procedures in dyslexic children through two marker effects, namely, the word frequency effect and the effect of contextual grapheme-to-phoneme conversion rules. Although dyslexics were slower and less accurate than controls, they were affected by word frequency, grapheme contextuality, and their interaction in a similar manner as average readers. These results show the use of lexical reading in Italian dyslexics, and refute the claim of a deficit in whole-word processing with consequent over-reliance on the nonlexical route.     

Comparing children with and without dyslexia on the Movement Assessment Battery for Children and the Test of Gross Motor Development

Dyslexia is the most commonly occurring learning disability in the United States, characterized by difficulties with word recognition, spelling, and decoding. A growing body of literature suggests that deficits in motor skill performance exist in the dyslexic population. This study compared the performance of children with and without dyslexia on different subtests of the Test of Gross Motor Development and Movement Assessment Battery for Children and assessed whether there were developmental changes in the scores of the dyslexic group. Participants included 26 dyslexic children (19 boys and 7 girls; 9.5 yr. old, SD = 1.7) and 23 age- and sex-matched typically developing (17 boys and 6 girls; 9.9 yr. old, SD = 1.3) children as a control group. Mann-Whitney U tests indicated that the dyslexic group performed significantly lower than the control group only on the Total Balance subtest of the Movement Assessment Battery for Children. Additionally, the young dyslexic group performed significantly better on the Total Balance subtest, compared to the older dyslexic group. These results suggest that cerebellar dysfunction may account for differences in performance.