Auditory temporal processing, phonological awareness, and oral language ability in prereaders: Can we identify children at risk for reading disability more accurately?

Psychophysical indices of perceptual functioning in dyslexia: A psychometric analysis

An influential causal theory attributes dyslexia to visual and/or auditory perceptual deficits. This theory derives from group differences between individuals with dyslexia and controls on a range of psychophysical tasks, but there is substantial variation, both between individuals within a group and from task to task. We addressed two questions. First, do psychophysical measures have sufficient reliability to assess perceptual deficits in individuals? Second, do different psychophysical tasks measure a common underlying construct? We studied 104 adults with a wide range of reading ability and two comparison groups of 49 dyslexic adults and 41 adults with normal reading, measuring performance on four auditory and two visual tasks. We observed moderate to high test–retest reliability for most tasks. While people with dyslexia were more likely to display poor task performance, we were unable to demonstrate either construct validity for any of the current theories of perceptual deficits or predictive validity for reading ability. We suggest that deficient perceptual task performance in dyslexia may be an associated (and inconsistent) marker of underlying neurological abnormality, rather than being causally implicated in reading difficulties.

Comorbidity of auditory processing, language, and reading disorders

PURPOSE

The authors assessed comorbidity of auditory processing disorder (APD), language impairment (LI), and reading disorder (RD) in school-age children.

METHOD

Children (N = 68) with suspected APD and nonverbal IQ standard scores of 80 or more were assessed using auditory, language, reading, attention, and memory measures. Auditory processing tests included the Frequency Pattern Test (FPT; F. E. Musiek, 1994; D. Noffsinger, R. H. Wilson, & F. E. Musiek, 1994); the Dichotic Digit Test Version 2 (DDT; F. E. Musiek, 1983); the Random Gap Detection Test (R. W. Keith, 2000); the 500-Hz tone Masking Level Difference (V. Aithal, A. Yonovitz, & S. Aithal, 2006); and a monaural low-redundancy speech test (compressed and reverberant words; A. Boothroyd & S. Nittrouer, 1988). The Clinical Evaluation of Language Fundamentals, Fourth Edition (E. Semel, E. Wiig, & W. Secord, 2003) was used to assess language abilities (including auditory memory). Reading accuracy and fluency and phonological awareness abilities were assessed using the Wheldall Assessment of Reading Passages (A. Madelaine & K. Wheldall, 2002) and the Queensland University Inventory of Literacy (B. Dodd, A. Holm, M. Orelemans, & M. McCormick, 1996). Attention was measured using the Integrated Visual and Auditory Continuous Performance Test (J. A. Sandford & A. Turner, 1995).

RESULTS

Of the children, 72% had APD on the basis of these test results. Most of these children (25%) had difficulty with the FPT bilaterally. A further 22% had difficulty with the FPT bilaterally and had right ear deficits for the DDT. About half of the children (47%) had problems in all 3 areas (APD, LI, and RD); these children had the poorest FPT scores. More had APD-RD, or APD-LI, than APD, RD, or LI alone. There were modest correlations between FPT scores and attention and memory, and between DDT scores and memory.

CONCLUSIONS

LI and RD commonly co-occur with APD. Attention and memory are linked to performance on some auditory processing tasks but only explain a small amount of the variance in scores. Comprehensive assessment across a range of areas is required to characterize the difficulties experienced by children with APD.

Cost-effective prediction of reading difficulties

This study addressed 2 questions: (a) Can preschoolers who will fail at reading be more efficiently identified by targeting those at highest risk for reading problems? and (b) will auditory temporal processing (ATP) improve the accuracy of identification derived from phonological processing and oral language ability? A sample of 227 preschoolers was screened for Performance IQ and was tested on phonological awareness (PA). The upper and lower quartiles of the PA distribution were selected as being at lowest and highest risk, respectively, for reading failure. Children with good and poor PA were tested on ATP, phonological short-term memory, rapid automatized naming, oral language, receptive vocabulary, and 2 measures of listening comprehension. Reading outcomes were measured at the end of Year 2. Only 1 child in the good-PA group became a poor reader by the end of Year 2, confirming that being in the top quartile for PA predicts positive reading outcomes. Discriminant analysis using the authors' test battery within the poor-PA group identified poor readers with sensitivity of.91 and specificity of.84, but ATP did not improve classification accuracy afforded by phonological and oral language. A brief screening procedure was formulated using only PA, phonological short-term memory, and demographic variables, with which 80% of children with poor PA who are at risk of reading problems can be identified. Further refinements of this screening procedure would increase accuracy of identification at the cost of only a small increment in required testing time.