Do reading and spelling share orthographic representations? Evidence from developmental dysgraphia

ABSTRACT

Both spelling and reading depend on knowledge of the spellings of words. Despite this commonality, observed dissociations between spelling and reading in cases of acquired and developmental deficits suggest some degree of independence between the cognitive mechanisms involved in these skills. In this paper, we examine the relationship between spelling and reading in two children with developmental dysgraphia. For both children, we identified significant deficits in spelling that affected the processing of orthographic long-term memory representations of words. We then examined their reading skills for similar difficulties. Even with extensive testing, we found no evidence of a reading deficit for one of the children. We propose that there may be an underlying difficulty that specifically affects the learning of orthographic word representations for spelling. These results lead us to conclude that at least some components of lexical orthographic representation and processing develop with considerable independence in spelling and reading.

KEYWORDS:

• Developmental cognitive neuropsychology
• developmental dysgraphia
• orthographic knowledge
• spelling

Acknowledgements

We are grateful to P.J.T., A.K.R., and their families for their support for this project and their cheerful participation in long hours of testing. We are also grateful to Michael Gascoigne for his help with testing materials and normative data for the visual learning task.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Christopher Hepner http://orcid.org/0000-0001-8999-1231

Notes

1 The role of O-WM in reading is a rather under-researched topic. However, it has been argued (Caramazza et al., 1996; Tainturier & Rapp, 2003) that the degree to which O-WM is engaged is determined by task demands. While spelling always places demands on O-WM, “normal” horizontal word reading is typically carried out in parallel with few demands placed on O-WM. In contrast, vertical word reading, reading words with letters presented serially, or even pseudoword reading places greater demands on O-WM. In support of the hypothesis of shared O-WM processes in reading and spelling, Caramazza et al. (1996) and Tainturier and Rapp (2003) reported cases of individuals with acquired dysgraphia with deficits affecting O-WM in spelling who showed similar patterns of errors and length effects in spelling, pseudoword reading, and reading with alternative formats (e.g., mirror-reversed and orally presented letters).

2 Note that both the DiSTi and the WRAT include words that a child of A.K.R.’s age would not be expected to spell correctly (e.g., CACOPHONY, IRIDESCENCE). Accordingly, although her 67% error rate is higher than expected for a child of her age, it does not reflect catastrophic spelling impairment. Note also that the spelling corpus for P.J.T., described below, includes a larger proportion of words a child of his age would be expected to spell correctly, and hence his somewhat lower error rate (53%) does not imply a less severe spelling impairment.

Additional information

Funding

Preparation of this article was supported by a Johns Hopkins Science of Learning Institute grant to Michael McCloskey; by the National Institutes of Health [grant number DC006740] to Brenda Rapp; and by a generous gift from a donor to the Johns Hopkins University.