Resounding failure to replicate links between developmental language disorder and cerebral lateralisation
- Published
- Accepted
- Subject Areas
- Neuroscience, Cognitive Disorders, Psychiatry and Psychology
- Keywords
- laterality, language, handedness, developmental language disorder, fTCD
- Copyright
- © 2017 Wilson et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2017. Resounding failure to replicate links between developmental language disorder and cerebral lateralisation. PeerJ Preprints 5:e3352v1 https://doi.org/10.7287/peerj.preprints.3352v1
Abstract
Background. It has been suggested that failure to establish cerebral lateralisation may be related to developmental language disorder (DLD). There has been weak support for any link with handedness, but more consistent reports of associations with functional brain lateralisation for language. The consistency of lateralisation across different functions may also be important. We aimed to replicate previous findings of an association between DLD and reduced laterality on a quantitative measure of hand preference (reaching across the midline) and on language laterality assessed using functional transcranial Doppler ultrasound.
Methods. From a sample of twin children aged from 6 to 15 years, we identified 107 cases of DLD and 156 typically-developing (TD) comparison cases, all of whom had useable data from fTCD yielding a laterality index (LI), as well as measures of handedness.
Results. Indices of handedness and language laterality for this twin sample were similar to those previously reported with these measures for single-born children. There was no difference between the DLD and TD groups on quantitative measures of handedness or language lateralisation, or on a categorical measure of consistency of left hemisphere dominance. Contrary to prediction, there was a greater incidence of right lateralisation for language in the TD group (19.90%) than the DLD group (9.30%), confirming that atypical laterality is not inconsistent with typical language development. We also failed to replicate associations between language laterality and language test scores.
Discussion. Given the large sample studied here and the range of measures, we suggest that previous reports of atypical manual or language lateralisation in DLD may have been false positives.
Author Comment
This is a submission to PeerJ for review.