WRITE

Full title: By (writing) hand: Investigating the cerebral laterality during writing using functional transcranial Doppler ultrasonography and the genetic relationship of laterality with special learning difficulties (dyslexia, dysgraphia)

This research work is supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “1st Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high value research equipment grant” (Project Number: HFRI-FM17-746).

The cerebral lateralization of language (also known as laterality or hemispheric dominance / asymmetry), i.e. the fact that the left hemisphere of the brain predominantly processes language in the majority of individuals, is of central focus in the neuropsychological literature. The neural underpinnings of writing in particular are of great interest, as writing is utilized nearly every day and it is a skill that demands the contribution of several cognitive and motor functions. Moreover, disorders of writing are implicated in special learning disabilities, such as dyslexia and dysgraphia.

However, the literature focuses on oral language; research on cerebral lateralization during writing is extremely limited. Moreover, only four studies (two by the principal investigator) have included left-handers, who constitute approximately 10% of the population making it important to account for this variation. Furthermore, cerebral laterality for writing has not been studied in atypical populations (e.g., dyslexia and dysgraphia), nor has the possible cortical re-organization after intervention in individuals with dyslexia been investigated. Other important questions that remain unanswered include cerebral lateralization during typing, the relationship of writing quality with cerebral lateralization, the possible cortical re-organization after non-dominant hand writing training, and the genetics of lateralization.

In this project we aim to address the above questions. For neuroimaging purposes we will employ functional transcranial Doppler ultrasound (fTCD), a reliable measurement of continuous blood flow with excellent temporal resolution, which lends itself to the study of writing as its signal is not disrupted by movement artifacts. New digital tools will be used to collect behavioral indices of lateralization. DNA samples will be further collected for inclusion in large genetic studies (GWAS).

Overall, this interdisciplinary project contributes to the broader question of individual differences in brain organization and function, both in typical and non-typical populations, with applications in special education.