Vowel Dysgraphia

EasyChair Preprint no. 6516

Abstract

We describe a new type of developmental dysgraphia, vowel dysgraphia, characterized by a deficit in the sublexical route for writing that selectively affects vowels. We identified 30 participants(aged 8-45) with a selective difficulty in vowel writing.They made omissions, additions, transpositions, and substitutions of vowels, significantly above their age-matched controls (total N of control participants=741), without, or almost without, parallel errors in consonants.Their vowel deficit manifested itself only in nonwords or, in case they also had surface dysgraphia, in words and nonwords. Indicating their impairment was in the sublexical route, in the conversion of vowels into vowel-letters.We analyzed their error patterns and the effects that influenced their writing, and found that they showed no per-letter length effect, ruling out a buffer impairment. Most of the participants had more vowel errors in the root than in the morphological affix (Wilcoxon z=3.28, p=.001). These results indicate that the sublexical writing route includes separate routes for phoneme-grapheme conversion and for the conversion of morphological affixes from their phonological to their orthographic representation. In addition to the 30 participants reported above, we also identified a further group of 27 participants with vowel dysgraphia who made predominantly vowel omissions in writing (which were not attributable to surface dyslexia).These findings cast new light on vowel errors in writing, which until today were ascribed to a deficit in the orthographic output buffer. We concluded that the impairment underlying vowel dysgraphia is a selective deficit in the sublexical route that affects the conversion of vowel phonemes to graphemes.The results also indicate that there is a separate module in the sub-lexical route for morphological conversion. The findings of the study have theoretical implications for the dual-route model for writing, as well as for treatment.

Keyphrases: Dysgraphia, vowel, writing

@Booklet{EasyChair:6516,
  author = {Maya Yachini and Naama Friedmann},
  title = {Vowel Dysgraphia},
  howpublished = {EasyChair Preprint no. 6516},

  year = {EasyChair, 2021}}