The organization of letter-form representations in written spelling: evidence from acquired dysgraphia.
We report on an Italian brain-damaged patient with impaired written spelling. The patient's errors, in different fonts and scripts, consist mainly of letter substitutions (e.g., filo [thread] --> TILO). The results of various tests indicate that letter substitution errors arise because of a deficit in accessing the letter-form representations supporting written spelling. Letter substitutions occurred predominantly between letters with common strokes (e.g., C and G; b and p). Similarities in terms of global letter shape or letter sound were not valid predictors of letter substitution errors. Letter frequency, consonant-vowel status, and letter gemination were factors affecting letter substitution errors. The results of our investigation suggest that information about letter strokes are stored at the level of letter-form representations, and that access to these representations is sensitive to letter frequency. The results further indicate that letter-form representations do not specify whether a letter is a consonant or a vowel, or is a geminate.
Miozzo
Michele
M
Department of Psychology, Columbia University , New York, NY 10027, USA. michele@psych.columbia.edu
De Bastiani
Pierluigi
P
D000381:Agraphia / Q000175:diagnosis* / Q000209:etiology; D002249:Carbon Monoxide Poisoning / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D011596:Psychomotor Disorders / Q000175:diagnosis / Q000209:etiology; D012720:Severity of Illness Index; D014705:Verbal Behavior