Failure to learn a new spatial format in children with developmental dyslexia.
A general problem in studying children with developmental dyslexia is how to separate inefficiency in learning on the one hand from exposure to written texts on the other. To evaluate dyslexic children's learning abilities with graphemic materials, we tested their improvement in a condition that minimized previous experience with words (i.e., "novel words") and with the standard, horizontal spatial letter array (i.e., a non-canonical "zigzag" format). We selected five pairs of children with dyslexia and (younger) typically developing readers matched for reading speed and accuracy in these specific conditions. Reading performance on novel words in the zigzag format was measured in 23 sessions; learning curves were fitted by power functions. Similar to typically developing readers, children with dyslexia improved their reading of novel words presented in the new format; however, their rate of learning was slower than that of typically developing readers. Furthermore, their learning to read in the new format did not generalize to novel untrained items, whereas significant generalization was present in typically developing readers. As the failure to generalize learning of the spatial format could not be attributed to reduced experience, it indicates a genuine disability and points to impaired perceptual learning as a factor in developmental dyslexia.
1] Neuropsychology Unit, IRCCS Fondazione Santa Lucia, via Ardeatina 306, 00179 Rome, Italy [2] Psychology Department, Sapienza University of Rome, via dei Marsi, 78, 00185 Rome, Italy.
Maria
M
Pontillo
Neuropsychology Unit, IRCCS Fondazione Santa Lucia, via Ardeatina 306, 00179 Rome, Italy.
Maria
M
De Luca
Department of Psychology, University of York, York, YO10 5DD, United Kingdom.
Andrew W
AW
Ellis
Neuropsychology Unit, IRCCS Fondazione Santa Lucia, via Ardeatina 306, 00179 Rome, Italy.
Chiara Valeria
CV
Marinelli
1] Neuropsychology Unit, IRCCS Fondazione Santa Lucia, via Ardeatina 306, 00179 Rome, Italy [2] Department of Human Movement, Social and Health Sciences, University of Rome "Foro Italico", piazza Lauro De Bosis 15, 00135 Rome, Italy.
Donatella
D
Spinelli
1] Neuropsychology Unit, IRCCS Fondazione Santa Lucia, via Ardeatina 306, 00179 Rome, Italy [2] Psychology Department, Sapienza University of Rome, via dei Marsi, 78, 00185 Rome, Italy.
Pierluigi
P
Zoccolotti
D000293:Adolescent; D002648:Child; D004410:Dyslexia / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time; D011932:Reading