The relationship between visuo-spatial attention and nonword reading in developmental dyslexia

Abstract

Focused visuo-spatial attention was studied in 10 developmental dyslexic children with impaired nonword reading, 10 dyslexic children with intact nonword reading, and 12 normally reading children. Reaction times to lateralized visual stimuli in a cued detection task showed that attentional facilitation of the target at the cued location was symmetrical in the three groups. However, dyslexics with impaired nonword reading selectively showed a lack of attentional inhibition for targets at the uncued location in the right visual field. This result was replicated in a second group of 13 dyslexics with impaired nonword reading. Individual differences in the ability of right attentional inhibition across the entire sample of dyslexics accounted for 17% of unique variance in nonword reading accuracy after controlling for individual differences in age, IQ, and phonological skills. A possible explanation based on the role of spatial attention mechanisms in the graphemic parsing process is discussed. Our results suggest that focused visuo-spatial attention may be crucial for nonword decoding.

The authors would like to thank M. Pezzani for access to a clinical unit, C. Baracchetti and A. N. Trussardi for help in collecting the clinical data, K. Priftis and T. Gianesini for helpful discussions, and A. Hillis and three anonymous reviewers for help in improving this manuscript. This work was supported by the Italian National Research Council, the Ministry of Health, the “Amici della Pediatria” Association of Bergamo General Hospital to A.F., the Italian Ministry of University and Scientific Research to C.U. and M.Z., and the Canadian Institute of Health Research to L.C.

Notes

¹ All our previous studies on visuo-spatial attention and DD except one (i.e., Facoetti et al., 2000b) controlled for the presence of ADHD. In other cited studies (i.e., Brannan & Williams, 1987; Hari & Renvall, 2001) the comorbidity of ADHD was not specified.

² As noted by one anonymous referee, the word-reading impairment associated to normal nonword reading ability in the DDN + group (Z-scores:−4.01 vs. − 0.61, respectively), t(9) = 4.51, p < .002, might suggest a surface dyslexic profile. However, such a diagnosis cannot be firmly established because participants did not read a specific list of irregular words. Moreover, note that DDN + children are much less frequently found than DDN − children. In the current study, only 10 DD in an unselected consecutive sample of 33 dyslexic children conformed to the criteria for the DDN + group.