Another possibility is that core language processes, e.g., semantic, phonological, or syntactic, acquire representation in visual cortex as a result of adaptations to blindness. A new study tests this hypothesis by studying blind individuals using a language task involving hearing instead of Braille reading. The researchers selected verb generation of "heard nouns" as the behavioral task. This potent, semantic paradigm has been extensively studied in sighted subjects.
A New Study
A new experiment can be compared to previous studies of verb generation to Braille read nouns except that the tasks are identical except for input word modality, i.e., auditory versus Braille. The authors of "Adaptive Changes in Early and Late Blind: A fMRI Study of Verb Generation to Heard Nouns," are H. Burton, A. Z. Snyder, J. B. Diamond, and M. E. Raichle, all from the Washington University School of Medicine, St. Louis, MO. Their findings appear in the December 2002 edition of the Journal of Neurophysiology.
Eight early blind, six late blind, and eight sighted subjects participated in the study. Results were excluded from one early blind, five late blind, and three sighted individuals because of excessive head movement, abnormal brain anatomy by structural imaging, or inadequate performance on post-fMRI scan recall testing. Early blind subjects had no sight at birth or by age three. The average age at onset of blindness in the late blind group was age 19.2 (range, seven to 36). All blind subjects, but no sighted subjects, were fluent Braille readers. Average Braille reading rates for the early blind and late blind subjects were 106.3 words/min (wpm) and 79.7 wpm, respectively.