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How low can you go: spatial frequency sensitivity in a patient with pure alexia



How low can you go: spatial frequency sensitivity in a patient with pure alexia



Brain and Language 126(2): 188-192



Pure alexia is a selective deficit in reading, following lesions to the posterior left hemisphere. Writing and other language functions remain intact in these patients. Whether pure alexia is caused by a primary problem in visual perception is highly debated. A recent hypothesis suggests that a low level deficit - reduced sensitivity to particular spatial frequencies - is the underlying cause. We tested this hypothesis in a pure alexic patient (LK), using a sensitive psychophysical paradigm to examine her performance with simple patterns of different spatial frequency. We find that both in a detection and a classification task, LK's contrast sensitivity is comparable to normal controls for all spatial frequencies. Thus, reduced spatial frequency sensitivity does not constitute a general explanation for pure alexia, suggesting that the core deficit in this disorder is at a higher level in the visual processing stream.

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Accession: 036936685

Download citation: RISBibTeXText

PMID: 23774289

DOI: 10.1016/j.bandl.2013.05.006


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