TY - JOUR

T1 - How low can you go?

T2 - Spatial frequency sensitivity in pure alexia

AU - Starrfelt, Randi

AU - Nielsen, Simon

AU - Habekost, Thomas

AU - Andersen, Tobias S.

PY - 2013

Y1 - 2013

N2 - 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.

AB - 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.

U2 - 10.1016/j.bandl.2013.05.006

DO - 10.1016/j.bandl.2013.05.006

M3 - Journal article

VL - 126

SP - 188

EP - 192

JO - Brain and Language

JF - Brain and Language

SN - 0093-934X

IS - 2

ER -