SELECTIVE READING SLOWNESS IN A TRAUMATIC PATIENT WITH IMPAIRMENT IN BASIC VISUAL PROCESSES

Following a closed-head injury, G.M., a 17-year-old male, showed a rea ding disturbance in the absence of other cognitive deficits. G.M.'s re ading was exceedingly slow, although virtually error free. Analysis of his disorder indicated an inability to read words presented tachistos copically to the left (spared) visual field. Therefore the reading def icit cannot be interpreted as simply due to the visual field reduction (hemianopic alexia). Reading speed was clearly affected by word lengt h, a finding typical of letter-by-letter reading. Both behavioral and psychophysical testing indicated a selective reduction of visual discr imination and detection (particularly in the range of high spatial fre quency information) in portions of the left hemifield which appeared s pared upon perimetric examination. Overall, it is suggested that the r eading deficit, phenomenologically similar to that of other letter-by- letter readers, can be interpreted as due to a combination of basic vi sual perturbations: visual field cut with macular splitting and defici t of processing of high spatial frequency information.