RECOVERY PROCESS OF COLOR NAMING DEFECTS IN PURE ALEXIA - A 5-YEAR LONGITUDINAL EXPERIMENTAL-STUDY

The present study investigated the recovery process of colour naming d efects and the ability for matching seen colour to colour name given v erbally (colour pointing) in a patient with pure alexia (M.S.). The re covery process of the patient's ability to process the physical parame ters involved in colour information processing was also examined. To l ook at how M.S. processed the physical parameters, the similarity judg ment tasks of internal representation of colour generated by verbal an d visual stimuli were employed. While colour pointing ability became p ractically normal 22 months postonset, colour naming defects took long er to recover. The analysis of the results of similarity judgment usin g multidimensional scaling revealed that: (1) verbal stimuli generated consistently more stable internal representation of colour than visua l stimuli; and (2) colour information processing of M.S. altered 'hue with lightness' dependent to more 'hue' dependent in the 5 years since the onset of illness. The underlying neuropsychological mechanism was discussed for these findings.