MULTIPLE ROUTES FOR READING WORDS, WHY NOT NUMBERS - EVIDENCE FROM A CASE OF ARABIC NUMERAL DYSLEXIA

This paper describes a patient (SF), suffering from a probable dementi a of Alzheimer's type, with a severe difficulty in reading aloud arabi c numerals and a spared ability to read aloud alphabetical material. T his pattern of impairment completed a double dissociation with the ''n umber sparing effect'' observed in some alexic patients (e,g. Dejerine , 1892; Anderson, Damasio, and Damasio, 1990), Through a systematic in vestigation of the patient's performance on various tasks it was estab lished that he could recognise and understand arabic numerals and prod uce verbal numerals as responses to number fact or ''what comes next?' ' questions, This study allowed the conclusion that arabic numerals an d alphabetically written stimuli are read by two processes which are a t least partly dissociable. The patient's performance was interpreted as a consequence of damage to a postulated asemantic route for arabic numeral reading.