Letter-by-letter Reading: Psychological Descriptions of a Neurologial Syndrome

Abstract

Following a general description of the characteristics of letter-by-letter reading and a summary of previous explanations of this reading deficit in both neurological and psychological models, four single-case studies of patients with this syndrome are presented. One central topic, addressed by experimental investigation, concerns comprehension of written words. Despite the use of multiple techniques, no evidence was obtained for the hypothesis that comprehension of a word could occur prior to or in the absence of the letter-by-letter analysis required for oral reading. It appears that these patients must do sequential letter identification of a word in order both to understand it and to report it. A second central topic, addressed through analysis of reading errors, concerns procedures for word recognition. Two of the four patients showed a “pure” letter-by-letter syndrome, with no difficulty in word recognition once the component letters had been identified. For the other two patients, an additional lexical deficit often prevented a correctly identified sequence of letters from achieving recognition as the correct word. Alternative interpretations of these patterns are discussed in terms of a process model.