Analysis of the spontaneous writing errors of normal and aphasic writers.

Samples of spontaneous writing were collected from 150 normal subjects, 13 Broca's aphasics, 23 Wernicke's aphasics and 14 conduction aphasics. The errors obtained were classified using a system derived from investigations of slips of the pen in normal subjects. All three aphasic groups made a higher proportion of word-level errors than did the normal writers. Word-level errors tended to be selection errors (substitutions, blends, neologisms, and omissions) rather than movement errors (anticipations, perseverations and reversals). Conduction aphasics showed proportionately more letter movement and fewer letter selection errors than normal writers while Wernicke's and Broca's aphasics showed similar proportions. Graphic and phonetic similarity was no more important a determinant of letter errors in aphasics than in normals. The span of movement errors was particularly restricted in the Broca's and conduction aphasics. Asking patients to write connected text yields insight into the nature of the underlying disorder that could not be obtained from studying the writing of single words.