Exploring the aphasiac's naming disturbances; a new approach using the neighbourhood limited classification method.
The patterns of errors observed in eighteen patients with aphasia naming 42 different items presented 5 times in random succession were analyzed by the N.L.C. (Neighbourhood Limited Classification) method. The initial and last responses for each item were considered. The procedure allowed the computation of an improvement coefficient for each patient, illustrating the capacity to modify an initially erroneous response. For each type of response a cluster analysis was performed and a grouping of patients was obtained; in both cases some patients had close to normal scores. Clustering was chiefly a function of severity of word-finding disturbance. Phonemic paraphasias follow a more independent course, allowing additional clustering. In the future, more importance should be given to their discriminative value in the taxonomy of naming disturbances.