Towards a taxonomy of aphasic errors. A pilot study.

Error patterns occurring in an aphasic population performing a naming task were explored by factor analysis. This confirmed the existence of two error types: a phonemic and a semantic one. The latter was about twice as important as the former; as a consequence, a weighting system restoring the balance between both was required before submitting patients' scores to cluster analysis. Suitable weighting coefficients were computed according to data obtained by factor analysis. As defect severity interfered with the results of cluster analysis, scores were weighted in order to neutralize the severity dimension.