Principled syllabic dissolution in a primary progressive aphasia case

Abstract

In this longitudinal study, the syllabic paraphasias (here defined as insertions or deletions of a phoneme) produced by a Primary Progressive Aphasia case to syllabic adaptations of loanwords were compared. It is shown that paraphasias are phonologically principled and thus highly predictable. More specifically, it it shown that the repair strategies applied by the patient are very similar to those applied by normal speakers when they adapt borrowings. The rate of segment preservation as opposed to segment deletions is very high in borrowings and in the syllabic errors produced by the patient. However, the type of repair strategy applied by the patient changes with the progression of thephonological deficit, segment deletions being more frequent than segment insertions in the late stages of the illness. The evolution of the syllabic error pattern is accounted for by the effect of two principles: the Preservation and the Threshold Principles. The combined effects of these two principles entail that segment preservation has the edge over segment deletion except when the preservation of a segment requires too many phonological operations. It is suggested in this study that the Preservation Principle remains effective even in the late stages but its effect is reduced with the progression of the deficit because the patient's tolerance threshold to complex (multi-step) repair is lowered.