Effects of Phonological Complexity on Error Production and Pseudoword Training in Acquired Phonological Dyslexia

Abstract

Individuals with acquired phonological dyslexia experience difficulty associating written letters with their corresponding sounds, especially in pseudowords. Several studies have attempted to improve reading in this population by training letter-to-sound correspondence, general phonological skills, or a combination of these approaches; however, their success has generally been limited to trained words. Training studies with other clinical populations have shown increased generalization when items were manipulated based on linguistic complexity. Sonority, the relative measure of intensity related to openness of the vocal tract, is one variable of phonological complexity that has been investigated in aphasic error production and training of phoneme production in children with phonological disorders. To date, however, no studies of acquired phonological dyslexia have systematically manipulated phonological complexity in order to investigate error production or to improve reading ability. The present study examined phonological complexity as a predictor of error production (Experiment 1) and a training variable for letter-to-sound reading (Experiment 2) in acquired phonological dyslexia.

Ten participants in Experiment 1 read aloud and repeated single-syllable real words and pseudowords controlled for phonological complexity. Results indicated phonological complexity was a significant predictor of syllable onset accuracy, particularly for segment 2 of the onset (e.g., /l/ in cluster /bl/), with significantly greater accuracy for “simple” clusters compared to “complex” clusters. Two consonant clusters were selected for training in Experiment 2: one cluster representing a “complex” onset (e.g., /fl/) and the other representing a “simple” onset (e.g., /kl/) as predicted by sonority. Three participants were trained on the “complex” cluster and two were trained on the “simple” cluster, while tracking oral reading accuracy of both onsets. Training involved a combination of letter-sound correspondence and phonological skill instruction. Consonant cluster oral reading accuracy of training and generalization items was measured with weekly probes. As predicted, participants who received training in the “complex” condition demonstrated improved ability to orally read pseudowords with the trained cluster onset as well as generalization to pseudowords with the untrained, “simple” onset, but not vice versa. The present findings suggest phonological complexity can be used to improve generalization to untrained phonologically related words in acquired phonological dyslexia.