Electropalatographic Analysis of Japanese Abnormal Alveolar Sounds Produced by Patients with Cleft Palate

Abstract

Objectives: The aim of this study was to analyze abnormal alveolar sounds by electropalatography (EPG).
Materials & Methods: The subjects were ten post-operative cleft palate patients who underwent visual feedback training with EPG because of residual articulation disorders. The average age at initiating the EPG therapy was 11; 7. Speech samples were 3 Japanese alveolar sounds in VCV syllables: /ata/, /asa/ and /atsɯ/. The cumulative tongue-palate contact patterns were generated for these consonants, and classified into the abnormal patterns described by Gibbon (2004).
Results & Discussion: A variety of tongue-palate contact patterns were observed. The “retracted” pattern was most often observed, followed by “increased contact,” “double contact,” “fronting” and so forth. The retracted positions were also diverse. When the EPG palate was divided into 3 sections —anterior (A), middle (M) and posterior (P)— the M-P contact pattern was most often observed, followed by A-M-P pattern, and P pattern.
“Japanese palatalized misarticulation” is defined as distorted alveolar sounds which are produced at the posterior border of the hard palate and the anterior of the soft palate. If so, neither the M-P nor A-M-P pattern is classified into this category. Moreover, the term “palatalized” might cause misunderstanding in global terms.
Conclusion: It is necessary to reconsider the classification and terminology of Japanese articulation disorders in order to promote mutual understanding domestically and globally. Electropalatography is a useful tool for objective analysis of abnormal articulations.