Automatic evaluation of speech impairment caused by wearing a dental appliance

Abstract

In dentistry, speech evaluation is important for ap-propriate orofacial dysfunction rehabilitation. The speech intelligibility test is often used to assess pa-tients' speech, and it involves an evaluation by human listeners. However, the test has certain shortcomings, and an alternative method, without a listening pro-cedure, is needed. The purpose of this study was to test the applicability of an automatic speech intelligi-bility test system using a computerized speech recog-nition technique. Speech of 10 normal subjects, when wearing a dental appliance, was evaluated using an automatic speech intelligibility test system that was developed using computerized speech recognition software. The results of the automatic test were re-ferred to as the speech recognition scores. The Wil-coxon signed rank test was used to analyze differ-ences in the results of the test between the following 2 conditions: with the palatal plate in place and with the palatal plate removed. Spearman correlation co-efficients were used to evaluate whether the speech recognition score correlated with the result of con-ventional intelligibility test. The speech recognition score was significantly decreased when wearing the plate (z = −2.807, P = 0.0050). The automatic evalua-tion results positively correlated with that of conven-tional evaluation when wearing the appliance (r = 0.729, P = 0.017). The automatic speech testing system may be useful for evaluating speech intelligibility in denture wearers.