New simple evaluation method of the monosyllable /sa/ using a psychoacoustic system in maxillectomy patients

An objective assessment of speech would benefit the prosthetic rehabilitation of maxillectomy patients. This study aimed to establish a simple, objective evaluation of monosyllable /sa/ utterances in maxillectomy patients by using a psychoacoustic system typically used in industry.

This study comprised two experiments. Experiment 1 involved analysis of the psychoacoustic parameters (loudness, sharpness and roughness) in monosyllable /sa/ utterances by 18 healthy subjects (9 males, 9 females). The utterances were recorded in a sound-treated room. The coefficient of variation (CV) for each parameter was compared to identify the most suitable parameter for objective evaluation of speech. Experiment 2 involved analysis of /sa/ utterances by 18 maxillectomy patients (9 males, 9 females) with and without prosthesis, and comparisons of the psychoacoustic data between the healthy subjects and maxillectomy patients without prosthesis, between the maxillectomy patients with and without prosthesis, and between the healthy subjects and maxillectomy patients with prosthesis.

The CV for sharpness was the lowest among the three psychoacoustic parameters in both the healthy males and females. There were significant differences in the sharpness of /sa/ between the healthy subjects and the maxillectomy patients without prosthesis (but not with prosthesis), and between the maxillectomy patients with and without prosthesis.

We found that the psychoacoustic parameters typically adopted in industrial research could also be applied to evaluate the psychoacoustics of the monosyllable /sa/ utterance, and distinguished the monosyllable /sa/ in maxillectomy patients with an obturator from that without an obturator using the system.