Effects of Computer System and Vowel Loading on Measures of Nasalance

Abstract

Purpose The purpose of this study was to determine similarities and differences in nasalance scores observed with different computerized nasalance systems in the context of vowel-loaded sentences. Methodology Subjects were 46 Caucasian adults with no perceived hyper- or hyponasality. Nasalance scores were obtained using the Nasometer 6200 (Kay Elemetrics Corp.), the Nasometer II 6400 (Kay Elemetrics Corp.), and the NasalView (Tiger DRS, Inc.) for sentences loaded with mixed, high front, high back, low front, or low back vowels. Results Measures of nasalance obtained with the NasalView were significantly higher than those obtained with the Nasometer 6200, and the measures of nasalance obtained with the Nasometer 6200 were significantly higher than those obtained with the Nasometer II 6400. However, similar effects of vowel loading on measures of nasalance were observed, regardless of system. For all systems, the high front vowel sentence tended to result in higher measures of nasalance than did the high back, low front, and low back vowel sentences—the mixed vowel sentence tended to have a higher degree of nasalance than did any of the other sentences. Conclusions Although nasalance data computed using different systems are not readily comparable, all three systems that were evaluated produced similar effects of vowel loading on nasalance. Increased nasalance for high front versus low back vowels may be due to factors such as increased oral impedance, reduced radiated oral sound pressure, possible increases in airflow via the nasal cavity, and increased transpalatal nasalance.