The relationship between spectral characteristics and perceived hypernasality in children

The purpose of this study was to quantify perceived hypernasality in childr en. One-third octave spectra of the isolated vowel [i] were obtained from 3 2 children with cleft palate and 5 children without cleft palate. Four expe rienced listeners rated the severity of hypernasality of the 37 speech samp les using a 6-point equal-appearing interval scale. When the average 1/3-oc tave spectra from the hypernasal group and the normal resonance group were compared, spectral characteristics of hypernasality were identified as incr eased amplitudes between F1 and F2 and decreased amplitudes in the region o f F2, Based on the findings of the children's speech, 36 speech samples wit h manipulated spectral characteristics were used to minimize the influences of voice source characteristics on perceived hypemasality. Multiple regres sion analysis revealed a high correlation (R=0.84) between the amplitudes o f 1/3-octave bands (1 k, 1.6 k, and 2.5 kHz) and the perceptual ratings. In creased amplitudes of bands between F1 and F2 (1 k, 1.6 kHz) and decreased amplitude of the band of F2 (2.5 kHz) was associated with an increasing per ceived hypemasality. These results suggest that the amplitudes of the three 1/3-octave bands are appropriate acoustic parameters to quantify hypernasa lity in the isolated vowel [i]. (C) 2001 Acoustical Society of America.