Nasalance distance and ratio: two new measures.

OBJECTIVES: Mean nasalance in speakers with perceptually normal nasal resonance can differ in magnitude considerably. In addition, categorizations of speech based on nasalance scores may not agree with perceptual judgments. To overcome this limitation, we evaluated two new simple measures derived from mean nasalance data: the nasalance distance (range between maximum and minimum nasalance) and the nasalance ratio (minimum nasalance divided by maximum nasalance). SETTING: Department of Oral and Maxillofacial Surgery, University of Technology, Munich, Germany. SUBJECTS: The sample consisted of 133 cleft lip and palate patients with normal nasal resonance or varying degrees of hypernasality. PROCEDURES: Oral and nasal acoustic measurements were made using the NasalView system. Nasalance distance and nasalance ratio were calculated for five non-nasal and three nasal sentences from the modified Heidelberg Rhinophonia Assessment Form. RESULTS: Optimum cutoffs were derived from receiver-operating characteristics. Results for the sentence stimuli ranged from 64.4% to 89.6% sensitivity and from 91.2% to 94.1% specificity. When the analysis was limited to only one nonnasal and one nasal sentence, results ranged from 79.7% to 87.5% sensitivity and from 88.2% to 97.1% specificity. CONCLUSIONS: We conclude that the two new measurements are valuable in routine clinical examinations. Nasalance distance and ratio derived from sentence stimuli are two useful and easily applicable measures that can be used to supplement the nasalance mean value.

Speaking fundamental frequency characteristics of white, African American, and Hispanic kindergartners.

Speech samples from groups of White, African American, and Hispanic kindergarten-age children were compared on measures of mean speaking fundamental frequency (F(zero)), maximum and minimum speaking F(zero), pitch sigma, and speaking range (in semitones). Results indicate that there are significant differences between racial groups on measures of mean speaking F(zero) and speaking range. In particular, the Hispanic children were observed to have increased mean speaking F(zero)S in comparison with the African American children and reduced speaking ranges as compared to both African American and White racial groups. Results indicate that the speech-language pathologist must exercise discretion when assessing the speaking F(zero) characteristics (particularly mean speaking F(zero) and speaking range) of children from different racial groups.

Improvements in estimating the harmonics-to-noise ratio of the voice.

An improved algorithm for computing harmonics-to-noise ratio (HNR) of the voice was developed and tested using synthesized vowels at various fundamental frequencies and known HNR values. The described algorithm implements a stringent routine for the identification of pitch pulse boundary markers based on a combination of peak-picking and zero-crossing procedures. Results showed mean absolute errors between computed versus expected HNR to be < 2 dB, a significant improvement over previously reported methods. Computational errors were minimized most effectively with vowel samples in the range of 17 to -10 dB HNR. Normative data for young adult males and females indicate that HNR < 13 dB may be considered abnormal in a majority of cases.

Superimposition of speaking voice characteristics and phonetograms in untrained and trained vocal groups.

This study details a comparison of the speaking F0 and intensity values of young male and female adults with and without vocal training, as well as the superimposition of the speaking F0 and intensity data upon phonetograms. Results indicated that (a) trained vocalists have similar mean speaking F0's than do untrained vocalists, but exhibit significantly greater speaking F0 ranges than do untrained vocalists; (b) trained vocalists are significantly greater mean intensity levels in speech, as well as significantly greater speaking intensity ranges than do untrained vocalists; (c) the mean speaking F0 for both trained and untrained vocalists was found in the vicinity of the 5-7% frequency level of the entire phonational F0 range (in Hz), equivalent to 12-16% of the phonational F0 range in semitones; (d) the overall speech area (mean speaking F0 and minimum and maximum speaking F0 peaks) was found in the lower 23-31% of the entire phonational F0 range (in semitones), with the untrained subjects utilizing the lower 25% of the phonational range (in semitones) and the trained subjects extending this area to the lower 28-31%; and (e) significant correlations were observed between the total intensity range and intensity range used in speech in trained female vocalists and between total F0 range and speaking F0 range in the combined trained male and female group. These results have important implications for the use of the phonetogram, as well as the clinical applicability of vocal training exercises in various speech and voice therapy cases.

Speaking fundamental frequency characteristics of centenarian females.

Speaking fundamental frequency (F(0)) characteristics were determined for nine centenarian females and nine young adult females. Mean, maximum, and minimum F(0) values were obtained for each subject from a minimum of 20 s of continuous speech. Results indicated that female centenarians have significantly lower mean and minimum speaking F(0) values than young adult females, as well as significantly greater speaking F(0) ranges (in both Hz and semitones). The present results extend the investigation of the ageing continuum as it affects vocal F(0), and indicate that excessively low mean and minimum speaking F(0) values must be considered within the normal spectrum of voice characteristics for the female centenarian population.