Normative Thresholds for Acoustic Estimates of Relative Fundamental Frequency.

PURPOSE

The purpose of this study was to establish normative thresholds for relative fundamental frequency (RFF) referencing individuals with typical voices.

METHOD

A total of 150 speakers (75 males, 75 females) without voice disorders were evenly divided into three age groups: 18-39, 40-64, and 65+ years. Each participant produced three repetitions of the utterances /ɑfɑ/, /ifi/, and /ufu/ at their typical pitch and loudness, which were recorded for analysis. A semi-automated RFF algorithm calculated the offset and onset cycles of the vowels (/ɑ/, /i/, /u/) before and after each /f/ production. Resulting mean offset and onset values were aggregated across utterances for each participant. A multivariate analysis of variance (MANOVA) was completed to assess the effect of speaker sex, age group, and their interaction for offset cycle 10 (OFF10) and onset cycle 1 (ON1) values. Normative thresholds for OFF10 and ON1 were established based on the mean and standard deviations of these measures according to significant effects indicated by follow-up univariate ANOVA models.

RESULTS

Effects of sex and age group were significant in the MANOVA models for OFF10 and ON1. Follow-up univariate ANOVAs indicated that age group was a significant factor for OFF10, and speaker sex was significant for ON1.

CONCLUSIONS

The current study identified statistically significant effects of age on RFF values for OFF10 and sex on RFF values for ON1. Normative thresholds for RFF at these cycles were therefore established based on these demographic factors. Future research should explore the clinical utility of these thresholds for distinguishing individuals with voice disorders from those with typical vocal function.