A longitudinal pilot study on phonetograms/voice profiles in pre-pubertal choir boys.
The phonetogram or voice profile, measuring frequency combined with intensity of the voice, has replaced simple measurement of tone ranges for analysis of professional boys choirs. Knowledge of the relationship between pubertal, sex hormones, and phonetogram development has been established in stratified studies. The connection between the singing voice in puberty and other pubertal phenomena needs documentation in longitudinal studies also. Therefore, a pilot study was carried out, where three boys aged 13-15 years were analysed at intervals of 2 months. Measurement of phonetograms, free and total serum testosterone and sex hormone binding globulin (SHBG) showed a significant relationship between SHBG and lowering of the lowest tones in the phonetograms (P < 0.01) confirming earlier stratified studies.