Acoustic fidelity of internet bandwidths for measures used in speech and voice disorders.

The purpose of this study was to explore the impact of different bandwidths on acoustic measures when using low-cost internet technology of teletherapy in the field of speech and language rehabilitation. Normal speech and voice samples were collected at a clinic and a remote place by connecting the computers to Skype and VoiceEmotion software, while the disordered speech samples were collected through teaching CD samples from a quality voice textbook. Pure tones at 200 and 1000 Hz were also collected. The acoustic parameters: average fundamental frequency (F0), jitter percent, shimmer percent and noise-to-harmonic ratio (NHR) were used for fidelity analysis. The average F0 increased across all samples and bandwidths. There was greater increase and variability on the disordered voice samples. Speaking F0 was shown to both increase and decrease in no identifiable pattern with the different bandwidths. Jitter, shimmer and NHR were significantly different on pre- and post-transmission trials. The study provided preliminary pilot data on the fidelity effect of internet transmission on acoustic variables for voice and speech. Cautious suggestions were also provided to speech and language therapists who would consider using teletherapy for speech and voice diagnosis and treatment.