Background and Objective: The aim of this study is the assessment of quality of voice in patients who had radiotherapy to the neck in regards to parameters such as basic frequency, perturbation, and percent voiced, to investigate the effect of radiotherapy on patients' quality of voice.
Subjects and Methods:  34 patients with head and neck cancer that received radiation therapy as their only form of treatment underwent a voice analysis. The voice analysis consisted of an audio recording made to include three samples of a sustained phonation of the vowel/a/.  Volume Unit Meter was monitored to peak at 0 during a practice count to 10. The best phonation of the three samples was played back for voice analyzer. Up to 9 seconds of the sustained vowel sound /a/ was analyzed for perturbation, percent of voicing and average fundamental frequency. This analysis was repeated 6 months following the completion of radiotherapy.
Results: The voice parameters of 15 patients with laryngeal tumors re analyzed separately from the 19 patients with non-laryngeal tumors. Patients with laryngeal tumors had 12% increase in the  fundamental frequency, 14% improvement in perturbation and 52% improvement in percent voiced. Changes in percent voiced were statistically significant. Patients with non-laryngeal tumors had 42 % increase in the  fundamental frequency compared to the baseline frequency before radiotherapy, 14% improvement in perturbation and 52% improvement in percent voiced. Patients with non larygeal head and neck tumors had 42% improvement in basic frequency compared to the baseline frequency before radiotherapy. Conclusion: Radiotherapy has significantly improved the voice quality of patients with early stage of laryngeal tumors.