Voicing recovery in males following radiotherapy for larynx cancer

Larynx cancer patients receive radiotherapy as a non-invasive alternative to surgery and cure rates are high. Inevitably this impacts vocal fold functional-ity. Hence, voice recovery as a prerequisite for resuming normal life is of special interest. Voicing recovery following radiotherapy is studied in this paper. Complexity analysis, using approximate entropy to concisely quantify the collective spectral pattern derived from the electro-glottogram, has revealed a double banded male normal voicing reference standard. Forty-eight male larynx cancer patients have been studied by applying this technique in parallel with an unrestricted perceptual analysis before and one year after radiotherapy. Two thirds of radiotherapy patients had improved voice quality one year after treatment. Approximate entropy increased to reach normal population reference levels. These patients were predominantly in the less aberrant perceptual categories. However, a quarter of patients showed reduced approximate entropy and were predominantly in the most aberrant perceptual categories. Complexity analysis has the potential to be a reliable, single parameter measure of voicing quality for use in monitoring radiotherapy patient recovery.