The Contribution of Voice Therapy to Voice Quality and Quality of Life in Patients With Early Glottic Cancer Treated With Transoral CO Laser Microsurgery.

[OBJECTIVE] The purpose of the present study was to investigate the contribution of voice therapy in improving voice quality and voice-related quality of life (QOL) in patients treated for early glottic cancer with Transoral CO Laser Microsurgery (TLM).

[STUDY DESIGN] This is a randomized-controlled study of 40 patients (20-intervention group and 20-control group). All underwent TLM surgery, and only the intervention group participated in voice therapy. The same voice assessment and recording protocol was applied in both groups and included subjective and objective voice measurements. Patients in the intervention group were assessed four times (presurgery, after voice therapy, 1 month after voice therapy, and 6 months postsurgery). Patients in the control group were assessed twice (presurgery and 6 months postsurgery).

[METHODS] Each patient of the intervention group attended eight voice therapy sessions. Voice assessment included the self-reported Voice Handicap Index (VHI-30), perceptual voice analysis using the GRBAS scale, and acoustic voice analysis [Mean F0, Jitter (local), Shimmer (local), and Mean Harmonic-to-Noise Ratio (HNR)] was computed using Praat software. For the inter-rater reliability (between raters-first author), two expert raters assessed the voice samples with the GRBAS scale for both groups.

[RESULTS] Statistical analysis showed significant voice quality improvement in both subjective (perceptual) and objective (acoustic) assessments for the intervention group. Additionally, a significant improvement was observed in the QOL of intervention group patients, related to the enhancement of their voice quality after voice therapy. Inter-rater results showed similarities which were more pronounced in the "Grade" parameter for Connected Speech and less pronounced in the "Grade" parameter for Maximum Phonation Time /i/.

[CONCLUSIONS] The present study proved the efficacy of voice therapy in voice rehabilitation for patients treated for early glottic carcinoma with TLM surgery. Improvements in voice quality and voice-related QOL were confirmed by VHI, GRBAS, and Praat measurements.