Gender and lesion characteristics modulate the sibilant acoustics in continuous speech after tongue cancer surgery

Oral and oropharyngeal cancer and its treatment can have a devastating impact on speech. The acoustics of 4385 productions of /s/ from 89 patients (66M,23F) mean age 58.67 (range 22–82 years) were analyzed before and after (1, 6, and 12 months) glossectomy surgery. Center of gravity of the fricative power spectrum (COG) was analyzed with a linear mixed effects model with assessment time, age, gender, and amounts of resections (%) within oral and pharyngeal structures as fixed effects and random intercepts for speaker and phonetic context. Before surgery, greater tumor invasion into the floor of the mouth, male sex, and older age lowered the COG. After surgery, COG was reduced (1 month: 1900 Hz; 6 months: 1520 Hz; 1 year: 1080 Hz) and dropped more for women than men. Lesion site impacts COG: the greater the tumour invasion in the tongue, the more the 1-month COG was lowered compared to the rest of the model pointing to a transient aggravating effect. The results suggest partial recovery of speech function at 1 year. The recovery is gendered with women remaining further away from the pre-treatment values after surgery. Future analysis will consider the effects of chemo-therapy and radiation. [Work supported by the Alberta Cancer Foundation, Grant RES0061908.]