Analysis of formant frequencies in patients with oral or oropharyngeal cancers treated by glossectomy.

AIMS To compare voice quality as defined by formant analysis using a sustained vowel in patients who have undergone a partial glossectomy with a group of normal subjects. METHODS & PROCEDURES The design consisted of a single centre, cross-sectional cohort study. The setting was an Adult Tertiary Referral Unit. A total of 26 patients (19 males) who underwent partial glossectomy and 31 normal volunteers (18 males) participated in the study. Group comparisons using the first three formant frequencies (F1, F2 and F3) using linear predictive coding (Laryngograph Ltd, London, UK) were performed. The existence of any significant difference of F1, F2 and F3 between the two groups using the sustained vowel /i/ and the effects of other factors, namely age, first presentation versus recurrence, site (oral cavity, oropharynx), subsite (anterior two-thirds of the tongue, tongue base), stage, radiation, complication, and neck dissection, were analysed. OUTCOMES & RESULTS Formant frequencies F1, F2 and F3 were normally distributed. F1 and F2 were significantly different in normal males versus females. F1, F2 and F3 were not different statistically between male and female glossectomees. Comparison of only women showed significant differences between normal subjects and patients in F2 and F3, but none in F1. This was the opposite in men where F1 was significantly different. Age, tumour presentation, site, subsite, radiation and neck dissection showed no significant difference. Postoperative complications significantly affected the F1 formant frequency. CONCLUSIONS The study found that the formant values in patients following a partial glossectomy were altered significantly as compared with the normal control subjects. Only gender and complications and not the age, site, subsite, radiation and neck dissection were seen to influence the formant scores.