Effects of adenotonsillectomy on speech spectrum in children

The vocal tract, which starts from the glottis and extends to the lips is considered to be a resonator for speech production. Enlarged palatine tonsils may cause hypernasal speech, oral breathing or muffled voice. Changes in the structure of this resonator are assumed to modify the speech characteristics. The aim of this study was to evaluate changes in acoustic feature of speech after adenotonsillectomy in children and to establish concepts of management and rational therapeutic approach.

Before and after surgery, an acoustic analysis was made to 40 children, aged between 5 and 14 years old, with enlarged palatine tonsils and hypetrophic adenoids. Phonetically balanced sentences were carried out and digitalized with Multi Dimensional Voice Program (MDVP, Kay Elemetrics). As a control group, 40 healthy children were identified. These parameters were estimated: average of fundamental frequency (Fo), Jitt, Shim, noise to harmonics ratio (NHR), voice turbulence index (VTI), soft phonation index (SPI), degree of voiceless (DUV) and degree of voice breaks (DVB).

After adenotonsillectomy, our data showed an improvement in all the parameters: the analysis of Fo, Jitt, Shim, NHR, VTI, SPI, DUV and DVB showed a postoperative decrease; comparison with healthy children highlighted a postoperative normalization of NHR, VTI and DVB.

The postoperative improvement of the parameters suggests a reduction of the nasal resonance and the improvement of voice quality. MDVP method may be useful for analyzing speech characteristics, evaluating the effects of surgical excision and therapeutic approach: in selected cases of patients with enlarged tonsils, the decision to perform tonsillectomy depends on its potential positive effect on speech too.