Acoustic and perceptual voice parameters in subclinical and overt primary hypothyroidism.

Objective: Hypothyroidism is a common endocrine disorder affecting various systems of the body. Only a few studies have focused on the effect of primary hypothyroidism on voice with objective parameters, and none of them compared the effect of subclinical and overt hypothyroidism on voice. The aim of the present study is to evaluate and compare the acoustic and perceptual parameters of voice in patients newly diagnosed with subclinical and overt hypothyroidism.

Methods: The study included 26 subclinical hypothyroidism, 26 overt hypothyroidism patients and 30 euthyroid control participants. Perceptual evaluation of voice with GRBAS (grade, roughness, breathiness, asthenia, strain) scale, voice handicap index (VHI)-10, and acoustic voice analysis by using Multi-Dimensional Voice Program were performed for all the participants.

Results: The voice parameters which showed a statistically significant difference between the groups were frequency parameters (Fo; p= 0.003, Fhi; p=0.010, Flo; p= 0.002) and VHI-10 (p= 0.047). A statistically significant decrease in frequency parameters and a statistically significant increase in VHI-10 were found in overt hypothyroidism group comparing with control group (Fo; p= 0.002, Fhi; p=0.009, Flo; p= 0.001 and VHI-10; p= 0.046). Voice parameters in subclinical hypothyroidism group did not show a statistically significant difference comparing with both control and overt hypothyroidism groups.

Conclusion: In the present study, overt hypothyroidism is found to affect frequency parameters and patients' own subjective assessment of voice. Primary hypothyroidism does not seem to have significant effect on voice parameters until thyroxine levels are affected.