Effects of Weight Loss on Acoustic Parameters After Bariatric Surgery

Patients with morbid obesity may present vocal alterations, since large accumulation of fat in the vocal tract may interfere with voice production of these individuals.

Verify the neck circumference and the acoustic parameters of voice in obese women, before and after the bariatric surgery, and compare the results with a control group, with normal weight.

Observational, longitudinal, descriptive study with patients referred to the SCODE (Obesity Surgery and Related Disorders Center) in a university hospital. The sample consisted of 25 morbidly obese women, age range 28–43 years and 23 non-obese women, aged 21–41 years control group. To measure the neck circumference, a tape measure was used and all participants were seated upright with the head positioned in the Frankfort horizontal plane. The fundamental frequency was calculated through the sustained emission of vowel [a] at usual intensity and pitch, to measure the fundamental frequency of the voice, that is, how much the vocal fold vibrates per second. After the recording, participants were prompted to produce vowels [a], [i], and [u] sustained at usual intensity and pitch, and a stopwatch was used to measure the maximum phonation time, to verify the balance between myoelastic and dynamic forces of the larynx. After 8 months post-surgery, the patients were recruited to be re-evaluated using the same pre-surgical data collection procedures.

There was an increase in the mean value of f0. The maximum phonation time of all vowels increased after surgery.

Obese individuals with post-surgery weight loss may present neck circumference, fundamental frequency, and maximum phonation time values closer to the mean values of normal weight individuals. In this study, weight loss was sufficient to adjust the acoustic parameter measurements.