Acoustic analysis of subjects with vocal cord paralysis.

Theoretically, there should be a close relationship between the vibratory pattern and acoustic output. The study aims at differentiating unilateral vocal cord paralysis (VCP) from normal subjects and also between right VCP and left VCP based on the acoustic analysis of the subjects voice. The study also aims at comprehensively investigating the phonatory disturbance resulting from VCP on the Indian population. Results indicate that statistically significant differences were found among the following acoustic parameters: fluctuation per sec, in fimdamental frequency (fo), fluctuation per sec, in amplitude, extent of fluctuation in fo, extent of fluctuation in amplitude, jitter ratio, jitter factor, shimmer. Psigma and maximum phonation duration in differentiating unilateral VCP from normal subjects. Also the acoustic parameters: fluctuation per sec, info, extent of fluctuation in fo and Psigma could statistically differentiate between right VCP and left VCP. It can be concluded that the above parameters can be successfully used for diagnosing VCP and also the type of VCP. This is of particular significance in difficult to visualize patients and to monitor the therapeutic outcomes of vocal rehabilitation, following unilateral vocal cord paralysis. These results need to be further clinically validated by using a larger number of subjects.