The influence of pathological conditions on vocal cord’s displacement: A numerical method and data analysis

In this study, one-mass model of vocal cord is solved by using cubic trigonometric B-spline (CTBS) in order to generate displacements of healthy and pathological vocal cord. By utilizing CTBS, this work aims to investigate the relationship between five vocal cord conditions and its displacements generation throughout phonation process. The approximate displacements derived from CTBS are then compared to displacement generated by ode45 built-in solver through MATLAB software. The errors from both methods are then calculated which represented the effectiveness of the CTBS method in generating vocal cord displacements. Any discrepancies between the results generated by using CTBS and ode45 can be analysed to prove the reliability of CTBS method. Besides, an error analysis is demonstrated in order to quantitatively evaluate the accuracy of the approximate solutions. The generated approximate displacements of CTBS have shown to be approximately close to ode45 results. Thus, it can be concluded that CTBS is a reliable numerical method. The relationship between vocal cord conditions and its generated displacements has represented the distinction between healthy and pathological vocal cord outcomes. Healthy vocal cord has generated a steady decline displacements value while vocal cords with pathological condition have generated fluctuated displacement values throughout the phases of phonation process. The fluctuation trend of displacements value has revealed the irregular displacements value generation which is one of pathological vocal cord feature caused by low stiffness.