## 5 Results and Discussion
### Effect of Medial Compression  
As discussed in Section 2.1, HSV was captured with and without medial compression for \(p_{\text{sub}}=1\,\mathrm{kPa}\). Since it was difficult to measure the degree of medial compression experimentally, the actual pre-stress is highly uncertain. As such, the initial position parameter \(x_{0}\) in the FE model is included as an estimated parameter for both cases. Table 4 presents the estimated material properties for both medial compression cases. The estimated properties (excepting \(x_{0}\)) agree well with each other and with the \"ground truth\" values. This is encouraging in two respects: the same silicone VFs were used in both cases, and the pre-stress in the medial compression case is captured in \(x_{0}\) and thus does not appreciably bias the stiffness estimates. However, the higher parameter uncertainties for the medial compression case is very likely due to the fact that the pre-stress associated with medial compression can be approximated by varying other stiffness parameters. This yields more overall uncertainty in the results, as other parameter combinations can explain the observed data. The estimates for the initial position parameter, \(x_{0}\), are statistically different between the two cases. When there is no medial compression the initial position is estimated to be \(8.39\,\mathrm{mm}\) (\(8.4\,\mathrm{mm}\) corresponds to zero compression, see Figure 2a); with compression, \(x_{0}\) is estimated to be \(8.27\,\mathrm{mm}\). This \(0.12\,\mathrm{mm}\) difference in the estimates is more than double the sum of the two estimated standard deviations, with a t-value of \(3.67\), indicating that the FE model was capable of distinguishing between the experimental configurations. This does differ from the \(0.4\,\mathrm{mm}\) shim placed experimentally to produce the medial compression, though again, the actual degree of experimental medial compression was very difficult to ascertain. Comparing the case without medial compression with the results in Table 3 shows that the uncertainties in the estimated parameters are larger in the present case despite using the same observation data. By including the extra fitting parameter, \(x_{0}\), the estimated uncertainties increase due to the higher dimensionality (more parameters being fit given the same input data). That is, with the addition of \(x_{0}\) as a parameter, there is now an alternative pathway to influence the energy in the system. That said, the uncertainties in both estimates are large enough and the estimated values are similar enough that the two data sets cannot be distinguished statistically. Figure 5 presents the measured and estimated GAWs for the two medial compression cases, wherein the FE models employ the material properties given in Table 4. Both estimates fit the data reasonably well given the simplified FE model being used. The open quotient and speed quotients are both lower for the FE models, with the effect more pronounced for the case with medial compression. This results in a more peaked GAW in comparison with the HSV. The case without medial compression exhibits larger maximum glottal area, however the maximum contact pressure experienced during collision in the case