TABLE 2. Mean and Standard Deviation of Considered Feature Values. AP Represents the Anterior-Posterior Axis, ML the Medial-Lateral Axis and SI the Superior-Inferior Axis of Swallowing Vibrations. SS Represents Swallowing Sounds.
| Extracted features | SI | ML | AP | SS |
|---|---|---|---|---|
| Time domain | ||||
| Standard deviation | 0.036 ± 0.018 | 0.011 ± 0.006 | 0.029 ± 0.014 | 0.032 ± 0.018 |
| Skewness | −0.417 ± 1.125 | 0.135 ± 0.903 | 0.614 ± 1.281 | −0.338 ± 1.316 |
| Kurtosis | 13.021 ± 13.529 | 12.951 ± 13.348 | 12.175 ± 10.060 | 11.919 ± 14.187 |
| Normalized entropy rate | 0.926 ± 0.026 | 0.944 ± 0.019 | 0.925 ± 0.029 | 0.904 ± 0.042 |
| Lempel-Ziv complexity | 0.233 ± 0.060 | 0.197 ± 0.057 | 0.220 ± 0.058 | 0.279 ± 0.071 |
| Frequency domain | ||||
| Peak frequency (Hz) | 9.694 ± 4.116 | 10.460 ± 7.568 | 11.330 ± 15.077 | 9.885 ± 12.703 |
| Bandwidth (Hz) | 61.643 ± 46.661 | 94.796 ± 89.831 | 84.707 ± 54.732 | 51.759 ± 22.390 |
| Spectral centroid (Hz) | 37.173 ± 23.724 | 43.369 ± 29.115 | 43.584 ± 33.284 | 36.498 ± 17.811 |
| Time-frequency domain | ||||
| Wavelet entropy | 1.025 ± 0.654 | 0.973 ± 0.654 | 0.877 ± 0.736 | 1.054 ± 0.821 |