Objective
To investigate the temporal and kinematic parameters of hyoid bone excursion (HBE) in head and neck cancer (HNC) patients with and without aspiration.
Methods
Videofluoroscopic swallowing study images from 28 HNC patients were divided into aspiration and non-aspiration groups. The kinematic parameters of HBE, including displacement, instantaneous velocity, and instantaneous acceleration, as well as the timing of reaching maximal values in these parameters, were analyzed.
Results
The timings of reaching maximal horizontal (2.37±1.10 seconds vs. 1.09±1.58 seconds, p=0.010; 0.68±0.28 vs. 0.37±0.26, p=0.010 for percentage of time), vertical (1.83±2.06 seconds vs. 0.86±1.42 seconds, p=0.020) and hypotenuse instantaneous velocities (2.36±1.96 seconds vs. 0.79±1.20 seconds, p=0.006; 0.60±0.33 vs. 0.33±0.24, p=0.028 for percentage of time), as well as the timings of reaching maximal horizontal (2.22±1.50 seconds vs. 0.90±1.26 seconds, p=0.009; 0.60±0.32 vs. 0.37±0.29, p=0.041 for percentage of time), vertical (2.09±1.94 seconds vs. 0.83±1.19 seconds, p=0.003), and hypotenuse instantaneous accelerations (2.49±1.93 seconds vs. 0.81±1.24 seconds, p=0.004; 0.65±0.34 vs. 0.34±0.28, p=0.026 for percentage of time) were significantly prolonged in the aspiration group. After signal smoothing, the aspiration group exhibited delayed timing in reaching maximal horizontal instantaneous velocity (2.07±1.09 seconds vs. 0.74±1.10 seconds, p=0.004; 0.58±0.29 vs. 0.32±0.24, p=0.017 for percentage of time), as well as maximal horizontal (2.18±1.16 seconds vs. 1.12±1.46 seconds, p=0.008) and hypotenuse accelerations (2.21±2.50 seconds vs. 0.81±1.21 seconds, p=0.011). There were no significant between-group differences in other kinematic parameters, except for horizontal displacement (7.66±6.26 mm vs. 12.14±5.82 mm, p=0.042).
Conclusion
The timings of reaching maximal instantaneous velocities and accelerations of HBE, rather than the maximum values of these kinematic parameters, may be critical parameters related to aspiration in HNC patients.