Temporal and Kinematic Measurements of Hyoid Bone Excursion in Patients With Head and Neck Cancer.

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.