K AverageVelocity
 U Max Velocity








 Thin Thick

Figure 3-3. Figure depicting the change in average and max velocity as a function of
 bolus consistency.

Case Studies

 Below the data output from the MATLAB hyoid trajectory program is provided for

a single subject with both a safe (P-A=1) and unsafe (P-A=8) swallow.

Table 3-11. Order of swallow events and hyoid trajectory measurements for "safe
 swallow".
Swallow Event Frame No. Angle Displacement Velocity
Onset Bolus Transit 1 0.157 1.279 42.641
Palatal onset 11 2.45 -0.154 34.900
Bolus at ramus 12 2.059 -0.609 15.144
UES opening 17 2.741 1.288 14.484
Max Laryngeal Closure 20 1.549 2.258 71.923
UES closing 27 0.220 5.028 17.711
Palatal offset 34 7.788 -2.136 32.096

 Following are the figures depicting the trajectory of the hyoid in terms of angle and

in terms of displacement (Figures 3-4 through 3-9). Although the pattern of movement

is similar, in the "safe and "unsafe" swallows, in the "unsafe" swallow the first three

events (onset bolus transfer, palatal onset, and bolus head at ramus) have occurred within