CHAPTER 4
 DISCUSSION

 The current study assessed the effects of bolus consistency on swallow timing and

P-A score in persons with PD. The findings were mainly consistent with the hypotheses

set forth, with the exception of some minor differences that will be discussed in greater

detail below. The current study also presents exploratory data quantifying the motion of

the hyoid bone in relation to measures of bolus transit and penetration/aspiration. These

measures were obtained utilizing an innovative MATLAB program which provides

information about angle, displacement, and the order of events relative to hyoid motion.

The following discusses the research findings and their clinical importance.

 Primary Aim

Measures of Bolus Transit

 When measuring bolus transit, the primary dependent variables included oral transit

time, pharyngeal transit time, and number of tongue pumps. Both oral and pharyngeal

transit time have been used to address bolus transit in varying populations (i.e., De

Vincentiis et al., 2004; Han, Paik, & Park, 2001; Monte, da Silva-Junior, Braga-Neto,

Nobre e Souza, & Sales de Bruin, 2005; Nagaya et al., 1998; Robbins, Levine, Maser,

Rosenbek, & Kempster, 1993). In the current study, a significant difference was found in

oral transit time as a function of the thickness of the bolus, with oral transit time

increasing with thicker boluses. These findings are not surprising. Past research has

found that thicker consistencies lead to greater oral transit times (Dantas et al., 1990), but