Meeting Abstract
Chewing is a mammalian motor behavior used to reduce and mix food with saliva before swallowing. During chewing, the jaw moves continuously through opening and closing phases (pitch) while rotating about a vertical axis (yaw) to generate the grinding motion of the teeth in contact with the food. Previously, chewing studies were based upon measurements taken at a finite set of heuristic time points in continuous movements, but functional data analysis allows comparing movements continuously and in their entirety throughout the gape cycle. We hypothesize that variability in jaw movements during chewing will include food-, individual-, and degree-of-freedom (dof)-specific differences. Chewing movements were quantified in 4 pigs feeding on 3 foods (almonds, carrots, and apples) using XROMM. The time series of the three main dofs (pitch, yaw, and condylar translation) were transformed into continuous functional objects and a functional analysis of variance (fANOVA) was used to test differences between individuals, foods, and two-way interactions. Results demonstrate that significant differences exist between individuals, and between food types. However, not all dof were affected similarly. Most of the individual differences occurred in jaw pitch and condylar translation, whereas jaw yaw was consistently inflexible. Pig chewing is therefore characterized by non-negligible individual differences that become richly expressed across foods and that highlight how multiple performances can achieve the same behavior.
