Development of oral side preference during chewing and its relation to hand preference in normal 2- to 8-year-old children.

Normative data on skills of the tongue used in eating are presented. Normal children 5 to 8 years old were studied regarding their preference of placing food either on the right or left side of the mouth when starting to eat. A developmental curve spanning 2 to 8 years was generated by including data from an earlier study. Data of oral side preference were correlated with data of preferred hand use. In addition, the ability to move a small piece of food from one side of the mouth to the other was studied. It was found that normal children undergo a transition from placing solid food predominantly on the right side at 2 years of age to placing it on the left side at 4 years of age. The left side preference persists until at least 8 years of age for both viscous and solid food textures. Oral side preference did not correlate with hand preference. The ability to move food from one side of the mouth to the other (lateralizing) was found to undergo a developmental progression: The inability to lateralize in a third of 2-year-olds gave way to rolling movements. Concomitantly, a consistent increase in slow and then smooth movements was found to occur from 2 to 8 years of age. These data provide the clinician with a normative baseline against which eating-impaired children can be compared.