A study in 2014 completed by Dr. Michelle Ciucci et al., the effect of tongue exercise on rats in a neurotoxin model of Parkinson's disease. They discussed how Parkinson's disease can lead to significant swallowing problems, including difficulty forming the food or liquids into a bolus and propulsion of the bolus from the mouth into the pharyngeal phase of the swallow, and problems with food and/or liquids then entering the airway. "As the disease progresses, these deficits cause debilitating health complications, including death from aspiration pneumonia." ( Ciucci et al.)
In the study, they hypothesized that training targeting tongue exercises would improve timing and force measures and also lead to striatal dopamine sparing. They had the rats complete tongue exercises through complex licking tasks. Results demonstrated that the rats in the exercise group performed better for maximal lingual force, average lingual force, and lingual press rate than the rats in the no exercise control group. Sparing of striatal dopamine was not found. Study authors concluded: "Thus, targeted exercise can improve tongue force and timing deficits related to 6-OHDA lesions and this exercise likely has a central, versus peripheral (muscle strength) mechanism. However, this mechanism is not related to sparing of striatal dopamine content."
Exercise-induced rescue of tongue function without striatal dopamine sparing in a rat neurotoxin model of Parkinson disease; Michelle R Ciucci, PhD,corresponding author Allison J Schaser, MS, and John A Russell, MS; Behav Brain Res. Author manuscript; available in PMC 2014 Sep 1. Published in final edited form as: Behav Brain Res. 2013 Sep 1; 252: 239–245.
Published online 2013 Jun 10. doi: 10.1016/j.bbr.2013.06.004, PMCID: PMC3742558