Parkinson’s Disease (PD) is a progressive neurological disorder that affects movement. Its symptoms may include tremors, rigidity, and blank faces. Slowing or jerky movements are also characteristic of this disease. Comorbidities of Parkinson’s include difficulty sleeping, forward head posture, problems with balance, and other neurologic problems. Symptoms of the disease usually begin between 50 and 60 years old, although some have experienced earlier symptom onset (WebMD, 2010). Various diagnostic tests are used to determine PD, although there are many disorders that resemble Parkinson’s symptoms.
Genetic and environmental factors play a role in the presentation of the disease in one individual versus another (PDF, 2012). A family history of Parkinson’s, in some cases, increases the susceptibility of a younger person developing the disease (A.D.A.M. Medical Encyclopedia, 2011). PD is believed to be the result of a neurochemical (dopamine) deficiency that affects muscle movement and control. A decrease in dopamine supply essentially disrupts the message relay system of the brain, leading to muscle function loss (A.D.A.M. Medical Encyclopedia, 2011). As PD is a progressive disease, damage to the body becomes worse over time.
Despite this neurochemical explanation for Parkinson’s, the cause of PD is still relatively unknown. New research is bringing to light a “trigeminal disturbance hypothesis” for PD, stating that problems in the trigeminal system, which affects motor movement, may be responsible for the symptoms seen in Parkinson’s (Jennings, 2011). In applying this to tremors, a major symptom of PD, the signal being relayed to the reticular formation (nerves that, when stimulated, cause the head and neck muscles to turn toward the same side as the stimulation) is altered by the disturbances in the trigeminal nerve (Jennings, 2011; Sims & Demerjian, 2012).
Treatment for PD include medication that decreases the specific problem symptoms associated with the disease, deep brain stimulation (DBS) surgery that mainly treats the disabling tremors some patients experience with PD (PDF, 2012), and, under the trigeminal disturbance hypothesis, bite therapy (Jennings, 2011). Treatment of Parkinson’s symptoms, such as tremors or balance problems, using an oral orthotic has shown to be effective in specific case studies of PD. Disturbances in the trigeminal nerve have the potential to alter normal functions of the cerebellum (which is involved in maintaining balance and posture) and can induce the balance and motor symptoms found in the disease (Sims & Demerjian, 2012). When these disturbances are corrected using an oral orthotic, it can lead to improvement of balance and gait as well as decrease or elimination of tremors, correction of head posture or position, and release of neck tension (Demerjian, Sims, & Stack, 2011).
A.D.A.M. Medical Encyclopedia, 2011. Parkinson’s disease. National Center for Biotechnology Information. Retrieved on September 14, 2012 at http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001762/
Demerjian, G., Sims, A., & Stack, B. (2011). Proteomic signature of Temporomandibular Joint Disorders (TMD): Toward diagnostically predictive biomarkers. Bioinformation, (5)7, 282-284.Jennings, D., 2011. Trigeminal disturbance hypothesis of Parkison’s. Retrieved on September 6, 2012 at http://parkinsonstmj.com/trigeminal-disturbance-hypothesis-of-parkinsons/