Parkinson’s Disease

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by loss of dopaminergic neurons that arise in the substantia nigra and project to the striatum.7,25-28 Cardinal features of striatal dopamine deficiency, characterized by impaired ability to control skeletal muscle movement, include akinesia, bradykinesia, rigidity, tremors, and in the later stages postural instability.25-28

Akinesia and bradykinesia manifest as poverty of spontaneous movements and slowness in initiation of movements, respectively. Rigidity is characterized by increased muscle tone in response to passive movements. Tremors, present during rest, disappear on purposeful movement. During stress or anxiety-provoking situations tremors increase and initiation of movement becomes increasingly difficult, extremely fatiguing, and ponderously inefficient.

Tongue and pharyngeal motor deficits result in difficulties with mastication and speech; inability to form an adequate bolus; hesitancy in initiating swallowing; ptyalism (lack of salivary control); and disruption of peristalsis that can result in silent aspiration and lead to bronchopneumonia, a common cause of death in patients with PD. Other findings include orthostatic hypotension, anosmia, depression, psychosis, and dementia.

Levodopa (Table 3), a dopamine precursor, is the most effective drug for the treatment of PD.2,25-28 Dopamine agonists (Table 3) alone are useful for the early treatment of PD and as adjunct therapy in patients taking levodopa.2,25-28 Anticholinergic agents (Table 3) are useful for the symptomatic control of tremor in patients younger than 60 years without cognitive impairment; however, their use is limited by bothersome anticholinergic effects.2,25-28

When providing oral healthcare to patients with PD, the goals are to develop and implement timely preventive and therapeutic strategies. In the early stages, patients are able to participate in oral healthcare-related decision-making and are able to cooperate in their treatment. However, in the advanced stages communication is hindered and patients become uncooperative as they perceive the dental setting as unfamiliar or threatening.