Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by accumulation of cerebral amyloid plaques, loss of cholinergic neurons in the basal nucleus of Meynert, and excessive glutamatergic activity.22-24 AD progresses through three stages over a period of fifteen or more years.22-24 Decline in memory, time disorientation, lack of spontaneity, errors in judgement, and decline in personal appearance and hygiene characterize stage one.
During the second stage, there is a more rapid decline in intellectual capacity. Patients may show an inability to recognize self in a mirror (mirror sign, loss of self). They may find it difficult to carry out purposeful movements such as eating or walking, and lose the ability for self-care. Patients lose ability to understand speech, to perform calculations, to recognize familiar objects, and experience partial or total loss of speech (alogia).
The third or terminal stage leaves the patient apathetic, disoriented, and unable to walk. Significant body wasting, seizures, anxiety, aggressive behavior, hallucinations, and delusional episodes are common. Other complications include malnutrition, aspiration pneumonia, pressure necrosis of the skin, and oral/odontogenic problems. Death usually results from infection secondary to a weakened immune system.
Patients have reduced submandibular salivary flow rates.22 Reduced antibacterial, lubricating, and buffering capacity of saliva places patients at increased risk for caries and periodontal diseases; dysfunctional speech, chewing, and swallowing; and ageusia or dysgeusia.22 During later stages patients with AD tend to touch/examine objects with their mouth (hyperorality) and exhibit forced gripping (hypermetamorphosis).22
Donepezil, an acetylcholinesterase inhibitor (Table 3), is the only centrally acting cholinergic inhibitor approved for use in all stages of Alzheimer’s disease.2,8,23,24 Combination therapy with donepezil and memantine, a glutamatergic NMDA-receptor antagonist (Table 2), is approved for treating moderate-to-severe disease.2,6,23,24 Atypical antipsychotic agents (Table 3) can improve some behavioral manifestations of Alzheimer’s disease.23,24
When providing oral healthcare to patients with AD, the goals are to develop and implement timely preventive and therapeutic strategies. In stage one, patients are able to participate in oral healthcare-related decision-making and are able to cooperate in their treatment. However, in advanced stages communication is hindered, patients become uncooperative, and may perceive the dental setting as unfamiliar or threatening.