Definition and Cause of Alzheimer Disease

AD is the most common form of dementia, which is the loss of intellectual and social abilities severe enough to interfere with daily functioning. AD is a progressive, degenerative disease that attacks the brain and results in impaired memory, thinking, and behavior It typically occurs after age 65 with prevalence increasing with advanced age. From age 70, prevalence doubles every 5 years. By age 85, more than 40% of individuals will have developed AD. Although an estimated 5.2 million people in the United States have AD, the prevalence is predicted to triple by the year 2050. An average dental practice of 2000 adult patients is predicted to include about 46 patients who have AD.

The cause of AD is unknown, although the following have been shown to be associated risk factors: advanced age (85+), having trisomy 21 (Down’s syndrome), a history of severe head trauma, or having a first-degree relative who has the disorder. Recent findings suggest that unidentified factors trigger the deposition of beta-amyloid plaques, initiating an inflammatory response that results in neurofibrillary tangles and the loss of cortical neurons. This process begins in the hippocampus and entorhinal cortex and spreads to the areas in the brain responsible for memory and learning (the temporal, parietal, and frontal lobes). Eventually, continued destruction of neurons leads to atrophy of the cerebral cortex and enlargement of the ventricles. However, motor, visual, and somatosensory portions of the cerebral cortex generally remain intact.

Genetic predisposition, known as familial Alzheimer disease, contributes less than 20% of all cases. Numerous environmental factors, such as aluminum, mercury, and viruses have been proposed as causes of AD but none have been proved as causative factors. Risk factors for AD are seen in Box 1 .

Mild cognitive impairment is the decline in memory function that may occur in normal aging, or be a precursor to AD. The focus of studies on mild cognitive impairment is to discover factors that may decrease the risk for AD. Current findings are listed in Box 2 . Further research is needed to determine the importance of each in controlling/preventing AD.

Dementia and Alzheimer Disease

Dementia is the loss of intellectual functions (such as thinking, remembering, and reasoning) to such an extent that it interferes with a person’s daily life and activities. Dementia is not a disease in itself, but a group of symptoms that often accompanies a disease or condition. More than 70 different diseases or conditions can cause dementia, some of which are treatable, whereas others are less responsive or not possible to treat. Table 1 lists causes of dementias, including those that are less responsive to treatment or are incurable.

AD is the most prevalent form of dementia and is considered progressive and incurable. The cost of caring for a person who has AD either at home or in a skilled nursing facility was estimated to be $47,000 per year in 1996 and is estimated to have risen to $75,000 per year in 2002. The total cost to society at present is estimated at $100 billion, ranking behind heart disease ($183 billion) and cancer ($109) as the third costliest disease in the United States.

The human costs of caring for patients who have AD (and dementias) are incalculable and include the burdens born by family members who act as the primary caregivers and health care personnel (nurses and nursing assistants/licensed practical nurses) who provide daily care such as cleaning the oral cavity and teeth. Emotional burdens are often overwhelming for family members who struggle with symptoms of a loved one (patient) for a disease that has no cure and becomes progressively worse. The Alzheimer Association ( www.alz.org ) estimates that for every person who has AD, at least two to three family members see their lives significantly affected by caring for that individual.

Clinical Signs and Symptoms

The clinical course of AD can be divided into three stages. The early stage usually begins subtly, with the first sign generally being recent memory loss. To many older adults, this occurrence is frightening, because they may feel they are experiencing symptoms of AD. However, normal aging changes can also lead to recent memory loss (benign senescence) and may not be a sign of AD. In AD, however, memory problems increase, ultimately interfering with a person’s ability to keep up with daily activities such as balancing a checkbook or finances, finding his/her way around, or remembering where he/she put things. Other signs of AD in the early stage include a gradual and steady deterioration in the ability to remember names, recent events, and conversations; misplacing items; missing appointments; and repeating questions or answers during conversations. In this stage, the person prefers familiarity and can be easily upset when confronted with new situations. Family members, relatives, or coworkers may report strange behaviors (eg, getting lost on the way home or to work), which may be accompanied by the onset of emotional outbursts when confronted. Some patients remain unaware of these problems, and others are aware of them and become frustrated and anxious.

The middle, or moderate, stage may occur within a few months or years. In this stage, the person is unable to work, becomes easily lost and confused, and has lost the ability to care for him/herself. Patients become agitated easily and have disturbances in language use, learning skills, judgment, and decision making. Although they remain ambulatory, they are at significant risk for falls or accidents secondary to confusion. Behavioral problems include agitation, hostility, uncooperativeness, or physical aggressiveness. During this stage, the patient has lost all sense of time and place and begins to have perceptual problems (may not recognize his/her own face in a mirror).

The late, or severe, stage finds the patient profoundly apathetic, disoriented, incontinent, and totally dependent. Recent and remote memory are completely lost. Aggressiveness and anxious behavior are common, and a typical behavioral complication is for patients to reach and grasp objects that are close by. Patients in this stage are at risk for pneumonia, malnutrition, aspiration, and pressure necrosis of the skin. The progression of the disease is gradual, with some patient’s symptoms seeming to plateau for a time. The end stage is coma and death.

General Suggestions for Patients who have Alzheimer Disease

Most patients who have AD will have been clinically diagnosed before their dental visit. If not, dentists should be able to recognize the signs and symptoms of dementia, such as a decline in recent memory, inability to follow directions, or obvious personality changes, and refer them for medical evaluation and treatment.

The patient who has AD should always be treated with respect and approached in an empathetic way. A humane way to view the patient who has AD is as someone who has a progressive terminal disease, not as a child who has no autonomy or abilities.

Regardless of the stage of dementia, the dentist should begin with a careful medical and dental history, including a review of medications. Communication should always take place in the presence of a family caregiver (spouse, child, or responsible adult). If the patient is able to understand and respond to questions, the dentist should address the patient directly. Verbal directions should be presented in short, simple phrases, giving only one direction at a time. It may be appropriate to address the patient by his/her first name or nickname, because they may forget their own last name at times. One should be prepared to repeat comments or questions frequently, and to repeat the words exactly in a calm, slow, and clear voice, at a low pitch. Rephrasing questions leads to confusion. One should only ask/respond to one question/comment at a time and wait for a response. Nonverbal communication is even more important in these patients and includes a relaxed, calm, and confident manner, using direct eye contact. Firm but gentle touching on the patient’s hand, arm, or shoulder can be used as a sign of encouragement. Demonstrating procedures before performing them is a good management strategy.

The presence of a caregiver (likely a family member) will often alleviate a dementia patient’s anxiety. Because dementia interferes with the patient’s ability to communicate, it is important to have the caregiver’s input to verify reported symptoms such as dental pain. Often, caregivers will be able to interpret the meaning behind a sudden worsening of behavior, moaning, or increased restlessness as an indicator of dental pain. Facial expressions appear to be helpful in assessing dental pain in dementia patients.

Informed Consent

The dentist and staff should always determine whether the patient is legally able to make informed decisions. The elements of informed consent include the capability of the patient to make decisions by the demonstration of (1) understanding relevant information, (2) understanding the situation and consequences, (3) manipulating the information rationally, and (4) communicating a choice. If the patient who has AD is verbally aggressive (cursing), resistant (moving away, refusing to open), or combative (striking out), the important questions to ask are, “Does the patient really not want dental care?” and if so, “Is the informed consent process in place?” If the patient is legally competent and capable of making decisions, he/she should sign his/her own consent. If unable to sign his/her own consent, the legal guardian or health care proxy has the authority to give permission. If no proxy is identified, state law takes precedence and usually the person in the closest, loving relationship can give consent.

If patients wander or curse, or are restless, resistant, or combative, nonpharmacologic and pharmacologic approaches of management should be considered. Nonpharmacologic approaches include having the caregiver hold the patients hand or hands, keeping the caregiver in the operatory for familiarity and helping with management, reducing background noise, reducing excess activity, using an extraoral mouth prop (eg, Molt prop), cradling the head to reduce movements, having the patient hold onto a soft textured object (stuffed animal), and moving with the patient. If a soft (cloth) restraint is used to hold a patient in the chair to keep him/her from wandering/getting up during treatment, it is important to follow the guidelines for restraint use. It is important to document clearly why the restraint was used, where it was placed and for how long a period of time, and whether a separate consent was given for its use.

Dental Treatment by Stage

Table 2 provides some suggestions for dental management of the patient who has AD at different stages. In a patient who has mild dementia, good oral health should be attained aggressively, with restorative work completed and early lesions restored (no “watches”). Restorations should be long lasting and easily maintained. Crowns would be preferable to large restorative buildups, in most cases. Materials selected should be based on the ability to manage the patient and to maintain a dry operating field (eg, can you use a rubber dam?). Glass ionomers are good materials for root surfaces because of their ability to release fluoride and prevent recurrent decay.

For moderately demented patients, subsequent care should concentrate on preventing dental disease through aggressive home care and frequent recalls (every 3 months). Complex dental procedures should rarely be performed (if at all) before the disease has reached the advanced stage. If a patient loses a partial or denture, it is hard to predict whether or not new removable prostheses should be made. General guidelines include discussing this with the caregiver and making the decision based on the perceived risk/benefit. An understanding should be reached with the caregivers that the patient will not likely be able to wear prostheses in the future. If the caregiver is willing to assume the risk and cost, a new partial/denture can be fabricated, but the long-term prognosis is questionable at best.

Patients in the advanced stage often display behavior problems such as anxiety, hostility, wandering, and inability to sit still and open their mouths, and are generally uncooperative. These patients are difficult to treat but likely will require short appointments for simple procedures (like fluoride treatments or treatment planning) and sedation (oral or intravenous) for everything else. Nitrous oxide is not indicated because of the inability of the patient to understand and cooperate, but short-acting oral benzodiazepines (lorazepam/Ativan or triazolam/Halcion) work well for some procedures. Intravenous sedation works well for longer or complex procedures such as oral surgery and restorative care. However, Midazolam/Versed should be used with extreme caution in older patients who have AD because it has a profound effect at low doses. Rarely should more than 1 mg be given as an incremental dose, with a maximum total dose for a 1 hour procedure totaling to no more than 5 mg in most cases.

Several specially adapted preventive products are helpful for caregivers to use with patients who have AD. A foam mouth prop called the Open-Wide Plus (Specialized Care Com., Edison, New Jersey) is designed for caregivers to use to keep the mouth open during oral hygiene. A specialized toothbrush, the Collis Curve (Collis Curve, Inc., Brownsville, Texas) has three rows of bristles that, when placed correctly, can clean the lingual, facial, and occlusal surfaces of teeth at the same time. Approved by the American Dental Association for assisted brushing, the Collis Curve uses a simplified scrubbing motion, making it easier for caregivers to use than conventional or electric brushes.

Other conventional preventive products may be helpful for caregivers to maintain oral hygiene in patients who have AD. For cleaning between teeth, proxabrushes work well. Caregivers need to be reminded to keep their fingers from between the teeth of their patients because of the danger of biting. Finally, fluoride use is an essential preventive tool. Toothpaste, mouth rinses (if the patient is not late stage and at risk for aspiration), the use of gels at home or varnish in the office should all be considered as part of a daily plan to prevent new caries.