Are hallucinations an Alzheimer's symptom?

Conditions Expert Dr. Otis Brawley Chief Medical Officer,
American Cancer Society

Expert answer

Auditory hallucinations are the hearing of sounds, usually human voices, that are not there. Visual hallucinations involve seeing things that do not exist. It can rarely be seen in patients with Alzheimer's disease and several of the common dementias, but it's more often associated with a number of other conditions.

Hallucinations are most commonly associated with psychoses, especially schizophrenia. Confusion at night in unfamiliar surroundings, such as a hospital, can be associated with visual and auditory hallucinations in the elderly. This is commonly called "sundowning."

Auditory hallucinations can be a side effect of drugs, especially narcotic pain relievers, antidepressants, anti-anxiety drugs and even common anti-hypertensive drugs. The list of causes of auditory hallucinations includes seizure disorder. Hallucinations can be the only manifestation of a seizure. Alcohol withdrawal and even migraine headache have been associated with auditory hallucinations.

Very treatable conditions that can present with auditory and visual hallucinations as symptoms are hypothyroidism (thyroid deficiency), hyperparathyroidism (a hyperactive parathyroid leading to a high amount of calcium in the blood), severe vitamin B12 deficiency and advanced syphilis infection.

You asked about Alzheimer's. It is one of a number of reasons for dementia and perhaps the most common cause of dementia in the elderly.

Alzheimer's is rarely found in people younger than 60. Other causes are more common in younger people with dementia. The diagnosis of any dementia should be made only by a trained professional. When suspected, it should be evaluated as there are treatable dementias. Even early treatment of Alzheimer's can be beneficial. Assessment includes a battery of memory tests and radiologic imaging of the brain.

Alzheimer's is a degenerative disorder that gets progressively worse. Certain symptoms occur early in the disease and some occur later. Auditory hallucinations are rare in Alzheimer's, and when they occur, they usually occur late in the disease.

Common clinical features of early Alzheimer's include a distinctive pattern of memory impairment. Recall of episodes, especially recent episodes, is impaired early in the disease whereas long-term memory is less impaired. In the early to mid-stages of Alzheimer's, visuospatial impairments are seen. This manifests as misplacement of items and difficulty navigating in first unfamiliar and later in familiar terrain.

The inability to recognize objects and faces is a later feature the disease, as is difficulty in performing motor tasks such as dressing. Word-finding becomes difficult, impairing spontaneous speech and comprehension.

Patients at this point commonly have a change in personality and develop depression. This can lead to the emergence of behavioral disturbances, including agitation, aggression, wandering and psychosis. It is at this point that auditory and visual hallucinations can occur.

Other dementias to be distinguished from Alzheimer's disease are:

-- Vascular dementia, caused by either ischemic or hemorrhagic strokes.

-- Frontotemporal dementia, a disorder characterized by degeneration of the frontal and/or temporal lobes of the brain. Early changes in personality, behavior and executive functioning (the ability to concentrate and make decisions) distinguish this from Alzheimer's.

-- Dementia with Lewy bodies is the second-most common type of degenerative dementia after Alzheimer's. It is characterized by early appearance of visual hallucinations and/or auditory hallucination, along with Parkinsonian shakiness, fluctuation in cognition, rapid or slow heartbeat and sleep disorders.

Alzheimer's disease can occur with other dementias. This influences clinical presentation and creates diagnostic challenges.

Next week: The treatment of Alzheimer's disease.