Symptoms and Causes to dementia with Lewy bodies

What is dementia with Lewy bodies?

Symptoms such as “visual hallucinations” (seeing people who are not actually present) and abnormal behaviors (screaming or making strange noises during sleep) are prominent. Some patients have parkinsonian symptoms, such as trembling of the limbs and short-stepped gait. Dementia with Lewy bodies is characterized by changes in conditions from day to day, such as having a clear head on one day and being muddle-headed on another.


Abnormal clusters of proteins, called “Lewy bodies,” are observed in the neurons of the brain. Widespread distribution of Lewy bodies in the cerebrum results in the development of dementia.

(Conceptual diagram)

Major symptoms

Cognitive impairment

Cognitive impairment

Symptoms, such as impaired attention and things looking distorted, appear. In dementia with Lewy bodies, memory impairment may not be prominent at first.

Fluctuations in cognitive function

Fluctuations in cognitive function

The condition of the patient alternates, within each day and from day to day, between being clear-headed, being able to understand well and making good judgements, and being muddle-headed, with a severely impaired ability to understand and make judgments.

Behavioral and psychological symptoms of dementia (BPSD)

Behavioral and psychological symptoms of dementia (BPSD)

Visual hallucinations
Visual hallucinations refer to the symptom wherein the patient vividly sees things that are actually not present. In most cases, patients see small animals or humans and could say things like, “I can see rats crawling about on the wall” or “A stranger is sitting in the room.” In addition, patients often have “optical illusions” in which they mistake a doll for a girl or a roll of clothes for an animal.

Abnormal behaviors during sleep
Patients may shout loudly, scream, make strange noises or act violently during sleep. These behaviors tend to occur during REM sleep and are referred to as REM sleep behavior disorder.

REM sleep is a state in which the body is sleeping while the brain is active, and people often dream during REM sleep.

Depressive symptoms

Patients with depressive symptoms feel down, feel sad and have decreased motivation. It is said that approximately 50% of patients suffering from dementia with Lewy bodies have depressive symptoms.

Physical symptoms

Physical symptoms

Parkinsonian symptoms
These symptoms include slow movements, amimia, muscle stiffness, short-stepped gait with a stoop, and a tendency to fall.

Autonomic symptoms
The autonomic nervous system, which controls the blood pressure, body temperature and visceral functions, does not function well, causing various physical disorders, such as orthostatic dizziness, constipation, abnormal sweating/night sweats, pollakiuria, and lassitude. In some cases, there is a risk of dizziness resulting in falling or syncope.

“Dementia with Lewy bodies,” which is difficult to detect

Dementia with Lewy bodies manifests differently in different patients. Furthermore, the symptoms fluctuate within each day and from day to day, making accurate diagnosis difficult.
Thus, in some cases, parkinsonian symptoms occur first, leading to a diagnosis of “Parkinson’s disease,” and then memory impairment occurs, which then leads to the diagnosis of dementia with Lewy bodies. On the other hand, in some cases, the patient seems to present with forgetfulness, as in Alzheimer-type dementia, and then parkinsonian symptoms occur, which then leads to the diagnosis of dementia with Lewy bodies. In addition, some elderly patients first manifest depressive symptoms and are diagnosed as having depression and then gradually develop symptoms of dementia with Lewy bodies.

Points of management by family members

Caution should be exercised to prevent the patient from falling.

Parkinsonian symptoms cause muscle and joint stiffness and short-stepped gait, resulting in a tendency to stumble and fall. In addition, when the patients stand up, dizziness or vertigo may occur, causing falling or syncope.

  • Patients should be encouraged to use the handrails, when rising from a chair or going up or down the stairs.
  • Things that the patients could stumble upon should be removed, with the living quarters cleaned regularly.

Patients have difficulty in swallowing food

As the symptoms progress, the swallowing function declines and saliva or food may enter the trachea (aspiration). If patients can cough well and spit out the saliva or food, then, no problems will occur; otherwise, they are at a risk for developing pneumonia.

  • Patients should sit hunched up during a meal, and the family members should watch over the patients.
  • The cooking should be done in such a manner that the food is cut into small pieces and not runny, but thick in consistency.