Lewy Body Dementia

Diagnosis

Though symptoms for dementia with Lewy bodies overlap with symptoms for Alzheimer's and Parkinson's disease, it is important to obtain a correct diagnosis. The disease progresses differently from Alzheimer's and Parkinson's and will respond differently to drugs used to treat those diseases.

There is no single test to diagnose Lewy body dementia. The Lewy bodies themselves can only be detected through an autopsy. Instead, the disorder is diagnosed by considering which symptoms are present and excluding other conditions that might be causing the signs and symptoms. Because of the complexity of the disorder, each patient may have numerous tests and questions that can help exclude other conditions. Since behavior changes are often associated with the disorder, a psychiatrist may make the initial evaluation.

Mental Status and Neuropsychological Assessments

To determine which thinking and memory functions may be affected and to what degree, the patient will be asked questions to measure cognitive functions for attention, learning, recall, language and visuospatial abilities. The test results are compared to the test results of other people of similar age and education.

The patient and people familiar with him or her will be interviewed about the patient's emotional state and day-to-day routines. They will also be asked about possible alcohol or drug abuse, head trauma and other causes for memory loss. Family members or close friends can provide valuable information about how the patient's behavior and personality have changed.

Psychiatric Assessments

In addition, the patient may have a psychiatric assessment to uncover possible depression or other mental illness.

Blood Tests

The patient's blood will be checked for infections or conditions such as vitamin deficiency, anemia, medication levels, disorders of the thyroid, kidneys or liver, and other factors that can cause memory loss.

Brain Imaging

Internal images of the brain help detect strokes, tumors or other conditions that may have affected the brain, and may show changes to structures in the brain that are associated with memory, such as the hippocampus. Several brain imaging techniques offered at Mayo Clinic.

Computed Tomography (CT scan)

In this test, an X-ray machine rapidly rotates around the brain using a series of thin X-ray beams to produce two-dimensional images of the brain.

Magnetic Resonance Imaging (MRI)

This test uses powerful magnets and radio waves to produce a detailed, three-dimensional view of the brain.

Positron Emission Tomography (PET) or Single-Photon Emission Computerized Tomography (SPECT)

These two fairly new techniques may be needed for clinical-related or research-related study. For both tests, a small amount of radioactive material is injected into the patient and then detectors are placed on the brain to capture emissions. PET provides visual images of activity in the brain. SPECT is used to measure blood flow to various regions of the brain.

Most patients will be asked to undergo an MRI scan. In some patients, another scanning technique may be performed. The physician will determine which tests are most appropriate to establish the correct diagnosis.

Other Tests

Other tests that sometimes provide important diagnostic information include an electroencephalogram (EEG), electromyogram (EMG), urine tests, and tests on the cerebrospinal fluid (CSF) obtained by a lumbar puncture. The physicians discuss with the patient and his/her family which tests are most appropriate to establish the correct diagnosis.