Exams and Tests

Changes in personality, behavior, or cognitive functions have many different causes. The causes vary by age, sex, and various other factors. Your health care provider will have the difficult job of sorting out all the possible different causes of your symptoms. He or she will ask many questions, perform examinations, and conduct tests to try to pinpoint the cause.

The medical interview will include questions about your symptoms and how they started, your medical problems now and in the past, your family members’ medical problems, your medications, your habits and lifestyle, and your work, military, and travel history. The physical examination will focus on signs of ALS and other disorders that can cause similar symptoms. It will also include tests of mental status, such as answering questions and following simple directions. Since depression is common in ALS, the medical interview will include an evaluation for depression.

Lab tests

There is no lab test that will diagnose dementia. Blood may be tested for other conditions that can cause dementia symptoms.

Imaging studies

Brain scans are the best way to find brain abnormalities that can cause dementia.

• CT scan is like an x-ray but shows greater detail. It may show frontal lobe shrinkage (atrophy) in ALS with dementia.
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• MRI shows even greater detail.
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• Single-photon emission computed tomography (SPECT) images can show problems in brain functioning. SPECT is available at only a few large medical centers.

Other tests

• Electroencephalography (EEG) measures electrical activity in the brain. It is sometimes helpful in distinguishing various causes of dementia symptoms.
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• Electromyography (EMG) measures electrical activity in muscles. It can be used to distinguish ALS from other conditions that cause similar symptoms but are not motor neuron diseases.