Dementia in Amyotrophic Lateral Sclerosis (ALS)
Symptoms of Dementia in ALS
Fronto-temporal dementia-like symptoms in ALS usually appear as a change in personality and behavior. The exact nature of this change varies from person to person. The following symptoms are common:
Apathy (lack of interest, withdrawal)
- Lack of emotion
- Reduced spontaneity
- Loss of inhibition
- Restlessness or overactivity
- Social inappropriateness
- Mood swings
Cognitive symptoms include the following:
- Memory loss
- Loss of speech and/or language, partial or complete
- Loss of reasoning or problem-solving ability
Some individuals develop repetitive rituals involving hoarding, dressing, wandering, or using the bathroom. Others may overeat or develop strange eating rituals.
Cognitive changes can precede, follow, or coincide with the movement symptoms of ALS. Throughout the course of the dementia, the following typical signs and symptoms of ALS also progress:
- Limb weakness
- Muscle wasting (atrophy)
- Muscle twitches (fasciculations)
- Shortness of breath
When to Seek Medical Care for ALS
You are the best person to judge whether you are experiencing changes that suggest ALS and dementia. Because dementia is not a common feature associated with ALS, and can have many causes, it is important to see your health care provider if you develop any changes in personality, behavior, speech, or memory.
Exams and Tests for ALS and Dementia
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 exams, 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 exam will focus on neurological 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. Because depression is also common in ALS, the medical interview will include an evaluation for depression.
Lab tests for dementia
There is no lab test that will diagnose dementia. Blood may be tested for other conditions that can cause dementia symptoms.
Imaging studies for dementia
Brain scans are the best way to find brain abnormalities that can cause dementia. Here are the types used to look at the brain:
A CT scan uses finely focused X-rays to show greater detail than a simple X-ray. It may show frontal lobe shrinkage (atrophy) in ALS with dementia.
MRI scans use magnets to show even greater detail of brain structures.
Single-photon emission computed tomography (SPECT) images are also sometimes used to show problems in brain functioning. SPECT is available at only a few large medical centers.
Other tests for dementia
- Electroencephalography (EEG) measures electrical activity in the brain. It is sometimes helpful in distinguishing various causes of dementia symptoms.
- 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.