A preliminary diagnosis of Huntington's disease is based on your answers to questions, a general physical exam and your family medical history. Neurological tests and an evaluation of your mental health also is done.
Neurological exam
A neurologist asks you questions and conducts relatively simple tests of your:
- Motor symptoms, such as reflexes, muscle strength and balance.
- Sensory symptoms, including sense of touch, vision and hearing.
- Psychiatric symptoms, such as mood and mental status.
Neuropsychological testing
The neurologist also may perform standardized tests to check your:
- Memory.
- Reasoning.
- Mental agility.
- Language skills.
- Spatial reasoning.
If needed, more thorough neuropsychological testing may be done by licensed psychologists.
Mental health evaluation
You'll likely be referred to a psychiatrist who can look for a number of factors that could contribute to your diagnosis, including:
- Emotional state.
- Patterns of behaviors.
- Quality of judgment.
- Coping skills.
- Signs of disordered thinking.
- Evidence of substance abuse.
Brain-imaging and function tests
Brain-imaging tests can provide information on the structure or function of the brain. These tests may include MRI or CT scans that show detailed images of the brain.
These images may reveal changes in the brain in areas affected by Huntington's disease. These changes may not show up early in the course of the disease. These tests also can be used to rule out other conditions that may be causing symptoms.
Genetic counseling and testing
If symptoms strongly suggest Huntington's disease, members of your healthcare team may recommend a genetic test for the nontypical gene.
This test can confirm the diagnosis. The test also may help if there's no known family history of Huntington's disease or if no other family member's diagnosis was confirmed with a genetic test. But the test won't provide information that might help determine a treatment plan.
Before having such a test, the genetic counselor explains the benefits and drawbacks of learning test results. The genetic counselor also can answer questions about the inheritance patterns of Huntington's disease.
Predictive genetic test
A genetic test can be given if you have a family history of the disease but don't have symptoms. This is called predictive testing. The test can't tell you when the disease will begin or what symptoms will appear first.
Some people may have the test because they find not knowing to be more stressful. Others may want to take the test before having children.
Risks may include problems with insurability or future employment and the stresses of facing a fatal disease. In principle, federal laws exist that make it illegal to use genetic testing information to discriminate against people with genetic diseases.
These tests are only performed after consultation with a genetic counselor.