The physician will interview the individual intensively to obtain the medical history and rule
out other conditions. He or she will perform a neurological examination including tests of the person's hearing, eye movements,
strength, sensation, reflexes, balance, movement, and mental status, and will probably order a number of laboratory tests
as well. Together, these tests form the neurological examination.
In addition, the physician will ask about recent intellectual or emotional problems, which may
be indications of HD.
In addition to direct testing, another tool used by physicians to diagnose HD is to take the
family history, sometimes called a pedigree or genealogy. It is extremely important for family members to be candid and truthful
with a doctor who is taking a family history.
People with HD commonly have impairments in the way the eye follows or fixes on a moving target.
Abnormalities of eye movements vary from person to person and differ depending on the stage and duration of the illness. |
The physician may ask the individual to undergo a brain imaging test. The computed tomography
(CT) scanner provides an excellent image of brain structures with little if any discomfort.
Those with HD may show shrinkage of some parts of the brain--particularly two areas known as
the caudate nuclei and putamen--and enlargement of cavities within the brain called ventricles.
These changes do not definitely indicate HD however, because they can also occur in other disorders.
In addition, a person can have early symptoms of HD and still have a normal CT scan. When used in conjunction with a family
history and record of clinical symptoms, however, CT can be an important diagnostic tool.
Other technologies for brain visualization, such as magnetic resonance imaging (MRI) and
positron emission tomography (PET), are an important part of HD research efforts, but their usefulness to physicians
trying to diagnose HD has not yet been established. |
