What Exams and Tests Diagnose Progressive Supranuclear Palsy?
Many different conditions can cause dementia symptoms. According to the National Institutes of Health, there is no blood or imaging test to confirm that you have PSP. However, some researchers suggest that an MRI that demonstrates atrophy of the midbrain tegmentum (shaped like a hummingbird) approaches nearly 100% PSP diagnosis while others report about 70% specificity. Your doctor has the difficult task of finding the cause of your symptoms. This is very important, because some causes of dementia are reversible with treatment, while others are not.
The process of narrowing down the clinical possibilities to reach your diagnosis is complicated. Your health care provider will gather information from several different sources. At any time in the process, he or she may consult an expert in brain disorders (neurologist or psychiatrist).
The first step in the evaluation is the medical interview. You will be asked questions about your symptoms and when they appeared, about medical problems now and in the past, about medications you have taken now and in the past, about family medical problems, about your work and travel history, and your habits and lifestyle. You may need a family member to help you answer these questions. A physical examination will look for physical disabilities and signs of underlying conditions such as high blood pressure and heart disease. It will include a mental status examination. This involves answering questions and following simple directions. Neuropsychological testing may be done to identify the extent of dementia. Other tests and/or imaging systems may be done to help distinguish PSP from ET (essential tremor or et), Parkinson's disease, multisystem atrophy, or Alzheimer’s.
No lab test can confirm the diagnosis of PSP. However, blood tests may be done to rule out other conditions that cause dementia symptoms. These include infections, blood disorders, chemical abnormalities, hormonal disorders, and liver or kidney problems.
Brain scans are not very helpful in establishing the diagnosis of PSP in some patients, but they can rule help out many other neurodegenerative disease conditions that cause dementia in a patient.
- MRIs and CT scans may be done to rule out other causes of dementia such as stroke. MRIs may also show additional changes in the later stages of the disease. This does not confirm PSP because these changes can occur in other conditions that cause dementia.
- Positron-emission tomography (PET) or single-photon emission computed tomography (SPECT) scan sometimes helps distinguish PSP from Parkinson's disease and other conditions. These scans are available only at certain large medical centers.
Neuropsychological testing is the most accurate method of pinpointing and documenting a person’s cognitive problems and strengths. Results vary with the size and severity of damage in the brain.
- This testing can help give a more accurate diagnosis of the problems and thus can help in treatment planning.
- The testing involves answering questions and performing tasks that have been carefully prepared for this purpose. Testing is done by a psychologist or other specially trained professional.
- It evaluates the individual’s appearance, mood, anxiety level, and experience of delusions or hallucinations.
- It assesses cognitive abilities such as memory, attention, orientation to time and place, use of language, and ability to carry out various tasks and follow instructions.
- Reasoning, abstract thinking, and problem-solving also are tested.
Sleep studies may be ordered because sleep patterns are often abnormal in people with PSP. You may undergo a sleep test called a polysomnogram.