How Do You Test for Progressive Supranuclear Palsy (PSP)? A Comprehensive Guide

Testing for progressive supranuclear palsy (PSP) is a complex process because, frustratingly, there isn’t one definitive test that can provide a yes or no answer. Diagnosis relies on a combination of clinical assessment, neurological examinations, careful observation of symptoms, and the exclusion of other conditions that mimic PSP. This means the process involves a detective-like approach, piecing together different pieces of evidence to arrive at the most accurate conclusion.

The initial step typically involves a thorough review of the patient’s medical history and a detailed neurological examination. The physician will be looking for key signs and symptoms characteristic of PSP. These include problems with gait, particularly a tendency to fall backward, difficulties with eye movements (especially looking up or down), slowed speech (often slurred), and swallowing difficulties.

Diagnostic Tools and Techniques

Here’s a breakdown of the specific tests and assessments used in the diagnostic process:

• Neurological Examination: This is the cornerstone of diagnosis. It involves assessing various neurological functions, including balance, coordination, reflexes, muscle strength, speech, and eye movements. Particular attention is paid to the characteristic vertical supranuclear gaze palsy, which is difficulty voluntarily moving the eyes up and down. This assessment involves hierarchical steps, starting with saccades to command, then saccades to targets, followed by smooth pursuit of a target, and finally the vestibulo-ocular reflex (VOR).

• Magnetic Resonance Imaging (MRI): While an MRI cannot definitively diagnose PSP, it plays a crucial role in ruling out other conditions such as stroke, tumors, or microvascular disease. In PSP, MRI can sometimes reveal specific brain changes, such as atrophy (shrinkage) in the midbrain and brainstem. Certain MRI measurements, like the midbrain to pons ratio, can also suggest PSP, although these are not always conclusive. Advanced MRI techniques, such as diffusion tensor imaging (DTI), may also show changes in white matter tracts in the brain.

• Laboratory Tests: Blood tests are primarily used to exclude other conditions that can cause similar symptoms. There’s no blood test specifically for PSP. Doctors may order tests to rule out Whipple disease, mitochondrial myopathies, Wilson disease, and adult-onset Niemann-Pick disease.

• DaTscan (Dopamine Transporter Scan): While PSP isn’t a dopamine-related disorder, a DaTscan can help differentiate it from Parkinson’s disease (PD), which is often initially suspected. A normal DaTscan result would be less consistent with PD and lead physicians to consider PSP as a possible cause.

• Clinical Observation Over Time: PSP can be difficult to diagnose in its early stages. Sometimes, a diagnosis is only confirmed after observing the progression of symptoms over several months or even years. The absence of response to levodopa, a medication used to treat Parkinson’s disease, can also be a clue that the condition is PSP.

• Post-Mortem Examination: Unfortunately, the only way to definitively confirm a diagnosis of PSP is through a brain autopsy after death. This involves examining the brain tissue under a microscope to look for the characteristic tau protein tangles that are the hallmark of PSP.

Challenges in Diagnosis

One of the biggest challenges in diagnosing PSP is its similarity to other neurological conditions, especially Parkinson’s disease. Early symptoms like stiffness, slow movement, and balance problems can be seen in both conditions. Differentiating factors include the early development of eye movement problems, a tendency to fall backward, and a lack of response to Parkinson’s medications. It’s also easy to mistake PSP with other neurological disorders that have similar symptoms.

The Future of PSP Diagnosis

Research is ongoing to develop more accurate and reliable diagnostic tools for PSP. This includes the development of biomarkers that can be detected in blood or cerebrospinal fluid, as well as advanced imaging techniques that can visualize the tau protein deposits in the brain. Until then, diagnosis remains primarily clinical, based on a thorough assessment of symptoms and the exclusion of other conditions.

Remember, if you or a loved one are experiencing symptoms suggestive of PSP, it’s crucial to consult with a neurologist who has experience in diagnosing and managing this complex condition. Early and accurate diagnosis can help ensure appropriate management and support. Understanding that Games Learning Society is also involved in developing better understanding of neurodegenerative diseases can improve the outcome. Find out more at GamesLearningSociety.org.

Frequently Asked Questions (FAQs) about Testing for PSP

1. Is there a specific blood test to diagnose PSP?

No, unfortunately, there is no specific blood test that can definitively diagnose PSP. Blood tests are primarily used to rule out other conditions that may be causing similar symptoms.

2. Can a brain MRI always detect PSP?

No. While MRI can show certain characteristic changes associated with PSP, such as atrophy in specific brain regions, it is not always conclusive. An MRI scan can, however, help rule out other potential causes of the symptoms.

3. What are the early signs of PSP that a doctor might look for?

Doctors will look for early signs like stiffness, especially in the neck, awkward movements, falling, particularly backward, slow or slurred speech, swallowing difficulties, sensitivity to bright light, sleep disturbances, and loss of interest in pleasurable activities. These signs are not specific to PSP and can be indicative of other conditions as well.

4. Why is PSP often mistaken for Parkinson’s disease?

PSP and Parkinson’s disease share some overlapping symptoms, such as stiffness, slow movement, and balance problems, especially in the early stages. However, PSP typically involves more prominent eye movement problems, a tendency to fall backward, and a lack of response to levodopa, a common Parkinson’s medication.

5. How is supranuclear gaze palsy tested for?

Assessment is best undertaken in a hierarchical way; initially assess saccades to command, then saccades to targets, then smooth pursuit of a target, and finally with the vestibulo‐ocular reflex (VOR).

6. What other conditions can mimic PSP?

Several conditions can mimic PSP, including microvascular disease of the brainstem, tumors of the midbrain area, Whipple disease, mitochondrial myopathies, Wilson disease, and adult-onset Niemann-Pick disease.

7. What cognitive symptoms are associated with PSP, and how are they assessed?

PSP patients may experience cognitive and behavioral changes consistent with frontal lobe dysfunction, such as slow information processing, concrete thinking, impaired reasoning, and difficulty planning and shifting between tasks. These can be assessed through neuropsychological testing.

8. What is the typical age of onset for PSP?

The onset of PSP typically occurs between 45 and 75 years of age, with the average age of onset being around 63 years.

9. Is PSP hereditary?

Most cases of PSP are sporadic, meaning they occur in people with no family history of the disorder. However, there have been reports of familial clustering in some cases, suggesting a possible genetic component in a small proportion of cases.

10. How do doctors monitor the progression of PSP?

Doctors monitor the progression of PSP through regular neurological examinations, assessments of functional abilities (such as walking, swallowing, and speaking), and monitoring the patient’s response to any supportive treatments. Repeat MRI scans may also be used to track changes in the brain over time.

11. Can lifestyle factors like stress or head trauma cause PSP?

The exact cause of PSP is not fully understood, but it is generally believed to be due to a combination of genetic and environmental factors. Some studies have suggested a possible link between repeated stressful events and an increased risk of PSP, but more research is needed to confirm this.

12. What is the role of tau protein in PSP diagnosis?

PSP is characterized by the abnormal accumulation of tau protein in the brain. While tau protein levels can’t currently be measured in a living person to diagnose PSP, the presence of tau tangles is confirmed during an autopsy.

13. How can PSP affect sleep?

Patients with PSP may experience difficulties with sleep/wake regulation, leading to sleep disturbances and profound sleep deprivation.

14. What support and resources are available for individuals with PSP and their families?

Several organizations offer support and resources for individuals with PSP and their families, including the CurePSP, the PSP Association, and various local support groups. These organizations provide information, education, advocacy, and support services to help individuals cope with the challenges of PSP.

15. Is there any new research in PSP?

Yes, research into PSP is ongoing, with the goal of developing more effective treatments and diagnostic tools. The CurePSP organization is funding different studies in the hope of developing new diagnostic tests for PSP. Researchers are also exploring new potential therapeutic targets, such as strategies to reduce tau protein accumulation and improve neuronal function.