Progressive Supranuclear Palsy (PSP): What Is It?

· April 8, 2019
Progressive supranuclear palsy is a neurodegenerative disease with an unknown cause. It can impact someone's motor skills, cognitive abilities, and psychological state.

Progressive supranuclear palsy is an extremely rare illness that affects fine motor skills, cognition, and emotions, among other things. For example, people who suffer from it can have difficulties moving, balancing, and talking.

This condition affects approximately six people per 100,000. This means that it’s also a very under-researched syndrome that we don’t know much about. Unfortunately, that also means treatment for it still isn’t very precise.

Steele, Richardson, and Olszewski discovered the disease in 1964. This is also why it’s known as Steele–Richardson–Olszewski syndrome.

Progressive supranuclear palsy (PSP)

Jiménez-Jiménez (2008) defined it as a neurodegenerative disease that causes a buildup of neurofibrillary tangles in your neurons and glial cells. This slowly shrinks these areas and eventually keeps them from sending messages to the frontal lobe.

Until scientists do more research, we won’t really know what causes it. As of yet, the two big theories are genetics and potential environmental factors.

An illustration highlighting the basal ganglia in the brain, one of the main parts that progressive supranuclear palsy affects.

Clinical picture

Progressive supranuclear palsy affects the brain in many different ways. Ardeno, Bembibre, and Triviño (2012) summarized some of its consequences:

  • Fine motor skills disorders. This includes gait disorders, postural instability, and Parkinson’s disease
  • Vision and eyelid disorders.
  • Cognitive and behavioral disorders, such as apathy, depression, and social isolation.
  • Pseudobulbar affect. This is an emotional disorder that can cause uncontrollable bursts of laughter, crying, dysphagia, dysarthria, etc.

Variations

In 1994, Lantos described three different types of progressive supranuclear palsy.

  • Frontal PSP causes cognitive and behavioral problems.
  • The classic variation of PSP is characterized by postural instability, ophthalmoparesis (eye paralysis), and pseudobulbar affect.
  • The Parkinson’s variation involves akinetic-rigid symptoms.

Diagnosis

This disease is usually diagnosed after death, as it’s really hard to diagnose someone while they’re still alive partly because it’s so rare. The lack of research on this disease causes doctors to often mistake it for other disorders. This is why most doctors nowadays perform differential diagnoses of Parkinson’s, multiple system atrophy, corticobasal degeneration, frontotemporal dementia, and Lewy body dementia.

Here are some of the tools doctors resort to diagnose this disease:

  • MRI scans. 
  • Single-photon emission computed tomographies to get more detailed images of patients’ brains.
  • Positron-emission tomographies.

According to the National Institute of Neurological Disorders and Stroke and the Progressive Supranuclear Palsy Association, there are several diagnostic criteria for this disease:

A picture showing a woman laying down about to be sent into an MRI by a nurse.

Possible progressive supranuclear palsy

  • Gradually progressive disorder with onset when the individual is aged 40 years or older.

  • Either vertical supranuclear palsy or both slowing of vertical saccades and prominent postural instability with falls in the first year of onset.

  • No evidence of other diseases that can explain the clinical features.

Probable progressive supranuclear palsy

  • Symmetric proximal greater than distal akinesia or rigidity.

  • Abnormal neck posture, especially retrocollis.

  • Poor or absent response of Parkinsonism to levodopa therapy.

  • Early dysphagia and dysarthria.

  • Early cognitive impairment with at least 2 of the following: apathy, abstract thought impairment, decreased verbal fluency, imitation behavior, or frontal release signs.

Definitive PSP

  • History of probable or possible PSP.

  • Histopathologic evidence that is typical of the disease.

  • Early cognitive deterioration, along with at least two of the following symptoms: apathy, reduction of verbal fluency, problems with abstract thought, imitative behaviors, or frontal release signs.

Evaluation

Because this disease is so rare, we don’t have a concrete, standard way to evaluate it. Thus, doctors have to do case-by-case evaluations and use different tests, exams, and questionnaires with each patient.

Arnedo, Bembibre, and Triviño (2012) have talked about how they evaluated one specific patient, along with the tools they used:

  • Attention: Trail Making Test, tap counting, the A-test, and color blindness tests.
  • Language: The Boston Naming Test, semantics and phonetics, interviews, and language evaluation.
  • Memory: Digit test (WAIS-III), Spatial Span (WMS-III), and the Rey-Osterrieth complex figure test.
  • Executive functions: A matrix subtest (WAIS-III), similarities test (WAIS-III), and the Wisconsin Card Sorting Test.
  • Visual-perceptual skills: A battery of visual perception tests.
  • Praxia: The Rey-Osterrieth complex figure test, WAIS-III, basic transitive and intransitive motions, a movement sequence, and the ability to use objects.
  • Processing speed: Timed tests.
  • Psychopathological rating scales: A neuropsychiatric inventory.
  • Functional scales: The Barthel index and the Lawton-Brody scale.
An older woman talking to a young psychologist in her office.

Treatment and conclusion

There yet isn’t an effective, concrete treatment for progressive supranuclear palsy. All we can do right now is help keep the patients’ symptoms under control so they can live their lives. Because we don’t know how to treat it, the goal is to slow it down and also help the patient become as independent as possible.

The treatments involve multiple specialists including neurologists, psychologists, and physical therapists. Doctors might prescribe things like L-DOPA, fluoxetine, amitryptiline, or imipramine to treat it. Some patients also do speech therapy, cognitive stimulation therapy, and occupational therapy.