Progressive Supranuclear Palsy


Quick Start: Progressive Supranuclear Palsy

Definition
  • Progressive supranuclear palsy (often abbreviated to PSP) is a neurodegenerative disease caused by the accumulation of hyperphosphorylated tau protein isoforms in the brain.

  • Main features include abnormalities of vertical eye movements (supranuclear palsy), along with postural instability with backwards falling, gait like “a drunken sailor,” axial rigidity, frontal lobe signs and symptoms, and eventually difficulty talking and swallowing (pseudobulbar palsy).

Prevalence
  • Progressive supranuclear palsy has a prevalence of 5 to 6 per 100,000.

  • The mean age of onset of the disease is 63 years.

  • The usual prognosis ranges from 5 to 10 years from diagnosis to death.

Cognitive and behavioral symptoms
  • Early cognitive and affective symptoms may include slowing of all aspects of mental processing, executive dysfunction, dysarthria and/or apraxia of speech, irritability, irascibility, and apathy, introversion, and depression.

Diagnostic criteria (See text for additional elements)
  • Sporadic occurrence

  • Age 40 years or older at onset

  • Gradual progression of symptoms

  • No clinical, imaging, laboratory, or genetic findings strongly suggestive of another disorder

  • Ocular motor dysfunction, consisting of either:

    • Vertical supranuclear gaze palsy, or

    • Slow velocity of vertical saccades

  • Plus one of the following core clinical features:

    • Postural instability, consisting of either:

      • Repeated unprovoked falls within 3 years, or

      • Tendency to fall on the pull-test within 3 years

    • Akinesia, consisting of either:

      • Progressive gait freezing within 3 years, or

      • Parkinsonism, akinetic-rigid, predominantly axial, and levodopa resistant, or

      • Parkinsonism, with tremor and/or asymmetric and/or levodopa responsive

    • Cognitive dysfunction, consisting of:

      • Frontal cognitive/behavioral presentation

Treatment Symptomatic treatments to consider include levodopa/carbidopa (Sinemet), memantine, amantadine, botulinum toxin, and desmopression.
Top differential diagnoses Corticobasal degeneration, dementia with Lewy bodies, vascular dementia, frontotemporal dementia, Creutzfeldt-Jakob disease, normal pressure hydrocephalus, Huntington's disease, multiple sclerosis, medication side effects.

A 62-year-old man presented to the clinic with a curious tale. The patient had been driving from California to Boston. When he stopped for gas, the attendant thought he was drunk and called the police. The police heard his slurred speech, found him unable to walk heel-to-toe in a straight line, and arrested him for driving under the influence. Ultimately, it was determined that he was not intoxicated, and he was released. In the clinic, the patient complained most that he had difficulty talking, and his speech was quite slow, hesitant, and dysarthric. His examination was notable for slow voluntary eye movements in all directions, including vertical gaze. Eye movements improved and became smooth by having the patient look straight ahead while his head was gently moved. He walked with a very wide-based gait and often staggered although he did not fall. He showed great difficulty with tests of executive function such as the Trail Making Test Part B and Digit Span Backwards; he was unable to correctly draw a clock.

Prevalence, Prognosis, and Definition

Progressive supranuclear palsy (often abbreviated to PSP and sometimes referred to as the Steele–Richardson–Olszewski syndrome) is a neurodegenerative disease of the brain caused by the accumulation of hyperphosphorylated tau protein isoforms in the brain. Its main feature is an abnormality of vertical eye movements (supranuclear palsy), along with postural instability with falls, axial rigidity, frontal lobe signs and symptoms, and difficulty swallowing and talking (pseudobulbar palsy). It has a prevalence of 5 to 6 per 100,000, with approximately only 1.5 per 100,000 being accurately diagnosed. The mean age of onset of the disease is 63 years, with a usual prognosis ranging from 5 to 10 years from diagnosis to death; median 7 ( ). More rarely patients have been observed to succumb as quickly as 2 years or as slowly as 28 years ( ). The disease received increased attention in the popular press when the comedian Dudley Moore was diagnosed with it in 1999.

Terminology

Supranuclear Palsy

A “supranuclear palsy” causing eye movement abnormalities means that there is dysfunction of the part of the brain that controls voluntary eye movements above ( supra in Latin) the level of the oculomotor nucleus (in the midbrain, the upper part of the brainstem). This type of palsy affects mainly voluntary eye movements, while involuntary movements are relatively spared. (Involuntary movements may be controlled by a group of neurons called the superior colliculus.) Testing for a supranuclear palsy involves comparing eye movements for voluntary and involuntary gaze. Testing for voluntary gaze may be easily accomplished by having the patient look rapidly between two points (often called “saccades”), usually between the thumb on one hand and the index finger on the other (“Look at my thumb, look at my finger,” and so on). Testing for involuntary gaze is best performed by having the patient stare at a stationary point while you gently move their head up and down and back and forth, thus moving their eyes in their head. In a supranuclear palsy the rapid, voluntary eye movements will be abnormal while the involuntary movements will be normal (or relatively normal) demonstrating that the eye movement problem is in the voluntary gaze centers, above the oculomotor nucleus.

Pseudobulbar Palsy

If a patient has a “pseudobulbar palsy,” it indicates that there is dysfunction of part of the brain that mimics dysfunction of the lower part of the brainstem, the medulla. A “pseudobulbar palsy” refers to dysfunction of the part of the brain above the medulla that controls movements of the tongue, pharynx, and larynx. Thus the patient with a pseudobulbar palsy typically exhibits slurred and otherwise abnormal speech (dysarthria), and difficulty eating and swallowing (dysphagia).

Criteria and Diagnosis

The cardinal feature of progressive supranuclear palsy is an abnormality of vertical eye movements. Because up-gaze is sometimes impaired in normal aging, abnormalities of down-gaze are particularly sought for as confirmatory clinical signs when this diagnosis is being considered. Diagnostic criteria developed by the Movement Disorder Society not only provide a for a diagnosis of progressive supranuclear palsy but also of eight different clinical phenotypes. Boxes 12.1 and 12.2 provide a summary of the criteria for a clinical diagnosis of progressive supranuclear palsy; those who are interested in the phenotypes are referred to the original paper ( ) as well others which have tried to streamline the issue of multiple phenotypes ( ).

Box 12.1
Diagnostic Criteria for the Clinical Diagnosis of Progressive Supranuclear Palsy
Modified from Höglinger, G. U., Respondek, G., Stamelou, M., et al. (2017). Clinical diagnosis of progressive supranuclear palsy: the Movement Disorder Society criteria. Movement Disorders, 32 (6), 853–864.
See Box 12.2 for operationalized definitions.

Mandatory Inclusion Criteria

  • Sporadic occurrence

  • Age 40 years or older at onset of first progressive supranuclear palsy-related symptom

  • Gradual progression of progressive supranuclear palsy-related symptoms

Mandatory Exclusion Criteria

  • No clinical, imaging, laboratory, or genetic findings strongly suggestive of Alzheimer’s disease, multiple system atrophy, Lewy body disease, dementia with Lewy bodies, amyotrophic lateral sclerosis, vascular etiology, prion disease, encephalitis, or any other cause of cognitive and/or motor dysfunction.

Definite Progressive Supranuclear Palsy (Gold Standard)

  • Neuropathological diagnosis

Probable Progressive Supranuclear Palsy (Specific but Not Very Sensitive)

  • Ocular motor dysfunction, consisting of either:

    • Vertical supranuclear gaze palsy, or

    • Slow velocity of vertical saccades

  • Plus one of the following core clinical features:

    • Postural instability, consisting of either:

      • -

        Repeated unprovoked falls within 3 years, or

      • -

        Tendency to fall on the pull-test within 3 years

    • Akinesia, consisting of either:

      • -

        Progressive gait freezing within 3 years, or

      • -

        Parkinsonism, akinetic-rigid, predominantly axial, and levodopa resistant, or

      • -

        Parkinsonism, with tremor and/or asymmetric and/or levodopa responsive

    • Cognitive dysfunction, consisting of:

      • -

        Frontal cognitive/behavioral presentation

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