Atypical Parkinsonisms
(Progressive Supranuclear Palsy, Multiple System Atrophy)

Progressive Supranuclear Palsy (PSP)

PSP is a rare neurodegenerative disease that was first described by Richardson in the 1960's. It is characterized by the presence of parkinsonian symptoms in combination with limited ocular movements, specifically inability to look down voluntarily. PSP unlike PD begins on both sides at the same time. PSP patients rarely have tremor. The major disability is difficulty with balance. However, patients can have speech and swallowing dysfunction and memory problems as well. PSP can be misdiagnosed as PD, especially early in the disease. The cause of PSP remains unknown. Generally symptoms progress more rapidly then in PD, and patients do not respond to PD medications. The main interventions are supportive care and family education.

Mutiple System Atrophy (MSA)

MSA is a global term used, since 1969, to describe a group of neurodegenerative conditions that are characterized by the presence of parkinsonism in conjunction with symptoms of other bodily functions. Hence the term “multiple system” atrophy. MSA presents with autonomic or motor deficits. Resting tremor may occur in MSA, but is not a predominant feature. MSA symptoms vary in onset and severity from one person to another. MSA takes several different forms.

Forms of MSA

• Shy-Drager Syndrome (SDS): Patients with SDS have pronounced autonomic instability, manifested in symptoms of bodily functions that do not involve conscious control, such as urinary function and blood pressure, in conjunction with parkinsonism.
  
• Striatonigral Degeneration (SND): SND causes parkinsonian symptoms such as slowed movements and rigidity that generally do not respond to levodopa therapy. Patients may also have other neurological features like myoclonus or pyramidal weakness.
  
• Olivopontocerebellar Atrophy (OPCA): Patients with OPCA have difficulties with balance, coordination, and speech.

"Pure" manifestations of these MSA syndromes are rare. There is no single diagnostic test that assures 100% certainty in making the diagnosis. Sometimes patients present with clinical findings similar to PD. It is only with the progression of the disease that patients will develop the atypical features of MSA. Generally, patients with MSA do not have a robust response to PD medications, though some patients do benefit from such medications, especially early in the disease process. MSA progresses faster than PD, and similar or slightly slower to that of PSP. There is no known familial predisposition to MSA.