Progressive supranuclear palsy is a relentless, rapidly progressive neurodegenerative disorder. Although rare in the general population (approximately 6 out of 100,000 people are affected), it is the most common form of Parkinsonism aside from Parkinson’s disease. It’s most famous victim, Dudley Moore, passed away in 2002. More recently, PSP has gained attention as a research model for potential therapeutic agents in the most common neurodegenerative disorder — Alzheimer’s disease. Both disorders are due to an abnormal accumulation of a normal protein in the brain called tau, and are therefore classified as “tauopathies.” Unfortunately for patients with PSP, many go for years without the correct diagnosis and subsequently do not receive the care they need and deserve.
Identifying PSP is more difficult early in the course of the disease, when the classic signs and symptoms may not be pronounced or even present. Initially there may be personality changes, difficulty with balance, or blurred vision. Eventually the disorder causes slowness of movement, neck stiffness and rigidity, cognitive dysfunction, inappropriate laughter or crying, inability to open one’s eyelids, slowed and often slurred speech, and difficulty swallowing.
What ultimately distinguishes PSP from other Parkinsonian disorders is the inability to look up or down (a symptom known as “vertical supranuclear gaze palsy”), combined with severe postural instability leading to unexplained falls. On average, PSP patients fall 16.8 months after symptom onset, compared to 108 months after symptom onset in Parkinson’s disease. Unexplained falls backwards, not associated with a loss of consciousness, are most common.
Although antiparkinsonian medications such as Levodopa may improve the slowness, stiffness, and imbalance in some patients with PSP, the effect is usually temporary and not nearly as effective as in Parkinson’s disease. The combination of falls and difficulty swallowing leads to significant morbidity, and mortality usually occurs within a decade after the onset of symptoms.
Balance and gait can be improved through individualized rehabilitation programs, by therapists specifically trained in treating Parkinsonian disorders.
Botulinum toxin injections have proven to be extremely effective in treating several symptoms seen in PSP including blepharospasm/apraxia of eyelid opening (inability to open one’s eyelids), cervical dystonia (neck stiffness and rigidity), and sialorrhea (drooling caused by decreased ability to swallow).
Oral medications can improve many “non-motor” features of PSP. Behavioral symptoms such as depression and apathy, as well as inappropriate laughter or crying often respond to the appropriate medication. REM behavioral disorder (RBD), a common feature of Parkinsonian disorders characterized by acting out of dreams that are intense, vivid, and violent, can be treated with melatonin.
Speech therapy can improve one’s ability to talk and swallow. In later stages of the disorder, PEG tube placement can prevent aspiration, the most common cause of morbidity in PSP.
The disorder’s leading national nonprofit agency, CurePSP, is developing a national Centers of Excellence initiative to establish criteria for medical care in PSP and other related disorders. Establishing Centers of Excellence will optimize standards of patient care, increase general awareness of PSP spectrum disorders, and allow outside providers to easily identify centers to refer patients for clinical trials and better overall management.
CurePSP is currently funding a Whole Exome Sequencing Project, which will expand on the findings of a large Genome Wide Association Study (GWAS) recently performed to evaluate for common genetic variations that may contribute to risk of developing PSP. The results of these studies can potentially be translated to other, more common neurodegenerative disorders, such as Alzheimer’s disease.
At the Cleveland Clinic Lou Ruvo Center for Brain Health, we strive to provide optimal care to patients suffering from PSP and their loved ones, while continuing to search
for a cure.