Progressive supranuclear palsy (PSP) is a rare brain disorder that affects approximately 6 in 100,000 people worldwide. It causes muscle weakness and affects gait, balance and overall movement, as well as the patient’s mood, cognitive skills and behavior.
Identifying the distinctive symptoms of PSP is crucial when making the right diagnosis, as a number of symptoms overlap with those of Parkinson’s disease and other neurodegenerative disorders.
Motor Movement, Instability and Falls in PSP
PSP results in weakness of the muscles (palsy) and affects the patients’ ability to walk, maintain balance, and commonly leads to falling or bumping into objects. Unlike typical Parkinson disease, falls begin within the first year of PSP and are common by year three. This is one of the main indicators used in making a differential diagnosis.
Patients most commonly fall backwards, as their reflexes are affected. It is typical for the patients to lunge forward when starting to move leading to frequent falls. Difficulty with walking and maintaining balance worsens over time, including slow movement (bradykinesia) and clumsiness.
Muscle stiffness is also commonly experienced by patients suffering from PSP, resulting in the loss of fluidity of movement and often affecting the person’s sleep patterns.
Dysphagia, or poor swallowing, also manifests itself in the course of the disease. This can lead to difficulty with feeding resulting in malnutrition.
Vision and Facial Expression
The motor neurons that control the extraocular muscles are affected in the course of the disease. This results in blurring of vision as one of the more distinct symptoms of the condition, an important factor in the diagnosis.
Often one of the first symptoms noted during a physical examination is the slow vertical movement of the eyes. Patients will complain of having difficulty reading, as their ability to gaze downwards and upwards (vertical saccades) is affected. Typically, downgaze palsy is experienced first, followed by upgaze palsy.
Blurring of vision is common as the extraocular muscle response slows over time. Eventually, gaze palsy may be present in all directions, leading to a loss of all eye movement.
Sometimes the eyelids do not open properly, and this may lead to the need to turn the head in different directions if one has to look there, as well as drooping eyelids, and too little blinking.
Patients with PSP whose eyesight is affected, along with eyeball and eyelid movements, may seem to be not looking at the speaker, and/or may be unable to hold the speaker’s gaze during a conversation. Their facial expression may mimic surprise or astonishment as well.
Cognitive and Behavioral Changes
PSP exhibits itself in a number of behavioral and cognitive changes as well, as some areas of the brain located in the frontal lobe are affected.
Patients experience difficulties with memory, reasoning, problem-solving and decision-making and may lose interest in activities which they have previously found pleasurable.
Typical cognitive changes include:
- difficulty focusing attention
- difficulty switching between tasks
Some of the cognitive symptoms include:
Some patients report compulsive-obsessive symptoms. This often leads to patients trying to perform motor tasks that they are not able to do, for example, to get up and walk on their own. This can lead to falls.
The Effect on Sleep
Sleep disturbances and sensitivity to light are common among patients with PSP. Muscle stiffness is an added factor which makes the patients uncomfortable and hinders sleep. They typically experience early or late insomnia and difficulties in maintaining sleep.