Motor Abnormalities in PSP & CBS – by Cameron Dietiker MD

---

Editor’s Note:  These are brief notes from Elizabeth Wong about what she got out of the presentation and what she learned from the Q&A. Following the summary are more detailed notes, in case you are interested in reading further!

 

This talk focused on movement abnormalities and challenges faced by individuals with Progressive Supranuclear Palsy (PSP) and Corticobasal Syndrome (CBS). Both conditions often involve parkinsonism, characterized by slowness, stiffness, tremor, and balance problems, but they have distinct features. PSP typically presents with more stiffness in the neck and trunk, early falls, eye movement difficulties, and dystonia. CBS, on the other hand, often affects one side of the body, causing akinesia (lack of movement), severe rigidity, and myoclonus (muscle jerks). CBS also frequently involves difficulties with skilled movements (apraxia), sensory problems, and the unusual phenomenon of alien limb syndrome. Treatment strategies focus on managing specific symptoms with medications, BotoxⓇ injections for dystonia, physical therapy, and other supportive measures.

The Q&A session provided further clarification on a range of topics. It emphasized the need to carefully assess dizziness to determine its underlying cause, highlighted the role of prism glasses in aiding eye alignment, and addressed concerns about hand clenching, limb weakness, and eyelid paralysis. The discussion also touched on the potential for speech and swallowing difficulties, pain, weight loss, and the benefits of exercise. Importantly, it was noted that individuals with apraxia are often aware of their challenges, which can be a source of frustration

 

“Motor Abnormalities in Progressive Supranuclear Palsy (PSP) and Corticobasal Syndrome (CBS)”

Presented during Progressive Supranuclear Palsy / Corticobasal Degeneration Symposium 

Speaker: Cameron Dietiker, MD, Movement Disorder Specialist, UCSF

Symposium Host: Brain Support Network and Stanford Movement Disorder Clinic

Symposium Date: June 29, 2024

Summary by: Elizabeth Wong, Stanford Parkinson’s Community Outreach

The terms "motor abnormalities" and "motor signs" refer to movement problems whether it is excessive, involuntary, or a lack of ability to move normally.

Parkinsonism

• Bradykinesia is the hallmark symptom of parkinsonism: Slowness of movement, with decreasing amplitude and speed over time. As a movement is continuously performed, it gets slower and smaller.
• Other features of Parkinsonism:
  • Rigidity which is muscle stiffness and resistance of the muscles with passive movement of body
  • Rest tremor which is slow, low frequency tremor in the resting limb.
  • Postural instability which is loss of postural reflexes that impairs balance and increases the risk of falling.
  • Gait impairment which is characterized by shuffling, small steps, reduced arm swing, and sometimes freezing of gait where feet get stuck to ground and hard to lift off the ground.
• Diagnosis of parkinsonism requires bradykinesia plus either rigidity or rest tremor.

Progressive Supranuclear Palsy (PSP)

In PSP, the parkinsonism tends to have more axial rigidity, meaning stiffness midline of the body, in the neck and trunk. 

Comparing PSP to Parkinson’s

• Tend to see early and frequent falls in PSP, sooner than in Parkinson's disease. The first fall occurs on average 16 to 17 months after onset in PSP, versus 108 months in someone with Parkinson's. 
• See eye movement abnormalities in PSP, particularly when looking up and down.
  • The eye abnormalities in PSP affect vertical gaze before horizontal gaze. Because upward gaze can be impacted by normal aging, impaired downgaze is actually the most sensitive sign in PSP. We also see "round the houses sign," where people use their horizontal eye movements to help them look up and down, creating a circular motion. The speed of eye movements is affected before amplitude, they may have a full range of gaze, but the speed of the movement of their eyes to get to a position is slowed.
• In Parkinson's disease, the posture tends to be flexed forward, knees flexed. 
• In PSP, we sometimes see the opposite; the neck and back are more extended, the stance has more knee extension, leading to a backward leaning posture. 
• In PD falls can be triggered by shifting weight or turning, in PSP falls can be triggered as well, but in PSP falls can be more spontaneous. Additionally, because of the backward posture in PSP, falls tend to occur in that direction. Falls can also be related to disinhibition and impulsivity, moving too quickly, not getting one’s bearing before getting going, sometimes defined by the "rocket sign," where someone stands up too quickly and falls backward into the chair.

Dystonia is characterized by muscle spasms or contractions that lead to abnormal posturing and present in many different movement disorders. In PSP, we often see axial dystonia (the midline body), often involving the neck, causing a backward positioning called retrocollis. We also see trunk involvement, facial dystonia with spasms of the eyelids (like forced closure of eye), frontalis muscle activation leading to a “surprised” appearance, and procerus muscle (muscle between the eyebrows) activation creating a frowning or worried appearance. Blepharospasm can cause frequent blinking and forced eyelid closure.

Bulbar symptoms of PSP, which refer to the symptoms affected by the brainstem. The brainstem contains neurons that control swallowing and speech and when affected, it can lead to dysphagia (trouble with swallowing) and dysarthria (trouble with speech articulation). Speech can be slowed and slurred with nasal quality to speech.

Corticobasal syndrome (CBS). 

See parkinsonism in CBS but it tends to present asymmetrically, often in a single limb, usually the arm or same side of body. 

See the following in CBS:

• • Akinesia, the most severe form of bradykinesia, meaning no movement. 
    • Akinetic-rigid syndrome is common in CBS, often present in one arm, but later on in disease can move onto the leg and  side of the body. Rigidity can be severe, making it difficult to move the limb.

• Rigidity

• Dystonia often seen in the involved limb, typically the upper arm. It usually develops within the first two years.
• Myoclonus is a sudden jerk or twitch of a muscle. In CBS, myoclonus is abnormal and common in cases of CBS, and it is typically in the involved limb and can be spontaneous when a person is at rest or can be triggered by sensory stimulation like touching the arm, activation like when they move. Can look like tremor, but it is more jerky and irregular.
• Cortex involvement leading to specific abnormalities such as:
  • Apraxia, the inability to perform a previously learned task despite adequate strength and comprehension.
    • Ideomotor apraxia is difficult miming a movement, can think of it as “idea” of “motor or movement”, where you ask someone to picture a task and ask them to pretend to do it, like wave goodbye or pretend to hammer a nail, but if you actually give them a tool they can do it, so there is disconnect between what they are actually able to do and then having them miming or pretending to do something.
    • Limb-kinetic apraxia is inaccurate or clumsy movement of the fingers or hand. 
  • Cortical sensory signs, leading to an inability to identify objects by touch.

• Alien limb phenomenon the limb seems to move purposefully on its own accord when it is not intended. People experiencing this often have difficulty recognizing the limb as their own. One manifestation is levitation, where a limb is lifted and forgotten about. Sometimes it can be induced by visual or tactile stimuli, like reaching for something.

Therapies for movement symptoms in PSP and CBS are similar for both syndromes. We take a symptomatic approach, treating symptoms as they arise. 

• For parkinsonism, we commonly try carbidopa-levodopa. It's not usually as effective in PSP and CBS as it is in Parkinson's disease, but early in disease it may be effective so any improvement in quality of life is worthwhile to try. 
• For dystonia, BotoxⓇ injections are the gold standard. We have other medications (baclofen, trihexyphenidyl, clonazepam), but they can have side effects. 
• For gait dysfunction and falls, physical therapy is the mainstay of treatment. Cognitive enhancing medications (donepezil and rivastigmine) are rarely used, can make things worse in PSP and CBS, but can be helpful for freezing of gait, but rarely used but could potentially be considered.
• For myoclonus, anti-epileptic drugs are the most effective treatments, but they have side effects, so often will use zonisamide that is better tolerated.
• For eye movement abnormalities, prism glasses can be helpful in early stages that can be prescribed by optometrist or neuro ophthalmologist, tend to be more effective in early stages of disease when eyes are still moving well. 
• For swallowing problems, speech therapy is key.
• For speech problems, speech therapy, augmentative communication devices, and speech amplification devices are options.

Q & A 

Q: Is dizziness a common symptom in both disorders? Is it an early indicator? What can you do about it?

A: Dizziness is a tricky symptom. It can mean lightheadedness (caused by low blood pressure), vertigo, or disequilibrium. It's not a hallmark of either syndrome, but it wouldn't be surprising. It requires further questioning to figure out the cause.

 

Q: Could you explain what prism glasses are?

A: It’s a prescription you can get in your glasses. They have prisms in the lenses to help focus your eyes together.

 

Q: Is it common in PSP or CBD to be unable to unclench the fist?

A: It can be. The cause needs to be determined. It could be dystonia, in which case BotoxⓇ might help, or rigidity, in which case carbidopa-levodopa might be worth trying. Occupational therapy and stretches are also important.

 

Q: Is partial loss of control of one side of the body typical in CBD?

A: Yes, very typical. It can start on one limb first and spread to the other limb on the same side. It can be due to apraxia, rigidity, or dystonia.

 

Q: Does everyone with PSP eventually get eye palsy?

A: Most of the time, but to varying degrees.

 

Q: Is myoclonus specific for CBD? Could it also be seen in PSP?

A: It's more common in CBS, but we see it in other movement disorders as well. Myoclonus not specific to CBD.

 

Q: Is the total inability to speak or swallow indicative of either PSP or CBD?

A: Speech and swallowing changes can occur in both syndromes. There's a lot of overlap in the symptoms.

 

Q: Is pain associated with PSP or CBD?

A: Yes, it can be, especially with rigidity and dystonia. Treatments for those can also help with pain.

 

Q: Could PSP cause temporary whole body rigidity lasting 12 to 16 hours?

A: Whole body rigidity can occur in PSP. Exacerbations can be caused by infections, poor sleep, or other factors.

 

Q: Is dramatic weight loss common in these disorders? What might be causing it?

A: We can see weight loss in these conditions. Causes include difficulty swallowing, slowness in eating, loss of appetite, and a higher metabolic rate. There are medications to stimulate appetite and we counsel people to increase healthy calories.

 

Q: Can BotoxⓇ help the muscles in Pisa syndrome?

A: PIsa syndrome is dystonia that pulls your body/trunk to one side. Botox is not as helpful for Pisa syndrome because the trunk muscles are so large. We also worry about weakening the core muscles so BotoxⓇ there is not something we would generally do.

 

Q: Can exercise be helpful for the motor symptoms of PSP or CBS?

A: Absolutely. Exercise is important for slowing progression and preserving strength and movement.

 

Q: If the arm levitates during sleep, is that alien limb syndrome?

A: That's a great question. Movements in sleep are usually suppressed, so if the arm is moving during sleep, it's probably something different than alien limb syndrome.

 

Q: Is there any use of TMS to treat these disorders?

A: The question is whether there's any evidence that transcranial magnetic stimulation (TMS) can help with either of these disorders. I'm not aware of any strong research or evidence that shows it can be helpful. That being said, it's a relatively non-invasive therapy with minimal side effects, so if someone is recommending it, I don't think it's necessarily a bad thing. I just don't think there's a lot of good evidence for it.

 

Q: About the lady in the video who was peeling the potato and dialing the phone, could she be dialing an old rotary phone?

A: I'm so sorry, I forgot about rotary phones! Maybe that's the case, but she did make that same spinning movement when she was writing with a pen and trying to put a key in a lock. So, possibly she was dialing a rotary phone and maybe she got that one correct.

 

Q: Did the woman who was trying to peel a potato have any insight into the fact that she was doing it incorrectly?

A: I can't answer for that specific patient, as it wasn't my patient. But I can say that people with apraxia do have insight. They know they're not doing the movement correctly, and it's very frustrating. I think you could see her frustration in the video. She knew she wasn't doing it right. She had insight into it, and it was frustrating for her, but she was also smiling and good-natured. She did a good job with some of the other tasks.