Corticobasal Degeneration (CBD) and progressive supranuclear palsy (PSP) are Parkinson’s-plus syndrome, meaning that they are diseases that share some of the symptoms of Parkinson Disease such as slowing of movements, stiffness, tremors, falls, and shuffling of the feet. They may both also cause changes in memory and thinking.
In addition to these symptoms, people with PSP also develop problems moving their eyes, called supranuclear palsy, a wide-eyed appearance, and difficulty swallowing. Unlike Parkinson Disease, people often fall backward instead of forward. They may also develop severe stiffness in the neck.
There are several variations on the name of CBD, such as corticobasal syndrome or disease, and corticobasal ganglionic degeneration. It is named after the parts of the brain that are damaged, the cortex, which is the outer part of the brain, and the basal ganglia, which are deep within the brain. Like Parkinson Disease, slowing of movements, stiffness, tremors, falls, and shuffling of the feet can be seen. Problems with movements occur on one side of the body, such as stiffness, shaking, or loss of control. People with CBD may be unable to get their arm to do what they want even if they know how. Sometimes, the arm on that side might move on its own, called alien limb syndrome.
Not all people with PSP and CBD develop problems with memory, thinking, behavior or language. However, in some people, these problems do arise. In fact, sometimes these problems are the first symptoms, and the more classic symptoms listed above develop later.
People with PSP can develop a loss of motivation. They may lose interest in their everyday activities. Problems may arise with attention and concentration. They may lose the ability to control their mouth to speak, called apraxia of speech, or progressive slurring of speech, called dysarthria.
People with CBD can develop loss of inhibition. They may act or speak rudely or crudely, or seem to lose empathy for others. They may also have difficulty with attention and concentration. A type of language difficulty where understanding grammar and speaking in full sentences can develop, or can be the first symptom.
All the symptoms of PSP and CBD get worse as the diseases progress. Eventually, people may become completely bedbound and unable to safely walk. Swallowing problems may lead to choking on food or getting food in the lungs, leading to pneumonia. On average, people with these diseases die within 5 years of diagnosis. Death is usually from complications of falls or swallowing problems.
Diagnosis and Treatment
How it’s diagnosed
CBD and PSP are diagnosed based on the signs and symptoms above by a qualified doctor. Oftentimes, an MRI and basic bloodwork is done to make sure that there are no other explanations for the symptoms.
There are currently no drugs that are proven to reverse the damage in either PSP or CBD. However, some medications can be helpful for symptom control in these conditions. Some people have improvement of their movements with Parkinson Disease medication, such as carbidopa-levodopa, but in general, they are less effective than in Parkinson Disease. For people with severe stiffness, muscle relaxants and Botox may be useful. Depression and motivation problems may respond to antidepressants. In severe disease, antipsychotic medications can help treat agitation, but should not be used except when absolutely needed.
Supportive treatment for problems with behavior, swallowing, speech and communication, falls and mobility are available. Many people with PSP or CBD benefit immensely from occupational therapy, physical therapy, and speech therapy.
Currently, a clinical trial is underway to see if a new medication called davunetide will be useful in treatment of PSP. We do not yet know what the results will be.