Cortico-basal Degeneration (CBD) or Cortico-basal Syndrome (CBS)

What is CBD or CBS?

It is a brain disorder causing Parkinson disease like symptoms (from involvement of basal ganglia areas of brain) and additional symptoms from involvement of cerebral cortex, the top of the brain. Traditionally, it has been called CBD, while the new terminology is CBS.

What is the problem in CBS?

The main issue is degeneration of neurons in certain areas of brain. Degeneration of dopamine producing neurons in basal ganglia causes parkinsonism and degeneration of neurons in the cerebral cortex may cause variety of cortical dysfunction.

How common is CBS?

It is a rare disorder. A general neurologist may see a case every few years.

What are symptoms of CBS?

Symptoms from basal ganglia involvement: Rigidity of one arm or leg, abnormal posturing of a limb (dystonia), tremor, spasticity, difficulty speaking, gaze impairment, and unsteadiness.

Symptoms from cerebral cortex involvement: Apraxia (loss of dexterity or inability to perform certain learned tasks despite having good strength), Alien limb (patient may not recognize their limb), difficulty speaking, localized myoclonus, frontal dementia, change in personality.

How is DCS diagnosed?

It is diagnosed based upon its presenting symptoms and examination.

Does imaging help with the diagnosis?

Imaging of brain with CT or MRI usually provides indirect help by excluding many other causes. There are supportive but no specific imaging findings for this diagnosis.

Are there various types of CBS?  

Based upon clinical features, neurologist may differentiate it in following manner:

1. Classic CBD: Rigidity, decreased movements, and abnormal posturing of one limb, plus apraxia (as described above).
2. Frontotemporal dementia variant: With significant behavioral or personality change.
3. Posterior cortical atrophy: Significant visual disturbance, apraxia, and Alzheimer type features.
4. PSP type: With gaze palsy.

How is CBS treated?

There is no specific medicine available to slow down, stop, or reverse the abnormal process in CBS. It is one of the parkinsonian syndromes, which means that it has some symptoms of Parkinson disease. Taking that lead, smaller doses of carbidopa/levodopa, amantadine, or a dopamine agonist can be tried. Most of these meds may not work and may result in more problems. Carbidopa/levodopa may help with balancing, or walking. Some other medicines can also be considered, like Botox for dystonia or glycopyrrolate or anticholinergics for excessive salivation.

Every patient and the family can benefit from a candid discussion about this condition and its repercussions. Dementia may be a part of this illness, which may not be obvious in early stages. I provide following recommendations to the patient and their families:

1. Learn about this condition. This article is written for that purpose.
2. Make appropriate changes in living situation to minimize falls and injuries. This may include having one floor living space.
3. Avoid stairs.
4. Remove loose rugs.
5. Keep nightlight on.
6. For some patients, a walker for safety.
7. Install handicap type features in the house and especially in the bathroom.
8. Take sitting showers.
9. Have a Will, Health Proxy and Financial Power of Attorney papers done.
10. Consider early retirement, especially if cognition is affected.
11. Minimize driving. Don’t drive at night, during rush hours, in bad weather, and long-distance.
12. Try speech therapy to improve and maintain speech.
13. While drinking, do it slowly with smaller sips, in erect sitting or standing position.
14. While eating, do it slowly with smaller bites, in erect sitting or standing position. Avoid food that may seem difficult to chew or swallow. A different formulation of the same food item may help to avoid choking. For example, if eating meat, avoid steak or bigger pieces, try minced meat or burger.
15. If speech is affected, consider a microphone and a speaker for better communication. In more severe cases, consider electronic keyboard for communication.
16. Consider a wheelchair when balance is significantly off, especially for outdoor appointments.
17. If living at home, consider getting couple of hours of help during most days to help with cleaning and meals.
18. For patients with excessive blinking causing eye closure, treatment with Botox injections can help.
19. A different type of eyeglasses lens may help with the limitation of vision.
20. Physical therapy can help to improve strength and balance.
21. Occupational therapy may help to make appropriate changes in day to day living, especially to avoid falls and injuries.
22. If available, consider joining a support group. If not, at least contact Elder Care services for any help.
23. When coming for appointments, either bring the list of all medicines you take, or the prescription bottles. Also, write down the questions you may have for the doctor.

 

Do I need to see a specialist neurologist if I have CBS?

CBS is usually diagnosed by a neurologist. Some neurologists specialize in this type of disorders, and they are called movement disorders specialists. If not satisfied with your neurologist, consider a consultation with a sub-specialist. Another advantage of seeing a movement disorder specialist, especially in a larger or tertiary care center, is to have opportunity to be involved with an investigational protocol or medicine.

Where can I get more information about CBS?

American Academy of Neurology

International Parkinson and Movement Disorder Society