Corticobasal degeneration is a neurological disorder about which much remains undiscovered. It is a rare form of Parkinsonism that is difficult to treat and has devastating effects on a person's quality of life. It is fatal typically after six to eight years.
Definition & Facts
Parkinsonism describes any disorder that causes a combination of movement anomalies similar to that which is seen in Parkinson's disease. According to the National Parkinson Foundation, corticobasal degeneration is the least common form of Parkinsonism.
Corticobasal degeneration is a progressive condition that features the shrinking of numerous areas of the brain, especially the basal ganglia and the cerebral cortex and the loss of nerve cells. The progression of this disorder is gradual and takes decades. It is a disorder associated with aging and the first symptoms typically manifest at the age of about 60 years.
Symptoms & Complaints
Patients retain their normal strength. However, their limbs progressively lose their function as apraxia slowly sets in. Apraxia is the interruption of the coordination between the brain and muscles leading to an individual’s inability to make intentional movements despite having the strength to do so. The patients initially lose the ability to make complex movements and later lose even the ability for basic movements.
Symptoms that plague patients suffering from this disorder include disequilibrium, loss of coordination, and abnormal muscle posture. Brief muscular jerks (myoclonus), dystonia, cognitive impairments (including acalculia), memory loss, difficulty in swallowing, visual impairments, halting speech, and difficulty in comprehending language occur at later stages of the disease.
Five years after the onset of the initial symptoms, a person with corticobasal degeneration becomes totally immobile. They may succumb to death with the onslaught of pneumonia and various other bacterial infections. The disease is progressive in nature, and symptoms increase in severity as time passes.
It has been recently determined that brain cells of the deceased affected by the disease carry irregular amounts and forms of a type of protein called tau. The protein plays integral roles in the function and formation of neurons. Tau proteins have also been recently implicated in another neurogenerative disorder that frequently affects football players, chronic traumatic encephalopathy.
That said, its cause remains unclear to medical science.
Diagnosis & Tests
To diagnose corticobasal degeneration, a medical practitioner must first suspect it. The condition at first manifests as other neurodegenerative disorders and differentiating it from frontotemporal dementia and Alzheimer's disease is difficult. Strokes will also need to be ruled out.
Comprehensive neurological examinations will be conducted. Electroencephalography (EEG)'s will be taken to examine loss of brain function. Computerized tomography (CT) scans are useful in diagnosis, and magnetic resonance imaging (MRI) scans are also essential in determining whether or not a person has corticobasal degeneration.
These scanning and imaging tests are meant to help doctors observe the structure and function of the brain. When doctors can examine the cerebral atrophy of the patient’s brain, they can tell whether or not that person has this condition.
Treatment & Therapy
Unfortunately, unlike Parkinson's disease, this type of Parkinsonism does not react to any drugs. It is not even possible to counter the symptoms that are similar to Parkinson's disease with the drugs administered to Parkinson's disease patients such as levodopa. They do not show any significant or long-term efficacy.
There is no specialized treatment for the progressive development of corticobasal degeneration. Patients with this disease are subject to treatments that target alleviating specific symptoms and not the whole disease in general. However, a majority of these symptoms are unresponsive to drugs.
Benzodiazepines such as clonazepam may at times effectively control the asymmetrical and unintentional contraction of muscles. However, benzodiazepines should be administered cautiously as they often cause grievous side effects. Contractions and pain may be reduced by the administration of botulinum toxin.
Physical therapy and occupational therapy can help patients retain their ability to make movements and improve functioning in their day-to-day lives, respectively. Other kinds of therapy include speech therapy. All of these therapies, accompanied by specialized function devices such as assistive canes and visual-auditory equipment, help people affected with the disorder live functionally.
Prevention & Prophylaxis