Corticobasal degenerative disease

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at October 21, 2016
StartDiseasesCorticobasal degenerative disease

Corticobasal degenerative disease (CBD) is a progressive neurological disorder. Nerve cell shrinkage and loss occurs in multiple areas of the brain, including the cerebral cortex, which is associated with higher functions like personality, thinking and understanding language. The disease progresses for six to eight years and results in death from complications like sepsis (systemic infection) or pulmonary embolism.

Contents

Definition & Facts

Corticobasal degenerative disease (CBD) typically presents around the age of 60. Women are thought to be somewhat more affected than men. Approximately five people in 100,000 are affected, but misdiagnosis is common and so the actual prevalence of the condition is not known. The age range for onset is between 45-70.

Symptoms that involve the impairment of movement resemble Parkinson's disease, but the medications for PD are ineffective for CBD. The range of CBD symptoms can be complex and unique, so it is best to refer people with CBD symptoms to a neurologist who has experience with the disorder.

Symptoms & Complaints

At onset of CBD, individuals may complain of unexplained changes in sensation. The subtle sensation changes will present in one limb at first, and follow with an inability to smoothly execute mental commands with the affected limb.

At first, the apraxia a person with this condition experiences, which is the inability to perform certain tasks or movements, may be mistakenly attributed to ordinary stiffness or weakness.

Some symptoms of apraxia affecting the hand might be clumsiness in brushing teeth, weakness in opening a jar, using a can-opener or turning a door knob. If a leg is affected first, a slight lack of coordination in a complex movement like a dance step may be noted. Later, the person may begin to trip and fall in the absence of an impediment.

As the disease progresses, stiffening, twisting or contracting of the affected limb may occur without warning. Uncontrolled jumping of the hand or leg may begin when the person is startled or when the limb is tapped. Myoclonus can occur which are jerks and spasms of muscles.

A strange effect called alien hand syndrome can cause consternation. A person may state that her hand does not feel like a part of her body and move on its own, rising to touch the face or hair involuntarily.

Difficulty with verbal expression is common and progressive. Word retrieval is impaired, and reading, writing and math skills falter. Personality changes with inappropriate behaviors are characteristic of the disease, but the repetitive questioning and forgetfulness of recent events so frequently seen in dementia is less noticeable.

Causes

Exact causes of CBD are unknown at this time. The nerve disease may begin through multiple factors, from the normal aging process to environmental factors or genetic factors.

An abnormality found in corticobasal degeneration and other similar brain diseases is the dysfunction of a protein called tau. The dysfunction first manifests itself in just a few neurons, but soon spreads profusely. The abnormal accumulation of tau causes neurons to misfire, deteriorate and die. The prevention of tau pathology is thought to be key to understanding and treating degenerative brain disease in the future. 

Diagnosis & Tests

There is no single, definitive test for corticobasal degenerative disease, as a cluster of other neurodegenerative disorders have similar symptoms. Diagnosing this condition necessitates ruling out other neurological conditions that resemble CBD.

A neurologist will be consulted, and brain scans ordered. A magnetic resonance imaging scan (MRI) will provide detailed pictures of the brain from multiple angles. A positron emission tomography (PET) scan is another imaging technique.

Because these tests are inconclusive for exact diagnosis of CBD, the doctor may prescribe a limited course of levodopa, a medication that is used for Parkinson's disease. If the medication causes no change in symptoms, the physician may then rule out PD.

Neuropsychological testing will look at concentration skills, memory, language understanding, number recollection, counting and putting words to pictures.

Treatment & Therapy

There is no specific cure or treatment for CBD today. Symptoms are addressed and alleviated as much as possible. Anti-seizure medication and muscle relaxants have been successful in dealing with muscle twitching and twisting. 

At times, behaviors and memory difficulties can respond to donepezil, which is used for dementia. Anxiety and depression can be treated with drugs such as sertraline. Physical therapy is important to maintain muscle strength and counteract the deformities of contraction often seen with neurological impairment. Occupational therapy and speech therapy do much to keep a person engaged and able to communicate for as long as possible.

Mobility aids such as wheelchairs and walkers should be considered, and safe feeding techniques will be imperative as the disease progresses, due to lesser swallowing capabilities. Aid to physical hygiene is important, because infections of skin and urinary bladder may arise. Nursing-care placement or at-home care-giver relief are vital considerations. 

A diagnosis of CBD can be devastating for an individual. Patients, caregivers and family should consider long-term management of the disease and seek assistance through counseling for emotional and financial burdens.

Prevention & Prophylaxis

Preventative measures for CBD remain unknown at this time. Natural or holistic remedies may be able to mitigate certain symptoms of the disease though clinical research remains mixed on their efficacy. Antioxidants like alpha lipoic acid, pycnogenol and omega-3 fatty acids may facilitate brain function. A healthy diet and activity to the best it can be achieved promotes overall strength and facilitates coping with the disease.