Corticobasal Degeneration

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Corticobasal Degeneration is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • CBGD
  • CBD
  • cortical basal ganglionic degeneration

Disorder Subdivisions

  • None

General Discussion


Corticobasal degeneration (CBD) is a rare progressive neurological disorder characterized by cell loss and deterioration of specific areas of the brain. Affected individuals often initially experience motor abnormalities in one limb that eventually spreads to affect all the arms and legs. Such motor abnormalities include muscle rigidity and the inability to perform purposeful or voluntary movements (apraxia). Affected individuals may have sufficient muscle power for manual tasks, but often have difficulty directing their movements appropriately. Although CBD was historically described as a motor disease, it is now recognized that cognitive and behavioral symptoms also herald CBD and not uncommonly predate motor symptoms. Initial symptoms typically appear in people during the sixth decade, and may include poor coordination or difficulty accomplishing goal-directed tasks (e.g., buttoning a shirt). The exact cause of corticobasal degeneration is unknown.


Because signs and symptoms associated with corticobasal degeneration are frequently caused by other neurodegenerative disorders, researchers use the term "corticobasal syndrome" to indicate the clinical diagnosis based on signs and symptoms. The term "corticobasal degeneration" refers to those meeting the neuropathological criteria for the disorder at autopsy. This is an important distinction because clinicopathological series indicate that about less than half of patients diagnosed with corticobasal syndrome during life actually has corticobasal degeneration at autopsy.


The symptoms, progression, severity and presentation of corticobasal degeneration can vary greatly from one individual to another. It is important to note that affected individuals may not have all of the symptoms discussed below. Affected individuals should talk to their physician and medical team about their specific case, associated symptoms and overall prognosis.

In many cases, affected individuals develop progressive stiffening or tightening of muscles in the limbs (progressive asymmetric rigidity). Affected individuals are often unable to make voluntary, purposeful movements with the affected limb (apraxia). Affected individuals have sufficient muscle power for manual tasks but have difficulty directing their movements appropriately. Difficulties with the affected limb progressively worsen over time. People with corticobasal degeneration may first become aware of the disorder when they have difficulty coordinating movements in the performance of manual tasks such as buttoning a shirt, combing their hair or gesturing with their hands. Affected individuals often described their actions as stiff, clumsy or uncoordinated. In some cases, affected individuals may be unaware of the movement of a limb or unable to control the movement of a limb (alien limb syndrome). Symptoms typically begin on one side of the body (unilateral), but usually progress over time to affect both sides and all four limbs. In rare cases, the legs may be affected before the arms.

Additional symptoms of corticobasal degeneration may include a slight tremor while in particular positions (postural tremor) or while performing a task (action tremor), and/or exaggerated slowness of movements (bradykinesia) or lack of movement (akinesia). Sudden, brief involuntary muscle spasms that cause jerky movements (myoclonus) may also occur. In some cases, limb dystonia may be present. Dystonia is a general term for a group of neurological conditions characterized by involuntary muscle contractions that force a certain part(s) of the body into abnormal, sometimes painful, movements and positions (postures). Affected individuals may also develop contractures, a condition in which a joint becomes permanently fixed in a bent (flexed) or straightened (extended) position, completely or partial restricting the movement of the affected joint.

Affected individuals may also have speech and language abnormalities including difficulties understanding or expressing language (aphasia), difficulty saying what they want to say despite knowing the right words (apraxia of speech) and speech difficulties due to problems with the muscles that enable speech (dysarthria). Additional symptoms that may occur include difficulty swallowing (dysphagia), an inability to control eyelid blinking, and/or an uncoordinated walk (ataxic gait). Eventually, affected individuals may be unable to walk unassisted.

For many years, corticobasal degeneration was seen as a neurological condition primarily associated with movement disorders. In recent years, researchers have noted that cognitive and behavioral abnormalities occur more frequently than initially believed. In some cases, the signs and symptoms of dementia may even precede the development of motor symptoms. Initial cognitive symptoms include a nonfluent, progressive aphasia and impairments in executive function. Individuals with corticobasal degeneration can develop a more global loss of intellectual abilities (dementia), usually later in the course of the disease. Affected individuals may also exhibit memory loss, impulsiveness, disinhibition, apathy, irritability, reduced attention span and obsessive-compulsive behaviors.

As corticobasal degeneration progresses, affected individuals may become unable to communicate effectively. Eventually, affected individuals may become bedridden and susceptible to life-threatening complications such as pneumonia, bacterial infections, a blood infection (sepsis) or blockage of one or more of the main arteries of the lungs, usually due to blood clots (pulmonary embolism).


The exact, underlying cause of corticobasal degeneration is unknown. Researchers believe that multiple different factors contribute to the development of the disorder including various genetic and environmental factors as well as factors related to aging.

The symptoms of corticobasal degeneration develop due to the progressive deterioration of tissue in different areas of the brain. Nerve cell loss occurs in specific areas, leading to atrophy or shrinkage in specific lobes of the brain. The severity and type of symptoms depend on the area of the brain affected by the disease. The cerebral cortex and basal ganglia are the two areas of the brain most typically affected, although other areas may become involved. The cerebral cortex is the outer layer of nerve tissue called gray matter that surrounds the cerebral hemispheres. The cerebral cortex is involved with higher brain functions including voluntary movement, memory and learning, and coordination of sensory information. The basal ganglia is a cluster of nerve cells that is involved with motor and learning functions.

Researchers have determined that a protein called tau is involved in the development of corticobasal degeneration. Tau is a specific type of protein normally found in brain cells. The function of tau within nerve cells is complex and not fully understood, although it is believed to be essential for the normal function of brain cells. In corticobasal degeneration, abnormal levels of tau accumulate in certain brain cells, eventually causing their deterioration. The exact role, that tau plays in the development of corticobasal degeneration is not fully understood. Abnormalities involving tau are also seen in other neurodegenerative brain disorders including Alzheimer's disease, Pick disease, progressive supranuclear palsy, Niemann-Pick disease type C and frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17). These disorders collectively are referred to as "tauopathies."

Affected Populations

Corticobasal degeneration is believed to affect males and females in equal numbers. However, in some studies it was reported to be more common in women. Symptoms usually begin between the ages of 50-70. No confirmed cases of corticobasal degeneration have been reported in the medical literature in individuals under 40. The disorder is estimated to affect 5 people per 100,000 in the general population, with approximately .62-.92 new cases per year per 100,000 people. However, cases may go undiagnosed or misdiagnosed making it difficult to determine the true frequency of corticobasal degeneration in the general population.

Standard Therapies


A diagnosis of corticobasal degeneration is suspected if characteristic neurologic symptoms occur in a slowly progressive course in the absence of a structural lesion such as a stroke or tumor. Distinguishing corticobasal degeneration from other, similar neurodegenerative disorders is difficult. There are no specific tests for a diagnosis of corticobasal degeneration. A clinical diagnosis is made based upon a thorough neurological exam involving a variety of specialized tests.

Clinical Testing and Work-Up

An electrocardiogram (EEG), a test which measures the electrical activity of the brain is generally unhelpful and not diagnostic of neurodegenerative disease.

Imaging techniques such as computerized tomography (CT) scanning and magnetic resonance imaging (MRI) may be used to rule out other conditions or reveal characterized brain tissue degeneration within the cerebral cortex and basal ganglia. During CT scanning, a computer and x-rays are used to create a film showing cross-sectional images of certain tissue structures including the brain. An MRI uses magnetic field pulses to produce cross-sectional images of particular organs and bodily tissues such as the brain.


There is no specific treatment that slows down the progression of corticobasal degeneration. Treatment is directed toward the specific symptoms that are apparent in each individual, although most cases prove resistant to such therapy.

Affected individuals may be treated with certain drugs such as levodopa and similar medications that are normally used to treat Parkinson's disease. These drugs are generally ineffective, but may help with the slowness or stiffness some individuals experience. Myoclonus may be controlled with medications such as clonazepam, however, benzodiazepines should be used sparingly as they may have undesired side effects in these patients. Botulinum toxin (Botox®) has been used to treat contractures and pain, but do not restore the ability to control movements. Baclofen is another drug that may be used to treat muscle rigidity.

Physical therapy may be beneficial in maintaining the mobility and range of motion of stiffened, rigid joints and prevent the development of contractures. Occupational therapy is beneficial in assessing the safety of an affected individual's home and in determining what adaptive medical equipment may increase a person's independence. Speech therapy may be beneficial in treating individuals where speech and language abnormalities associated with corticobasal degeneration. Affected individuals may need devices such as a cane or walker to assist in walking.

A report offering encouragement, advice, and support to those caring for a loved one with corticobasal degeneration, entitled the CBGD Caregivers Report, is available free of charge to all who would find it helpful. It can be downloaded at

Investigational Therapies

Information on current clinical trials is posted on the Internet at All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Toll-free: (800) 411-1222

TTY: (866) 411-1010


For information about clinical trials sponsored by private sources, in the main, contact:

Contact for additional information about corticobasal degeneration:

Suzee Lee, MD

Assistant Professor

UCSF Memory and Aging Center

MC: 1207

675 Nelson Rising Lane, Suite 190

San Francisco, CA 94158

Phone: 415-476-6880

Fax: 415-476-4800



Dickson DW. Sporadic Tauopathies: Pick's disease, corticobasal degeneration, progressive supranuclear palsy and argyrophilic grain disease. In: The Neuropathology of Dementia, 2nd ed. Esiri M, Lee VM-Y, Trojanowski JQ, editors. 2004 Cambridge University Press, New York, NY. pp. 227-256.

Litvan I. Corticobasal Degeneration. NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:524-525.


Lee SE, Rabinovici GD, Mayo MC, et al. Clinicopathological correlations in corticobasal degeneration. Ann Neurol. 2011;70:327-340.

Hassan A, Whitwell JL, Josephs KA. The corticobasal syndrome-Alzheimer's disease conundrum. Expert Rev Neurother. 2011;11:1569-1578.

Ludolph AC, Kassubek J, Landwehrmeye BG, et al. Tauopathies with parkinsonism: clinical spectrum, neuropathologic basis, biological markers, and treatment options. Eur J Neurol. 2009;16:297-309.

Webb A, Miller B, Bonasera S, et al. Role of the tau gene region chromosome inversion in progressive supranuclear palsy, corticobasal degeneration, and related disorders. Arch Neurol. 2008;65:1473-1478.

Geda YE, Boeve BF, Negash S, et al. Neuropsychiatric features in 36 pathologically confirmed cases of corticobasal degeneration. J Neuropsychiatry Clin Neurosci. 2007;19:77-80.

Pittman AM, Fung HC, de Silva R. Untangling the tau gene association with neurodegenerative disorders. Hum Mol Genet. 2006;15:R188-195.

Goedert M, Jakes R. Mutations causing neurodegenerative tauopathies. Biochim Biophys Acta. 2005;1739:240-250.

Boeve BF, Lang AE, Litvan I. Corticobasal degeneration and its relationship to progressive supranuclear palsy and frontotemporal dementia. Ann Neurol. 2003;54:S15-S19.

Dickson DW, Bergeron C, Chin SS, et al. Office of Rare Diseases neuropathologic criteria for corticobasal degeneration. J Neuropathol Exp Neurol. 2002;61:935-946.

Lee VM, Goedert M, Trojanowski JQ. Neurodegenerative tauopathies. Annu Rev Neurosci. 2001;24:121-159.


Barrett AM. Cortical Basal Ganglionic Degeneration. Emedicine Journal, June 19, 2012. Available at: Accessed on: 09/01/2012.

Dalvi AI, Bloomfield AS. Parkinson-Plus Syndromes. Emedicine Journal, February 7, 2012. Available at: Accessed on: 09/01/2012.


CurePSP: Foundation for PSP l CBD & Related Brain Diseases

30 E. Padonia Road, Suite 201

Timonium, MD 21093

Tel: (410)785-7004

Fax: (410)785-7009

Tel: (800)457-4777



NIH/National Institute of Neurological Disorders and Stroke

P.O. Box 5801

Bethesda, MD 20824

Tel: (301)496-5751

Fax: (301)402-2186

Tel: (800)352-9424

TDD: (301)468-5981


Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223


UCSF Memory and Aging Center

350 Parnassus Avenue

Suite 905

San Francisco, CA 94117

Tel: (415)476-6880

Fax: (415)476-4800



Association for Frontotemporal Degeneration

Radnor Station Building #2, Suite 320

290 King of Prussia Road

Radnor, PA 19087

Tel: (267)514-7221

Tel: (866)507-7222



For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see