Corticobasal degeneration (CBD) is a rare neurodegenerative disease involving the cerebral cortex and the basal ganglia.

Included in these fundamental features are problems with cortical processing, dysfunction of the basal ganglia, and a sudden and detrimental onset.

[2] Psychiatric and cognitive dysfunctions, although present in CBD, are much less prevalent and lack establishment as common indicators of the presence of the disease.

In a study of 147 patients with CBD, it was found that all of them had at least one Parkinsonian sign, 95% having two and 93% had some higher order dysfunction (cognitive impairments like acalculia, sensory loss, dementia, neglect, etc.).

[citation needed] Some of the most prevalent symptom types in people exhibiting CBD pertain to identifiable movement disorders and problems with cortical processing.

Additionally, sensory impairment, revealed through limb numbness or the sensation of prickling, may also concurrently arise with alien hand syndrome, as both symptoms are indicative of cortical dysfunction.

[7] Ideomotor apraxia (IMA), although clearly present in CBD, often manifests atypically due to the additional presence of bradykinesia and rigidity in those individuals exhibiting the disorders.

The IMA symptom in CBD is characterized by the inability to repeat or mimic particular movements (whether significant or random) both with or without the implementation of objects.

Some individuals with CBD exhibit limb-kinetic apraxia, which involves dysfunction of more fine motor movements often performed by the hands and fingers.

[6] Aphasia in CBD is revealed through the inability to speak or a difficulty in initiating spoken dialogue and falls under the non-fluent (as opposed to fluent or flowing) subtype of the disorder.

[8] Neuropathological findings associated with CBD include the presence of astrocytic abnormalities within the brain and improper accumulation of the protein tau (referred to as tauopathy).

[9] Postmortem histological examination of the brains of individuals diagnosed with CBD reveal unique characteristics involving the astrocytes in localized regions.

[11] This process involves exposing tissue samples to a silver staining material which marks for abnormalities in the tau protein and astroglial inclusions.

A recent study indicated that produces a high density of astrocytic plaques in the anterior portion of the frontal lobe and in the premotor area of the cerebral cortex.

[18] Recent findings in clinicopathology have made it possible to distinguish CBD from Parkinson's and increase the accuracy of diagnosis, using developments in MRI and nuclear medicine.

A clinical diagnosis of CBD is performed based upon the specified diagnostic criteria, which focus mainly on the symptoms correlated with the disease.

[21] Frequently, a differential diagnosis for CBD is performed, in which other diseases are eliminated based on specific symptoms that do not overlap.

Most of these diagnoses utilize the Gallyas-Braak staining method, which is effective in identifying the presence of astroglial inclusions and coincidental tauopathy.

However, despite their benefits, information learned from MRI and SPECT during the beginning of CBD progression tend to show no irregularities that would indicate the presence of such a neurodegenerative disease.

[24] Despite the undoubted presence of cortical atrophy (as determined through MRI and SPECT) in individuals experiencing the symptoms of CBD, this is not an exclusive indicator for the disease.

As a result, it is especially effective in identifying regions within different areas of the brain that have been negatively affected due to the complications associated with CBD.

To be specific, MRI of CBD typically shows posterior parietal and frontal cortical atrophy with unequal representation in corresponding sides.

[citation needed] SPECT studies of individuals diagnosed with CBD involve perfusion analysis throughout the parts of the brain.

SPECT evaluation through perfusion observation consists of monitoring blood release into different locations in tissue or organ regions, which, in the case of CBD, pertains to localized areas within the brain.

[4] Additional studies have revealed the presence of perfusion anomalies in the thalamus, temporal cortex, basal ganglia, and pontocerebellar (from the pons to the cerebellum) locations within subjects' brains.

For example, in relation to the motor aspect of disability, CBD has high resistance against treatments to improve dopamine intake, such as levodopa.

[citation needed] The partial (or total) use of a feeding tube may be necessary and will help prevent aspiration pneumonia, primary cause of death in CBD.

[22] Additional distinguishing neurological features of those diagnosed with CBD consist of asymmetric atrophy of the frontal and parietal cortical regions of the brain.

[2] Postmortem studies of patients diagnosed with CBD indicate that histological attributes often involve ballooning of neurons, gliosis, and tauopathy.

[22] Much of the pioneering advancements and research performed on CBD has been completed within the past decade or so, due to the relatively recent formal recognition of the disease.