Degenerescenta cortico-bazala este o tulburare neurologica progresiva caracterizata prin pierderea de

celule nervoase si atrofia a mai multor zone ale creierului, inclusiv cortexul cerebral si ganglionii bazali.  

Degenerescenta cortico-bazala progreseaza treptat. Simptomele initiale debuteaza in jurul varstei de 60 de

ani si pot sa apara intr-o singura parte a coprului (unilaterale) dar in cele din urma afecteaza ambele parti pe

masura ce boala progreseaza. 

Simptomele sunt similare cu cele ale bolii Parkinson, cum ar fi slaba coordonare, akinezie (absenta

miscarilor), rigiditate, dezechilibru (tulburari de dezechilibru) si distonie a membrelor (posturi musculare

anormale). 

Alte simptome includ deficientele congnitive si vizual-spatiale, apraxia (pierderea capacitatii de a face

miscari familiare, prin care sa se atinga scopul propus), ezitare in vorbire, miclonii si disfagie (dificultate la

inghitire). O persoana care sufera de degenerescenta cortico-bazala se va afla in cele din urma in

imposibilitatea de a merge.

Cuprins articol

1. Generalitati

2. Cauzele degenerescentei cortico-bazale

3. Simptomele degenerescentei corticobazale

Cauzele degenerescentei cortico-bazaleSus

Din pacate, cauza degenerescentei cortico-bazale este necunoscuta. In prezent, nu exista nici

o dovada care sa sugereze ca aceasta boala este ereditara si nici nu au fost identificati factori

de risc cum ar fi toxinele sau infectiile.

In urma analizelor testului cerebral la persoanele care sufereau de degenerescenta cortico-

bazala, s-au constatat anumite modificari caracteristice la nivelul celulelor. Modificari similare,

desi nu identice, au fost observate si in cazul altor doua boli neurodegenerative: boala Pick si

paralizia progresiva supranucleara. 

Aceste modificari implica o proteina numita tau care au oferit cercetatorilor unele indicii in

descoperirea cauzelor initiale ale degenerescentei cortico-bazale.

Simptomele degenerescentei corticobazaleSus

Simptomele bolii apar de obicei dupa varsta de 60 de ani. Initial acestea sunt:

rigiditatea

tremuraturi

lentoare in miscari

neindemanare fie manifestata la nivelul extremitatilor superioare sau inferioare.

Alte manifestari initiale pot fi

disfazie

dizartrie

dificultati in controlul muschilor de la nivelul fetei si gurii sau al mersului si al

echilibrului.

Simptomele apar, de obicei pe o parte a corpului si se regasesc treptat si in cealalta parte. Unii

pacienti pot avea probleme de memorie sau comportament.Degenerescenta cortico-bazala

este o boala progresiva ceea ce inseamna ca simptomele se agraveaza in timp. Pe parcursul

unuia sau a mai multor ani, manifestarilor celor mai multi dintre cei care sufera de

degenerescenta cortico-bazala se amplifica, iar simptomele vor implica atat extremitatile

superioare cat si cele inferioare sau alte zone ale corpului. 

Manifestarile avansate ale degenerescentei cortico-bazale includ:

rigiditate, miscari lente, instabilitate posturala

tremur

miclonii

distonie, blefarospasm

dificultati in sustinerea unui discurs

tulburari cognitive de la usoare pana la moderate (tulburari de memorie, dificultati de

planificare sau de executare a unor miscari, dementa)

pierderea senzatiilor.

fenomenul de mana/membru strain (dificultate in controlul actiunii unui membru care

pare sa efectueze miscari pe cont propriu, uneori combinata cu sentimentul ca membrul nu

apartine bolnavului).

Corticobasal degeneration (CBD) or Corticobasal ganglionic degeneration (CBGD) is a rare,

progressiveneurodegenerative disease involving the cerebral cortex and the basal ganglia.[1] It is

characterized by marked disorders in movement and cognitive dysfunction, and is classified as

one of the Parkinson plus syndromes. Clinical diagnosis is difficult, as symptoms of CBD are

often similar to those of other diseases, such as Parkinson's disease (PD) andprogressive

supranuclear palsy (PSP).

Contents

  [hide] 

1   Background and History

2   Occurrence and Epidemiology

3   Symptoms and Clinical Presentation

o 3.1   Motor and Associated Cortical Dysfunctions

3.1.1   Parkinsonism

3.1.2   Alien Hand Syndrome

3.1.3   Apraxia

3.1.4   Aphasia

o 3.2   Psychiatric and Cognitive Disorders

4   Corticobasal Syndrome

5   Neuroimaging

o 5.1   MRI

o 5.2   SPECT

o 5.3   FDOPA PET

6   Histological and Molecular Features

o 6.1   Astroglial Inclusions

o 6.2   Tauopathy

7   Diagnosis

o 7.1   Clinical vs. Postmortem

o 7.2   Overlap with Other Diseases

8   Treatment

9   See also

10   References

11   External links

Background and History[edit]

CBD was first identified by Rebeiz and his associates in 1968, as they observed three individuals

who exhibited characteristic symptoms of the unique and previously unknown disorder. They

initially referred to the neurodegenerative disease as “corticodentatonigral degeneration with

neuronal achromasia,” after which various other names were used, including “corticonigral

degeneration with nuclear achromasia” and “cortical basal ganglionic degeneration.”[2] Although

the underlying cause of CBD is unknown, the disease occurs as a result of damage to the basal

ganglia, specifically marked by neuronal degeneration or depigmentation (loss of melanin in a

neuron) in the substantia nigra.[3] 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.[3] 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.

Occurrence and Epidemiology[edit]

Clinical presentation of CBD usually does not occur until age 60, with the earliest recorded

diagnosis and subsequent postmortem verification being age 28.[4] Although men and women

present with the disease, some analysis has shown a predominant appearance of CBD in

women. Current calculations suggest that the prevalence of CBD is approximately 4.9 to 7.3 per

100,000 people. The prognosis for an individual diagnosed with CBD is death within

approximately eight years, although some patients have been diagnosed over 13 years ago

(1999) and are still in relatively good standing, but with serious debilitation such as dysphagia,

and overall limb rigidity. The partial (or total) use of a feeding tube may be necessary and will

help prevent aspiration pneumonia, primary cause of death in CBD. Incontinence is common, as

patients often can't express their need to go, due to eventual loss of speech. Therefore proper

hygiene is mandatory to prevent urinary tract infections. [5]

Symptoms and Clinical Presentation[edit]

Because CBD is progressive (it gradually worsens), a set of standard diagnostic criteria can be

used, which is centered on the disease’s evolution. 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.[5]

Motor and Associated Cortical Dysfunctions[edit]

Some of the most prevalent symptom types in people exhibiting CBD pertain to identifiable

movement disorders and problems with cortical processing. These symptoms are initial indicators

of the presence of the disease. Each of the associated movement complications typically appear

asymmetrically and the symptoms are not observed uniformly throughout the body. For example,

a person exhibiting an alien hand syndrome (explained later) in one hand, will not

correspondingly display the same symptom in the contralaterallimb. Predominant movement

disorders and cortical dysfunctions associated with CBD include:

Parkinsonism

Alien Hand Syndrome

Apraxia (Ideomotor Apraxia and Limb-Kinetic Apraxia)

Aphasia[5]

Parkinsonism[edit]

The presence of parkinsonism as a clinical symptom of CBD is largely responsible for

complications in developing unique diagnostic criteria for the disease.[6] Other such diseases in

which parkinsonism forms an integral diagnostic characteristic are PD and PSP. Parkinsonism in

CBD is largely present in an extremity such as the arm, and is always asymmetric. Common

associated movement dysfunctions that comprise parkinsonism are rigidity, bradykinesia, and gait

disorder, with limb rigidity forming the most typical manifestation of parkinsonism in CBD. Despite

being relatively indistinct, this rigidity can lead to disturbances in gait and correlated movements.

Bradykinesia in CBD occurs when there is notable slowing in the completion of certain

movements in the limbs. In an associated study, it was determined that, three years following first

diagnosis, 71% of persons with CBD demonstrate the presence of bradykinesia.[5]

Alien Hand Syndrome[edit]

Alien hand syndrome has been shown to be prevalent in roughly 60% of those people diagnosed

with CBD.[7] This disorder involves the failure of an individual to control the movements of his or

her hand, which results from the sensation that the limb is “foreign.”[2] The movements of the alien

limb are a reaction to external stimuli and do not occur sporadically or without stimulation. The

presence of an alien limb has a distinct appearance in CBD, in which the diagnosed individual

may have a “tactile mitgehen.” This mitgehen (German, meaning “to go with”) is relatively specific

to CBD, and involves the active following of an experimenter’s hand by the subject’s hand when

both hands are in direct contact. Another, rarer form of alien hand syndrome has been noted in

CBD, in which an individual’s hand displays an avoidance response to external stimuli.

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. Like most of the movement disorders, alien hand syndrome also presents

asymmetrically in those diagnosed with CBD.[8]

Apraxia[edit]

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. This form of

IMA is present in the hands and arms, while IMA in the lower extremities may cause problems

with walking. Those with CBD that exhibit IMA may appear to have trouble initiating walking, as

the foot may appear to be fixed to floor. This can cause stumbling and difficulties in maintaining

balance.[5] IMA is associated with deterioration in the premotor cortex, parietal association areas,

connecting white matter tracts, thalamus, and basal ganglia. Some individuals with CBD exhibit

limb-kinetic apraxia, which involves dysfunction of more fine motor movements often performed

by the hands and fingers.[7]

Aphasia[edit]

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.

This may be related to speech impairment such as dysarthria, and thus is not a true aphasia, as

aphasia is related to a change in language function, such as difficulty retrieving words or putting

words together to form meaningful sentences. The speech and/or language impairments in CBD

result in disconnected speech patterns and the omission of words. Individuals with this symptom

of CBD often lose the ability to speak as the disease progresses.[5]

Psychiatric and Cognitive Disorders[edit]

Psychiatric problems associated with CBD often present as a result of the debilitating symptoms

of the disease. Prominent psychiatric and cognitive conditions cited in individuals with CBD

include dementia, depression, and irritability, with dementia forming a key feature that sometimes

leads to the misdiagnosis of CBD as another cognitive disorder such as Alzheimer's disease

(AD).

Corticobasal Syndrome[edit]

All of the disorders and dysfunctions associated with CBD can often be categorized into a class of

symptoms that present with the disease of CBD. These symptoms that aid in clinical diagnosis

are sometimes collectively referred to as corticobasal syndrome (CBS) or corticobasal

degeneration syndrome (CBDS). It has been suggested that the nomenclature of corticobasal

degeneration only be used for naming the disease after it has received verification through

postmortem analysis of the neuropathology.[6]

Neuroimaging[edit]

The types of imaging techniques that are most prominently utilized when studying and/or

diagnosing CBD are:

magnetic resonance imaging (MRI)

single-photon emission computed tomography (SPECT)

fluorodopa positron emission tomography (FDOPA PET)

Developments or improvements in imaging techniques provide the future possibility for definitive

clinical diagnosis prior to death. 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.[5] FDOPA PET is used to study the

efficacy of the dopamine pathway.[4]

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.

Thus, the utilization of this factor in the diagnosis of CBD should be used only in combination with

other clinically present dysfunctions.[6]

MRI[edit]

MRI images are useful in displaying atrophied portions of neuroanatomical positions within the

brain. 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. In addition, atrophy has been noted in the corpus

callosum.[4]

Functional MRI (fMRI) has been used to evaluate the activation patterns in various regions of the

brain of individuals affected with CBD. Upon the performance of simple finger motor tasks,

subjects with CBD experienced lower levels of activity in the parietal cortex, sensorimotor cortex,

and supplementary motor cortex than those individuals tested in a control group.[4]

SPECT[edit]

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. Tissue can be characterized as experiencing overperfusion,

underperfusion, hypoperfusion, or hyperperfusion. Overperfusion and underperfusion relate to a

comparison with the overall perfusion levels within the entire body, whereas hypoperfusion and

hyperperfusion are calculated in comparison to the blood flow requirements of the tissue in

question. In general, the measurements taken for CBD using SPECT are referred to as

regional cerebral blood flow (rCBF).[4]

In general, SPECT reveals hypoperfusion within both the posterior regions of the frontal and

parietal lobes. As in images gathered through MRI, SPECT images indicated asymmetry in the

presentation of abnormalities throughout the brain.[6] 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.[4]

FDOPA PET[edit]

Research has suggested that the integrity of the dopamine system in the striatum has been

damaged as an effect of CBD. Current studies employing the use of FDOPA PET

scanning (FDOPA PET) as a possible method for identifying CBD have focused on analyzing the

efficiency of neurons in the striatum that utilize the neurotransmitter dopamine. These studies

have concluded that, in general, dopamine uptake was diminished in the caudate and

the putamen. This characteristic also has the potential to be useful in distinguishing CBD from the

similar PD, as individuals having been diagnosed with PD were more likely to have a lower

uptake of dopamine than in individuals with CBD.[4]

Other clinical tests or procedures that monitor the presence of dopamine within the brain (β-CIT

SPECT and IBZM SPECT) have shown similar findings. β-CIT serves as an indicator for

presynaptic dopaminergic neurons, whereas IBZM is a tracer that shows an affinity for the

postsynaptic neurons of the same type. Despite agreement with other imaging studies, these two

SPECT methods suffer some scrutiny due to better accuracy in other imaging methods. However,

β-CIT SPECT has proven to be helpful in distinguishing CBD from PSP and multiple system

atrophy (MSA).[4]

Histological and Molecular Features[edit]

Neuropathological findings associated with CBD include the presence of astrocytic abnormalities

within the brain and improper accumulation of the protein tau (referred to astauopathy).[9]

Astroglial Inclusions[edit]

Postmortem histological examination of the brains of individuals diagnosed with CBD reveal

unique characteristics involving the astrocytes in localized regions. The typical procedure used in

the identification of these astroglial inclusions is the Gallyas-Braak staining method. This

process involves exposing tissue samples to a silver staining material which marks for

abnormalities in the tau protein and astroglial inclusions.[10] Astroglial inclusions in CBD are

identified as astrocytic plaques, which present as annularly displays of blurry outgrowths from the

astrocyte. A recent study indicated that CBD produces a high density of astrocytic plaques in the

anterior portion of the frontal lobe and in the premotor area of the cerebral cortex.[11]

Tauopathy[edit]

The protein tau is an important microtubule-associated protein (MAP), and is typically found in

neuronal axons. However, malfunctioning of the development of the protein can result in

unnatural, high-level expression in astrocytes and glial cells. As a consequence, this is often

responsible for the astrocytic plaques prominently noted in histological CBD examinations.

Although they are understood to play a significant role in neurodegenerative diseases such as

CBD, their precise effect remains a mystery.[10]

Diagnosis[edit]

Clinical vs. Postmortem[edit]

One of the most significant problems associated with CBD is the inability to perform a definitive

diagnosis while an individual exhibiting the symptoms associated with CBD is still alive. A clinical

diagnosis of CBD is performed based upon the specified diagnostic criteria, which focus mainly

on the symptoms correlated with the disease. However, this often results in complications as

these symptoms often overlap with numerous other neurodegenerative diseases.[12] Frequently, a

differential diagnosis for CBD is performed, in which other diseases are eliminated based on

specific symptoms that do not overlap. However, some of the symptoms of CBD used in this

process are rare to the disease, and thus the differential diagnosis cannot always be used.[5]

Postmortem diagnosis provides the only true indication of the presence of CBD. Most of these

diagnoses utilize the Gallyas-Braak staining method, which is effective in identifying the presence

of astroglial inclusions and coincidental tauopathy.

Overlap with Other Diseases[edit]

Progressive supranuclear palsy (PSP) is frequently the disease most often confused with CBD.

Both PSP and CBD result in similar symptoms, and both display tauopathies upon histological

inspection.[3] However, it has been noted that tauopathy in PSP results in tuft-shaped astrocytes

in contrast with the doughnut-shaped astrocytic plaques found as a result of CBD.[11]

Individuals diagnosed with PD often exhibit similar movement dysfunction as those diagnosed

with CBD, which adds complexity to its diagnosis. Some other neurodegenerative diseases

including Alzheimer’s Disease (AD), dementia with Lewy bodies (DLB), and frontotemporal

dementia (FTD) also show commonalities with CBD.[5][13] FTDs have also been known to evolve

into corticobasal syndrome.[14]

Treatment[edit]

Because the exact cause of CBD is unknown, there exists no formal treatment for the disease.

Instead, treatments focus on minimizing the appearance or effect of the symptoms resulting from

CBD. The most easily treatable symptom of CBD is parkinsonism, and the most common form of

treatment for this symptom is the application of dopaminergic drugs. However, in general only

moderate improvement is seen and the relief from the symptom is not long-lasting. In addition,

palliative therapies, including the implementation of wheelchairs, speech therapy, and feeding

techniques, are often used to alleviate many of the symptoms that show no improvement with

drug administration.[15]