Corticobasal Syndrome (CBS)
Corticobasal syndrome (CBS) is a rare neurodegenerative disorder characterized by an association of motor and cognitive impairments. Clinically, it manifests with progressive asymmetric limb involvement and cortical disturbances such as apraxia, language disorders, and complex sensory phenomena. CBS represents a clinical phenotype that can derive from several underlying pathologies, including corticobasal degeneration (CBD).
The most common underlying cause of CBS is a primary tauopathy (CBD), characterized by the pathological accumulation of tau protein. However, significant biological heterogeneity exists: some cases derive from other tauopathies (PSP), synucleinopathies, Alzheimer’s disease, or TDP-43 related pathologies. This etiological complexity explains the wide clinical variability and the diagnostic difficulty.
The syndrome typically presents with an asymmetric onset. Characteristic signs include:
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Limb apraxia (difficulty in performing purposeful movements).
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Alien limb phenomenon.
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Asymmetric rigidity, bradykinesia, and dystonia.
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Cortical myoclonus.
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Cognitive alterations with executive impairment and non-fluent aphasia.
The progression leads to increasing motor disability and loss of functional autonomy.
The diagnosis is clinical, based on international criteria for CBS. Brain MRI may show asymmetric frontoparietal atrophy, but it is not pathognomonic. FDG-PET (glucose metabolism PET scan) reveals asymmetric frontoparietal hypometabolism. In selected cases, CSF biomarkers may be useful to exclude Alzheimer’s disease pathology.
Available therapies
Treatment is symptomatic and includes:
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Medications for rigidity and bradykinesia.
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Treatment of myoclonus (clonazepam, levetiracetam).
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Speech therapy for aphasia and dysphagia.
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Intensive physiotherapy to improve mobility and prevent falls.
Multidisciplinary support is essential for long-term management.
Research in progress
- Research focuses on identifying biomarkers to distinguish the various underlying pathologies, the development of anti-tau therapies, and preclinical models based on iPSCs to study specific degenerative mechanisms.
Reference laboratory
Contacts and informations
Dott. Alessio Di Fonzo
Mail: alessio.difonzo@policlinico.mi.it
Administrative Office: elena.oriani@policlinico.mi.it