ICD-10 Code G31.85 – Corticobasal Degeneration (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G31.85 – Corticobasal degeneration
What it is
G31.85 identifies corticobasal degeneration, a rare progressive neurodegenerative disorder. It affects movement and higher brain functions, often causing asymmetric motor impairment and cortical signs.
Clinical signs
Typical findings include limb rigidity, bradykinesia, dystonia, apraxia, and myoclonus. Clinical features vary; refer to documentation for asymmetric parkinsonism, cortical sensory loss, or other supporting neurologic findings.
When to use this code
Use G31.85 when the provider documents corticobasal degeneration or corticobasal syndrome attributed to this diagnosis. Code it for confirmed neurologic assessments, specialty consults, or problem lists that clearly name the condition.
Do not assign it from nonspecific movement symptoms alone. If the record only states parkinsonism, dementia, or gait disorder without this diagnosis, check documentation before coding.
Do not use for
Do not use this code for Parkinson disease, Alzheimer disease, or other dementias unless corticobasal degeneration is specifically documented. Avoid using it for uncertain or suspected diagnoses without confirmation.
Coding tip
Code from the exact neurologic diagnosis stated by the provider; if the record says “possible” or “rule out,” check documentation.