331 Other cerebral degenerations (331.0-331.9) ICD-9-CM
The 331.0-331.9 block classified 331 other cerebral degenerations with 14 legacy diagnosis codes. None remain valid for claim submission; each code below links to its reference page with the official ICD-10-CM replacement under the CMS General Equivalence Mappings.
Retired Code Set
ICD-9-CM stopped being valid for U.S. claims with dates of service on or after October 1, 2015, when ICD-10-CM replaced it. Use this index for historical lookups and crosswalking; for current coding, start from the ICD-10-CM codes list or the ICD-9 / ICD-10 converter.
Legacy Codes in the 331.0-331.9 Block 14 codes
None of these codes remain valid for claim submission. Each code page shows its ICD-10-CM replacement under the CMS General Equivalence Mappings.
- 331.0 Alzheimer's disease
- 331.11 Pick's disease
- 331.19 Frontotemp dementia NEC
- 331.2 Senile degenerat brain
- 331.3 Communicat hydrocephalus
- 331.4 Obstructiv hydrocephalus
- 331.5 Norml pressure hydroceph
- 331.6 Corticobasal degneration
- 331.7 Cereb degen in oth dis
- 331.81 Reye's syndrome
- 331.82 Dementia w Lewy bodies
- 331.83 Mild cognitive impairemt
- 331.89 Cereb degeneration NEC
- 331.9 Cereb degeneration NOS
Questions About This Page
Are the 331.0-331.9 codes still billable?
No. Every code in this block became invalid for U.S. claims after September 30, 2015. Each code page linked above shows the ICD-10-CM replacement CMS assigned in the General Equivalence Mappings, and the ICD-9 / ICD-10 converter translates any of them directly.
What did the 331.0-331.9 block classify?
The block classified 331 other cerebral degenerations with 14 codes in the final ICD-9-CM release. It sat under Diseases of the nervous system (320–359) in the legacy hierarchy.
Related References
Source: final CMS ICD-9-CM release (version date October 1, 2014). Retired from U.S. claims after September 30, 2015.
