ICD-10 · PDGM grouping
G31 Other degenerative diseases of nervous system, not elsewhere classified
All 14 codes in the G31 family, with the PDGM clinical group, comorbidity subgroup and primary-position rule CMS assigns, read from the CMS grouper crosswalk v07.2.26 and the CDC FY2027 code file.
Codes in family
14
Can lead a claim
13
Cannot lead a claim
1
What CMS assigns to G31
13 of the 14 codes group to Neuro Rehabilitation; 1 is assigned no clinical group. Comorbidity subgroups: 7 toward Alzheimer’s disease and related dementias; 1 toward Demyelinating Diseases of the Central Nervous System; 6 are assigned none. 13 of the 14 can lead a claim.
- Alzheimer’s disease and related dementias: counts toward the high comorbidity tier only in an interaction pair.
- Demyelinating Diseases of the Central Nervous System
Every code in G31
Descriptions are CDC’s FY2027 wording; where CMS’s grouper abbreviates one, its form is shown beneath.
| Code | Description | Primary position | Clinical group | Comorbidity subgroup |
|---|---|---|---|---|
| G31.0 Frontotemporal dementia | ||||
| G31.01 | Pick's disease | Can lead a claim | B | Alzheimer’s disease and related dementias |
| G31.09 | Other frontotemporal neurocognitive disorder | Can lead a claim | B | Alzheimer’s disease and related dementias |
| G31.1 | Senile degeneration of brain, not elsewhere classified | Can lead a claim | B | Alzheimer’s disease and related dementias |
| G31.2 | Degeneration of nervous system due to alcohol | Can lead a claim | B | Alzheimer’s disease and related dementias |
| G31.8 Other specified degenerative diseases of nervous system | ||||
| G31.80 | Leukodystrophy, unspecified | Can lead a claim | B | None |
| G31.81 | Alpers disease | Can lead a claim | B | None |
| G31.82 | Leigh's disease | Can lead a claim | B | None |
| G31.83 | Neurocognitive disorder with Lewy bodies | Can lead a claim | B | Alzheimer’s disease and related dementias |
| G31.84 | Mild cognitive impairment of uncertain or unknown etiology | Can lead a claim | B | None |
| G31.85 | Corticobasal degeneration | Can lead a claim | B | Alzheimer’s disease and related dementias |
| G31.86 | Alexander disease | Can lead a claim | B | Demyelinating Diseases of the Central Nervous System |
| G31.87 | Primary progressive apraxia of speech | Can lead a claim | B | None |
| G31.89 | Other specified degenerative diseases of nervous system | Can lead a claim | B | None |
| G31.9 | Degenerative disease of nervous system, unspecified | Cannot lead a claimPrincipal diagnosis not assigned to a clinical group | None | Alzheimer’s disease and related dementias |
Sources: CMS HH PPS Grouper Software v07.2.26, effective 2026-10-01, for the clinical group, comorbidity subgroup, code-first conventions and primary-position flags; CDC NCHS ICD-10-CM FY2027 code descriptions for the family title and code wording. This is the crosswalk Medicare runs a claim through. Grouping also depends on admission source, timing, the OASIS functional items and the rest of the diagnosis list.
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