Ill. Admin. Code tit. 89, § 144.TABLE E
Mental Age Level Equivalents With Level of Functioning
| Adult MA Functional Age | |
| Mild | 8 years, 6 months to 10 years, 1 month |
| Moderate | 6 years, 1 month to 8 years, 5 months |
| Severe | 3 years, 9 months to 6 years, 0 months |
| Profound | Below 3 years, 9 months |
(Source: Added at 14 Ill. Reg. 17988, effective October 29, 1990)