38 CFR §21.6503

1. (a)Program period. The term program period means the period beginning on February 1, 1985, and ending December 31, 1992.
2. (b)Qualified veteran. The term qualified veteran means a veteran who has a service-connected disability, or service-connected disabilities, not rated as total, but who has been awarded a rating of total disability by reason of inability to secure or follow a substantially gainful occupation as a result of such disability or disabilities. Such a rating is referred to as an IU (individual unemployability) rating. See §§ 3.340, 3.341, and 4.16 of this title.
3. (c)Receives an IU rating. The phrase receives an IU rating refers to the date of the rating decision authorizing total disability compensation based upon individual unemployability.