38 CFR § 3.341 - Total disability ratings for compensation purposes.
(a) General. Subject to the limitation in paragraph (b) of this section, total-disability compensation ratings may be assigned under the provisions of § 3.340. However, if the total rating is based on a disability or combination of disabilities for which the Schedule for Rating Disabilities provides an evaluation of less than 100 percent, it must be determined that the service-connected disabilities are sufficient to produce unemployability without regard to advancing age.
(b) Incarcerated veterans. A total rating for compensation purposes based on individual unemployability which would first become effective while a veteran is incarcerated in a Federal, State or local penal institution for conviction of a felony, shall not be assigned during such period of incarceration. However, where a rating for individual unemployability exists prior to incarceration for a felony and routine review is required, the case will be reconsidered to determine if continued eligibility for such rating exists.
(c) Program for vocational rehabilitation. Each time a veteran is rated totally disabled on the basis of individual unemployability during the period beginning after January 31, 1985, the Veteran Readiness and Employment (VR&E) Service will be notified so that an evaluation may be offered to determine whether the achievement of a vocational goal by the veteran is reasonably feasible.