20 CFR §220.105

1. (a)In some cases, the Board may determine that a claimant is not currently disabled but was previously disabled for a specified period of time in the past. This can occur when—
   1. (1)The disability application was filed before the claimant's disability ended but the Board did not make the initial determination of disability until after the claimant's disability ended; or
   2. (2)The disability application was filed after the claimant's disability ended but no later than the 12th month after the month the disability ended.
2. (b)When evaluating a claim for a previous disability, the Board follows the steps in § 220.100 to determine whether a disability existed, and follows the steps in § 220.180 to determine when the disability ended.