(a) General. The claimant for a disability annuity is responsible for providing evidence of the claimed disability and the effect of the disability on the ability to work. The Board will assist the claimant, when necessary, in obtaining the required evidence. At its discretion, the Board will arrange for an examination by a consultant at the expense of the Board as explained in §§ 220.50 and 220.51.

(b) Kind of evidence. The claimant must provide medical evidence showing that he or she has an impairment(s) and how severe it is during the time the claimant claims to be disabled. The Board will consider only impairment(s) the claimant claims to have or about which the Board receives evidence. Before deciding that the claimant is not disabled, the Board will develop a complete medical history (i.e., evidence from the records of the claimant's medical sources) covering at least the preceding 12 months, unless the claimant says that his or her disability began less than 12 months before he or she filed an application. The Board will make every reasonable effort to help the claimant in getting medical reports from his or her own medical sources when the claimant gives the Board permission to request them. Every reasonable effort means that the Board will make an initial request and, after 20 days, one follow-up request to the claimant's medical source to obtain the medical evidence necessary to make a determination before the Board evaluates medical evidence obtained from another source on a consultative basis. The medical source will have 10 days from the follow-up request to reply (unless experience indicates that a longer period is advisable in a particular case). In order to expedite processing the Board may order a consultative exam from a non-treating source while awaiting receipt of medical source evidence. If the Board ask the claimant to do so, he or she must contact the medical sources to help us get the medical reports. The Board may also ask the claimant to provide evidence about his or her -