Obtain the claimant's statement about the nature and frequency of the personal services
                  they perform and whether or to what extent the claimant's presence is required because
                  of the child's disability. Also, get a similar statement from the physically disabled
                  child. You may obtain these statements while developing evidence of the child's disability.
                  Development in the file on the child's disability may also contribute information
                  relevant to a determination of the claimant's performance of personal services. If
                  there is any question, obtain statements from others living in the household or from
                  other persons who have knowledge of the circumstances.