The Tennessee State Library and Archives also houses the Library for Accessible Books and Media. Their website is: Library for Accessible Books and Media | Tennessee Secretary of State (tn.gov).
There is an application and a Librarian can sign the form as a certifying authority if you are unable to have it certified by another "competent authority" in the eyes of the Library of Congress: "In cases of blindness, visual impairment, or physical limitations, “competent authority” includes doctors of medicine; doctors of osteopathy; ophthalmologists; optometrists; registered nurses; therapists; and professional staff of hospitals, institutions, and public or private welfare agencies (e.g., social workers, case workers, counselors, rehabilitation teachers, and superintendents). ). In the absence of any of these, certification may be made by professional librarians or by any person whose competence under specific circumstances is acceptable to the Library of Congress."