hi! numbness of the extremities have lots of causes. however, in your case you had a history of fall and that all test have been done already with still no answers. numbness is actually cause by the following: 1. nerve compression. it could be in one limb or area like in cases of median nerve compression or could be both upper and lower extremity like in cases of herniated disk which results from degeneration of the disk due to aging process. 2. severe vitamin b12 deficiency. there are diseases and conditions that can result to vit b 12 deficiency, like crohns disease, alcoholism, celiac disease, or results from conditions wherein there is inability to absorbs vit b12. deficient vit b12 will result s to pernicious anemia. severely deficient vit b12 will results to nerve damage. 3. stroke