<s>[INST] I have weakness in both arms, feel tired and could not feel tuning fork vibrating on my legs at docs office although I could feel the touch of tuning fork, ( don t know correct name of instrument) blood work is ordered doc says I may have to see neurologist, What is he checking for? [/INST] Hi, I had gone through your question and understand your concerns. Loss of vibrating sensation and weakness of arms may have several causes.These include polineuropathies ( damage of peripheral nerves from  different diseases like Diabetes, autoimmune disorders, etc.) cervical compression syndrome, toxic effects of drugs and chemicals etc.There is need for a careful neurological examination and tests in order to diagnose correctly your condition, that's why your Doctor asked a neurological opinion.Hope this helps. Wishing you good health. </s>