This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Amyotrophic Lateral Sclerosis and other motor neuron diseases, Subject name: Medicine
Which of the following tests is abnormal in patients with ALS (Amyotrophic Lateral Sclerosis)? 
Select and explain. 
A. V.E.P, B. MRI whole spine, C. CT whole Spine, D. Electromyography
D: Electromyography
Answer: D: Electromyography 
Explanation: ALS Neurodegenerative disorder characterized by death of anterior horn cells in the spinal cord and their brainstem homologs innervating bulbar muscles. V.E.P is used for evaluation of optic nerve involvement in multiple sclerosis. CT/MRI spine cannot visualize loss of anterior horn cells or pyramidal cells in the coex. In motor neuron disease: Peripheral nerve conduction studies Electromyography Above both is done to get diagnosis of Amyotrophic lateral sclerosis.