Tests for ALS and Ruling Out Other Conditions
Nerve Conduction Velocity
Another common test measures nerve conduction velocity (NCV). Specific abnormalities in the NCV results may suggest that the patient has a form of peripheral neuropathy (damage to peripheral nerves) or myopathy (muscle disease) rather than ALS.
Magnetic Resonance Imaging
Your physician may order magnetic resonance imaging (MRI), which is a noninvasive procedure that uses a magnetic field and radio waves to take detailed images of the brain and spinal cord. MRI scans can reveal evidence of other problems that may be causing the symptoms, such as a spinal cord tumor, a herniated disk in the neck, syringomyelia (a cyst in the spinal cord), or cervical spondylosis (arthritis of the neck).
Blood and Urine Tests
Based on your symptoms, the findings from the examination, and the findings from these tests, your physician may order tests on blood and urine samples to eliminate the possibility of other diseases.
In some cases, a muscle biopsy may be performed. In this procedure, a small piece of muscle tissue is removed and examined under a microscope.
Infectious diseases, such as human immunodeficiency virus (HIV), human T-cell leukemia virus (HTLV), and Lyme disease can cause ALS-like symptoms.
Also, some neurological disorders can mimic certain facets of ALS and should be considered by physicians who are attempting to make an ALS diagnosis. These conditions include: