Diagnosing CMT includes several different steps. First, there is a complete physical examination that includes tests of muscle function and sensory responses. Absent or weak reflexes is a sign that can confirm the diagnosis. Then a doctor will perform an electromyogram test, which measures the electrical activity of muscle cells. Usually nerve and muscle biopsies are done, especially when the symptoms are mild and there are no signs of a history of the disease. By looking at the sample under a microscope, you can determine if the disease is hypertrophic or neuronal.