Diagnosis

Your doctor will perform a thorough evaluation to rule out other nervous system conditions that have signs and symptoms similar to neuromyelitis optica.

To diagnose your condition, your doctor will review your medical history and symptoms and perform a physical examination. You might also undergo:

• Neurological examination. A neurologist will examine your movement, muscle strength, coordination, sensation, memory and thinking (cognitive) functions, and vision and speech. An eye doctor (ophthalmologist) also might be involved in your exam.
• MRI. This imaging test uses powerful magnets and radio waves to create a detailed view of your brain, optic nerves and spinal cord. Your doctor might be able to detect lesions or damaged areas in your brain, optic nerves or spinal cord.
• Blood tests. Your doctor might test your blood for the autoantibody NMO-IgG, which helps doctors distinguish NMO from MS and other neurological conditions. This test helps doctors make an early diagnosis of NMO. A myelin oligodendrocyte glycoprotein (MOG-IgG) antibody test also might be used to look for another inflammatory disorder that mimics NMO.

• Lumbar puncture (spinal tap). During this test, your doctor will insert a needle into your lower back to remove a small amount of spinal fluid. Doctors test the levels of immune cells, proteins and antibodies in the fluid. This test might help your doctor differentiate NMO from MS.

  In NMO, the spinal fluid might show markedly elevated white blood cells during NMO episodes, greater than normally seen in MS, although this doesn't always happen.

• Stimuli response test. To learn how well your brain responds to stimuli such as sounds, sights or touch, you'll undergo a test called evoked potentials or evoked response tests.

  Doctors attach small wires (electrodes) to your scalp and, in some cases, your earlobes, neck, arm, leg and back. Equipment attached to the electrodes records your brain's responses to stimuli. These tests help your doctor find lesions or damaged areas in the nerves, spinal cord, optic nerve, brain or brainstem.