Nearly 20 years spent believing she had ms ended when DeMonica Amerson’s diagnosis changed

An uncertain diagnosis in 2001

Amerson was shocked when doctors diagnosed her with multiple sclerosis in 2001. No one in her family had the autoimmune condition, and reaching the diagnosis had been difficult.

Doctors first suspected optic neuritis because her symptoms affected her eyes, then considered lupus. After a spinal tap, they diagnosed MS. Amerson said she felt mad, hurt, nervous and confused.

A severe flare in 2019

In 2019, Amerson experienced a significant flare, with lethargy and numbness in her legs. She went to the hospital and missed her daughter’s birthday party. In the emergency room, she felt pressure in her eyes and began vomiting.

An on-call neurologist examined her and ordered a specialized blood test. After her condition stabilized, she was discharged. A few days later, the neurologist called to say he believed she had a rare autoimmune disorder and advised her to see her neurologist, who referred her to a specialist.

Amerson said she was horrified to receive another diagnosis on top of MS. When a doctor told her she did not have MS, she recalled being so angry that she walked out of the office.

How the conditions can overlap

Dr. Mark Tullman, associate director of the White Plains Hospital MS Center, described NMOSD as a rare autoimmune disease affecting the central nervous system, particularly the spinal cord and the optic nerves connecting the eyes and brain. Tullman did not treat Amerson.

Bermel said misdiagnosis can happen when abnormalities on brain scans are misinterpreted. New diagnostic criteria published in 2025 aim to reduce that risk, though Gutman said diagnosis often involves a doctor’s interpretation.

Advocacy after a changed diagnosis

Amerson said her heart went out to Applegate. She has made raising awareness about NMOSD a new passion and hopes her advocacy and positive outlook will inspire her daughters.