MINNEAPOLIS – Recovery from an autoimmune inflammation of the brain may take three years or more, according to a study published in the November 20, 2024, online issue of Neurology® , the medical journal of the American Academy of Neurology .
Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is brain swelling caused when the immune system attacks the brain. A patient memoir titled "Brain on Fire" and a film based on the book have increased awareness of the disease first identified in 2005.
Anti-NMDAR encephalitis is rare and primarily affects young adults. Symptoms start with headache, fatigue and fever and progress to confusion, memory loss, movement problems, behavioral and personality changes, disordered thinking or speaking, hallucinations, seizures and even loss of consciousness. It may be misdiagnosed as schizophrenia or bipolar disorder. Ovarian tumors and previous brain swelling from herpes simplex virus have been identified as causes, but in most cases the cause is unknown. It can be treated with immunotherapy.
"While more than 80% of people treated for anti-NMDAR encephalitis return to living independently after one to two years, most report continued thinking and memory problems as well as social difficulties," said study author Maarten Titulaer, MD, PhD, of Erasmus University Medical Center in Rotterdam, the Netherlands, and member of the American Academy of Neurology.
The study involved 92 people with an average age of 29 who had been diagnosed with anti-NMDAR encephalitis in the Netherlands prior to 2023. Researchers reviewed medical records and conducted physical and neuropsychological examinations.
A sub-group of 85 participants were given thinking and memory tests to measure memory, language, attention, executive function and how their perceptions of the world are constructed. In addition, 87 participants completed assessments reporting their ongoing symptoms.
Researchers found that participants' scores on thinking and memory tests improved over time, with the fastest improvements in the first six months, and continued but slower improvements up to three years after diagnosis.
Assessments about ongoing symptoms beyond three years were available for 46 participants. After three years, researchers found 34% of participants had continued impairment and 65% scored below average in one or more areas of cognition with memory and language being most affected. Participants continued to report problems with emotional well-being, social functioning, energy levels and quality of life.
Of all participants, 30% did not go back to school or work and 18% needed adjustments to resume these activities. People who went back to school or work were more likely to have better scores on well-being and processing speed, how quickly the brain receives, understands and responds to information.
"Our study found that recovery from anti-NMDAR encephalitis takes longer than previously thought, up to three years, and often with lingering memory, emotional and social problems," said Titulaer. "Identifying subtle cognitive, social or emotional symptoms is imperative, especially since this disease primarily affects young adults. The impact on their school, work and social life can be immense."
A limitation of the study was that it included people less severely affected by anti-NMDAR encephalitis since it did not include children under age 16 at the time of assessment or people who had died of the condition.
The study was supported by the Dioraphte Foundation in the Netherlands and the Autoimmune Encephalitis Alliance.
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The American Academy of Neurology is the world's largest association of neurologists and neuroscience professionals, with over 40,000 members. The AAN's mission is to enhance member career fulfillment and promote brain health for all. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer's disease, stroke, concussion, epilepsy, Parkinson's disease, multiple sclerosis, headache and migraine.
