There are reports and videos on social media of people experiencing strange symptoms like trouble walking and even convulsions after getting a COVID-19 vaccine. People that see this stuff might think that the vaccine is dangerous, or that the reports are faked in some way. But neurologist and psychiatrist David Perez, M.D., M.M.Sc., the director of the Functional Neurological Disorders Unit at Massachusetts General Hospital (MGH), says that neither of those conclusions are correct. Instead, these individuals may be experiencing a phenomenon known as functional neurological disorder (FND). The study authors noted that it's important to educate the public about this condition.
"The spread of these videos could fuel vaccine hesitancy by giving an overly simplistic impression of potential links between the vaccine and major neurological symptoms," said senior study author Perez. "Instead, these are symptoms of a real, brain-based disorder that sits at the intersection of neurology and psychiatry."
Reporting in JAMA Neurology Viewpoint, researchers noted that FND can cause limb weakness, jerky movements, difficulty walking, tremors, or facial spasms. This neuropsychiatric disorder is sometimes seen after the injection of a vaccine or a saline placebo. It may also occur after other medical or surgical procedures or emotional or physical events including head injuries.
"Some people with FND have a heightened awareness of their body and increased state of arousal and threat, which may hijack normal neural networks controlling voluntary movements," Perez noted. "FND teaches us quite a bit about the complexities of the human brain."
It's also possible that the awareness of motor control is disrupted in FND, said first study author David Dongkyung Kim, M.D., a clinical fellow in Behavioral Neurology-Neuropsychiatry at MGH. "The body is moving, but the individual doesn't experience a sense of agency over their movements, such as tremors or movements of the trunk," added Kim.
While not everyone who has experienced chronic pain, medical procedures, disease, or adverse life events are susceptible to FND, some may be.
"The biopsychosocial model involving an interplay of risk factors, triggering events, and perpetuating factors is how we currently understand FND," said Kim.
FND is treatable using physical rehabilitation, educational, and psychotherapy techniques.
"Helping people understand FND will bring this disorder into mainstream medical conversations, and transparently addressing concerns will better allow people to make informed decisions for themselves on receiving the COVID-19 vaccine," said Perez.
COVID-19 seems to cause neurological symptoms in as many as a third of those infected. Vaccination is considered to be safe, with few side effects, and getting the vaccine helps stop the spread of this devastating pandemic.