For example, a study that compared functional magnetic resonance imaging (f MRI) scans found that people with AS showed “widespread brain connectivity alterations” compared with a control group .” Many of those brain changes correlated with blood markers for inflammation, such as erythrocyte sedimentation rate (ESR) and high-sensitivity C-reactive protein (hsCRP), that are also associated with AS, according to researchers. Experts point to several ways AS may raise the risk for problems with brain function, including pain, depression, anxiety, and poor sleep. Addressing them may be all it takes to clear up mental fog.
Central Pain
One potential link between AS and cognitive dysfunction is chronic, body-wide pain, known as fibromyalgia. There’s increasing recognition that a significant percentage of people with AS have centralized pain syndrome, according to Eric M. Ruderman, MD, a rheumatologist and professor of medicine at Northwestern University’s Feinberg School of Medicine in Chicago. “Certainly, a lot of those people have brain fog,” he says. According to a study published in March 2021 in the journal Frontiers in Medicine, participants with AS were 33% more likely to have fibromyalgia than those without AS. Broadly speaking, there are two types of pain, according to the University of California in San Francisco. Nociceptive pain originates in a specific area of the body, typically in response to an injury, and does not damage the nerve itself. Central, or neuropathic, pain occurs when nerves are irritated by inflammation or irritation and may be felt in parts of the body distant from the affected nerves. Sometimes, says Dr. Ruderman, central pain can be triggered by chronic nociceptive pain; in other words, the nervous system may respond to an onslaught of pain signals by overamplifying them. This may explain why central pain is linked with conditions, such as AS, that cause pain in specific areas of the body. If you experience central pain along with “mental fog,” your rheumatologist will most likely diagnose and treat the pain disorder according to treatment guidelines for fibromyalgia, according to Lenore Brancato, MD, a clinical assistant professor of medicine at New York University’s Grossman School of Medicine and rheumatologist with NYU Langone Health. These may include physical therapy, stress-reduction techniques, or medication, such as antidepressants or muscle relaxers that can also target central pain. Many AS patients develop the disease at a young age, when it can be very limiting and have a significant impact on psychosocial well-being, according to Wei Wei Chi, MD, a rheumatologist and assistant professor of medicine at the Icahn School of Medicine at Mount Sinai in New York City. A study published in March 2020 in the journal BMC Rheumatology found that people with AS had a more than 50 percent and 80 percent higher risk for depression symptoms and anxiety symptoms, respectively, compared with those who didn’t have AS. Ideally, says Dr. Chi, effective treatment of AS itself will help resolve depression or anxiety by addressing the pain or physical limitations at the root of mental and emotional distress. Joining an AS support group may also help, she says. But if AS treatment and support groups don’t do enough to resolve your depression or anxiety, the next step may be a referral from your doctor to mental health services to “start psychotherapy or mood disorder medication to control these symptoms,” says Chi.
Sleep Disturbances
Difficulty falling or staying asleep are common in people with AS. These can cause or exacerbate a variety of problems with brain function, according to Dr. Brancato. “Having pain can lead to sleep disturbance, and having poor sleep or not enough sleep — or lack of restorative sleep — can lead to a lower pain threshold,” she notes. “And not sleeping well can also lead to fatigue.” When you are sleep deprived or fatigued, you may “recognize that you aren’t thinking coherently or responding quickly to external stimuli because of cognitive fog,” Brancato adds. The first step to reducing sleep disturbances is to address any pain related to AS, “not necessarily with pain medication, per se, but with medication targeting your ankylosing spondylitis,” says Chi. Brancato notes that attention to sleep hygiene, such as making sure you’re in a restful environment and following a consistent sleep schedule, can help reduce sleep disturbances.
Raising Cognitive Concerns With AS
Whatever the cause of any cognitive dysfunction you may be experiencing, it’s important to share your concerns with your rheumatologist, says Chi. While your symptoms may be subtle, “It’s something you might notice if you’re experiencing related conditions like anxiety or depression and sleep disturbances,” she says. “You probably will notice that you’re having trouble remembering things or having a fogginess to your thinking.” Your rheumatologist can help you figure out what factors may be contributing to your symptoms and help you get the treatment and relief you need, although there may be some trial and error, says Chi. And no outcome is guaranteed. “That’s easier said than done for some people. It’s very individualized, the prognosis.”
