SAN DIEGO —
In fact, these effects may appear in the prodromal phase and carry through the headache and into the post-headache period, according to Richard Lipton, MD, who spoke about cognition and migraine at the annual meeting of the American Headache Society.
Dr. Richard Lipton
He pointed out existing evidence that migraine patients have cognitive impairment relative to the general population even during the interictal period. Such studies suggest that migraine, especially with aura, could be a risk factor for later dementia.
One important limitation of studies that compare people with migraines with controls is that a range of factors could explain an association between lower cognitive function and migraines, including socioeconomic factors, education, severe headaches requiring specialty care, and comorbidities, among others. Acute and preventative treatments could also affect cognition.
However, longitudinal studies of cognitive function in individual patients have been sparse. Questions remain, like whether cognitive performance differs between the headache period and the interictal period, as well as similar questions about the premonitory and post-drome phases. “And then there’s a long-term question: Do people with migraine show more interictal or ictal decline in cognitive performance relative to migraine-free controls?” said Dr. Lipton, professor of neurology at Albert Einstein College of Medicine in the Bronx, New York.
He showed evidence from a retrospective study by Lundbeck conducted at four sites that asked patients with chronic migraine about bothersome symptoms both before and after treatment. More than three-fourths (77.7%) rated “difficulty concentrating or thinking clearly” as a bothersome symptom.
Following treatment, 5.0% said their cognitive issues had completely improved, 32.0% that they were “very much” improved, 26.0% moderately improved, 23.0% slightly improved, and 14.0% not at all improved.
“I am not saying this is a rigorous study, but I am saying that it illustrates two points that are important for us today: One is that brain fog is very common in a subspecialty care sample of headache patients like the ones many of us treat, and it also suggests that there’s hope that treatment can improve cognitive impairment as migraine gets better,” said Dr. Lipton.
Cognition has received less attention than other migraine symptoms, and treatment can be a two-edged sword: “There’s some evidence that some treatments can reduce cognitive impairment, and obvious evidence that some treatments, topiramate and tricyclics, can induce cognitive impairment,” said Dr. Lipton.
Studies that compare cognition within the same patient at different time periods can get around some of the limitations of comparisons between populations, but face their own challenges. “Single shot” cognitive measures may not be reliably repeatable and differences seen on “good” versus “bad” days or proximity to recent headaches.
The solution, Dr. Lipton believes, is intensive repeated measures that avoid the practice effect, in which a participant improves at a test due to repetition.
He summarized a study that was presented later in the day at a poster session, which used smartphones or other devices to test 19 participants five times per day, over 5 days, in natural environments. Devices gathered both subjective and objective assessments of cognition, along with information on mood, stress, and status and fluctuations in pain, and have the potential to go further by measuring things like physical exertion, heart rate, pollution levels, and other variables.
“It clearly improves the reliability and the validity of cognitive assessment and makes it possible to link cognition to the stage of the headache cycle,” said Dr. Lipton.
The researchers found worse cognitive performance during the headache phase as compared with the interictal phase. “Objective cognitive performance measurably declines during the headache phase, and the next step is to fully control for acute medications that people may take during the headache phase,” said Dr. Lipton.
He expressed hope that improved measurements can improve outcomes, if it’s possible to identify therapies that don’t impact cognition. “We think it’s very likely that certain classes of acute and preventive medications may not cause cognitive impairment, and there is a strong hope that they may actually reduce the cognitive burden of disease and potentially even reduce cognitive decline. Those are areas that I’m very excited to explore in the future,” said Dr. Lipton.
The results emphasize the need to treat patients early, according to Nada Hindiyeh, MD, who attended the session and was asked for comment. “Generally, patients are going to come to you with episodic migraines. When migraines start to increase in frequency and severity, that means all of these other symptoms are going to come along with it and be increased in frequency and severity, so it’s important to recognize this early so you can get patients on the right treatments and preventives to really prevent these episodes from happening and prevent that cognitive decline,” said Dr. Hindiyeh, director of headache neurology at Metrodora Institute, West Valley City, Utah.
Dr. Lipton has financial relationships with Aeon, AbbVie/Allergan, Amgen, Biohaven, Dr. Reddy’s Laboratories, electroCore, Eli Lilly, GlaxoSmithKline, Lundbeck, Merck, Novartis, Pfizer, Teva, Axon, CoolTech, and Manistee. Dr. Hindiyeh has no relevant financial disclosures.