Cognitive impairment (Brain fog) in ME & LC

US researchers led by Drs Suzanne Vernon and Lucinda Bateman investigated cognitive problems in people with ME acquired both recently and over 10 years previously.

We believe that the closer to onset we study ME/CFS, the more likely we are to identify possible pathways that are causing the symptom(s) that can be targeted with treatment.

Patients with ME for more than 10 years had the lowest cognitive efficiency scores but higher heart rate and narrow pulse pressure was causing slower reactions times and lower cognitive efficiency in Long COVID and ME/CFS patients ill for less than 4 years.

“The take home message is that being sick with Long COVID together with orthostatic intolerance is driving brain fog.

Cognitive impairment in ME/CFS patients sick for <4 years was partially associated with the likely adaptive response of elevated heart rate.

It appears that the longer the duration of illness with ME/CFS, the more likely cognition is impaired in response to physiological stressors. Whether the cognitive deficits in executive function are stable, waxing-and-waning, or progressive is not known.

Regardless, cognitive impairment affects daily life causing problems in remembering, concentrating and decision making. These findings underscore the need for early diagnosis and treatment of ME/CFS and Long COVID to improve daily cognitive functioning.”

Cognitive impairment in post-acute sequelae of COVID-19 and short duration myalgic encephalomyelitis patients is mediated by orthostatic hemodynamic changes, by Heather Day,  Brayden Yellman,  Sarah Hammer,  Candace Rond,  Jennifer Bell,  Saeed Abbaszadeh,  Greg Stoddard,  Derya Unutmaz,  Lucinda Bateman and  Suzanne D Vernon in Front. Neurosci., 26 June 2023
Sec. Autonomic Neuroscience Vol 17 – 2023 [doi.org/10.3389/fnins.2023.1203514] This article is part of the Research Topic Fatigue: Physiology and Pathology

Introduction:

Cognitive impairment is experienced by people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-acute sequelae of COVID-19 (PASC). Patients report difficulty remembering, concentrating, and making decisions. Our objective was to determine whether orthostatic hemodynamic changes were causally linked to cognitive impairment in these diseases.

Methods: 

This prospective, observational cohort study enrolled PASC, ME/CFS, and healthy controls. All participants underwent clinical evaluation and assessment that included brief cognitive testing before and after an orthostatic challenge. Cognitive testing measured cognitive efficiency which is defined as the speed and accuracy of subject’s total correct responses per minute.

General linear mixed models were used to analyze hemodynamics and cognitive efficiency during the orthostatic challenge. Additionally, mediation analysis was used to determine if hemodynamic instability induced during the orthostatic challenge mediated the relationship between disease status and cognitive impairment.

Results: 

Of the 276 participants enrolled, 256 were included in this study (34 PASC, 71 < 4 year duration ME/CFS, 69 > 10 year ME/CFS duration, and 82 healthy controls). Compared to healthy controls, the disease cohorts had significantly lower cognitive efficiency scores immediately following the orthostatic challenge. Cognitive efficiency remained low for the >10 year ME/CFS 2 and 7 days after orthostatic challenge. Narrow pulse pressure less than 25% of systolic pressure occurred at 4 and 5 min into the orthostatic challenge for the PASC and ME/CFS cohorts, respectively.

Abnormally narrow pulse pressure was associated with slowed information processing in PASC patients compared to healthy controls (−1.5, p = 0.04). Furthermore, increased heart rate during the orthostatic challenge was associated with a decreased procedural reaction time in PASC and < 4 year ME/CFS patients who were 40 to 65 years of age.

Discussion: 

For PASC patients, both their disease state and hemodynamic changes during orthostatic challenge were associated with slower reaction time and decreased response accuracy during cognitive testing. Reduced cognitive efficiency in <4 year ME/CFS patients was associated with higher heart rate in response to orthostatic stress.

Hemodynamic changes did not correlate with cognitive impairment for >10 year ME/CFS patients, but cognitive impairment remained. These findings underscore the need for early diagnosis to mitigate direct hemodynamic and other physiological effects on symptoms of cognitive impairment.

see also:

Press release: Brain Fog in ME/CFS and Long COVID, by Suzanne Vernon