A cross-continental comparative analysis of the neurological manifestations of Long COVID, 2026, Jimenez et al

[forestglip]

A cross-continental comparative analysis of the neurological manifestations of Long COVID

Spoiler: Authors

Millenia Jimenez 1, Melissa Lopez 1, Janet Miller 1, Njideka U. Okubadejo 2,3, Carolina Hurtado 4, Anurag Kumar Singh 5, Oluwadamilola O. Ojo 2,3, Diego F. Rojas-Gualdron 4, Iorhen Akase 2,3, Osigwe P. Agabi 2,3, Kamlesh Kumar 6, Balvir Singh Tomar 7, Deepak Nathiya 5, Rebecca Jules 1, Eric M. Liotta 1 and Igor J. Koralnik

[Line breaks added]

Objective
To compare demographics, comorbidities, neurologic symptoms, quality of life, and cognitive outcomes among adult individuals with neurologic manifestations of post-acute sequelae of SARS-CoV-2 infection (Neuro-PASC) across countries with varying income levels: the United States (U.S.), Colombia, Nigeria, and India.

Methods
In this multi-country observational study, participants were evaluated in hospital clinics and recruited from institutional databases between 2020 and 2025. Patients were categorized as post-hospitalization Neuro-PASC (PNP) or non-hospitalized Neuro-PASC (NNP). Cognitive assessments were performed using the NIH Toolbox (U.S. and Colombia), the Montreal Cognitive Assessment (Nigeria), or the Mini-Mental State Examination (India).

Results
A total of 3,157 participants were enrolled (652 PNP; 2,505 NNP). PNP patients were predominantly male except in the US, while NNP patients were predominantly female, except in India. The most frequent neurologic symptoms were brain fog, myalgia, dizziness, headache, and sensory disturbances, with frequency highest in the U.S. and lowest in India.

There were significant differences for most neurologic and non-neurologic symptoms of PASC, driven by higher frequencies in U.S. and Colombia in both PNP and NNP cohorts. In addition, cognitive impairment measured with different instruments varied across countries for both PNP and NNP groups. Multiple correspondence analysis showed clustering of symptom burden between U.S./Colombia and Nigeria/India.

Conclusion
Neuro-PASC presents globally but symptom burden, and psychological distress vary across regions, likely influenced by sociocultural factors, healthcare access, and diagnostic tools. These findings highlight the need for culturally-adapted screening and post-COVID care worldwide.

Web | DOI | PDF | Frontiers in Human Neuroscience | Open Access

 

[Dolphin]

Long COVID brain fog far more common in US than India, other nations

Patients with long COVID-19 in the U.S. report far higher rates of brain fog, depression and cognitive symptoms than patients in countries such as India and Nigeria, according to a large international study led by Northwestern Medicine. The authors note that higher reported symptom burden in...

www.eurekalert.org

NEWS RELEASE 28-JAN-2026

Long COVID brain fog far more common in US than India, other nations​

Large study of patients in U.S., Colombia, Nigeria and India finds symptom burden highest in high-income countries

Peer-Reviewed Publication
NORTHWESTERN UNIVERSITY


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IMAGE:

DR. IGOR KORALNIK MEETS WITH A PATIENT IN THE COMPREHENSIVE COVID-19 CENTER AT NORTHWESTERN MEDICINE

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CREDIT: NORTHWESTERN MEDICINE

• Study of 3,100 patients is first to compare long COVID brain symptoms across continents
• Brain fog affected 86% of non-hospitalized U.S. patients, compared with 15% in India
• Symptom patterns clustered by income level, not geography
• Disparities likely reflect culture and healthcare access, not a different virus

CHICAGO --- Patients with long COVID-19 in the U.S. report far higher rates of brain fog, depression and cognitive symptoms than patients in countries such as India and Nigeria, according to a large international study led by Northwestern Medicine.

The authors note that higher reported symptom burden in the U.S. may reflect lower stigma and greater access to neurological and mental health care, rather than more severe disease.

The study, the first cross-continental comparison of long COVID neurological manifestations, tracked more than 3,100 adults with long COVID evaluated at academic medical centers in Chicago; Medellín, Colombia; Lagos, Nigeria; and Jaipur, India.

Among patients who were not hospitalized during their COVID infections (the majority in the study), 86% in the U.S. reported brain fog, compared with only 63% in Nigeria, 62% in Colombia and 15% in India. Rates of psychological distress showed a similar pattern: Nearly 75% of non-hospitalized patients in the U.S. reported symptoms of depression or anxiety, compared with only 40% in Colombia and fewer than 20% in Nigeria and India.

“It is culturally accepted in the U.S. and Colombia to talk about mental health and cognitive issues, whereas that is not the case in Nigeria and India,” said Dr. Igor Koralnik, senior study author and chief of neuro-infectious disease and global neurology at Northwestern University Feinberg School of Medicine.

“Cultural denial of mood disorder symptoms as well as a combination of stigma, misperceptions, religiosity and belief systems, and lack of health literacy may contribute to biased reporting. This may be compounded by a dearth of mental health providers and perceived treatment options in those countries.”

The study will publish Jan. 28 in Frontiers in Human Neuroscience.

Additional key findings

• Brain fog, fatigue, myalgia (muscle pain), headache, dizziness and sensory disturbances (such as numbness or tingling) were the most common neurological symptoms across all countries
• Insomnia was reported by nearly 60% of non-hospitalized U.S. patients, compared with roughly one-third or fewer of patients in Colombia, Nigeria and India
• Statistical clustering showed clear separation between high- and upper-middle-income (U.S., Colombia) and lower-middle-income (Nigeria, India) countries

How the study was conducted

The observational study enrolled adults with persistent neurological symptoms following COVID-19 infection between 2020 and 2025 across four academic medical centers. Researchers included both hospitalized and non-hospitalized patients and assessed symptoms using standardized neurological, cognitive and quality-of-life instruments available at each site.

Understanding long COVID

Long COVID affects millions of people worldwide and is characterized by symptoms persisting for weeks or even years after an acute COVID infection. Various studiesestimate that 10-30% of adults infected with COVID develop long-term symptoms, with neurological and cognitive complaints among the most common and disabling.

As the authors note in the study, long COVID “affects young and middle-aged adults in their prime, causing significant detrimental impact on the workforce, productivity and innovation all over the world.”

In this study, U.S. patients consistently reported the highest burden of neurological and psychological symptoms, which “affected their quality of life and ability to work,” says Koralnik, who also is the co-director of the Comprehensive COVID Center at Northwestern Medicine and leader of the program for global neurology at the Havey Institute for Global Health at Feinberg.

Lessons and what comes next

The authors say the findings underscore the need for culturally sensitive screening tools and diagnostic approaches for long COVID, as well as healthcare systems equipped to support long-term follow-up and treatment.

Building on this work, Koralnik and his international collaborators are now studying cognitive rehabilitation treatments for long COVID brain fog in Colombia and Nigeria, using the same protocols developed for patients treated at the Shirley Ryan AbilityLab in Chicago.

The study is titled “A cross-continental comparative analysis of the neurological manifestations of Long COVID.”

JOURNAL​

Frontiers in Human Neuroscience

DOI​

10.3389/fnhum.2025.1760173

ARTICLE TITLE​

A cross-continental comparative analysis of the neurological manifestations of Long COVID

ARTICLE PUBLICATION DATE​

28-Jan-2026

 

[Chandelier]

Northwestern study explores long COVID symptoms across countries

An international study led by Northwestern Medicine found that patients with long COVID-19 in countries such as the U.S. and Colombia were more likely to report neurological symptoms, including brain fog and fatigue, than patients in countries such as Nigeria and India. Feinberg Prof. Dr. Igor...

dailynorthwestern.com

An international study led by Northwestern Medicine found that patients with long COVID-19 in countries such as the U.S. and Colombia were more likely to report neurological symptoms, including brain fog and fatigue, than patients in countries such as Nigeria and India.

Feinberg Prof. Dr. Igor Koralnik, a study author and founder of the NM Neuro COVID-19 Clinic, said differing social and cultural norms may have been responsible for the differences in reports between countries.

“Here in the U.S., everybody is talking about their mental health, their brain fog and their symptoms the way they are,” Koralnik said. “In Colombia, it seems to be the case as well. This is based on the fact that most of the time, we know what’s going to be for dinner, and we have a roof over our head, and we’re not at war, so we can worry about those issues.”

“We did not expect to see this kind of a drastic difference in the symptom burden,” Koralnik said.

Koralnik said countries used different questionnaires and tests to assess quality-of-life ratings and cognitive function.

“It was interesting to discuss with the people from Colombia, India and Nigeria — every country is different,” Koralnik said. “It shows you that it’s not one-size-fits-all. You need to have culturally appropriate methods to even test those people.”

“For our grandparents, or even our parents, perhaps it was a bit of taboo talking about mental health,” Hurtado Montoya said. “We had very young patients in our study, and there’s a cultural shift in the newer generations to openly discuss mental health.”

“The main problem that occurred was the follow-up,” Singh said. “We get patients for the first time, but for the second, third or fourth time — because we need to reanalyze their symptoms every time — most of them don’t come.”

Koralnik said future research is already underway. His team has received funding to conduct a small pilot trial in Colombia, testing cognitive rehabilitation for long COVID brain fog, and has already treated some patients using the same approach as at NU’s Shirley Ryan AbilityLab. He described it as an intensive weeks-long program, “like physical therapy for the brain,” and that patients are improving.

 

[V.R.T.]

Northwestern study explores long COVID symptoms across countries

An international study led by Northwestern Medicine found that patients with long COVID-19 in countries such as the U.S. and Colombia were more likely to report neurological symptoms, including brain fog and fatigue, than patients in countries such as Nigeria and India. Feinberg Prof. Dr. Igor...

dailynorthwestern.com

Well, that's another way to throw patients under the bus. Oh you see your symptoms are because you're so privileged, you're not in a war zone (as far as I'm aware there's no war in India or Nigeria? Maybe they should have studied Sudan or Gaza). They acknowledged that there were huge cultural differences in what it's ok to talk about. Some cultures have even bigger taboos against laziness than we do in the West. People might not report fatigue because of that. And also, I spent three years telling doctors I don't feel tired, I feel ill because MECFS isn't just fatigue. I didn't see how I could have chronic fatigue syndrome (not that anyone was falling over themselves to diagnose me with it). And like, what even is brain fog? How does the nebulous concept of brain fog translate into Nigerian?

An intense weeks long programme of physical therapy for the brain? Sounds like people with PEM would have a terrible time.