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  • New study maps adolescent synapse hotspots, raising fresh questions about brain pruning and schizophrenia risk

    New study maps adolescent synapse hotspots, raising fresh questions about brain pruning and schizophrenia risk

    Researchers have identified previously overlooked synapse hotspots that form during adolescence, suggesting the teenage brain may actively build dense new connections alongside the well-known process of synaptic pruning. The findings, reported by Kyushu University scientists in Science Advances, add nuance to how neural circuits mature during a critical developmental window.

    Synapses are the communication points between neurons, and for decades a common model held that synapse numbers rise in childhood and then drop in adolescence as weaker links are removed. That pruning-focused framework has influenced theories of neuropsychiatric disorders, including the idea that excessive synapse loss could contribute to schizophrenia.

    The new work points to a more complex picture: localized bursts of synapse formation in specific parts of neurons. Using a tissue-clearing technique and super-resolution imaging, the team mapped dendritic spines across entire Layer 5 cortical neurons, which play a major role in integrating signals and producing cortical output.

    In young mice before weaning, dendritic spines were distributed more evenly along neurons. Between about three and eight weeks of age, the researchers observed a sharp rise in spine density in a single section of the apical dendrite, culminating in a tightly packed hotspot that was not present earlier.

    The authors argue this pattern means adolescent development is not defined solely by pruning, but also by targeted construction of new synaptic clusters. They also report that in mice carrying mutations in genes linked to schizophrenia risk, the hotspot did not develop normally because synapse formation during adolescence was reduced.

    While the results rely on mouse models and do not confirm the same mechanism in humans, they sharpen questions about which circuits are built during adolescence and how disruptions might alter brain function. The researchers say the next step is to identify the brain regions and inputs driving these newly formed connections during the adolescent period.

  • Childhood Air Pollution May Weaken Teen Brain Connectivity, New Generation R Study Suggests

    A study led by the Barcelona Institute for Global Health (ISGlobal) reports that children exposed to higher levels of air pollution early in life show weaker connections between key brain regions. The findings, published in Environment International, add to evidence that pollution may influence neurodevelopment.

    Researchers focused on functional connectivity, a measure of how strongly brain areas coordinate activity within and between networks. These networks support attention, movement control, sensory processing, and other cognitive functions that continue to mature through adolescence.

    What the researchers measured

    The analysis used data from 3 626 children in the long-running Generation R cohort in Rotterdam. Air pollution exposure at home addresses was estimated for particulate matter PM2.5 and PM10, plus nitrogen dioxide and other nitrogen oxides.

    Brain scans were taken at rest, first at around age 10 and again at an average age of 14. The team compared pollution exposure from birth to age three with exposure in the year immediately before each neuroimaging assessment.

    Signals seen across adolescence

    Higher pollution exposure from birth to age three was linked to lower connectivity between the amygdala and cortical networks involved in attention, somatomotor function, and auditory processing. The amygdala plays a central role in emotional processing and threat responses.

    Separately, higher recent exposure to PM10 in the year before scanning was associated with reduced connectivity between the salience network and the medial-parietal network. These networks are involved in detecting relevant stimuli and supporting introspection and self-referential thinking.

    Authors cautioned that the study identifies associations rather than proving causation, and that further work is needed to clarify biological mechanisms. Still, they noted that some links appeared to persist through adolescence, raising questions about longer-term effects on cognition and emotion.

    How this fits with earlier findings

    The same research group has also reported associations between prenatal and childhood pollution exposure and changes in brain volume in the Generation R cohort. In that work, higher prenatal exposure to PM2.5 and certain metals was tied to a smaller hippocampus at age 8, followed by signs consistent with compensatory growth later.

    Together, the studies reinforce concerns that common urban air pollution exposures may coincide with measurable differences in the developing brain. The researchers argue the results support policies aimed at reducing traffic-related pollution where children live, learn, and play.

  • Startavo „Gamtos herojai 2026“: kas gali kandidatuoti ir kaip iki spalio 31 dienos pateikti paraišką

    Aplinkosauginė iniciatyva „Kita forma“ paskelbė kvietimą teikti paraiškas konkursui „Gamtos herojai 2026“. Tai jau šeštą kartą rengiamas projektas, kuriuo siekiama viešai įvertinti žmones ir organizacijas, savo darbais prisidedančius prie aplinkos apsaugos ir tvarumo.

    Organizatoriai pabrėžia, kad vertinami ne pažadai, o realūs veiksmai: nuo kasdienių sprendimų bendruomenėje iki ilgalaikių iniciatyvų, keičiančių įpročius mokyklose ar organizacijose. Taip pat akcentuojamas aplinkosauginis švietimas ir gebėjimas įkvėpti kitus prisidėti.

    Kas gali pretenduoti?

    Šių metų konkurse numatytos trys nominacijų kryptys: tvarumą skatinanti nevyriausybinė organizacija ar iniciatyva, ekologiškiausias pedagogas bei aplinkai draugiškiausias mokinys arba studentas. Dalyvauti kviečiami įvairaus amžiaus ir patirties dalyviai, jei tik veikla susijusi su aplinkosauga ir tvarumu.

    Konkurso organizatoriai nurodo, kad darbai turi būti įgyvendinti per pastaruosius metus. Tokia sąlyga leidžia įvertinti aktualiausias iniciatyvas ir užtikrinti, kad apdovanojimai atspindėtų dabartines tvarumo tendencijas.

    Kaip vyks atranka ir apdovanojimai?

    Paraiškas dalyviai teikia užpildydami registracijos anketą, o dalyvavimas yra nemokamas. Nugalėtojams numatytos rėmėjų dovanos, o apdovanojimai planuojami gyvai Vilniuje, Jaunimo tvarumo festivalio metu.

    Registracija vyksta iki spalio 31 dienos. Organizatoriai ragina nedelsti ir pateikti informaciją aiškiai, akcentuojant konkrečius rezultatus: kokie pokyčiai pasiekti, kas įtraukta į veiklas ir kaip iniciatyva prisidėjo prie tvaresnių sprendimų.

    Partneriai ir kontaktai

    Projektą palaiko savivaldybės ir regioniniai atliekų tvarkymo centrai, tarp jų Vilniaus miesto savivaldybė, Prienų rajono savivaldybė, Klaipėdos miesto savivaldybė, Alytaus miesto savivaldybė, taip pat Kauno ir Šiaulių regionų atliekų tvarkymo centrai. Organizatoriai pažymi, kad partnerystės padeda konkursui pasiekti daugiau bendruomenių ir stiprina aplinkosaugines iniciatyvas regionuose.

    Dėl konkurso sąlygų ir dalyvavimo tvarkos galima kreiptis į organizatorių atstovę Tomą Jakutytę. Papildoma informacija skelbiama iniciatyvos „Kita forma“ oficialiuose kanaluose.

  • Study suggests common English phrases can boost perceived fluency more than advanced vocabulary

    Language learners often assume that using rare, complex vocabulary will make their speech sound more fluent. Research suggests that there is a close relationship between formulaic expression usage in speech and acoustic features of oral fluency. This implies that using formulaic expressions leads to faster articulation speed and fewer disruptions during speech. However, in terms of how listeners perceive speakers’ fluency, the role of formulaic expressions has been unclear.

    To investigate this, Ph.D. student, Kotaro Takizawa and Research Assistant Professor Shungo Suzuki from Waseda University, Japan, analyzed speech from 102 Japanese speakers of English, each delivering an argumentative speech. They measured the use of bigram and trigram expressions (two- and three-word sequences) and had fluency judged by 10 experienced raters. The study controlled for key fluency metrics, including articulation rate, pauses, and self-corrections, to isolate the effect of formulaic expressions on fluency perception. This study was published online in the journal Studies in Second Language Acquisition on February 12, 2025.

    The findings revealed that utterance fluency (smoothness of speech delivery) was the strongest predictor of fluency perception, accounting for 61% of the variance in ratings. However, high-frequency formulaic expressions added an extra 0.8% to fluency judgments, while rarer, more complex phrases had little to no effect.

    The study also reveals that the key to sounding fluent is not about using sophisticated words; it is about using the right phrases. Their study shows that common, everyday expressions have a small but significant impact on how fluency is perceived, even when a factor like smoothness is accounted for. “We found that common, oft-used formulaic expressions, rather than rare, sophisticated ones, significantly influenced rater judgment of speakers’ fluency,” said Takizawa.

    Fluency plays a crucial role in language learning and assessment, especially in standardized tests like TOEFL and IELTS, where expert raters evaluate how natural and smooth a speaker sounds. Traditionally, fluency has been associated with speed and uninterrupted speech, but the role of formulaic expressions (common multi-word phrases) has been less clear. Previous studies suggested that these expressions help speakers communicate more smoothly, but few have examined how they influence fluency perception on their own.

    Suzuki highlighted the practical implications: “It is generally observed that language teachers and learners tend to focus more on rare words or difficult phrases that sound more proficient. However, the current findings indicate that that should not necessarily be the focus, particularly if they want to improve their fluency perceived by others.”

    This research suggests that learners should shift their focus from advanced vocabulary to mastering everyday phrases that come naturally in conversation. For example, instead of saying “I agree the idea” — which sounds unnatural — learners should use “I agree with the idea.” These common expressions are easy to find in textbooks and everyday conversations, making them more accessible for learners of all levels.

    The study has significant implications for language testing, where fluency judgments can impact scores. It suggests that test-takers should focus on integrating natural phrasal expressions into their speech while maintaining the smoothness of their speech. Highlighting the importance of both aspects, “Our research shows that there is no denying that improving fluency in utterance contributes to good fluency judgment scores,” noted Takizawa.

    This study highlights the crucial role of common expressions in shaping how fluency is perceived, offering valuable insights for language learners and educators.

  • Vagus nerve stimulation implant shows lasting gains for treatment-resistant depression, and some patients reach remission

    Vagus nerve stimulation implant shows lasting gains for treatment-resistant depression, and some patients reach remission

    About one in five adults in the United States will experience major depression at some point in their lives. Many people improve after trying a few treatments, but for as many as one-third of patients, standard antidepressants or psychotherapy do not provide enough relief. This condition, known as treatment-resistant depression, can persist for years or even decades. New research now suggests that a small implanted device may offer meaningful and long-lasting improvement for people with the most severe forms of the illness.

    Scientists at Washington University School of Medicine in St. Louis led a large, multicenter clinical trial to evaluate this approach. The researchers found that a device designed to stimulate the vagus nerve was linked to sustained improvements in depressive symptoms, daily functioning, and overall quality of life. For most patients who showed improvement after one year, those gains continued for at least two years.

    The participants in the study had lived with depression for an average of 29 years and had already tried about 13 treatments without success. These included intensive options such as electroconvulsive therapy and transcranial magnetic stimulation, highlighting just how difficult their condition had been to treat.

    The latest results come from the ongoing RECOVER trial and were published Jan. 13 in the International Journal of Neuropsychopharmacology.

    “We believe the sample in this trial represents the sickest treatment-resistant depressed patient sample ever studied in a clinical trial,” said lead author Charles Conway, MD, a professor of psychiatry and director of the WashU Medicine Treatment Resistant Mood Disorders Center. “There is a dire need to find effective treatments for these patients, who often have no other options. With this kind of chronic, disabling illness, even a partial response to treatment is life-altering, and with vagus nerve stimulation we’re seeing that benefit is lasting.”

    How vagus nerve stimulation works

    The RECOVER study was designed to test whether adding vagus nerve stimulation (VNS) to ongoing care could improve outcomes for people with treatment-resistant depression. The therapy involves surgically placing a device under the skin in the chest. The device sends carefully controlled electrical signals to the left vagus nerve — a key communication pathway between the brain and many internal organs.

    The VNS Therapy System is made by LivaNova USA, Inc., which sponsored and funded the RECOVER trial. The study is collecting long-term data on mood, daily function, and quality of life in people with severe treatment-resistant depression. One aim of the research is to help the U.S. Centers for Medicare and Medicaid Services (CMS) decide whether to expand coverage for the therapy. Because many private insurers follow CMS decisions, approval could make the treatment accessible to far more patients, as cost has been a major barrier.

    Inside the RECOVER trial

    Nearly 500 patients were enrolled across 84 locations in the United States. About three-quarters of participants were so severely affected by depression that they were unable to work. All patients received the implanted device, but only half had the device activated during the first year to allow for comparison. Researchers tracked changes in depression severity, quality of life, and everyday functioning.

    A response was considered meaningful if symptoms improved by at least 30% compared with the start of the study. A reduction of 50% or more was classified as a “substantial” response.

    Conway emphasized that even modest improvements can dramatically change a person’s life. Severe depression can leave people feeling “paralyzed by life,” unable to manage basic daily activities and at higher risk of hospitalization or early death.

    Earlier findings from the blinded first year of the trial showed that patients with activated devices spent more time with improved mood, better functioning, and higher quality of life than those whose devices were not active. However, the primary measurement tool (the Montgomery-Åsberg depression scale, which measures the severity of depressive episodes) did not show a statistically significant difference between the two groups.

    Benefits that last over time

    In the newest analysis, the researchers focused on patients whose devices were active from the start of the trial. They wanted to see whether improvements seen at 12 months would continue through 24 months. They also examined whether some patients who did not improve in the first year might respond later with continued treatment.

    Out of 214 patients who received active treatment from the beginning, about 69%, or 147 people, showed a meaningful response at one year in at least one outcome measure. Among those who benefited at 12 months, more than 80% maintained or improved their results by the two-year mark across measures of depression, quality of life, and daily functioning. For patients with a substantial response at one year — defined as at least a 50% reduction in symptoms — 92% were still benefiting at two years.

    Nearly one-third of participants who had not improved after the first year reported benefits by the end of the second year, suggesting that the therapy may take longer to work for some individuals. Relapse rates remained low among those who responded, particularly among the strongest responders.

    The researchers also found that more than 20% of treated patients, or 39 people, were in remission after 24 months. This means their symptoms had eased enough for them to function normally in daily life, a result Conway described as especially notable.

    “We were shocked that one in five patients was effectively without depressive symptoms at the end of two years,” he said. “Seeing results like that for this complicated illness makes me optimistic about the future of this treatment. These results are highly atypical, as most studies of markedly treatment-resistant depression have very poor sustainability of benefit, certainly not at two years. We’re seeing people getting better and staying better.”

    Funding and disclosures

    The study was supported by LivaNova, PLC, the developer and manufacturer of the Vagus Nerve Stimulation therapy system. LivaNova, PLC supported the study design, data analysis, and preparation of the report. The U.S. Centers for Medicare & Medicaid Services approved the study under its NCD VNS for Treatment Resistant Depression. The authors alone made the final decision on the manuscript content and its submission for publication.

    Conway has received research support from the American Foundation for Suicide Prevention, Assurex Health, August Busch IV Foundation, Barnes-Jewish Hospital Foundation, LivaNova, National Institute of Mental Health, and the Taylor Family Institute for Innovative Psychiatric Research. He has also served as a consultant for LivaNova.

  • Schizophrenia study suggests brain prediction errors may drive hearing voices, and hints at an EEG biomarker

    Schizophrenia study suggests brain prediction errors may drive hearing voices, and hints at an EEG biomarker

    Researchers at UNSW Sydney say they have found some of the clearest evidence yet that auditory verbal hallucinations in schizophrenia may stem from a breakdown in how the brain recognizes its own inner speech. The team argues the brain may mislabel self-generated thoughts as if they were external voices.

    The study, published in Schizophrenia Bulletin, focuses on a well-known theory in psychiatry: that hallucinated voices can arise when the brain’s normal system for predicting the sound of one’s own speech fails. If that prediction signal misfires, activity in sound-processing regions may look more like the brain is hearing someone else.

    How inner speech is measured

    Because inner speech is private, testing it directly has long been difficult. The researchers used EEG recordings to track brain responses while participants silently imagined speaking simple syllables while hearing sounds through headphones.

    In everyday speech, the brain typically dampens activity in the auditory cortex because it anticipates the sensory consequences of one’s own voice. The new work examined whether that suppression effect also appears during imagined speech, and whether it differs in people who hear voices.

    What the EEG signals showed

    The experiment compared 55 people with schizophrenia spectrum disorders who had experienced auditory hallucinations within the previous week, 44 people with schizophrenia without recent hallucinations, and 43 healthy participants. During the task, participants imagined saying “bah” or “bih” while the same sounds were sometimes played aloud, without advance notice of a match.

    Healthy participants showed reduced brain responses when the imagined syllable matched the sound they heard, consistent with accurate prediction and sensory suppression. By contrast, people with recent hallucinations showed the opposite pattern, with stronger responses when the imagined and heard sounds matched.

    Participants with schizophrenia who had not recently heard voices showed responses between the other two groups. The authors say that gradient could indicate a link between the disrupted prediction mechanism and the current presence of hallucinations, rather than diagnosis alone.

    Could this become a biomarker?

    The team says the findings strengthen the case that some hallucinated voices feel real because the brain processes inner speech as if it were coming from outside. They also argue the EEG signature could eventually contribute to a biomarker approach, an area where schizophrenia still lacks definitive lab or imaging tests.

    Next, the researchers plan to test whether this response pattern can help identify people at elevated risk of psychosis before symptoms fully emerge. Earlier identification could support earlier intervention, although the authors note further validation is needed across broader populations and clinical settings.

  • Study links rejection sensitivity to classroom conformity and peer pressure in preteens

    Imagine you’re a child in a classroom, and your teacher tells everyone to form groups for a project. You sit and wait, watching as other kids pair up and wondering if anyone will pick you.

    This fear of rejection — familiar to many children and adults — can significantly impact how kids behave in their peer groups, according to new research from the University of Georgia.

    The study found that children who feel anxious about being rejected are more likely to conform to academic expectations like studying harder or following classroom rules. They’re also less likely to engage in troublemaking behaviors. On the other hand, children who actively expect rejection tend to resist conforming to both academic behaviors and popular trends.

    Rejection sensitivity refers to two categories of reactions to potential rejection: rejection expectancy, a cognitive tendency to expect rejection, and anxious or angry anticipation, the emotion felt when anticipating rejection.

    “Rejection sensitivity is a really concerning characteristic in children,” said Michele Lease, a professor in the Mary Frances Early College of Education’s department of educational psychology and co-author of the study. “When children are rejection sensitive, they might worry and become withdrawn or feel angry and become hostile. If they’re trying to fit in and not get rejected, they might learn to conform, ingratiate themselves or be less assertive. Rejection sensitivity is also a good predictor of depression, even before the onset of symptoms.”

    The research, led by recent UGA graduate Cayenne Predix, involved more than 350 fourth and fifth grade students. Participants completed questionnaires with scenarios to measure how likely they were to follow their friends’ behaviors in three areas: academics, trend-following and troublemaking.

    “As a social developmental task, what’s happening at this age is children are trying to learn how to navigate their entire peer network, including their status within their friend group, and that’s a very unique time for trying to understand how kids feel about their place in the group,” said Lease. “It’s not that they don’t have good friendships, they do — they play, they do other things, but at this age one of their primary tasks is learning how to fit in.”

    Interestingly, witnessing relational victimization including gossiping or bullying did not consistently influence children’s conformity across behaviors. Instead, children’s emotional and cognitive reactions to potential rejection were the strongest predictors of whether they would follow group norms.

    Specifically, anxious children were more inclined to avoid disruptive actions and match their peers’ positive academic behaviors such as studying more or participating in class. Conversely, those who expected rejection were less likely to conform academically or socially.

    “Overall, the study’s findings underscore the need to consider both the emotional and cognitive aspects of rejection sensitivity when investigating conformity, especially in the context of relational aggression within friendship groups,” Lease said.

    Lease and her research team including Mihyun Kim, UGA doctoral candidate, and Kyongboon Kwon, University of Wisconsin-Milwaukee professor, are continuing their research to explore how friendship group norms influence sensitivity to rejection and conformity.

  • EEG brain signals may offer a noninvasive path to restoring movement after spinal cord injury

    EEG brain signals may offer a noninvasive path to restoring movement after spinal cord injury

    Researchers are moving closer to a noninvasive way to help people with spinal cord injuries regain movement by decoding brain waves linked to intended actions. The approach centers on electroencephalography, or EEG, which records electrical activity from the scalp.

    In many spinal cord injuries, the brain can still generate normal movement commands, but damaged pathways prevent those signals from reaching muscles. That gap has driven efforts to build new routes for communication rather than repairing the spinal cord itself.

    A bid to avoid brain surgery

    A study published in APL Bioengineering by scientists in Italy and Switzerland examined whether EEG can reliably capture signals produced when patients attempt to move paralyzed limbs. The long-term goal is to translate those signals into commands that could drive assistive devices or stimulation therapies.

    Much of the earlier progress in brain-computer interfaces has relied on implanted electrodes that record activity directly from the brain. While implants can provide clearer signals, they also bring surgical risk and ongoing concerns such as infection and device complications.

    Why legs are harder to decode

    EEG is safer and easier to repeat, but it faces a fundamental limitation: signals recorded at the scalp are weaker and less precise than those captured inside the skull. This makes it difficult to pinpoint activity from deeper brain regions involved in movement control.

    The researchers noted that decoding attempts to move the legs can be especially challenging, because lower-limb control is represented more centrally in the brain. By contrast, signals for hand and arm movements are often easier to separate with surface recordings.

    Machine learning shows early promise

    To interpret the EEG patterns, the team used machine learning designed to work with small, complex datasets typical of clinical research. Patients wore an EEG cap and were asked to attempt simple movements while the system learned patterns associated with effort versus rest.

    The method could distinguish when a participant was trying to move versus staying still, but it struggled to reliably differentiate among specific movement types. The next step is improving classification so intended actions like standing or walking can be identified more consistently.

    Researchers say success would likely depend on better algorithms, improved EEG hardware, and careful integration with downstream technologies such as stimulators or external assistive systems. For patients, the appeal is clear: a potential route toward meaningful function without placing electrodes in the brain.

  • Lip Size and Attraction: New Study Finds Men and Women Judge Faces Differently

    A new psychology study suggests lip size can subtly shape how attractive a face is perceived, and that preferences can differ depending on the viewer’s gender. The research also indicates that recent visual exposure can shift what people see as appealing.

    The work was led by Professor David Alais at the University of Sydney and used digitally altered images of faces that varied only in lip size. Participants were asked to rate attractiveness, allowing researchers to isolate lip size as a single factor.

    Gender differences in lip preference

    Across participants overall, ratings tended to favor thinner lips on male-presenting faces and fuller lips on female-presenting faces. When broken down by gender, women showed a stronger preference for fuller lips on female faces, while men more often preferred female faces with unaltered, natural-looking lip size.

    The authors argue the pattern points to observer-dependent standards, meaning judgments are shaped not just by the face being viewed but also by who is doing the viewing. The findings were published in Proceedings of the Royal Society B.

    How fast exposure can shift taste

    The experiments also found an adaptation effect, where brief exposure to plumper or thinner lips changed what participants rated as attractive immediately afterward. After seeing fuller lips, people were more likely to rate fuller lips as attractive in subsequent faces, with a similar shift after exposure to thinner lips.

    Notably, the effect appeared even when participants adapted to lips presented without the full face context, suggesting the brain may encode lip size as a distinct feature. Researchers say this kind of rapid recalibration has been observed in other areas of visual preference.

    Implications for cosmetic trends and body image

    With lip augmentation widely promoted through celebrity culture and social media, the study raises questions about how repeated exposure to enhanced features may reset perceived norms. Alais warned that this could contribute to a slide toward ever-plumper ideals, sometimes described as lip dysmorphia.

    “Our research highlights the subjective nature of beauty and the powerful influence of social and cultural factors,” Alais said. The team says more research is needed to understand whether these short-term shifts accumulate into long-term changes in body image and aesthetic expectations.

    In the study, 32 students, split evenly between women and men, rated 168 manipulated faces spanning seven lip sizes from thinner to fuller than a defined norm. Each image was shown briefly, designed to capture quick, instinctive judgments rather than slow deliberation.

  • Study finds long COVID brain fog is reported far more in the U.S., raising questions about care and stigma

    Study finds long COVID brain fog is reported far more in the U.S., raising questions about care and stigma

    An international study comparing long COVID patients across four countries found that people treated in the United States reported markedly higher rates of brain fog and mental health symptoms than patients in India, Nigeria, or Colombia.

    Researchers say the gap is unlikely to be explained by biology alone and may instead reflect differences in culture, stigma, and access to diagnosis and follow-up care.

    The analysis tracked more than 3 100 adults with persistent neurological symptoms after COVID-19 who were evaluated at academic medical centers in Chicago, Medellín, Lagos, and Jaipur.

    Most participants were not hospitalized during their initial infection, allowing researchers to focus on long-term symptoms among people who experienced milder acute illness.

    Brain fog reports varied sharply

    Among non-hospitalized participants, 86% of U.S. patients reported brain fog, compared with 63% in Nigeria, 62% in Colombia, and 15% in India.

    Patterns for depression and anxiety were similarly uneven, with nearly three-quarters of non-hospitalized U.S. patients reporting these symptoms, far above rates reported at other sites.

    Investigators cautioned that higher reported symptom rates do not necessarily mean Americans have more severe disease.

    They argue that patients in some settings may be less likely to label cognitive problems as a medical issue or may have fewer opportunities to be screened and treated.

    Culture and healthcare access may matter

    Senior author Dr. Igor Koralnik of Northwestern University said it is more culturally accepted in the U.S. and Colombia to discuss mental health and cognitive changes.

    He added that stigma, health literacy, and limited availability of mental health providers could reduce reporting in other countries, masking the true burden.

    Across all regions, commonly reported neurological complaints included fatigue, headache, dizziness, muscle pain, sleep problems, and sensory disturbances such as numbness or tingling.

    The team said the findings underscore the need for culturally sensitive screening tools and more consistent long COVID follow-up, especially where care is harder to access.

    The study was published in Frontiers in Human Neuroscience and adds to growing evidence that long COVID can disrupt daily function and work capacity long after infection.

    Researchers involved in the project are also testing cognitive rehabilitation approaches for long COVID brain fog in partner sites, using shared protocols to compare outcomes.