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Brain Sciences

MDPI AG

Preprints posted in the last 7 days, ranked by how well they match Brain Sciences's content profile, based on 52 papers previously published here. The average preprint has a 0.05% match score for this journal, so anything above that is already an above-average fit.

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Cortical activity during narrative discourse production in individuals with post-stroke aphasia and controls measured via functional near-infrared spectroscopy

Braun, E. J.; Carpenter, E. A.; Gao, Y.; Yucel, M. A.; Boas, D. A.; Kiran, S.

2026-06-10 rehabilitation medicine and physical therapy 10.64898/2026.06.05.26354921 medRxiv
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Introduction: Aphasia is an acquired language disorder with a significant negative functional impact. Much of the research on aphasia has focused on word-level language comprehension and production. Further evaluation of discourse-level tasks, both at behavioral and neural levels, will allow for an ecologically valid understanding of the functional implications of language impairment in this population. Method: This study evaluated bilateral frontal, temporal, and parietal cortical activity during computer-based narrative production in 14 young neurotypical individuals, 17 individuals with post-stroke aphasia, and 15 age-matched neurotypical participants using functional near-infrared spectroscopy (fNIRS). Oxygenated hemoglobin (HbO) was measured during narrative production following short video clips and compared to HbO during counting aloud. In addition, behavioral measures quantifying in-task performance were correlated with averaged HbO values. Results: Young neurotypical individuals showed greater cortical activity in bilateral language regions for narrative production compared to counting aloud. In contrast, people with aphasia showed positive condition-related effects in the right frontal ROI and the age-matched group showed positive condition-related effects in the left frontal and right precentral ROIs. Each group showed different patterns in relationships between cortical activity and discourse performance measures. Conclusion: Overall, young participants showing more consistent condition-related effects for narrative discourse production than individuals with aphasia and age-matched controls. This study shows the potential for fNIRS to evaluate cortical activity for ecologically valid language tasks in individuals with post-stroke aphasia.

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Adapting a Regulation of Craving Magnetic Resonance Imaging Task to Generate Functional Repetitive Transcranial Magnetic Stimulation Targets for the Ventromedial and Dorsolateral Prefrontal Cortex in Treatment-Seeking Participants with Cannabis Use Disorder

Geoly, A.; McCalley, D. M.; Struckmann, W.; Azeez, A.; Wong, B.; Kim, B.; Ninomiya, S.; Ahmed, S.; Kim, J. P.; McRae-Clark, A. L.; Froeliger, B.; Sahlem, G. L.

2026-06-06 addiction medicine 10.64898/2026.06.04.26353616 medRxiv
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Background: Repetitive Transcranial Magnetic Stimulation (rTMS) is a promising treatment across addictive disorders including Cannabis Use Disorder (CUD). Targeting incentive-salience circuitry via the ventromedial prefrontal cortex (vmPFC) and central-executive circuitry via the left dorsolateral prefrontal cortex (LDLPFC) are both promising treatment approaches; however, to date structural targets have predominated whereas functional targeting may allow for more precision. In this pilot trial we adapted a functional Magnetic Resonance Imaging (fMRI) Regulation of Craving (ROC) task to generate fMRI-based rTMS targets in the vmPFC and LDLPFC. Methods: We recruited treatment-seeking participants with moderate or severe CUD as a part of an open-label trial and administered an adapted ROC-task during fMRI following 24-hours of cannabis abstinence. We identified sub-portions of maximal activation of the LDLPFC when participants thought of long-term consequences of cannabis use (Later) and of the vmPFC when participants thought of short-term positive aspects of cannabis use (Now). We hypothesized that our task would generate acceptable rTMS targets in >66% of baseline fMRI scans. Results: A total of 20-participants enrolled in the trial (50%F, age=33.3+9.8) and completed the baseline fMRI. The adapted ROC-task elicited group level activation in the LDLPFC and precuneus in the Later>Now and in the bilateral vmPFC, ACC, and striatum in the Now>Later contrast. Acceptable functional targets resolved in both the vmPFC and LDLPFC in 19 of 20 participants (one participant did not tolerate MRI). Conclusions: The adapted ROC-task elicits activation in incentive salience and central executive circuitry and can feasibly generate rTMS targets when using a cluster selection algorithm.

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Behavioral and Functional Neuroimaging Effects of Delivering a Course of Repetitive Transcranial Magnetic Stimulation to Personalized Targets Within the Ventrolateral Or Dorsolateral Prefrontal Cortex in Treatment-Seeking Participants with Cannabis Use Disorder

McCalley, D.; Wong, B.; Geoly, A.; Struckman, W.; Azeez, A.; Kaloiani, I.; Kim, B.; Ninomiya, S.; Ehrie, J.; Austelle, C. W.; Rolle, C. E.; Kim, J. P.; Froeliger, B.; McRae-Clark, A. L.; Sahlem, G.

2026-06-10 addiction medicine 10.64898/2026.06.08.26355193 medRxiv
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Background: Repetitive Transcranial Magnetic Stimulation (rTMS) is a promising treatment across addictive disorders including Cannabis Use Disorder (CUD). Stimulation of two rTMS-targets, the ventromedial prefrontal cortex (vmPFC) and the left dorsolateral prefrontal cortex (LDLPFC), limbic and executive control network hubs respectively, may yield differential effects. In this pilot trial, we explored the differential effects of 36-sessions of rTMS applied to either the vmPFC or LDLPFC. Methods: Treatment-seeking participants with moderate or severe CUD (n=20, 10F, age=33.3+9.8SD) were randomized to 36-sessions of open-label rTMS (two sessions-per-visit, two or three visits-per-week) to either the LDLPFC (3000-pulses; 10Hz) or vmPFC (900-pulses; 1Hz) using personalized functional Magnetic Resonance Imaging (fMRI) targets along with three-sessions of Motivational Enhancement Therapy. At baseline and following rTMS, the Time-Line Follow-Back was used to measure Days-per-week of cannabis use and the fMRI Regulation of Craving (ROC) task was used to measure network activation to cues associated with long-term negative ('Later') and short-term positive ('Now') consequences of cannabis use. Results: Eighty percent of participants completed study-rTMS. There was a significant decrease in days-per-week of cannabis use in both groups (vmPFC: d=7.9; DLPFC, d=3.1) between the four-weeks of baseline and seven-weeks of follow-up. LDPFC-rTMS reduced fMRI BOLD signal magnitude and increased LDLPFC functional connectivity in response to cues, while vmPFC-TMS reduced functional connectivity. Conclusions: Treatment-seeking participants with CUD reduced the number of days-per-week they used cannabis when receiving rTMS applied to either the LDPFC or vmPFC, while fMRI effects differed by treatment target. Future larger sham-controlled trials are needed for efficacy and biomarker determination.

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Multimodal approach to identify neuropsychophysiological subgroups in myalgic encephalomyelitis/chronic fatigue syndrome and their relevance for rehabilitation: protocol for a mechanistic cross-sectional and longitudinal study

Dooms, Y.; Qiu, L.; Coppieters, I.; Vergaelen, E.; Claes, S.; Dupont, P.; Hehl, M.; Cuypers, K.; Engler, H.; Dombrowski, K.; Verbeke, K.; Van den Bergh, O.; Raes, J.; Van Oudenhove, L.; Van Den Houte, M.; Bogaerts, K.

2026-06-08 neurology 10.64898/2026.06.05.26354983 medRxiv
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Introduction: Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS) is a debilitating condition characterised by severe fatigue and post-exertional malaise (PEM). Reported neuropsychophysiological abnormalities suggest ME/CFS is multifactorial, but current knowledge remains fragmented. This study protocol outlines a multimodal investigation designed to (1) compare neuropsychophysiological mechanisms between ME/CFS patients and healthy participants, (2) test an integrative model of ME/CFS, (3) identify neuropsychophysiological subgroups within the patient population, and (4) identify predictors of symptom response during rehabilitation. Methods and analysis: This study will enroll 115 ME/CFS patients and 55 healthy participants. Groups will be comparable in age, sex, and education level, with a larger patient sample enabling subgroup and longitudinal analyses. A cross-sectional assessment at baseline will be carried out in both groups. Patients will then be evaluated longitudinally throughout a standardized cognitive-behavioral therapy rehabilitation program delivered as routine care. Baseline measures include systemic inflammation and general health biomarkers, measures of autonomic and central nervous system function, neuroinflammation (magnetic resonance spectroscopy, [18F]DPA714 PET in a subsample), serum short-chain fatty acid levels, gut microbiota composition and function, and neuroendocrine and self-reported responses to psychosocial stress. Fatigue severity (physical and cognitive) and PEM will be assessed through validated questionnaires, ecological momentary assessment, and laboratory tasks. These will be re-evaluated during therapy, and all non-neuroimaging measures will be repeated after the rehabilitation program. Statistical analyses will comprise multivariate analysis of variance, general linear models, classification algorithms, structural equation models, least absolute shrinkage selection operator principal component regression (LASSO-PCR), cluster analysis and latent class growth analysis (LCGA).

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Inequalities in physical fitness in children with hearing loss: a systematic review and meta-analysis with implications for inclusive physical education and school curriculum

Diaz-Franco, M. V.; Caniuqueo-Vargas, A.; Lasekan, O. A.; Castillo-Sarmiento, C. A.; Rodriguez-Martin, B.

2026-06-09 otolaryngology 10.64898/2026.06.08.26355131 medRxiv
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Background: Childhood and adolescent hearing loss affects not only communication and cognitive development but also motor skills and school participation. Consequently, it generates inequalities in learning and educational inclusion. Nevertheless, no systematic review has yet analyzed these differences from an inclusive education perspective. Methods: A systematic review with meta-analysis was conducted following PRISMA guidelines and registered in PROSPERO. Observational studies comparing physical fitness between children and adolescents with hearing loss and their hearing peers were included. Methodological quality was assessed using the Newcastle--Ottawa Scale, and standardized effect sizes were calculated with a random-effects model. Results: Five studies (n=404) were analyzed. Findings revealed significant differences in strength, agility, speed, and balance. Moreover, the meta-analysis showed a large standardized effect favoring hearing children (ES=-2.35; 95% CI: -3.34 to -1.37). Conclusions: Children and adolescents with hearing loss present significantly lower physical fitness, which may affect the planning of physical education activities if their capacities are misinterpreted. Implementing inclusive and adapted strategies within the school curriculum is essential to ensure equal opportunities, improve physical fitness, and promote educational equity.

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Sensorimotor recovery and neuropathic pain reduction after remotely delivered cognitive multisensory rehabilitation or remotely delivered exercise in adults with spinal cord injury: a pilot clinical trial.

Van de Winckel, A.; Herrmann, A. A.; Carpentier, S. T.; Bottale, S.; Lopez, R. L.; Rapacz, A. D.; Larson, S. J.; Deng, W.; Zhang, L.; Hendrickson, T. J.; Mueller, B. A.; Nourian, R.; Morse, L. R.; Lim, K. O.

2026-06-09 rehabilitation medicine and physical therapy 10.64898/2026.06.02.26354574 medRxiv
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Introduction: Reduced or lost sensation and movement after a spinal cord injury (SCI) impairs the brain s ability to accurately localize paralyzed body parts, causing deficits in its internal body map, or mental body representations (MBR). These deficits hinder functional recovery and contribute to neuropathic pain. Medications for neuropathic pain are often ineffective and carry side effects. Our pilot trials found that in-person Cognitive Multisensory Rehabilitation (CMR), a physical therapy restoring MBR, led to prolonged pain reduction, improved sensorimotor function, and enhanced brain function, to greater extent than adaptive fitness. To explore more accessible interventions for those in rural areas or with transportation challenges, we examined whether 12 weeks of remotely delivered CMR or exercise would (1) improve function and reduce pain; (2) increase brain activity and connectivity related to sensorimotor function and MBR in adults with SCI. Methods: Of 19 adults with SCI who consented, 15 (51+/-15 years old, 8+/-10 years post-SCI) were randomized to 12 weeks of remotely delivered CMR or exercise (45min, 3x/week). Eight reported neuropathic pain equal or greater than 3/10. The Numeric Pain Rating Scale (NPRS), ASIA Impairment Scale (AIS), and Neuromuscular Recovery Scale (NRS) assessed pain and sensorimotor function at baseline, post-intervention, and 6-month follow-up. Functional MRI included resting-state and four tasks: imagining feeling the left leg, imagining moving the left leg, whole-body movement imagery, and a sensation task. Results: After CMR (n=8), participants improved on AIS (large effect sizes: touch: d=1.30; pinprick: d=1.21; lower limb motor function: d=1.83). Exercise (n=7) produced smaller improvements (touch: d=0.35; pinprick: d=0.36; lower limb motor function: d=0.80). CMR showed greater NRS effect sizes (core: d=1.48; upper limb: d=0.69; lower limb: d=1.25) than exercise (core: d=0.31; upper limb: d=0.74; lower limb: d=0.83). Benefits persisted at follow-up for both AIS and NRS, especially in the CMR group. Highest neuropathic pain intensity decreased in both groups post-intervention (CMR: d=-0.61; exercise: d=-0.73) and at 6-month follow-up (CMR: d=-0.55; exercise: d=-0.55). Unlike previous studies, group effects for CMR were not found due to high heterogeneity. Increased task-based activation, including in the lateral occipital cortex involved in visual body perception and spatial awareness, was seen for the exercise group (n=5). Discussion: These preliminary results support the potential of remotely delivered CMR and exercise to improve function and reduce neuropathic pain in adults with SCI, highlighting the need for larger trials. Clinicaltrial.gov: NCT05870189

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Neural basis of successful DBS for OCD after failed capsulotomy

Ryan, M. A.; El Jammal, R.; Soubra, S.; Paulo, D.; Bentley, J. H.; Hamre, T. A.; Giridharan, N.; Suzuki, H.; Vanegas Arroyave, N.; Storch, E. A.; Banks, G. P.; Goodman, W. K.; Provenza, N. R.; Sheth, S. R.; Heilbronner, S. R.

2026-06-10 neurology 10.64898/2026.06.08.26355178 medRxiv
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Background: Obsessive-compulsive disorder (OCD) is characterized by disturbing thoughts (obsessions) that initiate anxiety-reducing thoughts or behaviors (compulsions). For patients with treatment-resistant OCD (tr-OCD), neuromodulation techniques, like capsulotomy (a lesion in the anterior limb of the internal capsule) and deep brain stimulation (DBS), have emerged as interventions that likely regulate connectivity between the prefrontal cortex (PFC) and subcortical targets. Three patients (Cap-DBS1-3) underwent a failed capsulotomy followed by successful DBS. Here, we aimed to understand the brain connections disrupted by failed capsulotomy vs modulated by successful DBS. Methods: We used diffusion-weighted magnetic resonance imaging (dMRI) tractography in a control cohort with tr-OCD (n=12) and in two of the Cap-DBS patients themselves to determine connectivity profiles of the capsulotomy, volume of tissue activated (VTA), and potentially necessary tracts (VTA minus capsulotomy tracts). We used whole-brain, PFC-focused, and subcortically-focused tractography algorithms to fully explore the space of possible connections. Results: Capsulotomy regions-of-interest (ROIs) connected with a variety of PFC and subcortical regions. VTA ROIs and potentially necessary tracts had limited and inconsistent PFC connectivity but substantial subcortical connectivity. While correlated to the average OCD connectome (r = 0.214, 95% CI [0.177, 0.251]; r = 0.756, 95% CI [0.739, 0.772]), the Cap-DBS connectomes had many edges that were stronger (z-score > 3). Conclusions: The connectivity profile of potentially necessary tracts for successful DBS treatment after failed capsulotomy revealed a surprising proportion of subcortical regions and inconsistent PFC involvement, highlighting an often-ignored set of connections that may be critical to effective DBS.

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Improving Motivation in Post-stroke Apathy with Repetitive Transcranial Magnetic Stimulation (IMPART): A Phase-I Pilot Trial

Seidman, M.; Grewal, P.; Bowyer, C.; Dickens, I.; Eade, J.; Collins, E.; Patel, C. Y.; Arias Velasquez, D. E.; George, M. S.; Antonucci, M. U.; Caulfied, K. A.; McTeague, L. M.

2026-06-05 neurology 10.64898/2026.06.01.26354398 medRxiv
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Background: Post-stroke apathy (PSA) is a common, disabling syndrome with few evidence-based treatment options. We evaluated the safety, feasibility, acceptability, and evidence of effects of a three-day accelerated intermittent theta burst stimulation-repetitive transcranial magnetic stimulation (iTBS-rTMS) protocol targeting the left dorsomedial prefrontal cortex (dmPFC) in chronic stroke survivors with apathy. Methods: Stroke survivors with symptomatic apathy received open-label iTBS-rTMS at the left dmPFC (21,600 pulses across 36 sessions; 3 treatment days; 12 sessions/day within one week). Safety endpoints included adverse events, neuroradiological findings, and objective cognitive performance. Secondary outcomes included measures of apathy and other neuropsychiatric symptoms as well as psychosocial functioning, including quality of life and caregiver burden. Participants were followed up for one month. Results: Fourteen participants (mean age = 61.8 {+/-} 14.0 years; mean time since stroke = 55.6 {+/-} 31.6 months) completed the iTBS-rTMS treatment course. No serious adverse events occurred. Participants rated the treatment as highly acceptable, and cognitive performance was stable from pre- to post-rTMS with no treatment-related changes on structural MRI. Regarding apathy, participants had significant improvements with moderate to large effect sizes on the Lille Apathy Rating Scale (LARS), on both self (d = 0.78) and caregiver-rated versions (d = 1.28), p<0.05 pretreatment-to-one-month follow-up. In addition, secondary measures of psychosocial function also showed improvement with moderate to large effect sizes (Stroke Specific Quality of Life Scale: d = 0.62; Zarit Burden Interview: d = 0.72), and the Brief Inventory of Psychosocial Function: d = 0.89). Conclusions: In chronic stroke survivors with PSA, accelerated iTBS-rTMS targeting the left dmPFC appears to be safe, feasible, tolerable, and highly acceptable, with preliminary evidence suggesting a potential role in reducing apathy and secondarily promoting improvements in quality of life, caregiver burden, and broader psychosocial function.

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Safety and Tolerability of Low Intensity Focused Ultrasound to the Anterior Insula in Patients with Fibromyalgia

Kapoor, A.; Ni, Y.; Isaac, G.; Keyes, D. C. V.; Russo-Stringer, E. A.; Legon, W.

2026-06-09 pain medicine 10.64898/2026.06.01.26354382 medRxiv
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Background: Low-intensity focused ultrasound (LIFU) is an emerging noninvasive neuromodulation technique capable of targeting deep cortical and subcortical structures with high spatial precision. In healthy human volunteers, LIFU has demonstrated a favorable safety and tolerability profile across multiple studies. However, its safety and tolerability in clinical populations remains poorly characterized, representing a critical barrier to clinical translation. Here, we prospectively evaluate the safety and tolerability of LIFU targeting the left dorsal anterior insula (dAI) in patients with fibromyalgia (FM). Methods: In a single-blind, sham-controlled, within-subjects crossover design, 13 individuals with FM (43.1 +/- 13.2 years; 12 female) received 10 minutes of active LIFU (500 kHz, 1 kHz PRF, 36% duty cycle, 4.2 W/cm2 Isppa; 100 x 1-second pulse trains with a 5-second inter-train interval) targeting the left dorsal anterior insula (dAI) or sham on separate visits. Safety was evaluated through neuroradiological review of post vs. pre LIFU FLAIR MRI, quantitative voxel-wise FLAIR analysis, and patient report of symptoms (ROS). Tolerability was assessed using an experience assessment. Efficacy of the LIFU intervention was assessed using quantitative sensory testing (QST) including temporal summation of pain (TSP) and conditioned pain modulation (CPM). Results: Neuroradiological review identified no new evidence of edema, microhemorrhage, acute ischemia, or white matter injury on post-LIFU structural imaging. Quantitative FLAIR analysis using contralateral-mirror-referenced relative FLAIR (rFLAIR) showed no significant within-subject change in the stimulated beam volume (delta rFLAIR = 0.002 +/- 0.025, t(12) = 0.30, P = 0.769, Cohen's dz = 0.08). No serious adverse events were documented and ROS indicated no change due to LIFU sonication. Participants rated the procedure as comfortable and could not distinguish active from sham LIFU. LIFU did not result in statistically significant changes for TSP (p = 0.797) or CPM (p = 0.465). Conclusions: Ten minutes of LIFU targeting the left dAI was safe and well tolerated in individuals with FM, with no neuroradiological or quantitative MRI evidence of tissue effects and no serious adverse events. Blinding was preserved, and participants rated the procedure as comfortable. Although no significant changes were observed in experimental pain measures, these findings support the feasibility of targeting deep salience and pain amplification circuitry with LIFU in patients with FM and provide a foundation for adequately powered efficacy trials.

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Watching the FIFA World Cup and Adult Sleep Quality: A Cross-Sectional Online Survey

Aljamaan, F.; Alanteet, A. A.; Chaiah, Y.; Dasuqi, S. A.; Alarabi, M. A.; Saeed, E.; Al-khatib, S. M.; Darweesh, A. A.; Raina, M.; Saad, K.; Alhasan, K.; BaHammam, A. S.; Temsah, M.-H.

2026-06-08 sports medicine 10.64898/2026.06.07.26355072 medRxiv
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Major international sporting events frequently impose exogenous demands that challenge adult circadian rhythms, often leading to the misalignment of sleep-wake cycles and social schedules. This cross-sectional study investigated the impact of the FIFA 2022 World Cup on adult sleep patterns to assess the prevalence and determinants of tournament-associated circadian disruption. Through an online survey, we captured data on sleep duration, timing, and subjective quality from a diverse adult population using Pittsburgh Sleep Quality Index (PSQI) score. The results indicate that 81.3% had high problematic sleep according to PSQI scores, while only 9% perceived that their sleep pattern was impacted by watching matches during the tournament. While 83.7% of the participants had low or mild anxiety according to GAD-7 scores, we found that GAD-7 scores correlated significantly with PSQI scores. Married participants had significantly lower PSQI scores (RR 0.856, p = .005), while those who reported that their sleep hours had changed during the tournament had significantly higher PSQI scores (1.180, P-value <0.001). Males reported a significantly high impact of the tournament on their sleep (OR 2.622, P-value <0.001). In conclusion, our data demonstrate a discrepancy between self-perception of sleep quality and self-rated assessment by PSQI scores, as well as the substantial impact of major international sporting events on adult sleep hygiene. The results provide data-driven insights helpful in evaluating potential circadian risks and informing public health strategies for major sporting events such as the FIFA world cup.

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Surviving Severe Acute Brain injury: Care trajectories and missed opportunities

Bunker, A. L.; Engelberg, R. A.; Holloway, R. G.; Creutzfeldt, C. J.

2026-06-09 neurology 10.64898/2026.06.01.26354480 medRxiv
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INTRODUCTION Severe acute brain injury (stroke, traumatic brain injury or hypoxic-ischemic encephalopathy; SABI) is increasingly recognized as a chronic condition with care and communication needs beyond the initial hospitalization. This study aimed to characterize post-acute care patterns among SABI survivors, focusing on healthcare utilization and outpatient communication. METHODS Data were collected from a prospective cohort of hospitalized SABI patients using surveys, chart reviews, and the ED Information Exchange database. Socioeconomic disadvantage was assessed using the Area Deprivation Index (ADI), and qualitative analysis of outpatient notes examined conversations around palliative care needs and goals-of-care. RESULTS Two-thirds of patients (140/222) survived until discharge, primarily to nursing facilities (39%) or inpatient rehabilitation (38%). Among 109 with one-year follow-up, there were 89 hospitalizations, 104 ED visits, and 28 deaths. Patients from the most disadvantaged neighborhoods had significantly higher odds of rehospitalization or ED use within 30 days (OR 3.37, p=0.036). ADI was not linked to one-year utilization. seen outpatient by primary care (40%), neurology/neurosurgery (57%), and palliative care (1%), but conversations rarely revisited prognosis or goals-of-care. CONCLUSIONS Our findings highlight the need for improved long-term care planning and communication, particularly for socioeconomically disadvantaged survivors of SABI.

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Oxygen-based endotypes of Obstructive Sleep Apnea

Wellman, A.; Messineo, L.; Azarbarzin, A.; Esmaeili, N.; Aishah, A.; Vena, D.; Sumner, J.; White, D.; Sands, S.

2026-06-04 respiratory medicine 10.64898/2026.06.03.26354835 medRxiv
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Objective: Several endotypes contribute to the development of Obstructive Sleep Apnea (OSA). However, efforts to measure these endotypes have been challenging. In this paper, we propose a new method that overcomes some of these challenges. Methods: To test the feasibility of this new method, data from the Sleep Heart Health Study (SHHS) were analyzed and two oxygen-based endotypes were identified and plotted on a graphical model: the steady-state SpO2 and the SpO2 arousal threshold. The first is the oxygen saturation that would occur during sleep if there were no arousals, and it is a measure of upper airway collapsibility (a more collapsible airway produces a lower SpO2). The latter is the oxygen saturation that triggers arousals. These endotypes were validated by assessing their ability to detect positional and state-related changes in airway collapsibility and arousal threshold. Results: The study showed that it was feasible to measure oxygen-based endotypes in 95% of SHHS participants. As expected, steady-state SpO2 was lower during supine vs. non-supine sleep, as well as during REM vs. NREM sleep. Also, the SpO2 arousal threshold was similar between supine and non-supine sleep. However, SpO2 arousal threshold was not lower in REM sleep vs. NREM sleep. Therefore, in 3 of the 4 conditions, the oxygen-based endotypes moved in the expected direction due to positional or sleep state changes. Conclusion: Although further validation experiments are required, this study indicates that OSA endotyping using the pulse oximetry signal is feasible. The oxygen-based endotypes could be used to aid therapeutic decision making.

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Ultra-low-field MRI as a tool for measuring brain development in at-risk children in LMICS: feasibility, validity and clinical relevance.

Bradford, L. E.; Ringshaw, J. E.; Malaba, T. R.; Bourke, N. J.; Wedderburn, C. J.; Williams, S. C.; Deoni, S.; Reynolds, H.; Read, J.; Read, L.; Waitt, C.; Mrubata, M.; Stemmet, L.-A.; Davel, L.; Colbers, A.; Wang, D.; Khoo, S.; Myer, L.; Donald, K. A.

2026-06-05 hiv aids 10.64898/2026.06.02.26354785 medRxiv
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Background Children in low- and middle-income countries (LMICs) face an elevated risk of developmental delay, yet scalable neuroimaging tools to study early brain development in these contexts remain limited. Children who are HIV-exposed but uninfected (CHEU) represent a growing population with evidence of language and motor delays and altered brain development compared with children who are HIV-unexposed (CHU). Ultra-low-field (ULF) MRI offers a more affordable alternative to conventional high-field (HF) MRI, but its application in early childhood remains underexplored. Methods We compared brain volumes derived from ULF (64mT) and HF (3T) MRI in South African CHEU and CHU as part of the DolPHIN-2 PLUS study. Volumetric segmentation was performed using FreeSurfer v7.4.1 and SynthSeg on the Flywheel platform. Agreement between modalities was assessed using Pearsons and Lins concordance correlation coefficients across global and subcortical regions. Associations between ULF-derived brain volumes and developmental outcomes, measured by the Bayley Scales of Infant Development, Third Edition, were evaluated using partial correlations adjusted for sex and age. Results Forty-five children (9 CHEU, 36 CHU; mean age 45.6 months) had paired ULF and HF scans of usable quality. Strong correlations were observed between ULF and HF volumes for global white and grey matter regions (r > 0.92) and larger subcortical grey matter structures such as the thalamus, caudate, and putamen (r = 0.86-0.89). Moderate-to-weak correlations were evident in smaller structures (hippocampus, pallidum, amygdala). ULF underestimated most grey matter volumes, and overestimated total white matter volume relative to HF. ULF-derived global and subcortical volumes were associated with receptive and expressive communication (r = 0.34-0.59, all p < 0.05). Conclusions ULF MRI produces brain volume estimates comparable to HF MRI and captures meaningful associations with early language development. These findings support ULF MRI as a feasible and scalable tool for studying neurodevelopment in vulnerable paediatric populations in LMICs.

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Multivariate Machine Learning Analysis of M-ECG-derived Heart Rate Variability in TBI Veterans, With and Without Comorbid PTSD

Izadysadr, A.; Bagherzadeh, H. S.; Rowland, J.; Martindale, S. L.; Stapleton-Kotloski, J. R.; Godwin, D.

2026-06-08 psychiatry and clinical psychology 10.64898/2026.06.05.26354915 medRxiv
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Traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) frequently co-occur in Veterans, producing overlapping symptoms and shared autonomic dysregulation. Heart rate variability (HRV) offers a noninvasive measure of autonomic function. Univariate HRV analyses often fail to capture complex, multivariate patterns associated with comorbidity. This study applied machine learning to HRV features extracted from MEG-derived electrocardiogram (M-ECG) signals to differentiate Veterans with TBI alone (TBI-alone; n = 42) from those with comorbid PTSD (TBI+PTSD; n = 40). Time-domain, frequency-domain, geometric, and nonlinear HRV metrics were analyzed using nested cross-validated Random Forest and XGBoost classifiers, with Boruta-based feature selection and SHapley Additive exPlanations for model interpretability. Both classifiers achieved above-chance discrimination (Random Forest AUC = 0.663; XGBoost AUC = 0.635). Multivariate models identified distributed autonomic signatures in TBI+PTSD, including altered sympathovagal balance, increased low-frequency proportion, and greater heart rate complexity. In contrast, univariate HRV differences were subtle and did not survive correction for multiple comparisons. These findings demonstrate how using multivariate machine learning HRV analysis could help with detecting comorbidity-specific autonomic patterns, suggesting that HRV-derived signatures may serve as exploratory biomarkers for risk assessment and targeted interventions in Veterans with TBI and PTSD.

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Development of an Open-Access Action Observation Video Library for Upper Limb Motor Rehabilitation

Madison, M.; Wheaton, L. A.; Rowe, V.

2026-06-10 rehabilitation medicine and physical therapy 10.64898/2026.06.10.26355108 medRxiv
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Background: Occupational therapists can improve stroke survivors hand and arm movement and participation in daily activities through action observation (AO). AO involves watching another persons hand or arm complete a movement or task. While research generally supports the use of AO with stroke survivors, there are limited AO videos are available to occupational therapists which makes applying AO challenging. Objective: The purpose of this work is to develop structured and widely accessible tool to support access to AO for stroke survivors, occupational therapists, and researchers. Methods: To develop an AO video library for stroke rehabilitation, functional and non-functional upper limb task deficits were first identified through clinical observations and clinician interviews to establish a prioritized list of daily activities. In collaboration with media production specialists, healthy adult volunteers were recruited and filmed performing these tasks from both first- and third-person perspectives. The recorded videos were then systematically edited, enhanced with instructional title slides, and distributed via a public YouTube channel for clinical application and a categorized digital repository for research purposes. Results: Initial assessments revealed a complete lack of familiarity, awareness, and utilization of AO resources among local occupational therapists, despite high perceived clinical utility. To address this gap, a final library of 150 tasks was established, resulting in the production of 419 finalized, standardized videos featuring six healthy volunteers. For clinical application, these videos were hosted on a free, public YouTube channel organized into 18 functional playlists, while a parallel set was structured into distinct movement categories for research repository storage. Conclusion: By providing a structured and highly accessible tool, this repository enables clinicians, researchers, and caregivers to readily implement evidence-based action observation interventions in both clinical and home settings.

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Validation of the Fremantle Perineal Awareness Questionnaire (FrePAQ) in women with Chronic Pelvic Pain

Bond, J.; O'Connel, N.; Wand, B.; Chalmers, J.; Kal, E.

2026-06-08 pain medicine 10.64898/2026.06.05.26354913 medRxiv
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Chronic pelvic pain (CPP) affects up to 26% of women worldwide. While its pathophysiology is poorly understood, disturbances in body perception have been identified in various similar chronic musculoskeletal disorders. The Fremantle Perineal Awareness Questionnaire (FrePAQ) is a novel tool designed to specifically assess disturbed body perception in the pelvic region, but its structural validity and reliability require formal evaluation. Methods: Patient partners with lived experience contributed to study design. Participants with (n=417 and without (n=277) chronic pelvic pain completed the FrePAQ at baseline, as well as one week later. We assessed the validity and reliability of the FrePAQ following COSMIN guidelines for Classical Test Theory. Results: The validated FrePAQ comprises a two factor model, with a six item Distress & Disconnection (D&D) subscale and a two item Size & Shape (S&S) subscale. Confirmatory analysis showed excellent fit (CFI = .988; RMSEA = .048) and measurement invariance between diagnostic groups. Internal consistency was high (cronbach alpha = .838 CPP, .819 controls). Test retest reliability was high for D&D (ICC = .863) and acceptable for S&S (ICC = .695). FrePAQ scores showed a weak to moderate correlation with pain scores (r = .234 to .255), psychological distress (r = .226 to .443), and functional impact (r = .172 to .295), particularly for the D&D subscale. Conclusion: The FrePAQ is a reliable and valid instrument to measure perineal perceptual disturbances in CPP. Future research will evaluate the tools potential to support phenotyping and guide individualised interventions. Improved understanding of body perception disturbance in CPP can enhance diagnosis and treatment precision.

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Development of a Novel Blood-Based Assay for Brain-Derived Tau and Its Validation in Traumatic Brain Injury

Balogun, W. G.; Zeng, X.; Nafash, M. N.; Sehrawat, A.; Shi, R.; Svirsky, S. E.; Okonkwo, D. O.; Puccio, A. M.; Karikari, T. K.

2026-06-10 neurology 10.64898/2026.06.05.26354965 medRxiv
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Brain-derived tau (BD-tau) is an emerging blood-based biomarker for neurodegeneration, yet there are currently limited well validated BD-tau assays available for research and clinical use. To enhance access to this vital biomarker for neurological disorders including traumatic brain injury (TBI), we developed a novel blood-based immunoassay for BD-tau on the ultra-sensitive Quanterix HD-X platform using Single Molecule Array technology. Analytical validation assessed dilution linearity, specificity, precision, detection limits, and spike recovery, each recording robust metrics in agreement with international expert recommendations. The assay demonstrated robust validation metrics, achieving between-run stability of 95% when analyzing aliquots from six independent plasma and serum samples across five analytical runs. It also showed strong dilution linearity when diluted four-fold and achieved over 90% recovery when spiked with cerebrospinal fluid. Next, we evaluated the clinical utility of the assay in cohorts of individuals with traumatic brain injury (TBI), where strong performances were recorded whether using the 2-step or 3-step assay formats ({rho}= 0.94; p < 0.0001). Furthermore, plasma BD-tau distinguished samples from TBI patients based on time from injury and severity (AUC=0.93). Plasma BD-tau differentiated between favorable and unfavorable functional outcomes in the acute-severe group. Our findings underscore the significant potential of the BD-tau assay as a biomarker for TBI in the severe phase.

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Exploring the role of binge eating in the association between ADHD and BMI: A twin study

YOU, Y.; McAdams, T.; Oginni, O.; Liu, C.; Herle, M.; Zavos, H.

2026-06-05 psychiatry and clinical psychology 10.64898/2026.05.28.26354354 medRxiv
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Objective: ADHD has been associated with obesity indicators, including BMI, across the lifespan. A possible mechanism linking ADHD and BMI is binge eating. Previous research has found associations between ADHD, binge eating and BMI. However, the role of genetic and environmental influences on these associations remains unclear. Method: We utilized data from the Twins Early Development Study (TEDS), comprising 3,675 monozygotic and 7,063 dizygotic twin pairs. ADHD symptoms in childhood and adolescence were assessed using parent-reported questionnaires. Adult ADHD symptoms were measured using both self-report and parent-report questionnaires. Phenotypic mediation models examined whether binge eating mediated the association between ADHD and BMI, without controlling for genetic confounding. Subsequently, the etiological architecture underlying the associations among the three traits across childhood, adolescence, and adulthood were investigated by incorporating genetic and environmental influences into the models. Results: Binge eating significantly mediated the association between ADHD symptoms and BMI in both adolescence and adulthood. However, these mediation effects were no longer present once genetic and environmental influences were incorporated into the models. The best-fitting model in childhood, adolescence and adulthood was Cholesky decomposition models, where covariance between traits was explained by shared aetiology. Conclusions: This twin study reveals shared liability across ADHD, binge eating, and BMI. The mediating role of binge eating in the relationship between ADHD symptoms and BMI was largely confounded by shared genetic influences. Intervention strategies could focus more on common underlying behavioural and self-regulatory mechanisms across these traits, as well as placing more emphasis on symptom patterns within families.

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Global practices in paediatric olfactory dysfunction: a cross-sectional survey of paediatric ENT surgeons

Spencer, G. M.; Karim, K.; Dzioba, A.; Graham, M. E.; You, P.; Hummel, T.; Gellrich, J.; Coyle, P.; Burns, H.; Peer, S.; Zawawi, F.; Lechien, J. R.; Schriever, V. A.; Bhargava, E. K.; Whitcroft, K. L.

2026-06-06 otolaryngology 10.64898/2026.06.04.26354942 medRxiv
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Background: Olfactory dysfunction (OD) in children remains underdiagnosed and poorly characterised. Despite its known impacts on nutrition, quality of life, safety awareness, and psychosocial development, no standardised diagnostic or management pathway currently exists for paediatric OD. This study aimed to characterise global practice patterns and identify diagnostic and therapeutic challenges unique to paediatric care. Methodology/Principal: A 44-item cross-sectional online survey was distributed to a verified international network of paediatric otolaryngologists across 36 countries via a closed professional platform. The survey assessed five domains: diagnostic practices, management protocols, technology and innovation, education and training, and barriers to effective care. Regional grouping was used to facilitate meaningful statistical comparisons. Categorical variables were evaluated using chi-square tests, with odds ratios and 95% confidence intervals reported for significant findings. Results: Of 351 potential participants, 167 responded (47.6% response rate). Most respondents (83%) reported seeing children with OD, yet 95% saw fewer than ten such patients annually. Psychophysical testing was never performed by 54.8% of respondents, while 88.4% routinely ordered cross-sectional imaging. Testing frequency increased significantly with patient age (Cochran's Q p<0.001). The most common barriers to objective testing were insufficient training (44.3%), time constraints (29.9%), and funding limitations (28.1%). Multidisciplinary collaboration was negligible. Significant regional variation was observed across most practice domains. Conclusions: Paediatric OD care is characterised by functional underinvestigation, fragmented multidisciplinary collaboration, and systemic educational gaps. These findings support urgent development of standardised clinical guidelines, age-appropriate validated assessment tools, and formal interdisciplinary care pathways.

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Three-Month Observational Data for the MPS IIIB Sentinel Subject Following AAV9 Mediated Gene Therapy

Ma, X.; Gu, R.; Ma, W.; Xu, Q.; Wang, R.; Wang, W.; Liang, M.; Liu, X.; Yang, X.; Zhuang, L.; Zhang, W.; Zeng, X.; Xu, J.; Xu, X.; Wu, Z.; Xia, Y.; Liu, Y.; Zhou, J.; Zhu, X.; Wang, H.; Dong, Z.; Yang, W.; Dai, Y.; Pan, X.; Li, X.; Wang, Y.; Dong, X.; Wu, X.; Feng, Z.

2026-06-09 neurology 10.64898/2026.06.01.26354386 medRxiv
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Background: Mucopolysaccharidosis type IIIB (MPS IIIB) is a devastating neurodegenerative lysosomal storage disorder caused by alpha-N-acetylglucosaminidase (NAGLU) deficiency. There is currently no approved therapy. We report the 3-month outcomes of a novel intracerebroventricular (ICV) gene therapy in a child with MPS IIIB. Methods: In an open-label, single-center, investigator-initiated trial (ChiCTR2600121466), a single dose of RDGT-101 (2.0E14; vg of an AAV9 vector encoding human NAGLU) was administered via ICV infusion. Primary outcomes were safety and tolerability. Secondary outcomes included serum NAGLU activity, urinary heparan sulfate (HS) excretion, and neurocognitive function. Exploratory analyses included hematological parameters. Results: The patient achieved serum NAGLU activity (17.06 nmol/mL/hour) approaching that of healthy controls (17.75 {+/-} 1.37 nmol/mL/hour) by Month 3, accompanied by a 58.4% reduction in urinary HS. Clinically, previously severe hand and toe contractures resolved, allowing for full extension. Neurocognitive improvements were observed, including clear articulation, logical conversation, and sustained eye contact. Hematological analyses revealed normalized red blood cell indices and improved iron utilization. No dose-limiting toxicities, serious adverse events, or clinically significant laboratory abnormalities were observed. Conclusions: A single ICV infusion of RDGT-101 was safe and well-tolerated in this patient with MPS IIIB. Early biochemical correction was accompanied by marked improvements in somatic, neurocognitive, and hematological parameters. These findings support further investigation of ICV AAV9 gene therapy for MPS IIIB.