Search results
Found 23144 matches for
Self-supervised segmentation and characterization of fiber bundles in anatomic tracing data
Anatomic tracing is the gold standard tool for delineating brain connections and for validating more recently developed imaging approaches such as diffusion MRI tractography. A key step in the analysis of data from tracer experiments is the careful, manual charting of fiber trajectories on histological sections. This is a very time-consuming process, which limits the amount of annotated tracer data that are available for validation studies. Thus, there is a need to accelerate this process by developing a method for computer-assisted segmentation. Such a method must be robust to the common artifacts in tracer data, including variations in the intensity of stained axons and background, as well as spatial distortions introduced by sectioning and mounting the tissue. The method should also achieve satisfactory performance using limited manually charted data for training. Here, we propose the first deep-learning method, with a self-supervised loss function, for segmentation of fiber bundles on histological sections from macaque brains that have received tracer injections. We address the limited availability of manual labels with a semi-supervised training technique that takes advantage of unlabeled data to improve performance. We also introduce anatomic and across-section continuity constraints to improve accuracy. We show that our method can be trained on manually charted sections from a single case and segment unseen sections from different cases, with a true positive rate of (Formula presented.) 0.80. We further demonstrate the utility of our method by quantifying the density of fiber bundles as they travel through different white-matter pathways. We show that fiber bundles originating in the same injection site have different levels of density when they travel through different pathways, a finding that can have implications for microstructure-informed tractography methods. The code for our method is available at https://github.com/v-sundaresan/fiberbundle_seg_tracing.
Introducing the Tele-OCS: Preliminary evidence of validity for a remotely administered version of The Oxford Cognitive Screen.
BACKGROUND: Remote cognitive assessments are increasingly used with the rising popularity of teleneuropsychology. Here, we evaluated the performance of the remotely administered Oxford Cognitive Screen (Tele-OCS) compared to in-person administration in adult stroke survivors. METHODS: 40 stroke survivors ( M age = 69.30, SD = 10.44; sex = 30% female) completed in-person and remote versions of the OCS on average 30 days apart, with different trained examiners. The order of administration was counterbalanced. Cohen's d estimates were used to compare performance between modalities. RESULTS: We found that the proportion of OCS subtasks impaired did not differ across modalities ( d
Addressing Inequalities in Long Covid Healthcare: A Mixed‐Methods Study on Building Inclusive Services
ABSTRACTBackgroundLong Covid (LC) significantly impacts health, economic and social activities. Women, deprived, learning disability, homeless and some minority ethnic populations have high prevalence rates but low access to support, indicating health inequities in LC care.AimTo identify health inequities in LC care and inclusion strategies that align with the priorities of people with LC.Design and SettingMixed‐methods study employing qualitative data from people with LC, professional experts, LC clinic staff and primary care data from North West (NW) London GPs.MethodQualitative interviews with 23 people with LC and 18 professional experts explored the experience of diagnosis and support for people from disadvantaged groups. Framework analysis identified themes that informed the subsequent collection of clinic and primary care data. Staff from 10 LC clinics across England provided survey and qualitative data describing their initiatives to identify and reduce inequalities. Descriptive quantitative analysis of NW London adult primary care records (n = 6078), linked to hospital use across England, explored LC diagnosis and care pathways for diverse groups of people with LC.ResultsStudy participants from disadvantaged groups reported delays in formal diagnosis and specialist referrals being initated and had low trust in healthcare services. They described difficulties in obtaining information, advice and support as barriers to access specialist referrals. LC clinics confirmed the under‐referral of those from the most disadvantaged groups compared to the general population. Primary care data confirmed under‐referral of people with LC to specialist clinics; however, incomplete data across the LC clinical pathway prevented an analysis of equity in referral patterns between population groups.Clinics used various strategies to improve access and increase the flow of disadvantaged groups from primary care to LC services. Interventions included data collection to identify underserved groups, targeting outreach to primary care and community providers, adapting clinic provision and developing care pathways involving multidisciplinary teams (MDTs), primary and secondary care practitioners and third sector organisations. These activities were not widespread, however, and were particular to a few clinics.ConclusionStrategies to improve access to LC healthcare provide a starting point to explore inclusive care pathways for people with LC from disadvantaged social groups. Future research should focus on the effectiveness of initiatives to increase access to specialist LC provision among disadvantaged groups and establish greater trust in healthcare providers.Priorities of People With LC for Healthcare PracticeThis study highlights the need for health system practitioners to identify under‐represented groups and target inclusion initiatives at these populations in sensitive and appropriate ways. Improved diagnosis and support for such populations would be helped by training health and social care practitioners to recognise and accept the accounts of people with LC about their symptoms. Protocols that support consistent practice in referrals for specialist care are also needed. People with LC from disadvantaged groups often lack access to evidence‐based sources of advice and information. Practitioners should provide information on LC while individuals are waiting to receive specialist care and should advocate for support from employers, including work modifications.Patient and Public ContributionPeople with lived experience of LC were involved in the study as members of the research team and LOCOMOTION Patient Advisory Group (PAG). The PAG was involved in the wider study design, including the initial grant application, attending proposal planning meetings and helping to develop the research aim, objectives and questions. During the course of the study, the PAG met quarterly with each other and at least monthly with other research team members to review progress and feed into data collection and analysis processes. PAG members also attended a Quality Improvement Collaborative meeting involving academics and LC practitioners, which discussed initial findings from data analysis of qualitative interviews on LC inequalities. Through these meetings, the group supported and oversaw the study as a whole in terms of how data was collected, recruitment of participants, involvement in data analysis and interpretation, as well as providing more specific advice to all the individual workstreams within the study. A PPI facilitator within the study team provided training and support to PAG members in these areas and was available to respond to other needs expressed by the group. PAG members have also been involved in organising and contributing to a wide range of study dissemination events. PAG involvement throughout the study has ensured that the research is aligned with the key research priorities of people diagnosed with LC as well as those with LC symptoms but no formal diagnosis. PAG members were recruited through and linked to the LC clinics involved in the study and have helped disseminate study findings to local clinical practice, the lay public and other LC centres with which they are involved. S.E. is a PAG member from a minority ethnic background and a co‐author on the paper. She has been involved in overseeing and supporting data collection and interpretation relating to inequalities affecting people with LC and has contributed to the preparation of this manuscript from an early draft to production of the final version.
Clinical Relevance of 'Cap' and 'Track' Development after Recent Small Subcortical Infarct.
OBJECTIVE: After a recent small subcortical infarct (RSSI), some patients develop perilesional or remote hyperintensities ('caps/tracks') to the index infarct on T2/FLAIR MRI. However, their clinical relevance remains unclear. We investigated the clinicoradiological correlates of 'caps/tracks', and their impact on long-term outcomes following RSSI. METHODS: We identified participants with lacunar stroke and MRI-confirmed RSSI from 3 prospective studies. At baseline, we collected risk factors, RSSI characteristics, small vessel disease (SVD) features, and microstructural integrity on diffusion imaging. Over 1-year, we repeated MRI and recorded 'caps/tracks' blinded to other data. We evaluated predictors of 'caps/tracks', and their association with 1-year functional (modified Rankin Scale score ≥2), mobility (Timed Up-and-Go), cognitive outcomes (Montreal Cognitive Assessment [MoCA] score <26), and recurrent cerebrovascular events (stroke/transient ischemic attack/incident infarct) using multivariable regression. RESULTS: Among 185 participants, 93 (50.3%) developed 'caps/tracks' first detected at median 198 days after stroke. 'Caps/tracks' were independently predicted by baseline factors: larger RSSI, RSSI located in white matter, higher SVD score, and higher mean diffusivity in normal-appearing white matter (odds ratio [OR] [95% confidence interval {CI}], 1.15 [1.07-1.25], 6.01 [2.80-13.57], 1.77 [1.31-2.44], 1.42 [1.01-2.03]). At 1 year, 'cap/track' formation was associated with worse functional outcome (OR: 3.17, 95% CI: 1.28-8.22), slower gait speed (β: 0.13, 95% CI: 0.01-0.25), and recurrent cerebrovascular events (hazard ratio [HR]: 2.05, 95% CI: 1.05-4.02), but not with cognitive impairment. INTERPRETATION: 'Caps/tracks' after RSSI are associated with worse clinical outcomes, and may reflect vulnerability to progressive SVD-related injury. Reducing 'caps/tracks' may offer early efficacy markers in trials aiming to improve outcome after lacunar stroke. ANN NEUROL 2025;97:942-955.
Yawning as Therapy? The Potential of the Conditioned Yawn Reflex as a Novel Treatment for Insomnia Disorder.
In 1986, Provine, the pioneer of yawning research wrote that 'Yawning may have the dubious distinction of being the least understood, common human behaviour' (p. 120); and so yawning remains some 40 years later, as something of a biological and social curiosity. However, this article examines contemporary scientific understanding of this age-old conundrum, proposing not only that yawning is a universal component of sleep's normal stimulus control paradigm, but that the conditioned yawn reflex might be harnessed to treat insomnia disorder. The core features of yawning as a ubiquitous, involuntary, periodic and conditionable behaviour; its associated actions on arousal, biofeedback and selective attention, as well as thermoregulation and airway patency; and its potential to signal and promote sleep engagement, lead to the proposition that the conditioned yawn reflex as therapy (CYRaT) is a feasible and potentially effective novel therapeutic for sleep-onset and sleep-maintenance insomnia disorder. Much research is required to test this hypothesis, but the article describes preliminary protocols for the administration and testing of CYRaT that might be utilised for this purpose.
A Validated Model to Predict Severe Weight Loss in Amyotrophic Lateral Sclerosis
ABSTRACTSevere weight loss in amyotrophic lateral sclerosis (ALS) is common, multifactorial, and associated with shortened survival. Using longitudinal weight data from over 6000 patients with ALS across three cohorts, we built an accelerated failure time model to predict the risk of future severe (≥ 10%) weight loss using five single‐timepoint clinical predictors: symptom duration, revised ALS Functional Rating Scale, site of onset, forced vital capacity, and age. Model performance and generalisability were evaluated using internal–external cross‐validation and random‐effects meta‐analysis. The overall concordance statistic was 0.71 (95% CI 0.63–0.79), and the calibration slope and intercept were 0.91 (0.69–1.13) and 0.05 (−0.11–0.21). This study highlights clinical factors most associated with severe weight loss in ALS and provides the basis for a stratification tool.
Cryoneurolysis: A Novel Treatment for Management of Spasticity. Presentation of a Case Series
Background: Spasticity is a motor phenomenon occurring in disorders of the central nervous system that impacts on active and passive function, and quality of life. Pharmacological, physical and surgical management options are available, each of which have limitations. Cryoneurolysis is a technique developed for the treatment of pain which involves the controlled freezing and thawing of peripheral nerves. Recent case reports and series have suggested it may offer a novel treatment approach for pain associated with spasticity. Objectives: To report on the evaluation of cryoneurolysis in the first cohort of patients treated in a UK spasticity clinic. Methods: Eight patients with a variety of neurological conditions (aged 25-75 years) underwent cryoneurolysis. Each had been receiving regular botulinum toxin injections and had ongoing treatment goals. All patients first underwent diagnostic nerve blocks with local anaesthetic to determine their appropriateness for the treatment. Cryoneurolysis was then performed with ultrasound and nerve stimulator guidance. Assessments included goal attainment, Modified Ashworth Scale (MAS), ArmA, LegA and the patient reported impact of spasticity scale (PRISM), alongside patient satisfaction and side effect questionnaires. Assessments were at baseline and at regular intervals over 9 to 12 months. Results: All patients attained at least one of their goals, with sustained effect for more than 6 months. MAS demonstrated mixed or modest improvements. Functional outcome measures (ArmA/LegA) showed several meaningful improvements, particularly in passive function. There was an indication of an improvement in PRISM across domains, which plateaued at 6 months. Post-procedure pain was the most common side effect but subsided in all affected patients by 3 months. Patient satisfaction was positive. Conclusions: Our findings contribute to a growing base of case reports and series suggesting that cryoneurolysis could be a potentially useful treatment modality for spasticity. Future controlled studies should aim to evaluate cost-effectiveness and compare with existing treatments.
Registered reports in neuropsychology: Insights from the burning houses study
We recently completed our first registered report project within a neuropsychological population (Moore et al., 2025). In this project, we set out to evaluate the replicability of the seminal case study by Marshall & Halligan (1988) on pre-attentive semantic processing in neglect, and replicated this effect under stringent experimental conditions. Our undertaking of this registered report study spanned over five years. In this viewpoint, we aim to share our personal reflections on this project in the hope that our experiences (and setbacks) can prove helpful for future studies aiming to conduct registered reports in neuropsychological populations. More broadly, our experience with this project provides a salient example of the challenges faced by registered report studies which may help account for the low uptake of this format in neuropsychology. Ultimately, we believe that encouraging adherence to fundamental open science practices including openly pre-registering plans and open reporting of data/code should be prioritised in neuropsychology and call for targeted discussions surrounding registered report formats specific to neuropsychological studies.
The rising incidence of stroke in the young: epidemiology, causes and global impact.
Although reductions in stroke incidence have been reported over recent decades particularly in high-income countries, there has been a worrying trend since the start of the 21st century: stroke incidence in younger individuals (< 55 years) has not showed a similar decrease than at older ages. In high-income countries, several population-based studies have found an increase in the incidence of stroke at younger ages since 2000, reaching up to 90% in Oxfordshire, UK (2010-2018 vs 1981-1986) and 97% in Cincinnati, US (2010 vs 1993-1994). A similar picture has also been documented in low- and middle-income countries, both in population-based studies (Joinville, Brazil, 35% increase in 2012-2013 vs 2005-2006) and in the Global Burden of Diseases Study. The exact reasons for this very different picture seen in younger individuals are unknown. One possibility is that traditional modifiable risk factors are increasingly prevalent and often undertreated at younger ages. However, studies have also found increases in the incidence of young-onset cryptogenic stroke and in people with no traditional modifiable risk factors, suggesting a role for emerging risk factors. Potential culprits might include air pollution, long working hours, psychosocial stress, prior autoimmune diseases, and illicit drug use, although further research is required to determine whether these emerging risk factors are causally related to stroke at younger ages. Without further intervention, the global burden of stroke at younger ages is projected to increase further in the coming years. Therefore, there is an urgent need to better understand the drivers of these time trends in incidence, to potentially alleviate the individual and societal impacts of stroke in the young. In this narrative review, we examine the recent global changes in stroke epidemiology at younger ages, their potential drivers, and their projected consequences.