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1.
Am Heart J ; 271: 164-177, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38395294

RESUMO

BACKGROUND: Atrial fibrillation (AF) increases the risk of death, stroke, heart failure, cognitive decline, and healthcare costs but is often asymptomatic and undiagnosed. There is currently no national screening program for AF. The advent of validated hand-held devices allows AF to be detected in non-healthcare settings, enabling screening to be undertaken within the community. METHOD AND RESULTS: In this novel observational study, we embedded a MyDiagnostick single lead ECG sensor into the handles of shopping trolleys in four supermarkets in the Northwest of England: 2155 participants were recruited. Of these, 231 participants either activated the sensor or had an irregular pulse, suggesting AF. Some participants agreed to use the sensor but refused to provide their contact details, or consent to pulse assessment. In addition, some data were missing, resulting in 203 participants being included in the final analyses. Fifty-nine participants (mean age 73.6 years, 43% female) were confirmed or suspected of having AF; 20 were known to have AF and 39 were previously undiagnosed. There was no evidence of AF in 115 participants and the remaining 46 recordings were non-diagnostic, mainly due to artefact. Men and older participants were significantly more likely to have newly diagnosed AF. Due to the number of non-diagnostic ECGs (n = 46), we completed three levels of analyses, excluding all non-diagnostic ECGs, assuming all non-diagnostic ECGs were masking AF, and assuming all non-diagnostic ECGs were not AF. Based on the results of the three analyses, the sensor's sensitivity (95% CI) ranged from 0.70 to 0.93; specificity from 0.15 to 0.97; positive predictive values (PPV) and negative predictive values (NPV) ranged from 0.24 to 0.56 and 0.55 to 1.00, respectively. These values should be interpreted with caution, as the ideal reference standard on 1934 participants was imperfect. CONCLUSION: The study demonstrates that the public will engage with AF screening undertaken as part of their daily routines using hand-held devices. Sensors can play a key role in identifying asymptomatic patients in this way, but the technology must be further developed to reduce the quantity of non-diagnostic ECGs.


Assuntos
Fibrilação Atrial , Eletrocardiografia , Estudos de Viabilidade , Programas de Rastreamento , Humanos , Fibrilação Atrial/diagnóstico , Masculino , Feminino , Idoso , Eletrocardiografia/instrumentação , Eletrocardiografia/métodos , Programas de Rastreamento/métodos , Programas de Rastreamento/instrumentação , Inglaterra , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais
2.
J Infect Dis ; 225(6): 1070-1080, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-32845969

RESUMO

BACKGROUND: In cerebral malaria, the retina can be used to understand disease pathogenesis. The mechanisms linking sequestration, brain swelling, and death remain poorly understood. We hypothesized that retinal vascular leakage would be associated with brain swelling. METHODS: We used retinal angiography to study blood-retinal barrier integrity. We analyzed retinal leakage, histopathology, brain magnatic resonance imaging (MRI), and associations with death and neurological disability in prospective cohorts of Malawian children with cerebral malaria. RESULTS: Three types of retinal leakage were seen: large focal leak (LFL), punctate leak (PL), and vessel leak. The LFL and PL were associated with death (odds ratio [OR] = 13.20, 95% confidence interval [CI] = 5.21-33.78 and OR = 8.58, 95% CI = 2.56-29.08, respectively) and brain swelling (P < .05). Vessel leak and macular nonperfusion were associated with neurological disability (OR = 3.71, 95% CI = 1.26-11.02 and OR = 9.06, 95% CI = 1.79-45.90). Large focal leak was observed as an evolving retinal hemorrhage. A core of fibrinogen and monocytes was found in 39 (93%) white-centered hemorrhages. CONCLUSIONS: Blood-retina barrier breakdown occurs in 3 patterns in cerebral malaria. Associations between LFL, brain swelling, and death suggest that the rapid accumulation of cerebral hemorrhages, with accompanying fluid egress, may cause fatal brain swelling. Vessel leak, from barrier dysfunction, and nonperfusion were not associated with severe brain swelling but with neurological deficits, suggesting hypoxic injury in survivors.


Assuntos
Edema Encefálico , Malária Cerebral , Barreira Hematorretiniana/patologia , Edema Encefálico/complicações , Edema Encefálico/patologia , Criança , Humanos , Malária Cerebral/complicações , Estudos Prospectivos , Retina/patologia
3.
BMC Geriatr ; 22(1): 134, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35177024

RESUMO

BACKGROUND: Falls are the second leading cause of accidental deaths worldwide mainly in older people. Older people have poor vision and published evidence suggests that it is a risk factor for falls. Less than half of falls clinics assess vision as part of the multi-factorial assessment of older adults at risk of falls despite vision being an essential input for postural stability. The aim of our study was to investigate the relationship between all clinically assessed visual functions and falls amongst older adults in a prospective observational individually age-matched case control study. METHODS: Visual acuity (VA), contrast sensitivity (CS), depth perception, binocular vision and binocular visual field were measured using routinely used clinical methods in falls participants (N = 83) and non-falls participants (N = 83). Data were also collected on socio-demographic factors, general health, number of medications, health quality, fear of falling and physical activity. Logistic regression analysis was carried out to determine key visual and non-visual risk factors for falls whilst adjusting for confounding covariates. RESULTS: Older adults have an increased risk of experiencing a fall if they have reduced visual function (odds ratio (OR): 3.49, 1.64-7.45, p = 0.001), specifically impaired stereoacuity worse than 85" of arc (OR: 3.4, 1.20-9.69, p = 0.02) and reduced (by 0.15 log unit) high spatial frequency CS (18 cpd) (OR:1.40, 1.12-1.80, p = 0.003). Older adults with a hearing impairment are also at higher risk of falls (OR: 3.18, 95% CI: 1.36-7.40, p = 0.007). The risk decreases with living in a less deprived area (OR: 0.74, 0.64-0.86, <0.001), or socialising more out of the home (OR: 0.75, 0.60-0.93, p = 0.01). CONCLUSIONS: The combination of social, behavioural and biological determinants are significant predictors of a fall. The non-visual risk factors include older adults, living in deprived neighbourhoods, socialising less outside of the home and those who have a hearing impairment. Impaired functional visual measures; depth perception and contrast are significant visual risk factors for falls above visual acuity.


Assuntos
Sensibilidades de Contraste , Medo , Idoso , Estudos de Casos e Controles , Humanos , Fatores de Risco
4.
Sensors (Basel) ; 21(14)2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34300365

RESUMO

Changes of direction (COD) are an important aspect of soccer match play. Understanding the physiological and biomechanical demands on players in games allows sports scientists to effectively train and rehabilitate soccer players. COD are conventionally recorded using manually annotated time-motion video analysis which is highly time consuming, so more time-efficient approaches are required. The aim was to develop an automated classification model based on multi-sensor player tracking device data to detect COD > 45°. Video analysis data and individual multi-sensor player tracking data (GPS, accelerometer, gyroscopic) for 23 academy-level soccer players were used. A novel 'GPS-COD Angle' variable was developed and used in model training; along with 24 GPS-derived, gyroscope and accelerometer variables. Video annotation was the ground truth indicator of occurrence of COD > 45°. The random forest classifier using the full set of features demonstrated the highest accuracy (AUROC = 0.957, 95% CI = 0.956-0.958, Sensitivity = 0.941, Specificity = 0.772. To balance sensitivity and specificity, model parameters were optimised resulting in a value of 0.889 for both metrics. Similarly high levels of accuracy were observed for random forest models trained using a reduced set of features, accelerometer-derived variables only, and gyroscope-derived variables only. These results point to the potential effectiveness of the novel methodology implemented in automatically identifying COD in soccer players.


Assuntos
Desempenho Atlético , Corrida , Futebol
5.
NMR Biomed ; 33(11): e4386, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32729637

RESUMO

The utility of diffusion kurtosis imaging (DKI) for assessing intra-tumor heterogeneity was evaluated in a rat model of glioblastoma multiforme. Longitudinal MRI including T2 -weighted and diffusion-weighted MRI (DWI) was performed on six female Fischer rats 8, 11 and 14 days after intracranial transplantation of F98 cells. T2 -weighted images were used to measure the tumor volumes and DWI images were used to compute diffusion tensor imaging (DTI) and DWI based parametric maps including mean diffusivity (MD), mean kurtosis (MK), axial diffusivity (AD), axial kurtosis, radial diffusivity, radial kurtosis, fractional anisotropy (FA) and kurtosis fractional anisotropy (KFA). Median values from the segmented normal contralateral cortex, tumor and edema from the diffusion parameters were compared at the three imaging time points to assess any changes in tumor heterogeneity over time. ex vivo DKI was also performed in a representative sample and compared with histology. Significant differences were observed between normal cortex, tumor and edema in both the DTI and DKI parameters. Notably, at the earliest time point MK and KFA were significantly different between normal cortex and tumor in comparison with MD or FA. Although a decreasing trend in MD, AD and FA values of the tumor were observed as the tumor grew, no significant changes in any of the DTI or DKI parameters were observed longitudinally. While DKI was equally sensitive to DTI in differentiating tumor from edema and normal brain, it was unable to detect longitudinal increases in intra-tumoral heterogeneity in the F98 model of glioblastoma multiforme.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Imagem de Tensor de Difusão , Glioblastoma/diagnóstico por imagem , Animais , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Glioblastoma/patologia , Ratos Endogâmicos F344
6.
Retina ; 40(11): 2198-2206, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32032260

RESUMO

PURPOSE: To investigate whether early detection and treatment of uveal melanoma by screening was associated with a lower mortality rate. METHODS: Retrospective assessment of prospectively collected data comparing 132 patients with uveal melanoma referred by the National Diabetic Screening Service with 608 control patients referred through other means. RESULTS: Mean tumor diameter was smaller in the diabetic screening group (11.1 mm vs. 12.5 mm) as was tumor thickness (3.4 mm vs. 5.4 mm). The prevalence of high-risk monosomy 3 was also lower (17/40, 43% vs. 62/110, 56%). Despite a higher rate of systemic comorbidities in the patients diagnosed through screening and despite older age at diagnosis, the 5-year all-cause mortality was similar in both groups (17% vs. 20%); however, the metastatic mortality was lower in the diabetic screening group (11/132, 8% vs. 95/608, 16%). CONCLUSION: Despite higher rates of comorbidities, the patients detected at diabetic screening had a lower 5-year mortality rate. The diabetic screening programme enabled detection and treatment of posterior uveal melanomas at an earlier stage. However, the confounding factors of lead and length time bias are not to be ignored.


Assuntos
Retinopatia Diabética/diagnóstico , Melanoma/diagnóstico , Melanoma/mortalidade , Neoplasias Uveais/diagnóstico , Neoplasias Uveais/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Causas de Morte , DNA de Neoplasias/genética , Feminino , Humanos , Masculino , Melanoma/genética , Pessoa de Meia-Idade , Monossomia , Estudos Prospectivos , Estudos Retrospectivos , Taxa de Sobrevida , Reino Unido/epidemiologia , Neoplasias Uveais/genética , Adulto Jovem
7.
Proc Natl Acad Sci U S A ; 112(23): 7141-6, 2015 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-25995363

RESUMO

The signal-to-noise ratio (SNR), a commonly used measure of fidelity in physical systems, is defined as the ratio of the squared amplitude or variance of a signal relative to the variance of the noise. This definition is not appropriate for neural systems in which spiking activity is more accurately represented as point processes. We show that the SNR estimates a ratio of expected prediction errors and extend the standard definition to one appropriate for single neurons by representing neural spiking activity using point process generalized linear models (PP-GLM). We estimate the prediction errors using the residual deviances from the PP-GLM fits. Because the deviance is an approximate χ(2) random variable, we compute a bias-corrected SNR estimate appropriate for single-neuron analysis and use the bootstrap to assess its uncertainty. In the analyses of four systems neuroscience experiments, we show that the SNRs are -10 dB to -3 dB for guinea pig auditory cortex neurons, -18 dB to -7 dB for rat thalamic neurons, -28 dB to -14 dB for monkey hippocampal neurons, and -29 dB to -20 dB for human subthalamic neurons. The new SNR definition makes explicit in the measure commonly used for physical systems the often-quoted observation that single neurons have low SNRs. The neuron's spiking history is frequently a more informative covariate for predicting spiking propensity than the applied stimulus. Our new SNR definition extends to any GLM system in which the factors modulating the response can be expressed as separate components of a likelihood function.


Assuntos
Neurônios/fisiologia , Razão Sinal-Ruído , Potenciais de Ação , Animais , Córtex Auditivo/citologia , Cobaias , Funções Verossimilhança
8.
Emerg Infect Dis ; 23(7): 1102-1109, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28628441

RESUMO

We conducted a case-control study in Freetown, Sierra Leone, to investigate ocular signs in Ebola virus disease (EVD) survivors. A total of 82 EVD survivors with ocular symptoms and 105 controls from asymptomatic civilian and military personnel and symptomatic eye clinic attendees underwent ophthalmic examination, including widefield retinal imaging. Snellen visual acuity was <6/7.5 in 75.6% (97.5% CI 63%-85.7%) of EVD survivors and 75.5% (97.5% CI 59.1%-87.9%) of controls. Unilateral white cataracts were present in 7.4% (97.5% CI 2.4%-16.7%) of EVD survivors and no controls. Aqueous humor from 2 EVD survivors with cataract but no anterior chamber inflammation were PCR-negative for Zaire Ebola virus, permitting cataract surgery. A novel retinal lesion following the anatomic distribution of the optic nerve axons occurred in 14.6% (97.5% CI 7.1%-25.6%) of EVD survivors and no controls, suggesting neuronal transmission as a route of ocular entry.


Assuntos
Ebolavirus , Doença pelo Vírus Ebola/complicações , Doenças Retinianas/diagnóstico , Doenças Retinianas/etiologia , Sobreviventes , Adulto , Estudos de Casos e Controles , Feminino , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/história , Doença pelo Vírus Ebola/virologia , História do Século XXI , Humanos , Masculino , Oftalmoscópios , Vigilância da População , Prevalência , Doenças Retinianas/epidemiologia , Índice de Gravidade de Doença , Serra Leoa/epidemiologia , Acuidade Visual , Adulto Jovem
9.
Stat Med ; 36(24): 3858-3874, 2017 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-28762546

RESUMO

Recently developed methods of longitudinal discriminant analysis allow for classification of subjects into prespecified prognostic groups using longitudinal history of both continuous and discrete biomarkers. The classification uses Bayesian estimates of the group membership probabilities for each prognostic group. These estimates are derived from a multivariate generalised linear mixed model of the biomarker's longitudinal evolution in each of the groups and can be updated each time new data is available for a patient, providing a dynamic (over time) allocation scheme. However, the precision of the estimated group probabilities differs for each patient and also over time. This precision can be assessed by looking at credible intervals for the group membership probabilities. In this paper, we propose a new allocation rule that incorporates credible intervals for use in context of a dynamic longitudinal discriminant analysis and show that this can decrease the number of false positives in a prognostic test, improving the positive predictive value. We also establish that by leaving some patients unclassified for a certain period, the classification accuracy of those patients who are classified can be improved, giving increased confidence to clinicians in their decision making. Finally, we show that determining a stopping rule dynamically can be more accurate than specifying a set time point at which to decide on a patient's status. We illustrate our methodology using data from patients with epilepsy and show how patients who fail to achieve adequate seizure control are more accurately identified using credible intervals compared to existing methods.


Assuntos
Teorema de Bayes , Classificação/métodos , Probabilidade , Simulação por Computador , Tomada de Decisões , Análise Discriminante , Epilepsia/diagnóstico , Epilepsia/terapia , Humanos , Modelos Lineares , Estudos Longitudinais , Análise Multivariada , Prognóstico , Indução de Remissão , Sensibilidade e Especificidade
10.
Ophthalmic Plast Reconstr Surg ; 33(6): 452-458, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27861329

RESUMO

PURPOSE: To compare hydroxyapatite with acrylic implants after enucleation for uveal melanoma with respect to eyelid position, ocular motility, implant complications, and patient satisfaction. METHODS: Patients undergoing primary enucleation for uveal melanoma between May 2005 and November 2012 at the Liverpool Ocular Oncology Centre, United Kingdom, were randomized between hydroxyapatite and acrylic implants. Questionnaires were sent to patients and ocularists to comment on the main outcomes. RESULTS: A total of 416 patients were recruited in the study, of whom 281 were included, with 49.5% (139/281) and 50.5% (142/281) receiving a hydroxyapatite (HA) or acrylic (AC) implant. Mailed questionnaires completed at ≥18 months by patients showed no significant differences between the groups in eyelid position, prosthetic motility, socket complications, and patient satisfaction. Complications included implant extrusion (1% vs 4%), enophthalmos (26% vs 26%), and superior sulcus deformity (24% vs 24%) with HA and AC implants, respectively, (Fisher exact test p > 0.0125 in all, Bonferroni correction). Questionnaires completed by ocularists indicated no significant differences in eyelid opening, prosthetic motility, and other complications at 6 months (Fisher exact test, p > 0.05 in all); there was a higher prevalence of ptosis with AC than HA implants (46% vs 25%, p = 0.03) and a greater need for ocularists' treatment with HA than AC (50% vs 28%, p = 0.03). CONCLUSIONS: Patient-reported outcomes after enucleation for uveal melanoma indicate no major differences between hydroxyapatite and acrylic implants in surgical outcomes and patient satisfaction. There was a higher prevalence of ptosis with AC and a greater need of ocularists' visits with HA at around 6 months observed by ocularists.


Assuntos
Durapatita , Enucleação Ocular , Melanoma/cirurgia , Implantes Orbitários , Polimetil Metacrilato , Implantação de Prótese/métodos , Neoplasias Uveais/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Porosidade , Desenho de Prótese , Reoperação , Estudos Retrospectivos , Inquéritos e Questionários , Resultado do Tratamento , Adulto Jovem
11.
Stat Med ; 35(14): 2406-21, 2016 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-26842429

RESUMO

This paper introduces a new simple divergence measure between two survival distributions. For two groups of patients, the divergence measure between their associated survival distributions is based on the integral of the absolute difference in probabilities that a patient from one group dies at time t and a patient from the other group survives beyond time t and vice versa. In the case of non-crossing hazard functions, the divergence measure is closely linked to the Harrell concordance index, C, the Mann-Whitney test statistic and the area under a receiver operating characteristic curve. The measure can be used in a dynamic way where the divergence between two survival distributions from time zero up to time t is calculated enabling real-time monitoring of treatment differences. The divergence can be found for theoretical survival distributions or can be estimated non-parametrically from survival data using Kaplan-Meier estimates of the survivor functions. The estimator of the divergence is shown to be generally unbiased and approximately normally distributed. For the case of proportional hazards, the constituent parts of the divergence measure can be used to assess the proportional hazards assumption. The use of the divergence measure is illustrated on the survival of pancreatic cancer patients. Copyright © 2016 John Wiley & Sons, Ltd.


Assuntos
Estimativa de Kaplan-Meier , Modelos Estatísticos , Bioestatística , Humanos , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/terapia , Modelos de Riscos Proporcionais , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Estatísticas não Paramétricas , Equivalência Terapêutica
12.
Graefes Arch Clin Exp Ophthalmol ; 254(6): 1091-7, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27106623

RESUMO

PURPOSE: To determine the effect of changing illuminance on visual and stereo acuity. METHODS: Twenty-eight subjects aged 21 to 60 years were assessed. Monocular visual acuity (ETDRS) of emmetropic subjects was assessed under 15 different illuminance levels (50-8000 lux), provided by a computer controlled halogen lighting rig. Three levels of myopia (-0.50DS, -1.00DS & 1.50DS) were induced in each subject using lenses and visual acuity (VA) was retested under the same illuminance conditions. Stereoacuity (TNO) was assessed under the same levels of illuminance. RESULTS: A one log unit change in illuminance level (lx) results in a significant change of 0.060 LogMAR (p < 0.001), an effect that is exacerbated in the presence of induced myopic refractive error (p < 0.001). Stereoacuity scores demonstrate statistically significant overall differences between illuminance levels (p < 0.001). CONCLUSIONS: The findings of this study demonstrate that changes in illuminance have a statistically significant effect on VA that may contribute to test/retest variability. Increases in illuminance from 50 to 500 lx resulted in an improved VA score of 0.12 LogMAR. Differences like these have significant clinical implications, such as false negatives during vision screening and non-detection of VA deterioration, as the full magnitude of any change may be hidden. In research where VA is a primary outcome measure, differences of 0.12 LogMAR or even less could affect the statistical significance and conclusions of a study. It is recommended that VA assessment always be performed between 400 lx and 600 lx, as this limits any effect of illuminance change to 0.012 LogMAR.


Assuntos
Iluminação , Testes Visuais/instrumentação , Acuidade Visual/fisiologia , Adulto , Feminino , Humanos , Iluminação/normas , Masculino , Pessoa de Meia-Idade , Miopia/fisiopatologia , Visão Binocular/fisiologia , Adulto Jovem
13.
Graefes Arch Clin Exp Ophthalmol ; 254(5): 891-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26899899

RESUMO

PURPOSE: Many eye diseases require on-going assessment for optimal management, creating an ever-increasing burden on patients and hospitals that could potentially be reduced through home vision monitoring. However, there is limited evidence for the utility of current applications and devices for this. To address this, we present a new automated, computer tablet-based method for self-testing near visual acuity (VA) for both high and low contrast targets. We report on its reliability and agreement with gold standard measures. METHODS: The Mobile Assessment of Vision by intERactIve Computer (MAVERIC) system consists of a calibrated computer tablet housed in a bespoke viewing chamber. Purpose-built software automatically elicits touch-screen responses from subjects to measure their near VA for either low or high contrast acuity. Near high contrast acuity was measured using both the MAVERIC system and a near Landolt C chart in one eye for 81 patients and low contrast acuity using the MAVERIC system and a 25 % contrast near EDTRS chart in one eye of a separate 95 patients. The MAVERIC near acuity was also retested after 20 min to evaluate repeatability. RESULTS: Repeatability of both high and low contrast MAVERIC acuity measures, and their agreement with the chart tests, was assessed using the Bland-Altman comparison method. One hundred and seventy-three patients (96 %) completed the self- testing MAVERIC system without formal assistance. The resulting MAVERIC vision demonstrated good repeatability and good agreement with the gold-standard near chart measures. CONCLUSIONS: This study demonstrates the potential utility of the MAVERIC system for patients with ophthalmic disease to self-test their high and low contrast VA. The technique has a high degree of reliability and agreement with gold standard chart based measurements.


Assuntos
Computadores de Mão , Sensibilidades de Contraste/fisiologia , Diagnóstico por Computador/instrumentação , Autocuidado/métodos , Transtornos da Visão/diagnóstico , Testes Visuais/instrumentação , Acuidade Visual/fisiologia , Algoritmos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Software
14.
PLoS One ; 19(1): e0297190, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38252622

RESUMO

Mild Cognitive Impairment (MCI) is a condition characterized by a decline in cognitive abilities, specifically in memory, language, and attention, that is beyond what is expected due to normal aging. Detection of MCI is crucial for providing appropriate interventions and slowing down the progression of dementia. There are several automated predictive algorithms for prediction using time-to-event data, but it is not clear which is best to predict the time to conversion to MCI. There is also confusion if algorithms with fewer training weights are less accurate. We compared three algorithms, from smaller to large numbers of training weights: a statistical predictive model (Cox proportional hazards model, CoxPH), a machine learning model (Random Survival Forest, RSF), and a deep learning model (DeepSurv). To compare the algorithms under different scenarios, we created a simulated dataset based on the Alzheimer NACC dataset. We found that the CoxPH model was among the best-performing models, in all simulated scenarios. In a larger sample size (n = 6,000), the deep learning algorithm (DeepSurv) exhibited comparable accuracy (73.1%) to the CoxPH model (73%). In the past, ignoring heterogeneity in the CoxPH model led to the conclusion that deep learning methods are superior. We found that when using the CoxPH model with heterogeneity, its accuracy is comparable to that of DeepSurv and RSF. Furthermore, when unobserved heterogeneity is present, such as missing features in the training, all three models showed a similar drop in accuracy. This simulation study suggests that in some applications an algorithm with a smaller number of training weights is not disadvantaged in terms of accuracy. Since algorithms with fewer weights are inherently easier to explain, this study can help artificial intelligence research develop a principled approach to comparing statistical, machine learning, and deep learning algorithms for time-to-event predictions.


Assuntos
Disfunção Cognitiva , Aprendizado Profundo , Humanos , Inteligência Artificial , Algoritmos , Disfunção Cognitiva/diagnóstico , Aprendizado de Máquina
15.
Sci Rep ; 13(1): 2835, 2023 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-36808170

RESUMO

The amniotic membrane (AM) has special properties, making it ideal for clinical applications in various surgical fields like ophthalmology. It is used more frequently to cover conjunctival and corneal defects. In our retrospective study we have been combined 68 patients with epibulbar conjunctival tumors they have been surgically treated in the period of 2011-2021. Seven (10.3%) patients have been treated with AM application after surgical removal of the tumor. 54 (79%) cases were malignant, and 14 (21%) were benign. In the analyzed dataset the males had just slightly higher chance of malignancy than females, 80% versus 78.3%. For the significancy calculation the Fisher exact test was used and the result proved no significancy (p = 0.99). Six patients with AM application were malignant. The observed difference in the number of quadrants of the bulbar conjunctiva infiltrated versus significant malignancy with p = 0.050 calculated by Fisher Exact test and with p = 0.023 calculated by Likelihood-ratio test. The results of our study indicate that AM grafts are an effective alternative to cover defects after removal of epibulbar lesions due to their anti-inflammatory properties because the conjunctiva must be preserved, and especially the most important application is in malignant epibulbar conjunctival tumors.


Assuntos
Neoplasias da Túnica Conjuntiva , Masculino , Feminino , Humanos , Neoplasias da Túnica Conjuntiva/patologia , Estudos Retrospectivos , Âmnio/transplante , Túnica Conjuntiva/patologia
16.
Surv Ophthalmol ; 68(1): 17-41, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35985360

RESUMO

Glaucoma is a leading cause of irreversible vision impairment globally, and cases are continuously rising worldwide. Early detection is crucial, allowing timely intervention that can prevent further visual field loss. To detect glaucoma an examination of the optic nerve head via fundus imaging can be performed, at the center of which is the assessment of the optic cup and disc boundaries. Fundus imaging is noninvasive and low-cost; however, image examination relies on subjective, time-consuming, and costly expert assessments. A timely question to ask is: "Can artificial intelligence mimic glaucoma assessments made by experts?" Specifically, can artificial intelligence automatically find the boundaries of the optic cup and disc (providing a so-called segmented fundus image) and then use the segmented image to identify glaucoma with high accuracy? We conducted a comprehensive review on artificial intelligence-enabled glaucoma detection frameworks that produce and use segmented fundus images and summarized the advantages and disadvantages of such frameworks. We identified 36 relevant papers from 2011 to 2021 and 2 main approaches: 1) logical rule-based frameworks, based on a set of rules; and 2) machine learning/statistical modeling-based frameworks. We critically evaluated the state-of-art of the 2 approaches, identified gaps in the literature and pointed at areas for future research.


Assuntos
Glaucoma , Disco Óptico , Humanos , Inteligência Artificial , Fundo de Olho , Glaucoma/diagnóstico , Disco Óptico/diagnóstico por imagem , Aprendizado de Máquina
17.
Int J Cancer ; 130(10): 2387-96, 2012 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-21671473

RESUMO

Use of menopausal hormone therapy (HT) has been associated with reduced risk of colorectal cancer; evidence for its effect on other gastrointestinal cancers is limited. We conducted a nested case-control study within a UK cohort, and meta-analyses combining our results with those from published studies. Our study included women aged 50+ in the UK General Practice Research Database (GPRD): 1,054 with oesophageal, 750 with gastric and 4,708 with colorectal cancer, and 5 age- and practice-matched controls per case. Relative risks (RRs) and 95% confidence intervals (CIs) for cancer in relation to prospectively-recorded HT prescriptions were estimated by conditional logistic regression. Women prescribed HT had a reduced risk of oesophageal cancer (adjusted RR for 1+ vs. no HT prescriptions, 0.68, 95% CI 0.53-0.88; p = 0.004), gastric cancer (0.75, 0.54-1.05; p = 0.1) and colorectal cancer (0.81, 0.73-0.90; p < 0.001). There were no significant differences in cancer risk by HT type, estimated duration of HT use or between past and current users. In meta-analyses, risks for ever vs. never use of HT were significantly reduced for all three cancers (summary RR for oesophageal cancer, 0.68, 0.55-0.84, p < 0.001; for gastric cancer, 0.78, 0.65-0.94, p = 0.008; for colorectal cancer, 0.84, 0.81-0.88, p < 0.001). In high-income countries, estimated incidence over 5 years of these three cancers combined in women aged 50-64 was 2.9/1,000 in HT users and 3.6/1,000 in never users. The absolute reduction in risk of these cancers in HT users is small compared to the HT-associated increased risk of breast cancer.


Assuntos
Neoplasias Gastrointestinais/epidemiologia , Terapia de Reposição Hormonal , Menopausa , Idoso , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Neoplasias Gastrointestinais/etiologia , Humanos , Incidência , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco
18.
Disabil Rehabil ; 44(18): 5152-5161, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-34053393

RESUMO

PURPOSE: To determine any factors that predict how an individual will adapt to post-stroke hemianopic visual field loss, with close monitoring of the adaptation process from an early stage. MATERIALS AND METHODS: The Hemianopia Adaptation Study (HAST) is a prospective observational longitudinal cohort clinical study. Adult stroke survivors (n = 144) with new onset homonymous hemianopia were monitored using standardised mobility assessment course (MAC) as the primary outcome measure of adaptation. RESULTS: Several baseline variables were found to be good predictors of adaptation. Three variables were associated with adaptation status at 12-weeks post-stroke: inferior % visual field, % total MAC omissions, and MAC completion time (seconds). Baseline measurements of these variables can predict the adaptation at 12 weeks with moderate to high accuracy (area under ROC curve, 0.82, 95% CI 0.74-0.90). A cut-off score of ≤25% target omissions is suggested to predict which individuals are likely to adapt by 12-weeks post-stroke following gold standard care. CONCLUSIONS: Adaptation to hemianopia is a personal journey with several factors being important for prediction of its presence, including MAC outcomes and extent of inferior visual field loss. A clinical recommendation is made for inclusion of the MAC as part of a functional assessment for hemianopia.Implications for rehabilitationThe mobility assessment course (MAC) should be considered as an assessment of mobility/scanning in the rehabilitation of patients with homonymous hemianopia.A cut-off score of ≤25% omissions on MAC could be employed to determine those likely to adapt to hemianopia long-term.Targeted support and therapy for patients with significant visual loss in the inferior visual field area should be considered.


Assuntos
Hemianopsia , Acidente Vascular Cerebral , Adulto , Estudos de Coortes , Hemianopsia/complicações , Humanos , Estudos Longitudinais , Estudos Prospectivos , Acidente Vascular Cerebral/complicações , Transtornos da Visão/complicações , Campos Visuais
19.
Syst Rev ; 11(1): 63, 2022 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-35395931

RESUMO

BACKGROUND: Atrial fibrillation affects an estimated 33 million individuals worldwide and is a major cause of stroke, heart failure, and death. Anticoagulants substantially reduce the risk of stroke but are also associated with an increased risk of bleeding and especially intracranial hemorrhage which is the most concerning complication. Because of this, many patients are not offered anticoagulants, particularly patients at risk of falls or with a history of falls. It is unclear what anticoagulant treatment these patients should be offered. The Liverpool AF-Falls project aims to investigate this area, and this protocol for a systematic review and meta-analysis aims to define what is the most appropriate anticoagulant treatment option for the management of atrial fibrillation patients at risk of falls or with a history of falls. METHODS: This systematic review and meta-analysis will include randomized and non-randomized studies evaluating the safety and efficacy of different anticoagulant treatments (vitamin K antagonist and non-vitamin K antagonist oral anti-coagulant). Bibliographic databases (Cochrane Central Register of Controlled Trials, CINAHL, ClinicalTrials.gov , Embase, MEDLINE, Scopus and Web of Science) will be searched according to a pre-specified search strategy. Titles, abstracts, and full texts will be assessed by two independent reviewers and disagreements resolved with a third independent reviewer. The Cochrane Risk of Bias tool 2 (RoB 2) will be used to assess the risk of bias in randomized trials, and the Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I) tool will be used for non-randomized studies. A pairwise meta-analysis based on the fixed and random-effects models will be conducted. Publication bias will be evaluated with a funnel plot and Egger's test. Heterogeneity will be assessed with the I2 statistic. If conditions for indirect comparison are met and sufficient data are available, a network meta-analysis will be conducted using frequentist and Bayesian methodologies. DISCUSSION: This review will be the first to summarize direct and indirect evidence on the safety and efficacy of anticoagulant treatments in atrial fibrillation patients at risk of falls or with a history of falls. The findings will be important to patients, clinicians, and health policy-makers to inform best practices in the use of these treatments. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registry number: CRD42020201086.


Assuntos
Fibrilação Atrial , Acidente Vascular Cerebral , Administração Oral , Anticoagulantes/efeitos adversos , Fibrilação Atrial/complicações , Fibrilação Atrial/tratamento farmacológico , Teorema de Bayes , Humanos , Metanálise como Assunto , Literatura de Revisão como Assunto , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/prevenção & controle , Revisões Sistemáticas como Assunto
20.
Drug Saf ; 45(11): 1349-1362, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36121557

RESUMO

INTRODUCTION: Atrial fibrillation (AF) is a major cause of stroke. Anticoagulants substantially reduce risk of stroke but are also associated with an increased risk of bleeding. Because of that, many patients do not receive anticoagulants, particularly patients at risk of falls. This systematic review and meta-analysis aims to compare anticoagulant treatment options for the management of atrial fibrillation patients at risk of falls or with a history of falls. METHODS: We conducted a PRISMA systematic review (until March 2022), including studies evaluating safety and efficacy of different anticoagulants (vitamin K antagonist [VKA] versus non-vitamin K antagonist oral anticoagulant [NOAC]). Outcomes were ischemic stroke, major bleeding, intracranial hemorrhage, hemorrhagic stroke, myocardial infarction, gastrointestinal bleeding, cardiovascular and all-cause mortality. A multilevel meta-analysis was conducted adjusting for clustering effects within studies examining more than one effect size. RESULTS: A total of 919 articles were identified, 848 after removing duplicates. The full text of 155 were screened and 10 articles were retained for final quantitative synthesis. Risk of bias was moderate to serious for the included studies. In meta-analysis, NOACs were associated with superior effectiveness compared with VKA for ischemic stroke/systemic embolism (hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.69-0.98; p < 0.05) and safety (HR 0.53, 95% CI 0.40-0.71; p < 0.05) for intracranial hemorrhage. There were no differences in other outcomes. CONCLUSION: NOACs were associated with less intracranial hemorrhages and ischemic strokes/systemic embolisms than VKAs in AF patients at risk of falls. These findings suggesting preferred use of NOACs over VKAs have clinical implications for physicians, patients and policy makers.


Assuntos
Fibrilação Atrial , AVC Isquêmico , Acidente Vascular Cerebral , Acidentes por Quedas , Administração Oral , Anticoagulantes/efeitos adversos , Fibrilação Atrial/complicações , Fibrilação Atrial/tratamento farmacológico , Hemorragia Gastrointestinal/induzido quimicamente , Humanos , Hemorragias Intracranianas/induzido quimicamente , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/prevenção & controle
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