USP: an independence test that improves on Pearson’s chi-squared and the
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            -test

Berrett, Thomas B.; Samworth, Richard J.

doi:10.1098/rspa.2021.0549

Cited by 10 publications

(5 citation statements)

References 12 publications

(24 reference statements)

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“…Continuous variables were compared between groups using the Student t test and categorical variables through the U statistic permutation test of independence. 20 To examine the association between prevalent PD and retinal morphology, we fitted linear mixed-effects models with a random intercept at the individual level to account for the multilevel structure of eyes nested in participants. Models were fitted through maximum likelihood estimation and adjusted for age, sex, ethnicity group, diabetes mellitus, and hypertension.…”

Section: Discussionmentioning

confidence: 99%

Retinal Optical Coherence Tomography Features Associated With Incident and Prevalent Parkinson Disease

Wagner,

Romero-Bascones,

Cortina-Borja

et al. 2023

Neurology

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Background and objectives:Cadaveric studies have shown disease-related neurodegeneration and other morphological abnormalities in the retina of individuals with Parkinson disease (PD), however it remains unclear whether this can be reliably detected with in vivo imaging. We investigated inner retinal anatomy, measured using optical coherence tomography (OCT), in prevalent PD and subsequently assessed the association of these markers with the development of PD using a prospective research cohort.Methods:This cross-sectional analysis used data from two studies. For the detection of retinal markers in prevalent PD, we used data from AlzEye, a retrospective cohort of 154,830 patients aged 40 years and over attending secondary care ophthalmic hospitals in London, UK between 2008 and 2018. For the evaluation of retinal markers in incident PD, we used data from UK Biobank, a prospective population-based cohort where 67,311 volunteers aged 40-69 years were recruited between 2006 and 2010 and underwent retinal imaging. Macular retinal nerve fibre layer (mRNFL), ganglion cell-inner plexiform layer (GCIPL), and inner nuclear layer (INL) thicknesses were extracted from fovea--centred OCT. Linear mixed effects models were fitted to examine the association between prevalent PD and retinal thicknesses. Hazard ratios for the association between time to PD diagnosis and retinal thicknesses were estimated using frailty models.Results:Within the AlzEye cohort, there were 700 individuals with prevalent PD and 105,770 controls (mean age 65.5 ± 13.5 years, 51.7% female). Individuals with prevalent PD had thinner GCIPL (-2.12 μm, 95% confidence interval: -3.17, -1.07,p= 8.2 × 10-5) and INL (-0.99 μm, 95% confidence interval: -1.52, -0.47,p= 2.1 × 10-4). The UK Biobank included 50,405 participants (mean age 56.1 ± 8.2 years, 54.7% female), of whom 53 developed PD at a mean of 2653 ± 851 days. Thinner GCIPL (hazard ratio: 0.62 per standard deviation increase, 95% confidence interval: 0.46, 0.84,p=0.002) and thinner INL (hazard ratio: 0.70, 95% confidence interval: 0.51, 0.96,p=0.026) were also associated with incident PD.Discussion:Individuals with PD have reduced thickness of the INL and GCIPL of the retina. Involvement of these layers several years before clinical presentation highlight a potential role for retinal imaging for at-risk stratification of PD.

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Section: Discussionmentioning

confidence: 99%

Retinal Optical Coherence Tomography Features Associated With Incident and Prevalent Parkinson Disease

Wagner,

Romero-Bascones,

Cortina-Borja

et al. 2023

Neurology

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“…Continuous variables were compared between groups using the Wilcoxon-Mann-Whitney test and categorical variables through the U test . We fitted linear mixed-effects models using maximum likelihood estimation in line with the Advised Protocol for OCT Study Terminology and Elements (APOSTEL) recommendations .…”

Section: Methodsmentioning

confidence: 99%

Association Between Retinal Features From Multimodal Imaging and Schizophrenia

et al. 2023

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ImportanceThe potential association of schizophrenia with distinct retinal changes is of clinical interest but has been challenging to investigate because of a lack of sufficiently large and detailed cohorts.ObjectiveTo investigate the association between retinal biomarkers from multimodal imaging (oculomics) and schizophrenia in a large real-world population.Design, Setting, and ParticipantsThis cross-sectional analysis used data from a retrospective cohort of 154 830 patients 40 years and older from the AlzEye study, which linked ophthalmic data with hospital admission data across England. Patients attended Moorfields Eye Hospital, a secondary care ophthalmic hospital with a principal central site, 4 district hubs, and 5 satellite clinics in and around London, United Kingdom, and had retinal imaging during the study period (January 2008 and April 2018). Data were analyzed from January 2022 to July 2022.Main Outcomes and MeasuresRetinovascular and optic nerve indices were computed from color fundus photography. Macular retinal nerve fiber layer (RNFL) and ganglion cell–inner plexiform layer (mGC-IPL) thicknesses were extracted from optical coherence tomography. Linear mixed-effects models were used to examine the association between schizophrenia and retinal biomarkers.ResultsA total of 485 individuals (747 eyes) with schizophrenia (mean [SD] age, 64.9 years [12.2]; 258 [53.2%] female) and 100 931 individuals (165 400 eyes) without schizophrenia (mean age, 65.9 years [13.7]; 53 253 [52.8%] female) were included after images underwent quality control and potentially confounding conditions were excluded. Individuals with schizophrenia were more likely to have hypertension (407 [83.9%] vs 49 971 [48.0%]) and diabetes (364 [75.1%] vs 28 762 [27.6%]). The schizophrenia group had thinner mGC-IPL (−4.05 μm, 95% CI, −5.40 to −2.69; P = 5.4 × 10−9), which persisted when investigating only patients without diabetes (−3.99 μm; 95% CI, −6.67 to −1.30; P = .004) or just those 55 years and younger (−2.90 μm; 95% CI, −5.55 to −0.24; P = .03). On adjusted analysis, retinal fractal dimension among vascular variables was reduced in individuals with schizophrenia (−0.14 units; 95% CI, −0.22 to −0.05; P = .001), although this was not present when excluding patients with diabetes.Conclusions and RelevanceIn this study, patients with schizophrenia had measurable differences in neural and vascular integrity of the retina. Differences in retinal vasculature were mostly secondary to the higher prevalence of diabetes and hypertension in patients with schizophrenia. The role of retinal features as adjunct outcomes in patients with schizophrenia warrants further investigation.

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“…Categorical variables were compared using a U-statistic permutation test. 23 Odds ratios (OR) were computed using conditional maximum likelihood estimation. Categorical variables were compared using a χ 2 test and Fisher's exact test.…”

Section: Methodsmentioning

confidence: 99%

“…Numerical variables were compared using Student's t ‐test, a Wilcoxon rank‐sum test, or a Wilcoxon signed‐rank test depending on data normality. Categorical variables were compared using a U ‐statistic permutation test 23 . Odds ratios (OR) were computed using conditional maximum likelihood estimation.…”

Section: Methodsmentioning

confidence: 99%

Long‐term outcome of paediatric anti‐N‐methyl‐D‐aspartate receptor encephalitis

Flet‐Berliac

Tchitchek

Lépine

et al. 2022

Develop Med Child Neuro

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Aim: To study long-term clinical and cognitive outcomes of patients with anti-Nmethyl-d-aspartate receptor encephalitis (NMDAR-E), an acute autoimmune neurological disease with severe acute presentations. Method:In this French multicentre retrospective observational cohort study, patients no older than 18 years with a follow-up of at least 2 years were included. Data from clinical and cognitive assessments were collected.Results: Eighty-one patients were included (57 females, 24 males; median age 10 years 7 months [range 1-18 years], median follow-up 40 months [range 25-53 months]). At last follow-up, 35 patients (45%) had cognitive impairment, 48 (70%) had academic difficulties, and 65 (92%) needed rehabilitation. Seventy-one patients (88%) had a modified Rankin Scale score of no more than 2. A higher number of symptoms at diagnosis was associated with cognitive impairment (p = 0.01), while an abnormal electroencephalogram at diagnosis increased the risk of academic difficulties (p = 0.03).Interpretation: Although most children with NMDAR-E seemed to recover from motor disabilities, more than 45% had cognitive and academic difficulties. The initial severity of symptoms seems to have an impact on cognition and academic performances.

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USP: an independence test that improves on Pearson’s chi-squared and the G -test

Abstract: We present the U -statistic permutation (USP) test of independence in the context of discrete data displayed in a contingency table. Either Pearson’s χ 2 -test of independence, or the G -test, are typically us… Show more

Cited by 10 publications

References 12 publications

Retinal Optical Coherence Tomography Features Associated With Incident and Prevalent Parkinson Disease

Retinal Optical Coherence Tomography Features Associated With Incident and Prevalent Parkinson Disease

Association Between Retinal Features From Multimodal Imaging and Schizophrenia

Long‐term outcome of paediatric anti‐N‐methyl‐D‐aspartate receptor encephalitis

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