Background: Visual rating of medial temporal lobe atrophy (MTA) is an accepted structural neuroimaging marker of Alzheimer’s disease. Corneal confocal microscopy (CCM) is a non-invasive ophthalmic technique that detects neuronal loss in peripheral and central neurodegenerative disorders. Objective: To determine the diagnostic accuracy of CCM for mild cognitive impairment (MCI) and dementia compared to medial temporal lobe atrophy (MTA) rating on MRI. Methods: Subjects aged 60–85 with no cognitive impairment (NCI), MCI, and dementia based on the ICD-10 criteria were recruited. Subjects underwent cognitive screening, CCM, and MTA rating on MRI. Results: 182 subjects with NCI (n = 36), MCI (n = 80), and dementia (n = 66), including AD (n = 19, 28.8%), VaD (n = 13, 19.7%), and mixed AD (n = 34, 51.5%) were studied. CCM showed a progressive reduction in corneal nerve fiber density (CNFD, fibers/mm2) (32.0±7.5 versus 24.5±9.6 and 20.8±9.3, p < 0.0001), branch density (CNBD, branches/mm2) (90.9±46.5 versus 59.3±35.7 and 53.9±38.7, p < 0.0001), and fiber length (CNFL, mm/mm2) (22.9±6.1 versus 17.2±6.5 and 15.8±7.4, p < 0.0001) in subjects with MCI and dementia compared to NCI. The area under the ROC curve (95% CI) for the diagnostic accuracy of CNFD, CNBD, CNFL compared to MTA-right and MTA-left for MCI was 78% (67–90%), 82% (72–92%), 86% (77–95%) versus 53% (36–69%) and 40% (25–55%), respectively, and for dementia it was 85% (76–94%), 84% (75–93%), 85% (76–94%) versus 86% (76–96%) and 82% (72–92%), respectively. Conclusion: The diagnostic accuracy of CCM, a non-invasive ophthalmic biomarker of neurodegeneration, was high and comparable with MTA rating for dementia but was superior to MTA rating for MCI.

BackgroundThe ongoing pandemic has led to a global surge in coronavirus disease 2019 (COVID-19)-related mental health research. However, most related publications come from Western countries or China, and their findings cannot always be extrapolated to Arab countries.AimsThis study provides a quantitative and qualitative analysis of mental health research pertaining to Arab countries' response to the COVID-19 pandemic.MethodsA scoping review of the World Health Organization (WHO) COVID-19 database for publications on mental health was conducted by authors affiliated with Arab institutions, including articles from inception to 24 October 2020. The included publications were evaluated for their national distribution, international collaboration, publication type, and main research themes. Methodological quality analysis of the included research studies was performed using the original and modified versions of the Newcastle–Ottawa Scale.ResultsIn total, 102 articles were included in this study, averaging 4.6 articles per Arab country. Most of the articles emerged from the Kingdom of Saudi Arabia, Jordan, and Egypt. A majority of publications demonstrated international collaboration. Most of the publications were original research studies and cross-sectional in design. The predominant research theme was examining the pandemic’s mental health effects on the general population and healthcare workers. Only 28.0% of the studies were of high methodological quality, whereas 41.5% were moderate and 30.5% were low in quality.ConclusionsMental health research in response to the COVID-19 pandemic in the Arab region has quantitative and qualitative shortfalls. Arab institutions need to respond to the pandemic promptly in order to address the delineated research gap and to generate higher-quality research output.

Background: Visual rating of medial temporal lobe atrophy (MTA) is an accepted biomarker of Alzheimer’s disease. Corneal confocal microscopy (CCM) is a non-invasive ophthalmic imaging biomarker of neurodegeneration. We sought to determine the diagnostic accuracy of CCM to distinguish mild cognitive impairment (MCI) and dementia from no cognitive impairment (NCI) in relation to MTA rating.Methods: Subjects aged 60-85 with NCI, MCI and dementia were recruited from the geriatric and memory clinic in Rumailah Hospital, Doha, Qatar between 18/09/16 and 31/07/19. The diagnosis of MCI and dementia were based on the International Classification of Diseases (ICD-10) criteria. Subjects underwent cognitive screening using the Montreal Cognitive Assessment (MoCA), CCM and MTA rating on MRI. Statistical tests used were ANOVA with Bonferroni’s post hoc test, kappa statistics and receiver operating characteristic (ROC) curve analysis. A two-tailed P value of ≤0.05 was considered significant.Results: 182 subjects with NCI (n=36), MCI (n=80) and dementia (n=66), including AD (n=19, 28.8%), VaD (n=13, 19.7%) and combined AD (n=34, 51.5%) were studied. CCM showed a progressive reduction in corneal nerve fiber density (CNFD, fibers/mm2) (32.0±7.5 vs 24.5±9.6 vs 20.8±9.3, p<0.0001), branch density (CNBD, branches/mm2) (90.9±46.5 vs 59.3±35.7 vs 53.9±38.7, p<0.0001), and fiber length (CNFL, mm/mm2) (22.9±6.1 vs 17.2±6.5 vs 15.8±7.4, p<0.0001), in subjects with MCI and dementia compared to NCI. The MTA rating in the dementia group was significantly higher compared with the NCI and MCI group in the right (1.9±1.0 vs 0.5±0.6 and 0.6±0.8, p<0.0001) and left (2.1±1.1 vs 0.6±0.7 and 0.8±0.8, p<0.0001) hemispheres. The area under the ROC curve (95% CI) for the diagnostic accuracy of CNFD, CNBD, CNFL vs MTA-right and -left for MCI was 78% (67-90%), 82% (72-92%), 86% (77-95%) vs 53% (36-69%) and 40% (25-55%), respectively, and for dementia it was 85% (76-94%), 84% (75-93%), 85% (76-94%) vs 86% (76-96%) and 82% (72-92%), respectively.Conclusions: The diagnostic accuracy of CCM, a non-invasive ophthalmic biomarker of neurodegeneration was high and comparable with MTA rating for dementia and superior to MTA rating for MCI.