ABSTRACT
Background Olfactory impairments and anosmia from COVID-19 infection typically resolve within 2–4 weeks, although in some cases, symptoms persist longer. COVID-19-related anosmia is associated with olfactory bulb atrophy, however, the impact on cortical structures is relatively unknown, particularly in those with long-term symptoms. Methods In this exploratory, observational study, we studied individuals who experienced COVID-19-related anosmia, with or without recovered sense of smell, and compared against individuals with no prior COVID-19 infection (confirmed by antibody testing, all vaccine naïve). MRI Imaging was carried out between the 15th July and 17th November 2020 at the Queen Square House Clinical Scanning Facility, UCL, United Kingdom. Using functional magnetic resonance imaging (fMRI) and structural imaging, we assessed differences in functional connectivity (FC) between olfactory regions, whole brain grey matter (GM) cerebral blood flow (CBF) and GM density. Findings Individuals with anosmia showed increased FC between the left orbitofrontal cortex (OFC), visual association cortex and cerebellum and FC reductions between the right OFC and dorsal anterior cingulate cortex compared to those with no prior COVID-19 infection (p < 0.05, from whole brain statistical parametric map analysis). Individuals with anosmia also showed greater CBF in the left insula, hippocampus and ventral posterior cingulate when compared to those with resolved anosmia (p < 0.05, from whole brain statistical parametric map analysis). Interpretation This work describes, for the first time to our knowledge, functional differences within olfactory areas and regions involved in sensory processing and cognitive functioning. This work identifies key areas for further research and potential target sites for therapeutic strategies. Funding This study was funded by the 10.13039/501100000272National Institute for Health and Care Research and supported by the Queen Square Scanner business case.
ABSTRACT
Background: Olfactory impairments and anosmia from COVID-19 infection typically resolve within 2-4 weeks, although in some cases, symptoms persist longer. COVID-19-related anosmia is associated with olfactory bulb atrophy, however, the impact on cortical structures is relatively unknown, particularly in those with long-term symptoms. Methods: In this exploratory, observational study, we studied individuals who experienced COVID-19-related anosmia, with or without recovered sense of smell, and compared against individuals with no prior COVID-19 infection (confirmed by antibody testing, all vaccine naïve). MRI Imaging was carried out between the 15th July and 17th November 2020 at the Queen Square House Clinical Scanning Facility, UCL, United Kingdom. Using functional magnetic resonance imaging (fMRI) and structural imaging, we assessed differences in functional connectivity (FC) between olfactory regions, whole brain grey matter (GM) cerebral blood flow (CBF) and GM density. Findings: Individuals with anosmia showed increased FC between the left orbitofrontal cortex (OFC), visual association cortex and cerebellum and FC reductions between the right OFC and dorsal anterior cingulate cortex compared to those with no prior COVID-19 infection (p < 0.05, from whole brain statistical parametric map analysis). Individuals with anosmia also showed greater CBF in the left insula, hippocampus and ventral posterior cingulate when compared to those with resolved anosmia (p < 0.05, from whole brain statistical parametric map analysis). Interpretation: This work describes, for the first time to our knowledge, functional differences within olfactory areas and regions involved in sensory processing and cognitive functioning. This work identifies key areas for further research and potential target sites for therapeutic strategies. Funding: This study was funded by the National Institute for Health and Care Research and supported by the Queen Square Scanner business case.
ABSTRACT
IntroductionNo evidence of disease activity (NEDA) is a treatment goal when using disease modifying therapy for treating relapsing remitting multiple sclerosis (RRMS).1 However, predicting which patients may achieve NEDA is challenging.ObjectiveTo identify the baseline clinical and MRI features that predict NEDA in patients initiating dimethyl fumarate (DMF).Method: In our observational study, we retrospectively collected clinical and radiological data acquired for patients with RRMS initiating DMF. Demographics and clinical details at MS onset and at DMF initiation (baseline) were evaluated. We investigated the associations between all the baseline clinical and MRI findings and NEDA at 24 months using a combined multiple logistic regression.ResultsWe had a total of 670 patients in our cohort and only 339 (50%) achieved NEDA at 24 months. Lower EDSS (Log odds[95%CI]= -0.19[-0.30 to -0.03], p=0.01), lower number of new MRI lesions at baseline (Log odds[95%CI]= -0.14[-0.32 to -0.04], p=0.01) and lower number of relapses in the previous 12 months (Log odds[95%CI]= -0.39[-0.77 to -0.26], p=0.0001) significantly predicted NEDA at 24 months.ConclusionSignificant predictors for achieving NEDA were the number of relapses in the previous year, the number of new MRI lesions and the EDSS at DMF initiation. This could be useful in clinical practice to counsel patients regarding their potential response to DMF.