Olfactory deficit: a potential functional marker across the Alzheimer’s disease continuum

Frontiers in Neuroscience, Journal Year: 2024, Volume and Issue: 18

Published: Feb. 16, 2024

Alzheimer's disease (AD) is a prevalent form of dementia that affects an estimated 32 million individuals globally. Identifying early indicators vital for screening at-risk populations and implementing timely interventions. At present, there urgent need sensitive biomarkers to screen at risk AD. Among all sensory biomarkers, olfaction currently one the most promising Olfactory dysfunction signifies decline in ability detect, identify, or remember odors. Within spectrum AD, impairment olfactory identification precedes detectable cognitive impairments, including mild (MCI) even stage subjective (SCD), by several years. closely linked clinical symptoms neuropathological accompanied significant structural functional abnormalities brain. behavior examination can subjectively evaluate abilities identification, threshold, discrimination. magnetic resonance imaging (fMRI) provide relatively objective assessment capabilities, with potential become tool exploring neural mechanisms damage Here, we review recent literature on characteristics, neuropathology, AD continuum. We focus changes detected behavioral fMRI assessments discuss these techniques MCI preclinical Despite challenges limitations existing research, has demonstrated its value assessing neurodegenerative diseases may serve as indicator future.

Language: Английский

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Patients recovering from COVID-19 who presented with anosmia during their acute episode have behavioral, functional, and structural brain alterations

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: Aug. 17, 2024

Patients recovering from COVID-19 commonly exhibit cognitive and brain alterations, yet the specific neuropathological mechanisms risk factors underlying these alterations remain elusive. Given significant global incidence of COVID-19, identifying that can distinguish individuals at developing is crucial for prioritizing follow-up care. Here, we report findings a sample patients consisting 73 adults with mild to moderate SARS-CoV-2 infection without signs respiratory failure 27 infections attributed other agents no history COVID-19. The participants underwent screening, decision-making task, MRI evaluations. We assessed presence anosmia requirement hospitalization. Groups did not differ in age or performance. who presented exhibited more impulsive alternative changes after shift probabilities (r = − 0.26, p 0.001), while required hospitalization showed perseverative choices 0.25, 0.003). Anosmia correlated measures, including decreased functional activity during thinning cortical thickness parietal regions, loss white matter integrity. Hence, could be factor considered when at-risk populations follow-up.

Language: Английский

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A Comprehensive Review of COVID-19-Related Olfactory Deficiency: Unraveling Associations with Neurocognitive Disorders and Magnetic Resonance Imaging Findings

Diagnostics, Journal Year: 2024, Volume and Issue: 14(4), P. 359 - 359

Published: Feb. 7, 2024

Olfactory dysfunction (OD) is one of the most common symptoms in COVID-19 patients and can impact patients’ lives significantly. The aim this review was to investigate multifaceted on olfactory system provide an overview magnetic resonance (MRI) findings neurocognitive disorders with COVID-19-related OD. Extensive searches were conducted across PubMed, Scopus, Google Scholar until 5 December 2023. included articles 12 observational studies 1 case report that assess structural changes structures, highlighted through MRI, 10 correlating loss smell or mood patients. MRI consistently indicate volumetric abnormalities, altered signal intensity bulbs (OBs), anomalies cortex among persistent correlation between OD deficits reveals associations cognitive impairment, memory deficits, depressive symptoms. Treatment approaches, including training pharmacological interventions, are discussed, emphasizing need for sustained therapeutic interventions. This points out several limitations current literature while exploring intricate effects its connection disorders. lack objective measurements some potential validity issues self-reports emphasize cautious interpretation. Our research highlights critical extensive larger samples, proper controls, deepen our understanding COVID-19’s long-term neurological dysfunctions.

Language: Английский

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Impairment of quality of life due to COVID-19-induced long-term olfactory dysfunction

Frontiers in Psychology, Journal Year: 2023, Volume and Issue: 14

Published: April 20, 2023

Olfactory dysfunction is one of many long-lasting symptoms associated with COVID-19, estimated to affect approximately 60% individuals and often lasting several months after infection. The daily life problems can cause a decreased quality life.

Language: Английский

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Reported neurological symptoms after severe acute respiratory syndrome coronavirus type 2 infection: A systematic diagnostic approach

European Journal of Neurology, Journal Year: 2023, Volume and Issue: 30(9), P. 2713 - 2725

Published: June 12, 2023

Abstract Background and purpose Following increasing demands of patients with suspected neurological symptoms after infection severe acute respiratory syndrome coronavirus type 2 (SARS‐CoV‐2), the Department Neurology at Medical University Vienna established a new outpatient clinic to systematically assess, diagnose, document complaints potentially associated prior SARS‐CoV‐2 infection. Methods The data presented here include prospectively collected 156 outpatients from May 2021 April 2022. Patients underwent semistandardized interviewing about reported onset infection, examination, comprehensive diagnostic workup. Results Reported included fatigue (77.6%), subjective cognitive impairment (72.4%), headache (47.7%), loss smell and/or taste (43.2%), sleep disturbances (42.2%). Most had mild disease (COVID‐19) course (84%) comorbidities (71%), which most frequent were psychiatric disorders (34%). Frequency was not age, sex, or severity COVID‐19 course. A workup revealed no abnormalities in clinical electrophysiological imaging assessments majority ( n = 143, 91.7%). Neuropsychological assessment subgroup 28, 17.9%) showed that impairments executive functions attention, anxiety, depression, somatization highly common. Conclusions In this systematic registry, we identified fatigue, impairment, as frequently persisting Structural findings rare. We also suspect link between growing burden pandemic on personal lives increase complaints.

Language: Английский

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Impact of post-COVID-19 olfactory disorders on quality of life, hedonic experiences and psychiatric dimensions in general population

BMC Psychiatry, Journal Year: 2024, Volume and Issue: 24(1)

Published: Feb. 8, 2024

Abstract Background and objective Olfactory disorders in COVID-19 impact quality of life may lead to psychological impairments. Prevalence ranges from 8 85%, persisting about 30% cases. This study aimed evaluate the 6-month post-COVID-19 on life, hedonic experiences, anxiety depression due olfactory disorders. Additionally, it sought compare psychophysical tests self-perceived evaluations. Methods A prospective, longitudinal was conducted over baseline (T0) 6 months (T1) individuals with persistent for more than weeks. Psychophysical employed Sniffin’ Sticks Test® (TDI score), evaluation used a Visual Analogue Scale. Quality assessed an Olfactive Disorder Questionnaire French version Life Diet Questionnaire. Hedonic experiences were gauged using Snaith-Hamilton Pleasure Scale, while dimensions measured by The State-Trait Anxiety Inventory, Post Traumatic Stress Checklist Hamilton Rating Scale Depression. Participants classified into “normosmic group” (NG) “olfactory (ODG) at T0 T1 based TDI score. Results Were included 56 participants (58.93% women, 41.07% men) mean age 39.04 years duration 5.32 months. At T1, ODG had significantly lower NG. No significant differences observed between groups. T0, evaluations correlated both NG dimensions, whereas only experiences. Conclusion Individuals after six demonstrated compromised Self-perceived played role influencing dimension presence These findings emphasize importance considering patients’ perceptions comprehensively assess their well-being. Trial registration ClinicalTrials.gov number (ID: NCT04799977).

Language: Английский

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Cognitive impairment after recovery from COVID-19: Frequency, profile, and relationships with clinical and laboratory indices

European Neuropsychopharmacology, Journal Year: 2023, Volume and Issue: 79, P. 22 - 31

Published: Dec. 7, 2023

Cognitive impairment (CI) is regarded as a remarkable burden in COVID-19 survivors. Its prevalence and profile, relationships with the disease clinical laboratory indices, remain unclear. The present study investigated, large sample of patients recovered from COVID-19, frequency CI both face-to-face screening tool comprehensive test battery (MCCB). also evaluated profile its indices psychopathological features. Out 1344 subjects assessed for eligibility, 736 completed phase 11 months after infection; 402 participated baseline an depth cognitive, assessment about one month later. More than third screened presented (COG+); it was associated to age, education, male gender, severity, presence anosmia, dyspnea at rest exertional during acute phase. COG+ showed higher severity depression, anxiety post-traumatic distress, worse global functioning, without CI. MCCB that 45% had involving attention, working memory, verbal learning, visual reasoning problem solving. Finally, neurocognitive functioning inversely correlated LDH blood levels, potential biomarker severity. According our findings, cognitive should be routinely periodically patients, especially older subjects, who experienced more severe symptoms. In case persisting dysfunctions training programs considered treatment strategies.

Language: Английский

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Type I interferon signaling, cognition and neurodegeneration following COVID-19: update on a mechanistic pathogenetic model with implications for Alzheimer’s disease

Frontiers in Human Neuroscience, Journal Year: 2024, Volume and Issue: 18

Published: March 18, 2024

COVID-19’s effects on the human brain reveal a multifactorial impact cognition and potential to inflict lasting neuronal damage. Type I interferon signaling, pathway that represents our defense against pathogens, is primarily affected by COVID-19. however, known mediate cognitive dysfunction upon its dysregulation following synaptopathy, microgliosis In previous studies, we proposed model of outside-in tonic IFN-I signaling in This disruption would be mediated crosstalk between central peripheral immunity, could potentially establish feed-forward leading neuroinflammation potentially, neurodegeneration. We for CNS, second-order mediators intrinsic disease-associated molecular patterns (DAMPs) such as proteopathic seeds, without requirement neuroinvasion sustain inflammation. Selective vulnerability neurogenesis sites then lead clinical manifestations anosmia impairment. Since inception at beginning pandemic, growing body studies has provided further evidence SARS-CoV-2 infection CNS cognition. Several preclinical have displayed tauopathy gene expression neuropathological data new cases, correspondingly. Furthermore, neurodegeneration identified with predilection extended olfactory network furthermore supports neuroanatomical concept model, independence from fulminant encephalitis cause this perspective, summarize plausible mechanism impairment setting, contribution Alzheimer’s disease interplay

Language: Английский

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Age-dependent phenotypes of cognitive impairment as sequelae of SARS-CoV-2 infection

Frontiers in Aging Neuroscience, Journal Year: 2025, Volume and Issue: 16

Published: Jan. 7, 2025

Cognitive changes associated with PASC may not be uniform across populations. We conducted individual-level pooled analyses and meta-analyses of cognitive assessments from eight prospective cohorts, comprising 2,105 patients 1,432 controls Argentina, Canada, Chile, Greece, India, Italy, Russia, the UK. The meta-analysis found no differences by country origin. profile severity impairment varied age, mild attentional observed in young middle-aged adults, but memory, language, executive function older adults. risk moderate to severe doubled Moderately or was significantly infection diagnoses (chi-square = 26.57, p ≤ 0.0001) anosmia 31.81, 0.0001). distinct age-related phenotypes recovering COVID-19. identified acute illness presence olfactory dysfunction as primary predictors dementia-like

Language: Английский

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An immersive virtual reality-based object-location memory task reveals spatial long-term memory alterations in Long-COVID

Behavioural Brain Research, Journal Year: 2024, Volume and Issue: 471, P. 115127 - 115127

Published: June 25, 2024

Object-location memory (OLM) is a type of declarative for spatial information and consists the individual's ability to establish accurate associations between objects their locations. Long-COVID describes long-term effects COVID-19 disease. patients show medial temporal lobe dysfunction neuropsychological alterations affecting memory. This study aimed assess OLM in group patients, n=66, Control healthy individuals with similar age sex composition, n=21, using an immersive virtual reality (iVR)-based task. We also explored performance iVR-based task general cognitive function (MoCA), both verbal (VSTM) visuospatial (SSTM) span. The showed fewer correct responses, made more attempts, invested time than group. Delayed was severely altered immediate participants. Better MoCA scores were strongly associated shorter times complete recall Besides, months elapsed since infection slightly responses 24-hour recalls. These results corroborate previous findings syndrome task, adding new evidence on this population. Implementing iVR tasks clinical research may improve our understanding disorders.

Language: Английский

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