-
Parkinsonism & Related Disorders May 2024Olfactory dysfunction and REM sleep behavior disorder (RBD) are associated with distinct cognitive trajectories in the course of Parkinson's disease (PD). The underlying...
INTRODUCTION
Olfactory dysfunction and REM sleep behavior disorder (RBD) are associated with distinct cognitive trajectories in the course of Parkinson's disease (PD). The underlying neurobiology for this relationship remains unclear but may involve distinct patterns of neurodegeneration. This study aimed to examine longitudinal cortical atrophy and thinning in early-stage PD with severe olfactory deficit (anosmia) without and with concurrent probable RBD.
METHODS
Longitudinal MRI data over four years of 134 de novo PD and 49 healthy controls (HC) from the Parkinson Progression Marker Initiative (PPMI) cohort were analyzed using a linear mixed-effects model. Patients were categorized into those with anosmia by the University of Pennsylvania Smell Identification Test (UPSIT) score ≤ 18 (AO+) and those without (UPSIT score > 18, AO-). The AO+ group was further subdivided into AO+ with probable RBD (AO+RBD+) and without (AO+RBD-) for subanalysis.
RESULTS
Compared to subjects without baseline anosmia, the AO+ group exhibited greater longitudinal declines in both volume and thickness in the bilateral parahippocampal gyri and right transverse temporal gyrus. Patients with concurrent anosmia and RBD showed more extensive longitudinal declines in cortical volume and thickness, involving additional brain regions including the bilateral precuneus, left inferior temporal gyrus, right paracentral gyrus, and right precentral gyrus.
CONCLUSIONS
The atrophy/thinning patterns in early-stage PD with severe olfactory dysfunction include regions that are critical for cognitive function and could provide a structural basis for previously reported associations between severe olfactory deficit and cognitive decline in PD. Concurrent RBD might enhance the dynamics of cortical changes.
Topics: Humans; Parkinson Disease; Male; Female; Aged; Middle Aged; Longitudinal Studies; Magnetic Resonance Imaging; REM Sleep Behavior Disorder; Olfaction Disorders; Atrophy; Anosmia; Disease Progression; Brain
PubMed: 38430690
DOI: 10.1016/j.parkreldis.2024.106072 -
NeuroImage. Clinical 2023To explore the neuropsychological profile and the integrity of the olfactory network in patients with COVID-19-related persistent olfactory dysfunction (OD).
OBJECTIVES
To explore the neuropsychological profile and the integrity of the olfactory network in patients with COVID-19-related persistent olfactory dysfunction (OD).
METHODS
Patients with persistent COVID-19-related OD underwent olfactory assessment with Sniffin' Sticks and neuropsychological evaluation. Additionally, both patients and a control group underwent brain MRI, including T1-weighted and resting-state functional MRI (rs-fMRI) sequences on a 3 T scanner. Morphometrical properties were evaluated in olfaction-associated regions; the rs-fMRI data were analysed using graph theory at the whole-brain level and within a standard parcellation of the olfactory functional network. All the MR-derived quantities were compared between the two groups and their correlation with clinical scores in patients were explored.
RESULTS
We included 23 patients (mean age 37 ± 14 years, 12 females) with persistent (mean duration 11 ± 5 months, range 2-19 months) COVID-19-related OD (mean score 23.63 ± 5.32/48, hyposmia cut-off: 30.75) and 26 sex- and age-matched healthy controls. Applying population-derived cut-off values, the two cognitive domains mainly impaired were visuospatial memory and executive functions (17 % and 13 % of patients). Brain MRI did not show gross morphological abnormalities. The lateral orbital cortex, hippocampus, and amygdala volumes exhibited a reduction trend in patients, not significant after the correction for multiple comparisons. The olfactory bulb volumes did not differ between patients and controls. Graph analysis of the functional olfactory network showed altered global and local properties in the patients' group (n = 19, 4 excluded due to artifacts) compared to controls. Specifically, we detected a reduction in the global modularity coefficient, positively correlated with hyposmia severity, and an increase of the degree and strength of the right thalamus functional connections, negatively correlated with short-term verbal memory scores.
DISCUSSION
Patients with persistent COVID-19-related OD showed an altered olfactory network connectivity correlated with hyposmia severity and neuropsychological performance. No significant morphological alterations were found in patients compared with controls.
Topics: Female; Humans; Infant; Smell; Olfaction Disorders; Anosmia; COVID-19; Cognition; Cognitive Dysfunction
PubMed: 37104928
DOI: 10.1016/j.nicl.2023.103410 -
The Lancet. Neurology Jan 2021
Topics: Ageusia; Anosmia; COVID-19; Cerebrovascular Disorders; Guillain-Barre Syndrome; Humans; Inflammation
PubMed: 33340476
DOI: 10.1016/S1474-4422(20)30451-8 -
Journal of Biophotonics Jun 2023Along with other COVID-19 clinical manifestations, management of both olfactory and gustatory dysfunction have drawn a considerable attention. Photobiomodulation (PBM)...
Along with other COVID-19 clinical manifestations, management of both olfactory and gustatory dysfunction have drawn a considerable attention. Photobiomodulation (PBM) has emerged to be a possible effective therapy in restoring taste and smell functionality, but the evidence is scarce. Hence, the present pilot study is aimed to evaluate the effectiveness of intranasal and intraoral PBM administrations in management of anosmia and ageusia respectively. Twenty Caucasian subjects who diagnosed with anosmia and ageusia were recruited. Visual analogue scale was utilised to evaluate patients' self-reported for both olfactory and gustatory functionality. The laser-PBM parameters and treatment protocols for anosmia and ageusia were as follows respectively: 660 nm, 100 mW, two points intranasally, 60 J/session, 12 sessions; dual wavelengths (660 nm and 808 nm), 100 mW, three points intraorally, 216 J/session, 12 sessions. Our results showed a significant functionality improvement of both olfactory and gustatory functionality. Extensive studies with large data and long-term follow-up period are warranted.
Topics: Humans; COVID-19; Ageusia; Anosmia; Pilot Projects; SARS-CoV-2; Olfaction Disorders
PubMed: 36929335
DOI: 10.1002/jbio.202300003 -
Personality & Social Psychology Bulletin Aug 2022Olfactory deficits can play a detrimental role in everyday social functioning. Perception of 3-hydroxy-3-methylhexanoic acid (HMHA)-a body odor component-could also be...
Olfactory deficits can play a detrimental role in everyday social functioning. Perception of 3-hydroxy-3-methylhexanoic acid (HMHA)-a body odor component-could also be linked to this research area. However, no study so far has addressed the problem of HMHA perception in the context of the previously reported relationship between olfactory abilities and social difficulties. Here, we tested whether HMHA-specific anosmia predicted loneliness understood both as a cognitive evaluation of social participation and as one's social isolation, and we additionally analyzed the effects and correlates of HMHA perception in relation to sightedness. The study comprised 196 people, of whom 99 were blind. We found that subjects with blindness declared particularly high loneliness, but HMHA anosmia and the interaction of sightedness and HMHA anosmia predicted neither loneliness nor social withdrawal. In addition, HMHA pleasantness was positively associated with social withdrawal of the subjects with blindness and emotional loneliness correlated with HMHA familiarity regardless of sightedness.
Topics: Anosmia; Blindness; Humans; Hydroxy Acids; Loneliness; Odorants
PubMed: 34323148
DOI: 10.1177/01461672211034376 -
Current Opinion in Neurology Jun 2021To provide an overview on current knowledge of neurological symptoms and complications of COVID-19, and to suggest management concepts. (Review)
Review
PURPOSE OF REVIEW
To provide an overview on current knowledge of neurological symptoms and complications of COVID-19, and to suggest management concepts.
RECENT FINDINGS
Headache, dizziness, excessive tiredness, myalgia, anosmia/hyposmia, and ageusia/dysgeusia are common nonspecific neurological manifestations during early COVID-19 disease found in the majority of patients. Less frequent but more severe and specific neurological manifestations include Guillain--Barré syndrome, encephalopathy, encephalitis/meningitis, epileptic seizures, and cerebrovascular events. Beyond standard neurological examination, these require a more extensive work-up, including cerebrospinal fluid assessment, neurophysiological evaluation, neuroimaging, and cognitive testing. Symptomatic treatment is advisable unless the neurological complication's immune pathogenesis is proven.
SUMMARY
Neurological manifestations of COVID-19 occur during the acute, para-infectious, and 'recovery' phase. Therapeutic management depends on the clinical presentation and neurological work-up.
Topics: Anosmia; Brain Diseases; COVID-19; Humans; Nervous System Diseases
PubMed: 33709973
DOI: 10.1097/WCO.0000000000000930 -
Annals of the Royal College of Surgeons... Feb 2024Anosmia can have a significant impact on well-being and quality of life. Due to an ageing population and the coronavirus disease 2019, increasing numbers of patients are...
INTRODUCTION
Anosmia can have a significant impact on well-being and quality of life. Due to an ageing population and the coronavirus disease 2019, increasing numbers of patients are seeking online information on anosmia. This report systematically assesses the readability and quality of online information on anosmia.
METHODS
The terms 'anosmia' and 'loss of smell' were entered into Google. The first 50 websites generated for each search term were screened. Readability was assessed using the Flesch-Kincaid Reading Ease Score (FRES), Flesch-Kincaid Grade Level (FKGL), Simple Measure of Gobbledygook (SMOG) Index and Gunning Fog Index (GFI). Quality was assessed using the DISCERN instrument. Spearman's correlation between quality and readability was calculated.
RESULTS
A total of 79 websites met the inclusion criteria. The mean and 95% confidence interval for the FRES, FKGL, SMOG, GFI and DISCERN scores were 46.31 (42.94-49.68), 12.00 (11.27-12.73), 10.70 (10.16-11.23), 14.62 (13.85-15.39) and 2.90 (2.69-3.11), respectively. Significant negative correlation was noted between the DISCERN and FRES (=-0.500; <0.05).
DISCUSSION
Online information on anosmia is written above the recommended reading age guidance in the UK, and has moderate deficiencies in quality. As a result, the information may be used inappropriately and could result in worse health outcomes. We recommend that patients are directed to websites produced by health providers or nonprofit organisations that develop material for patient health education.
CONCLUSIONS
Online information on anosmia is of low readability and moderate quality. Healthcare professionals should direct patients towards high-quality resources written for the layperson.
Topics: Humans; Comprehension; Anosmia; Quality of Life; Smog; Reading; Internet
PubMed: 37051757
DOI: 10.1308/rcsann.2022.0147 -
Clinical and Experimental Pharmacology... Apr 2022Olfactory dysfunction (OD) is a recognized symptom of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is independently associated with... (Review)
Review
Olfactory dysfunction (OD) is a recognized symptom of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is independently associated with neurodegenerative disorders. Moreover, the central nervous system manifestations in patients infected with the coronavirus-2019 (COVID-19) have demonstrated cognitive decline and neuropsychiatric manifestations. Hence, OD in COVID-19 necessitates perusal of its mechanism and available treatment options to avert possible development of neurocognitive sequelae of the pandemic. The article presents a literature review organized from the published information about olfactory training (OT) for OD during COVID-19. The methodology comprised retrieval of available literature from database searches and subsequent scrutinization of relevant information. Inferentially, injury to the sustentacular cells, possessing angiotensin-converting enzyme 2 (ACE-2) receptors, is an important mechanism causing OD in COVID-19. Olfactory dysfunction may be prolonged in severe cases of anosmia predisposing to neurodegenerative and cognitive impairment in COVID-19 infection. Olfactory training demonstrates an effective treatment for OD based on human and animal-derived evidence through recent studies. It curtails the progression of OD, besides inducing neural rearrangement and changes in functional connectivity in patients receiving OT. Additionally, contemporary reports support that the administration of OT for COVID-induced anosmia is effective and encompasses no significant adverse effects. The present review highlights the prominence of olfactory training as a recommended intervention for OD in COVID-19. This review can guide the clinicians in curbing neurological repercussions of COVID besides enhancing cognitive rehabilitation through olfactory training.
Topics: Anosmia; COVID-19; Humans; Olfaction Disorders; Smell
PubMed: 35090056
DOI: 10.1111/1440-1681.13626 -
Revista Da Associacao Medica Brasileira... Oct 2021This study aimed to investigate whether the volume and morphology of the olfactory bulb are effective in the occurrence of anosmia in patients after COVID-19 infection.
OBJECTIVE
This study aimed to investigate whether the volume and morphology of the olfactory bulb are effective in the occurrence of anosmia in patients after COVID-19 infection.
METHODS
The olfactory bulbus volume was calculated by examining the brain magnetic resonance imaging of cases with positive (+) COVID-19 polymerase chain reaction test with and without anosmia. Evaluated magnetic resonance imaging images were the scans of patients before they were infected with COVID-19. The olfactory bulbus and olfactory nerve morphology of these patients were examined. The brain magnetic resonance imaging of 59 patients with anosmia and 64 controls without anosmia was evaluated. The olfactory bulb volumes of both groups were calculated. The olfactory bulb morphology and olfactory nerve types were examined and compared between the two groups.
RESULTS
The left and right olfactory bulb volumes were calculated for the anosmia group and control group as 47.8±15/49.3±14.3 and 50.5±9.9/50.9±9.6, respectively. There was no statistically significant difference between the two groups. When the olfactory bulb morphology was compared between the two groups, it was observed that types D and R were dominant in the anosmia group (p<0.05). Concerning olfactory nerve morphology, type N was significantly more common in the control group (p<0.05).
CONCLUSIONS
According to our results, the olfactory bulb volume does not affect the development of anosmia after COVID-19. However, it is striking that the bulb morphology significantly differs between the patients with and without anosmia. It is clear that the evaluation of COVID-19-associated smell disorders requires studies with a larger number of patients and a clinicoradiological approach.
Topics: Anosmia; COVID-19; Humans; Magnetic Resonance Imaging; Olfaction Disorders; Olfactory Bulb; SARS-CoV-2
PubMed: 35018981
DOI: 10.1590/1806-9282.20210678 -
European Archives of... Jul 2021From the start of the pandemic, many European otolaryngologists observed an unprecendented number of anosmic patients. Early reports proposed that anosmia could be the... (Review)
Review
BACKGROUND
From the start of the pandemic, many European otolaryngologists observed an unprecendented number of anosmic patients. Early reports proposed that anosmia could be the first or even the only symptom of COVID-19 infection, prompting calls for self-isolation in affected patients.
METHODS
In the present article, we review the COVID-19 anosmia literature and try to answer the following two questions: first, why is COVID-19 infection responsible for such a high incidence of anosmia? Second, in patients with more severe forms is anosmia really less prevalent and why?
RESULTS
In terms of the etiology of olfactory dysfunction, several hypotheses were proposed at the outset of the pandemic; that olfactory cleft inflammation and obstruction caused a localized conductive loss, that there was injury to the sustentacular supporting cells in the olfactory epithelium or, given the known neurotropic potential of coronavirus, that the virus could invade and damage the olfactory bulb. Olfactory cleft obstruction may contribute to the olfactory dysfunction in some patients, perhaps most likely in those that show very early resolution, it cannot account for the loss in all patients. Moreover, disordered regrowth and a predominance of immature neurons have been shown to be associated with parosmia, which is a common finding amongst patients with Covid-related anosmia. A central mechanism therefore certainly seems to be consistent with the group of patients with more prolonged olfactory deficits. Sustentacular cells showing ACE-2 immunohistochemical expression 200 to 700 times greater than nasal or tracheal epithelia seem to be the main SARS-CoV-2 gateway. As the pathophysiology of COVID-19 anosmia seems to be better understood, the question of why patients with a moderate to severe form of COVID-19 infection have less olfactory involvement remains unresolved. Different potential explanations are discussed in this review.
CONCLUSIONS
The last 5 months have benefited from great international collaborative research, first highlighting and then proving the value of loss of smell and taste as a symptom of COVID-19. Adoption of loss of smell into the case definition by international public health bodies will facilitate control of disease transmission.
Topics: Anosmia; COVID-19; Humans; Olfaction Disorders; SARS-CoV-2; Smell
PubMed: 32909060
DOI: 10.1007/s00405-020-06285-0