Olfactory identification associates with cognitive function and the third ventricle width in patients with relapsing-remitting multiple sclerosis

Differences in Brain Atrophy Pattern between People with Multiple Sclerosis and Systemic Diseases with Central Nervous System Involvement Based on Two-Dimensional Linear Measures

Conventional brain magnetic resonance imaging (MRI) in systemic diseases with central nervous system involvement (SDCNS) may imitate MRI findings of multiple sclerosis (MS). In order to better describe the MRI characteristics of these conditions, in our study we assessed brain volume parameters in MS (n = 58) and SDCNS (n = 41) patients using two-dimensional linear measurements (2DLMs): bicaudate ratio (BCR), corpus callosum index (CCI) and width of third ventricle (W3V). In SDCNS patients, all 2DLMs were affected by age (CCI p = 0.005, BCR p < 0.001, W3V p < 0.001, respectively), whereas in MS patients only BCR and W3V were (p = 0.001 and p = 0.015, respectively). Contrary to SDCNS, in the MS cohort BCR and W3V were associated with T1 lesion volume (T1LV) (p = 0.020, p = 0.009, respectively) and T2 lesion volume (T2LV) (p = 0.015, p = 0.009, respectively). CCI was associated with T1LV in the MS cohort only (p = 0.015). Moreover, BCR was significantly higher in the SDCNS group (p = 0.01) and CCI was significantly lower in MS patients (p = 0.01). The best predictive model to distinguish MS and SDCNS encompassed gender, BCR and T2LV as the explanatory variables (sensitivity 0.91; specificity 0.68; AUC 0.86). Implementation of 2DLMs in the brain MRI analysis of MS and SDCNS patients allowed for the identification of diverse patterns of local brain atrophy in these clinical conditions.

Processing speed test: Results from a Japanese normative sample of healthy participants compared with a US normative sample

BACKGROUND

The Processing Speed Test (PST), a validated iPad®-based cognitive screening test for MS, has been applied to the cognitive assessment of Japanese MS patients using US normative data.

METHODS

To develop PST normative data from Japanese healthy volunteers and compare the PST score distribution between Japanese and US healthy volunteers, 254 healthy Japanese-speaking volunteers were enrolled and stratified by age (20-65 years). Potential participants with a Mini-Mental State Examination score < 27 were excluded. PST raw scores (total correct) were from the Japan cohort and compared with age-restricted US normative data and propensity score-matched data created by matching sex, age, and educational level from a published study of 428 healthy participants. PST score distributions and standardized z-scores were compared using t-test and Kolmogorov-Smirnov test statistics.

RESULTS

The mean age of the Japan cohort was 44.1 years. The PST scores of Japanese volunteers were significantly different from those of the age-restricted (mean ± SD 61.8 ± 10.1 vs 53.7 ± 10.8; p < 0.001) and the propensity score-matched US cohort (62.1 ± 10.1 vs 53.3 ± 10.6; p < 0.001).

CONCLUSION

Regression analyses centered on US normative data could underestimate disease severity in Japanese MS patients, suggesting that separate normative data should be considered for each population sample.

The effects of cognition, quality of life, and fatigue on olfactory function in patients with multiple sclerosis

AIM

The frequency of olfactory dysfunction in patients with Multiple Sclerosis (MS) has revealed very different results in studies. Some studies have shown that olfactory dysfunction may be associated with cognitive impairment and poor quality of life. In these studies, different odor tests and cognitive tests were used and different results were obtained.

MATERIALS AND METHODS

Forty literate patients over the age of 18 and 24 healthy volunteers of similar age and education were included in the study. Sniffin' Sticks Odor Test, California Verbal Learning Test II, Symbol Digit Modalities Test, Revised Brief Visuospatial Memory Test, Trail-Making Test, Quality of Life Short Form-36, Fatigue Impact Scale, Beck Depression Inventory, and Beck Anxiety Inventory were applied to the individuals.

RESULTS

Olfactory dysfunction was detected in 50 % of the patients. High disability rate, low cognitive functions, low quality of life, and fatigue were identified as the factors affecting olfactory function negatively. Odor discrimination and identification abilities were associated with disability level and cognitive functions, whereas quality of life was linked to odor threshold scores. The olfactory function and cognitive abilities of patients with progressive MS (n = 5) were worse than those of patients with relapsing remitting MS (n = 35).

CONCLUSION

Olfactory dysfunction is common in patients with MS and is associated with disability and quality of life. Olfactory function can be used in the follow-up of patients and olfactory dysfunction deserves further study as a metric that might emerge as a biomarker.

Olfactory impairment in COVID-19: Two methods for the assessment of olfactory function

Background

Olfactory impairment is a major symptom of COVID-19. Is it necessary for COVID-19 patients to perform the detection of olfactory function, even how to select the olfactory psychophysical assessment tool.

Methods

Patients infected with SARS-CoV-2 Delta variant were firstly taken into three categories (mild, moderate, and severe) according to the clinical classification. The Odor Stick Identification Test for the Japanese (OSIT-J) and the Simple Olfactory Test were used to assess olfactory function. Moreover, these patients were divided into three groups based on the results of the olfactory degree (euosmia, hyposmia, and dysosmia), too. The statistical analysis of the correlations between olfaction and clinical characteristics of patients were performed.

Results

Our study demonstrated that the elderly men of Han were more susceptible to infected SARS-CoV-2, the clinical symptoms of the COVID-19 patients showed a clear correspondence with the disease type and the degree of olfactory disturbance. Whether or not to vaccinate and whether to complete the whole course of vaccination was closely related to the patient's condition. OSIT-J Test and Simple Test were consistent in our work, indicating that olfactory grading would worsen with the aggravation of symptoms. Furthermore, the OSIT-J method maybe better than Simple Olfactory Test.

Conclusion

The vaccination has an important protective effect on the general population, and vaccination should be vigorously promoted. Moreover, it is necessary for COVID-19 patients to perform the detection of olfactory function, and the easier, faster and less expensive method for determination of olfactory function should be utilized to COVID-19 patients as the vital physical examination.

Olfactory Dysfunction Reflects Disease Progression in Japanese Patients with Multiple Sclerosis

Objective Olfactory dysfunction is an important clinical feature in patients with multiple sclerosis (MS). The incidence and extent of olfactory dysfunction are reportedly higher in secondary progressive (SP) MS than in relapsing and remitting (RR) MS. We investigated the use of olfactory dysfunction for evaluating the disease status of Japanese patients with MS. Methods Olfactory identification was evaluated using the Odor Stick Identification Test for the Japanese (OSIT-J) in patients with RRMS (n=40) and SPMS (n=11) and compared the findings with those of healthy controls (n=40). Patients with RRMS for more than 10 years (L-RRMS, n=10) were included in the RRMS group. The cognitive function was evaluated using the Japanese version of the Wechsler Adult Intelligence Scale, 3rd edition. The third ventricle width (3rd VW) was measured as a marker of central brain atrophy using magnetic resonance imaging. Results SPMS patients had significantly lower OSIT-J scores than RRMS and L-RRMS patients. More SPMS patients had OSIT-J scores below the lower limit of the normal score (LLN) than RRMS patients. The LLN effectively discriminated between RRMS and SPMS (sensitivity 70%, specificity 91.5%, area under the curve 0.933, 95% confidence interval 0.874-1.000). Patients with SPMS had a significantly lower processing speed and larger 3rd VW than those with RRMS or L-RRMS. Conclusion The olfactory dysfunction was worse, along with cognitive impairment and brain atrophy, in SPMS patients than in RRMS patients, independent of disease duration, in our Japanese population. This directly reflected the disease progression and may have been able to distinguish SPMS from RRMS, independent of ethnic and cultural background.

Olfactory dysfunction in patients with multiple sclerosis; A systematic review and meta-analysis

Background

The importance and prevalence of olfactory dysfunction is recently gaining attention in patients with multiple sclerosis (MS) as a result of their chronic inflammatory disease, yet different prevalence rates are reported for it. Therefore, we have designed this systematic review to estimate the pooled prevalence of olfactory dysfunction in patients with MS. To our knowledge, this is the first systematic review and meta-analysis on the prevalence of olfactory dysfunction in MS patients.

Methods

We searched PubMed, Scopus, EMBASE, Web of Science, ProQuest, and gray literature including references from the identified studies, review studies, and conference abstracts which were published up to January 2021. Articles that were relevant to our topic and could provide information regarding the prevalence of olfactory dysfunction, or the scores of smell threshold, discrimination, or identification (TDI) among MS patients and healthy individuals were included. The pooled prevalence was calculated using a random-effects model and a funnel plot and Egger’s regression test were used to see publication bias.

Results

The literature search found 1630 articles. After eliminating duplicates, 897 articles remained. Two conference abstracts were included for final analysis. A total of 1099 MS cases and 299 MS patients with olfactory dysfunction were included in the analysis. The pooled prevalence of olfactory dysfunction in the included studies was 27.2%. Also, the overall TDI score in MS patients was lower than that in the control group, and the level of Threshold, Discrimination, and Identification per se were lower in MS compared with control respectively.

Conclusion

The results of this systematic review show that the prevalence of olfactory dysfunction in MS patients is high and more attention needs to be drawn to this aspect of MS.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Two-dimensional measurements with cut-off values are useful for assessing brain volume, physical disability, and processing speed in multiple sclerosis

BACKGROUND

Two-dimensional (2D) measures have been proposed as potential proxy measures for whole-brain volume in multiple sclerosis (MS); however, cut-off values that determine the degree of brain volume loss (BVL) have not been established. Since we had previously developed a system to categorize MS patients into clusters with significantly different degrees of BVL, we tried to identify cut-off values for 2D measurements that can discriminate MS patients on the basis of disease severity associated with brain atrophy.

METHODS

In this cross-sectional analysis, ninety-one consecutive Japanese MS patients-clinically isolated syndrome (5%), relapsing-remitting MS (78%) and progressive MS (17%)-were categorized into two clusters (CL1 and CL2) with a significantly different degree of BVL using the method described in our previous study. MS patients were also evaluated for 2D measurements, namely, third ventricle width, lateral ventricle width (LVW), bicaudate ratio (BCR), and corpus callosum index (CCI). Thereafter, we performed receiver operating characteristic analysis to determine the cut-off values of the 2D measurements for categorizing the MS patients into two clusters.

RESULTS

We identified optimal cut-off values for each 2D measure with high specificity and sensitivity. The cut-off values for LVW, BCR, and CCI divided the MS patients into two subgroups, in which whole-brain and grey matter volume, EDSS, and processing speed were significantly different.

CONCLUSION

LVW, BCR, and CCI with particular cut-off values are useful to discriminate MS patients with decreased brain volume, physical disability, and processing speed.

Olfactory Dysfunction and Cognition in Radiologically Isolated Syndrome and Relapsing-Remitting Multiple Sclerosis

BACKGROUND

Multiple Sclerosis (MS) is a neuroinflammatory, neurodegenerative, demyelinating disease that causes cognitive, olfactory, and other neurological dysfunctions. Radiologically Isolated Syndrome (RIS), in which only radiological findings are monitored, is accepted as the preclinical stage of demyelinating disease and is considered an important period for disease pathology. Therefore, in this study, we aimed to evaluate the olfactory and cognitive functions and their clinical correlation in RIS and Relapsing-Remitting MS (RRMS) patients and a healthy control group.

METHODS

Our study included 10 RRMS patients, 10 RIS patients, and 10 healthy controls. We conducted an olfactor evaluation via the "Sniffin' Sticks" test. The subjects underwent a neuropsychometric test battery to evaluate cognitive functions, including memory, visuospatial, and executive functions. Depression was evaluated using the Beck depression scale. Fatigue and daily life activity were evaluated using the Fatigue Severity Scale (FSS) and the 36-Item Short Form Survey (SF-36), respectively. Disability assessment was done with the Expanded Disability Status Scale (EDSS).

RESULTS

RRMS and RIS patients' olfactory test scores were significantly different from those in the control group (p < 0.05). There was a significant difference between the odor threshold scores of patients in the RRMS and RIS groups. There was a significant correlation between memory-oriented cognitive tests and olfactory tests in the RRMS and RIS groups.

CONCLUSION

Olfactory dysfunction can be seen in RIS patients, like in RRMS patients. Cognitive and olfactory dysfunction may be together a sign of degeneration in demyelinating diseases.

Olfactory Dysfunction in Patients With Relapsing-Remitting Multiple Sclerosis Treated With Disease-Modifying Therapies

BACKGROUND

Olfactory dysfunction evaluated with time-consuming tests was more common in patients with multiple sclerosis (MS) than in controls and correlated with neurological deficit. The aim of the present study was to compare olfactory function between patients with relapsing-remitting MS (RRMS) and controls with short and simple screening tool-the Sniffin' Sticks Identification Test (SSIT)-and search for its association with clinical and radiological features of the disease.

METHODS

The study included 30 controls and 30 patients with RRMS treated with disease-modifying therapies-injectables (interferon β or glatiramer acetate, N = 18) and oral drugs (dimethyl fumarate or fingolimod, N = 12). Hyposmia was defined as a score of 6 points or fewer in the SSIT olfactory test. The data concerning number of previous relapses, disability in Expanded Disability Status Scale (EDSS), and recent brain magnetic resonance imaging (MRI) scan were collected. Moreover, thalamic volume and third ventricle width were recorded in every patient. Additionally, cognition and fatigue in patients were evaluated 24 months after olfactory assessment with the Symbol Digit Modalities Test (SDMT) and Fatigue Scale for Motor and Cognitive Functions (FSMC), respectively.

RESULTS

Patients with RRMS had a higher risk of hyposmia than controls (66.7% vs 36.7%, OR = 1.82, 95% CI, 1.10-3.67, P = .02). Neither inflammatory (number of previous relapses or new brain MRI lesions) nor neurodegenerative (EDSS, SDMT, and FSMC scores; thalamic volume; third ventricle width) MS features did not correlate with SSIT score (P > .05). In patients treated with oral drugs, olfactory dysfunction correlated with FSMC cognitive subscale (r = -0.90, P = .006).

CONCLUSIONS

Olfactory dysfunction is nearly twice as common in RRMS as in controls and correlates with fatigue level in patients treated with dimethyl fumarate or fingolimod.

Smell as a clinical-marker for functional limitations in multiple sclerosis: A pilot study

BACKGROUND

Olfactory dysfunction is a common symptom of multiple sclerosis (MS). The questions of whether and to what degree olfactory dysfunction can serve as a clinical marker of MS disability (i.e. cognitive impairments and functional limitations) are not yet answered. The current study aimed to explore associations between olfactory function (i.e. smell identification) with cognitive capacities, functional performance and quality of life (QOL) in persons with MS.

METHODS

Olfactory function was measured by the University of Pennsylvania Smell Identification Test (UPSIT). Functional ability was assessed by the Actual Reality^TM (AR) task. QOL was assessed by the Multiple Sclerosis Quality of Life-54 (MSQOL-54). Cognition was assessed by the Brief International Cognitive Assessment for MS (BICAMS) in 23 MS patients and 15 matched healthy controls.

RESULTS

MS patients had lower UPSIT scores than healthy controls. Worse UPSIT scores were associated with reduced performances on the BICAMS and AR task as well as lower MSQOL-54 scores. Specifically, UPSIT scores were related to MSQOL-54 scores independent of BICAMS composite scores, while the relationship between UPSIT score and AR performance was mediated by BICAMS composite score.

CONCLUSION

This study confirms previous studies which concluded that olfactory function is impaired in MS. Furthermore, olfactory dysfunction is related to limitations in activity performance and QOL. Taken together with previous studies, olfactory function may be considered as a clinical marker related to MS disability. Longitudinal studies are needed to confirm these results.