Author Of 1 Presentation
P0893 - Olfactory dysfunction in patients with relapsing-remitting multiple sclerosis treated with disease modifying therapies (ID 357)
Abstract
Background
Previous studies showed that olfactory dysfunction was more common in patients with multiple sclerosis (MS) than in healthy individuals and correlated with neurological deficit and cognitive disturbances. However, most studies required the use of time-consuming olfaction examination.
Objectives
The aim of this study was to assess olfactory function in patients with relapsing-remitting MS (RRMS) and its possible correlation with inflammatory and neurodegenerative features of the disease with the use of short and simple screening olfactory test.
Methods
The study included 30 controls and 30 patients with RRMS matched for age and gender, all of Caucasian origin. Patients with RRMS were treated with disease modifying therapies (DMT) – 18 with injectables (interferon beta or glatiramer acetate) and 12 with oral drugs (dimethyl fumarate or fingolimod). Olfactory function was assessed with the Sniffin’ Sticks Identification Test (SSIT) comprising 8 pens with different scents. The score of 6 or less points was defined as hyposmia. The data concerning number of previous relapses, disability in Expanded Disability Status Scale (EDSS) and new T2 or gadolinium enhancing brain MRI lesions were collected from each patient. Cognition and fatigue in patients were evaluated with Symbol Digit Modalities Test (SDMT) and Fatigue Scale for Motor and Cognitive Functions (FSMC), respectively. Moreover, the volume of thalami and the width of the third ventricle on brain MRI were recorded in every patient.
Results
Patients with RRMS had nearly two-fold higher risk of hyposmia (odds ratio, OR=1.82, 95%CI: 1.10–3.67, p=0.02). The SSIT score did not correlate with disease duration (r=0.28, p=0.13), the length of DMT use (r=0.05, p=0.78) and the number of previous DMTs (r=0.26, p=0.17). Neither inflammatory (number of previous relapses, number of new T2 or gadolinium enhancing lesions on recent brain MRI) nor neurodegenerative (EDSS score and its progression, SDMT and FSMC scores, volume of thalami and the width of the third ventricle on MRI) MS features did not show any correlation with SSIT score (p>0.05). Hyposmia also did not correlate with new disease activity within the next 12 months after olfactory evaluation in relation to new clinical relapses (r=0.20, p=0.28) and new T2 (r=0.17, p=0.36) or gadolinium enhancing brain MRI lesions (r=-0.07, p=0.71). In the subgroup of patients treated with oral DMTs olfactory dysfunction strongly correlated with FSMC score (r=-0.90, p=0.006), mainly with its cognitive subscale (r=-0.90, p=0.006). Such correlation was not observed for patients receiving injectables.
Conclusions
Olfactory dysfunction is common in RRMS and correlates with the level of fatigue in cognitive functions in patients treated with dimethyl fumarate or fingolimod.