Correlation between olfactory dysfunction and various clinical parameters in patients with multiple sclerosis

Abstract

Background/Aim. Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by myelin destruction and axon loss. Among various clinical manifestations of MS cognitive disorders are frequent. Olfactory disorders are also noticed but they are rarely considered in clinical practice. The aim of the present study was to examine frequency of olfactory dysfunction in patients with MS and its relationship to clinical parameters. Methods. Our study comprised 61 consecutive patients with definite MS who were hospitalized at the Department for Multiple Sclerosis and Other Immune- Mediated Disorders of CNS, Institute of Neurology, Clinical Center of Serbia, Belgrade, and 45 gender-, age- and education-matched healthy voluntaries. The Pocket Smell Test (PST) was used for examination of olfactory function. Cognitive functions were analyzed using the tests from the Brief Battery of Neuropsychological Tests: Paced Auditory Serial Addition Test 3-minute Version (PASAT 3'), Word List Generation (WLG) and Symbol Digit Modalities Test (SDMT). Results. Olfactory dysfunction was found in 26 (43%) MS patients and 5 (11%) controls (p = 0.001). Statistically significant positive correlation was found only between PST score and WLG scores (r = 0.297, p = 0.030). In comparison with the previously published normative values, our subjects with MS had decrease in the mean indices of the PASAT 3' in 28%, SDMT in 51% and WLG in 90% of the subjects. Conclusion. Olfactory dysfunction is frequent in our population of patients with MS. This disturbance correlates with the impairment of cognitive functions in these patients.Uvod/Cilj. Multipla skleroza (MS) je hronicno inflamatorno oboljenje centralnog nervnog sistema (CNS) karakterisano destrukcijom mijelina i gubitkom aksona. Medju raznolikim klinickim manifestacijama MS, kognitivni poremecaji su cesti, ali su zapazeni i olfaktorni poremecaji koji se u klinickom radu i, inace, retko razmatraju. Cilj ove studije bio je da analizira ucestalost poremecaja olfaktorne funkcije kod osoba sa MS, kao i povezanost ovog poremecaja sa razlicitim klinickim karakteristikama bolesti. Metode. U studiju su bile ukljucene dve grupe ispitanika: grupa obolelih od MS (n = 61) koji su hospitalno leceni na Odeljenju za multiplu sklerozu i druge imunske bolesti CNS, Instituta za neurologiju Klinickog centra Srbije i kontrolna grupa sastavljena od 45 zdravih ispitanika, uparenih po polu, uzrastu i stepenu obrazovanja. Za ispitivanje funkcije mirisnog sistema koriscen je brzi test za procenu ocuvanja mirisa (PST). Kod svih obolelih od MS stepen kognitivnog poremecaja procenjivan je primenom testova iz Kratke baterije neuropsiholoskih testova: test slusnih signala u razmacima od 3 sekunde (PASAT 3'), test analogije simbola i cifara (SDMT) i lista generisanih reci (WLG). Rezultati. Na PST testu, 26 (43%) obolelih od MS nije ispravno prepoznalo sva tri mirisa, u odnosu na 5 ispitanika kontrolne grupe (11%) (p = 0,001). Poredjenjem sa ranije publikovanim normativnim vrednostima, utvrdjeno je postojanje snizenih vrednosti sva tri kognitivna testa kod osoba sa MS, i to kod 28% bolesnika na PASAT 3' testu, kod 51% na SDMT testu i kod 90% na WLG testu. Statisticki znacajna pozitivna korelacija nadjena je samo izmedju PST skora i rezultata postignutih na testu WLG (r = 0,297, p = 0,030). Zakljucak. Olfaktorna funkcija cesto je poremecena u nasoj populaciji obolelih od MS. Ovaj poremecaj znacajno korelise sa kognitivnim ostecenjima kod ovih bolesnika.