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 Centre 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 analysed 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.