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. 2014 Jul 21;9(7):e103151.
doi: 10.1371/journal.pone.0103151. eCollection 2014.

Detection of Olfactory Dysfunction Using Olfactory Event Related Potentials in Young Patients With Multiple Sclerosis

Free PMC article

Detection of Olfactory Dysfunction Using Olfactory Event Related Potentials in Young Patients With Multiple Sclerosis

Fabrizia Caminiti et al. PLoS One. .
Free PMC article


Background: Several studies reported olfactory dysfunction in patients with multiple sclerosis. The estimate of the incidence of olfactory deficits in multiple sclerosis is uncertain; this may arise from different testing methods that may be influenced by patients' response bias and clinical, demographic and cognitive features.

Aims: To evaluate objectively the olfactory function using Olfactory Event Related Potentials.

Materials and methods: We tested the olfactory function of 30 patients with relapsing remitting multiple sclerosis (mean age of 36.03±6.96 years) and of 30 age, sex and smoking-habit matched healthy controls by using olfactory potentials. A selective and controlled stimulation of the olfactory system to elicit the olfactory event related potentials was achieved by a computer-controlled olfactometer linked directly with electroencephalograph. Relationships between olfactory potential results and patients' clinical characteristics, such as gender, disability status score, disease-modifying therapy, and disease duration, were evaluated.

Results: Seven of 30 patients did not show olfactory event related potentials. Sixteen of remaining 23 patients had a mean value of amplitude significantly lower than control group (p<0.01). The presence/absence of olfactory event related potentials was associated with dichotomous expanded disability status scale (p = 0.0433), as well as inversely correlated with the disease duration (r = -0.3641, p = 0.0479).

Conclusion: Unbiased olfactory dysfunction of different severity found in multiple sclerosis patients suggests an organic impairment which could be related to neuroinflammatory and/or neurodegenerative processes of olfactory networks, supporting the recent findings on neurophysiopathology of disease.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.


Figure 1
Figure 1. Averaged OERP traces.
Filter band-pass 0.01–30 Hz. EEG averaging from 500 ms pre-stimulus to 2000 ms post-stimulus. (a) OERPs of healthy control subject; (b) OERPs of MS patient with normal latency and amplitude; (c) OERPs of MS patient without olfactory responses; (d) OERPs of MS patient with reduced N1-P2 amplitude and normal latency.
Figure 2
Figure 2. Box-plots comparing the parameters of OERP components of MS patients and healthy controls on Fz, Cz, Pz electrodes.
Box-plots represent the distribution of latency and amplitude of N1 and P2 components for both MS patients and controls in Fz, Cz, Pz canals. Significant differences emerged only in P2 amplitude values, which were lower in MS patients than in controls (Fz: p<0.0001; Cz: p<0.0001; Pz: p<0.001).

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    1. Doty RL (2012) Olfaction in Parkinson's disease and related disorders. Neurobiol Dis 46: 527–552. - PMC - PubMed
    1. Haehner A, Hummel T, Reichmann H (2009) Olfactory dysfunction as a diagnostic marker for Parkinson's disease. Expert Rev Neurother 9: 1773–1779. - PubMed
    1. Wattendorf E, Welge-Lüssen A, Fiedler K, Bilecen D, Wolfensberger M, et al. (2009) Olfactory impairment predicts brain atrophy in Parkinson's disease. J Neurosci 29: 15410–15413. - PMC - PubMed
    1. Singh S, Schwankhaus J (2009) Olfactory disturbance in Parkinson disease. Arch Neurol 66: 805–806. - PubMed
    1. Kjelvik G, Sando SB, Aasly J, Engedal KA, White LR (2007) Use of the Brief Smell Identification Test for olfactory deficit in a Norwegian population with Alzheimer's disease. Int J Geriatr Psychiatry 22: 1020–1024. - PubMed

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