Olfactory threshold is impaired in early, active multiple sclerosis

Abstract

We report evidence for qualitatively distinct hyposmia in MS, with increased smell threshold in the early inflammatory phases of the disease and impaired identification with a more widespread chronic disease.

Olfactory Dysfunction in Multiple Sclerosis: Evidence of a Decrease in Different Aspects of Olfactory Function

“…The correlation between identification ability and the EDSS score is consistent with data from the literature [8]. Another study demonstrated that the longer the disease had progressed, the greater the damage to odor identification [9]. Our study did not statistically validate this correlation.…”

“…Olfactory dysfunction also seems to be correlated to disability in patients, as shown by the Expanded Disability Status Scale (EDSS) score [8]. Data on the correlation between olfaction and quality of life or depression are inconsistent in the literature [6,9,10]. A recent study showed that olfactory function is significantly damaged in MS patients, affecting both the ability to identify odors and the detection threshold.…”

“…A recent study showed that olfactory function is significantly damaged in MS patients, affecting both the ability to identify odors and the detection threshold. It seems that this detection threshold is damaged in the early stage of the disease, whereas the ability to identify odors seems to be more correlated with disease progression span [9]. We propose to study the following three aspects of olfaction: detection threshold, ability to discriminate and to identify using the standardized, validated Sniffin Sticks® test [11].…”

Association between diabetes mellitus and olfactory dysfunction: current perspectives and future directions

“…Olfactory testing has been used as a preclinical indicator to predict the development and onset of diseases such as Parkinson's disease [10], multi-infarct dementia [11], multiple sclerosis [12] and Alzheimer's disease [11]. Previous studies have further reported a relationship between olfactory dysfunction and diabetes [13][14][15][16][17][18], as well as an inverse relationship between olfactory identification and discrimination scores and the presence of diabetic complications [13,14,16,19,20].…”

“…Limited cross-sectional studies have explored associations between diabetes and olfaction [13][14][15][16][17][18][19][20]37] with inconsistent findings (Table 2 [ [11][12][13][14][15][16][17][18]35,[38][39][40]). The variability in outcomes may be attributed to several methodological inconsistencies, such as selection bias, small sample sizes, comorbidities, lack of objective measures, and differences in diagnostic tests for olfactory dysfunction, and diabetes and its complications.…”