This study confirms the incidence of olfactory disorder in MS patients that has been reported in the literature. Interestingly, a significant correlation between orthonasal and retronasal OF testing was not shown. A higher incidence of gustatory dysfunction was shown and might serve as another potential marker for this disease.

The olfactory (OF) and gustatory function in multiple sclerosis (MS) patients and possible influencing variables of the disease, such as depression or fatigue, were determined. In an open prospective controlled clinical study 30 patients with MS and 30 healthy controls matched for age, sex and smoking-habits were investigated. With Mini Mental State Examination cognitive dysfunction was excluded, with Expanded Disability Status Scale the patient's ability to accomplish the tests was ensured. The severity of depression was measured with the self-reported Beck Depression Inventory. The orthonasal olfactory function was derived with olfactory event related potentials (OERP) and TDI-score (Threshold, Discrimination and Identification, Sniffin' Sticks). Retronasal olfactory function was tested with Taste-Powder-score, gustatory function with Taste-strip-score. There was a significant loss of olfactory function measured with TDI-score [12/30 (40%), p = 0.002] and gustatory function [5/23 (21.7%), p \ 0.001] in MS-patients, 23.8% (5/21) of MS-patients showed hyposmia with OERPs, significantly correlating with the TDI-score (p = 0.03). The Expanded Disability Status scale score inversely correlated with the TDI-score (p = 0.002). This study confirms the incidence of olfactory disorder in MS-patients and reveals a frequent gustatory deficit. The Identification subtest can be proposed as a marker of the OF in MS-patients: it includes complex cognitive tasks and may be influenced by depression and fatigue, which are common symptoms of MS. It inversely correlates with the disability status.

Background: Multiple sclerosis (MS) is a chronic disease characterized by CNS lesions causing physical and cognitive impairment. Using psychophysical testing, an olfactory disorder is diagnosed in 15-38.5% of patients with MS. Olfactometry permits objective testing of the sensory nerve function. Methods: The study looked at 20 patients with MS. Clinical, olfactory (chemosensory evoked potentials), and MRI data (volume of the bulbus olfactorius (BO), olfactory brain (OB), lesions in the CNS) were analyzed. Results: 25 percent of patients were hyposmic, exhibiting higher OB lesion volumes and smaller bulb volumes. H₂S and CO₂ latencies and the BO volume (inversely) correlated with the volume and number of MS lesions of the olfactory brain in all patients. Patients with a smaller olfactory bulb volume exhibited longer H₂S latencies (p = 0.025). Conclusion: A relationship between olfactory bulb volume, olfactory brain lesion load, and objective olfactory function testing in MS patients was investigated in all patients. Our data shows that brain damage characteristic of MS, including reduced bulb volume, causes an increase in chemosensory potential latencies and an olfactory function deficit.

Background: Olfaction is poorly characterized in COPD. To test the hypothesis that olfaction is reduced in COPD, we assessed olfaction with the “Sniffin’ Sticks” test and a questionnaire addressing olfaction in COPD and a corresponding control group in respect to age and sex. We also explored whether there is an association between COPD, chronic rhinosinusitis without nasal polyps (CRSsNP), and other predefined covariates with olfactory function. Methodology: Olfactory function was assessed by the score for threshold (T), discrimination (D) and identification (I), and the composite TDI score in the “Sniffin’ Sticks” test and by self-reported evaluation of impaired olfaction and of “decreased sense of smell and taste” in the 22-item Sino-Nasal Outcome Test (SNOT-22) in 90 COPD patients and 93 controls. A clinical interview and ENT-examination with nasal endoscopy, skin prick test and spirometry with reversibility were performed. Results: The TDI, D and I scores were significantly lower in the COPD group than in the control group. The T score was not significantly different between the two groups. Hyposmia and anosmia were present in up to 79% of patients with COPD. The prevalence of self-reported impaired olfactory function and for 'decreased sense of smell and taste'; - was more than two-fold greater in the COPD than in the control group. COPD, higher age, male sex and allergy were associated with a lower TDI score, while CRSsNP was not associated with the TDI score. Conclusions: COPD is associated with olfactory dysfunction and the underlying mechanisms for this dysfunction should be elucidated.

The validity of the united airway disease concept for rhinosinusitis (RS) and chronic obstructive pulmonary disease (COPD) has been questioned because of methodological limitations in previous studies. In this study we investigated the prevalence of RS without nasal polyps (RSsNP) and the severity of sinonasal symptoms in COPD and a corresponding control group. We also evaluated the diagnostic accuracy of these symptoms for RSsNP in COPD. 90 COPD patients and 93 controls were included in an observational cross-sectional study where globally accepted diagnostic criteria of RS and COPD (EPOS 2012 and GOLD) were incorporated; symptomatic and endoscopic criteria for the diagnosis of RS, and spirometry with reversibility for diagnosis of COPD. RS symptoms were identified by responses to the sinonasal outcome test (SNOT-22), nasal endoscopy identified signs of sinonasal disease and discriminated between RS with and without nasal polyps, and visual analogue scales (VAS) rated the severity of sinonasal symptoms. We found RSsNP in 51% of our COPD patients which is threefold greater than in the control group (p<0.001). Nasal discharge (72%) and nasal obstruction (62%) were the two most frequently reported symptoms in COPD. The diagnostic accuracy for RSsNP is better for the composite VAS for rhinological symptoms than for facial symptoms. We conclude that RSsNP is present in 51% of our COPD patients, which is significantly more prevalent compared to a corresponding control group. These results suggest that COPD is associated with RS.