Olfactory training in normosmic individuals: a randomised controlled trial.

BACKGROUND: Even if olfactory training (OT) is a well-established treatment for individuals with olfactory dysfunction, the effect on individuals with normosmia remains uncertain. In this randomised controlled trial, we explore how OT with different exposure lengths affect olfactory function in individuals with normosmia. METHODOLOGY: Two hundred normosmic individuals were randomly assigned to one of two intervention groups performing OT with different exposure lengths or to a control group. The OT groups did OT twice daily for three months, g four different odours (eucalyptus, lavender, mint, and lemon) for 10 seconds per bottle during either a total of 40 seconds (standard OT) or 4 minutes (extended OT), while the control group did not perform any OT. Olfactory function was assessed using a 48-item Sniffin Sticks test at baseline, after the intervention, and after one year. RESULTS: We found no significant effect of OT in either of the intervention groups on any aspect of olfaction after intervention or at follow-up. There was no association between sex, age, allergic rhinitis, education or olfactory scores at baseline, and changes in olfactory function after OT. The extended OT group performed significantly fewer training sessions compared to those in the standard OT group. CONCLUSIONS: OT had a limited effect on olfactory function in individuals with normosmia. Further, the superiority of a more extended OT is not supported by this study, and shorter training sessions seem to improve compliance with OT.

Peak nasal inspiratory flow in chronic obstructive pulmonary disease.

BACKGROUND: The nasal airflow in chronic obstructive pulmonary disease (COPD) is poorly characterized. Peak nasal inspiratory flow (PNIF) is a valuable instrument for assessing nasal airflow and the effect of pulmonary pathology such as COPD on PNIF remains unknown. To test the hypothesis that nasal airflow is reduced in COPD, we assessed airflow using PNIF in COPD and a control group. We also explored whether there is an association between COPD, chronic rhinosinusitis without nasal polyps (CRSsNP), and other predefined covariates with PNIF. METHODOLOGY: Ninety patients with COPD and 67 controls underwent PNIF and spirometry. The associations between PNIF and COPD and pre-bronchodilator forced expiratory volume in the first second (FEV1) (% predicted) were assessed by multivariable linear regression in two separate models. RESULTS: PNIF was significantly lower in the COPD group than in the control group. Multivariable linear regression showed that COPD and pre-bronchodilator FEV1 (% predicted) were significantly associated with lower PNIF after adjustment for age, sex, CRSsNP, weight and height. CRSsNP was not associated with PNIF in either of the adjusted regression analyses. CONCLUSIONS: PNIF is lower in COPD than in a control group. The finding of a low PNIF in the absence of disease in the upper airways may be due to obstructive lower airways diseases and special care should be taken when interpreting PNIF values in patients with COPD or reduced FEV1.

Olfaction in COPD.

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.

A comparison of minimal cross sectional areas, nasal volumes and peak nasal inspiratory flow between patients with obstructive sleep apnea and healthy controls.

BACKGROUND: The differences in nasal geometry and function between OSA patients and healthy individuals are not known. Our aim was to evaluate the differences in nasal geometry and function using acoustic rhinometry (AR) and peak nasal inspiratory flow (PNIF) between an OSA population and healthy controls. METHODOLOGY: The study was designed as a prospective case-control study. Ninety-three OSA patients and 92 controls were enrolled from 2010 to 2015. The minimal cross-sectional area (MCA) and the nasal cavity volume (NCV) in two parts of the nose (MCA0-3/NCV0-3 and MCA3-5.2/NCV3-5.2) and PNIF were measured at baseline and after decongestion. RESULTS: The mean MCA0-3 in the OSA group was 0.49 cm2; compared to 0.55 cm2 in controls. The mean NCV0-3 correspondingly was 2.51 cm3 compared to 2.73 cm3 in controls. PNIF measured 105 litres/minute in the OSA group and 117 litres/minute in the controls. CONCLUSIONS: OSA patients have a lower minimum cross-sectional area, nasal cavity volume and peak inspiratory flow compared to controls. Our study supports the view that changes in the nasal cavity may contribute to development of OSA.

The determining factors of peak nasal inspiratory flow and perception of nasal airflow in asthmatics.

BACKGROUND: The effect of pulmonary pathology on peak nasal inspiratory flow (PNIF) remains largely unknown. We investigated an association between a diagnosis of asthma and of lung function on PNIF when adjusted for possible confounders. Further, we investigated the perception of nasal obstruction in asthmatics compared to healthy controls when adjusted for PNIF. METHODOLOGY: Eighty-seven asthmatics and 92 non-asthmatic controls underwent PNIF (categorized into groups of high, medium and low), acoustic rhinometry (AR) and spirometry, and we assessed symptoms of nasal obstruction on visual analogue scales (VAS) in three categories. RESULTS: PNIF was significantly associated with asthma and forced expiratory volume in the first second (FEV1) (% predicted). Other factors associated with PNIF were the degree of nasal obstruction measured both subjectively on a VAS and objectively with AR, age and disease status. Asthma patients were 19 times more likely to be in a higher VAS category compared to non-asth- matic controls independent of PNIF group. CONCLUSION: Special care has to be taken when interpreting PNIF values in patients with asthma or reduced FEV1 (% predicted). The sensation of nasal obstruction in asthmatics is different from controls despite being in the same PNIF group.