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 repeatability of oVEMP in response to low-frequency vibration against the vertex and forehead.

BACKGROUND: The measurement of ocular Vestibular Evoked Myogenic Potentials (oVEMP) is a novel method for investigating vestibular function. Stimulus and recording techniques vary in the literature. A standardized test procedure is desirable in order to ensure repeatable results. OBJECTIVE: To investigate the magnitude and repeatability of the asymmetry ratio (AR) of oVEMPs in response to low-frequency bone conducted vibration (BCV) applied to the forehead and vertex in a healthy population. METHODS: 20 healthy subjects were tested three times by stimulating with 125 Hz BCV at the forehead and the vertex. The first two tests were performed with the subject remaining in the examining room and the electrodes in place. After a short break, a third test was performed with a new set of electrodes. The AR was calculated for each test based on the evoked oVEMPs responses from the left and the right side. The AR magnitude, variance and repeatability coefficients were evaluated to determine which of the two stimulus sites is best suited in clinical use. RESULTS: Stimulation at the forehead resulted in a statistically significant lower median AR compared to the vertex. The forehead had lower repeatability coefficients, and statistically significantly lower variances. CONCLUSIONS: This study indicates that the forehead is a better stimulation site than the vertex for low-frequency BCV in clinical use.

Ocular vestibular-evoked myogenic potentials (oVEMPs) in response to bone-conducted vertex vibration.

OBJECTIVE: To investigate low-frequency vertex bone-conducted (BC) vibration for evoking ocular vestibular myogenic potentials (oVEMPs) and its ability to discriminate between lesioned and healthy ears. METHODS: oVEMPs were analysed in response to 125-Hz single cycle vertex BC vibration in healthy subjects (n=50) and in patients with severe unilateral vestibular loss (n=10). Both positive and negative initial stimulus motions were used. RESULTS: In most healthy subjects, vertex BC vibration oVEMPs was successfully and symmetrically evoked from both ears. The response was dependent on the direction of the stimulus motion. The latency was shorter with negative initial stimulus motion; however, a positive initial stimulus motion generated somewhat larger amplitudes. Furthermore, there was no significant response from lesioned ears, whereas oVEMPs from the patients' healthy ears were similar to the responses in healthy subjects. CONCLUSION: The oVEMP low-frequency BC response was dependent on the direction of the initial stimulus motion. Testing oVEMPs in response to low-frequency vertex vibration can discriminate patients with unilateral vestibular function loss from healthy controls. SIGNIFICANCE: Low-frequency vertex BC vibration oVEMPs should be considered a possible clinical screening test to evaluate vestibular function.

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.