Nasal challenge with cold, dry air induces a late-phase reaction

Trigeminal Function in Sino-Nasal Health and Disease

The upper airway (nasal passages, paranasal sinuses, pharynx, and glottis) provides the sentinel portion of the human respiratory tract, with the combined senses of olfaction (cranial nerve I) and trigeminal sensation (cranial nerve V) signaling the quality of inspired air. Trigeminal function also complements the sense of taste (in turn mediated by cranial nerves VII, IX and X), and participates in the genesis of taste aversions. The ability of trigeminal stimulation in the upper aero-digestive tract to trigger a variety of respiratory and behavioral reflexes has long been recognized. In this context, the last three decades has seen a proliferation of observations at a molecular level regarding the mechanisms of olfaction, irritation, and gustation. Concurrently, an ever-widening network of physiological interactions between olfaction, taste, and trigeminal function has been uncovered. The objective of this review is to summarize the relatively recent expansion of research in this sub-field of sensory science, and to explore the clinical and therapeutic implications thereof.

Comparison of Short-Term and Long-Term Variability in Nasalance Scores

Objective:

To evaluate long-term nasalance score variability while accounting for short-term variation associated with subject performance and headgear change variability.

Stimuli:

Turtle and Mouse Passages.

Design:

Short-term immediate test-retest nasalance score variability was assessed with no headgear change (NCHG) and with change of headgear (CHG). Long-term variability was assessed with scores obtained in the morning and afternoon of the same day, 1 day apart, and 1 week apart. Scores from the long-term conditions necessarily reflect variability associated with headgear change plus variability, which may be attributed to time.

Participants:

Twenty-six adults (19 to 70 years of age) with normal speech and resonance.

Main Outcome Measures:

Forty-six nasalance scores per subject.

Results:

Mean nasalance difference scores across conditions were compared. Three contrasts were significantly different, each involving comparison of nasalance difference scores in the NCHG condition to difference scores from a CHG condition. Overall, long-term variability was slightly greater than short-term variability. For the Turtle Passage, in the short-term CHG condition, 92% of repeated scores were within five points. In the long-term conditions, 83% to 89% of scores were within five points. For the Mouse Passage, 88% of repeated scores in the CHG condition were within five points. In the long-term conditions, 81% to 83% of scores were within five points.

Conclusions:

Nasalance scores obtained over time showed slightly greater variability than scores obtained in immediate test-retest conditions; however, variability did not increase as the length of time between measures increased.

The effect of nasal decongestion on nasal patency and nasalance scores in subjects with normal speech

OBJECTIVE

The objective of this study was to evaluate the effects of pharmacological decongestion on nasalance scores.

PARTICIPANTS

The participants were 20 adults with normal speech and resonance.

METHODS

Nasal patency was first determined by measuring the mean minimal cross-sectional area of the nasal passages by acoustic rhinometry. Each participant then read two passages as two predecongestion nasalance scores were obtained. A nasal decongestant was then administered to each nostril without removing the separation plate. Ten minutes later, nasalance scores were repeated. Finally, the separation plate was removed and the mean minimal cross-sectional area was obtained again.

MAIN OUTCOME MEASURES

The outcome measures were the pre- and postdecongestion measurements of nasal patency and nasalance scores.

RESULTS

Minimal cross-sectional area increased significantly from 0.53 cm(2) before decongestion to 0.66 cm(2) after decongestion. For the Turtle Passage, the group mean nasalance for the two predecongestion measures (10.70% versus 11.55%) were significantly different and the pre- versus postdecongestion measures (10.70% versus 12.15%) were also significantly different. For the Mouse Passage, the group mean nasalance scores for the two predecongestion measures (32.10% versus 32.00%) were not significantly different but the pre- versus postdecongestion means (32.10 versus 34.40) were significantly different. Correlation coefficients showed a negligible relationship between measures of nasal patency and nasalance scores for both stimulus passages.

CONCLUSIONS

Nasalance score variability was small and not meaningful for standard clinical purposes. The correlation between nasalance scores and nasal patency was weak.

Efficacy of azelastine nasal spray in the treatment of vasomotor (perennial nonallergic) rhinitis

BACKGROUND

Azelastine hydrochloride is an antihistamine with anti-inflammatory properties that is available in the United States in a nasal spray formulation for the treatment of seasonal allergic rhinitis. Vasomotor (perennial nonallergic) rhinitis (VMR) is a noninfectious, chronic rhinitis usually not associated with inflammatory cell infiltration.

OBJECTIVE

Two multicenter, randomized, double-blind, placebo-controlled, parallel-group clinical trials were conducted to determine whether patients with symptoms of VMR (rhinorrhea, sneezing, postnasal drip, and nasal congestion) could be effectively treated with azelastine nasal spray.

METHODS

All of the patients who participated in the trials had a diagnosis of VMR, symptoms for at least 1 year, negative skin tests for a mixed panel of seasonal and perennial allergens, and a nasal cytology examination negative for eosinophils. After a 1-week, single-blind, placebo lead-in period, patients who met the symptom severity qualification criteria were randomized to receive either azelastine nasal spray (two sprays per nostril twice daily, 1.1 mg/day) or placebo nasal spray for 21 days. Patients recorded the severity of their VMR symptoms on diary cards each morning and evening of the trial using a four-point symptom rating scale (0 = none to 3 = severe). The primary efficacy variable was the overall reduction from baseline in the total vasomotor rhinitis symptom score (TVRSS) over the 21-day, double-blind treatment period.

RESULTS

In both studies, azelastine nasal spray significantly (study 1, P = .002; study 2, P = .005) reduced the TVRSS from baseline when compared with placebo. Significant improvement was observed within the first week and improvement in all symptoms favored treatment with azelastine nasal spray. No serious or unexpected adverse events were reported in either study. Bitter taste (19% vs 2%) was the only adverse experience that occurred with a statistically significantly greater incidence in the azelastine group than in the placebo group.

CONCLUSIONS

This is the first demonstration of the efficacy of an antihistamine in the therapy of VMR in two double-blind, placebo-controlled clinical trials.

Exercise- and cold-induced asthma

Exercise- and cold-induced asthma are commonly recognized respiratory disorders. The asthmatic response includes several factors contributing to airway narrowing, and thus increased airway resistance. These include airway smooth muscle contraction, mucus accumulation, and bronchial vascular congestion as well as epithelial damage and vascular leakage. The etiology for these disorders is nonantigenic. The primary stimulus is probably a combination of airway cooling and drying (leading to hypertonicity of airway lining fluid). Symptoms generally do not occur during the stimulus period (e.g., exercise) itself. This protection may in part be due to increased catecholamine levels during exercise. The early phase response, which occurs 5 to 15 min poststimulus, may be mediated through a combination of (a) direct influences, (b) vagal reflexes triggered by airway sensory receptors, or (c) responses to mediator release. Spontaneous recovery occurs within 30 min to 2 hrs. There is usually a refractory period of about 1 to 2 hrs during which responses to further stimuli are attenuated. This may be due to depletion of histamine and other mediators. As well, prostaglandin release (mediated via LTD4 which is released during exercise) inhibits further airway narrowing. A late phase response has been reported 4 to 10 hrs poststimulus in some patients. These reactions are accompanied by a second release of histamine and other mediators that cause inflammatory responses and epithelial damage. However, the exercise dependence of this response is debated.

Decrease in xenon clearance during response to cold, dry air: problems of interpretation

In order to increase our understanding of the nasal response to cold, dry air (CDA), we studied changes in xenon clearance as an indicator of nasal blood flow. Eight individuals previously shown to respond to CDA had measurements of xenon clearance made in the left inferior turbinate before, during, and after a 15-minute exposure to either CDA (-7 degrees C to 0 degrees C, less than 10% relative humidity) or room air. The half-life in seconds for xenon clearance on the day when CDA was inhaled was 56 +/- 6, 41 +/- 5, and 110 +/- 31, before, during, and 10 minutes after challenge, respectively. On the control day, with subjects breathing room air, the equivalent measurements of half-life in seconds were 54 +/- 8, 41 +/- 6, and 42 +/- 4, respectively. Xenon clearance was prolonged significantly (p less than .01) after exposure to CDA during the clinical response. The interpretation of the change in xenon clearance as an indicator of nasal blood flow is discussed.