By means of laryngofiberscopy, pneumatography and photoelectric glottography, the closure reflex activity of the larynx which was evoked by trasnasal stimulation with various concentrations of isovaleric acid and ammonia during inspiration was determined in 24 normal subjects and 53 patients with chronic sinusitis, anosmia, nasal allergy and chronic obstructive pulmonary diseases (COPD).
The reflex activity was characterized by a remarkable tendency to decrease in the majority of normal older subjects and most of the patients with conditions other than nasal allergy.
It was assumed that this reflex might be of great importance in preventing hazardous materials from going into the lung and that depression or absence of the reflex sensitivity in the upper respiratory tract might lead to a higher incidence of pulmonary diseases.
The results which were obtained here will help clarify the laryngeal clossure reflex. This methodology may be employed practically to serve as objective olfactometry.
