We demonstrated that the lack of airflow is, indeed, a prime contributor to the hyposmia associated with laryngectomy. This was done in a cross-sectional study by providing laryngectomized patients with a larynx bypass which allowed them to sniff odorants with near normal sniff airflows. Furthermore, with the reestablished airflow of the larynx bypass all the laryngectomees reached the """"""""normal"""""""" non-laryngectomy detection threshold for ammonia, but for vanillin 40% of the patients did not reach the """"""""normal"""""""" level and some could not detect it at all. However, on the basis of this cross-sectional study we could not conclude that whereas the lack of airflow was the sole explanation for the laryngectomy-induced hyposmia to ammonia (a strong trigeminal irritant), other mechanisms must be involved for vanillin (a non- trigeminal odorant). First, we could not know the patients' presurgical detection thresholds and, perhaps, the reestablished airflow did bring their vanillin thresholds back to their own presurgical levels. Secondly, we could not evaluate whether the patients duplicated with the larynx bypass their individual sniff characteristics which maximized their presurgical sensitivity. Therefore, to pursue the possibility that lack of nasal airflow contributes differentially to the hyposmia of laryngectomy depending upon the odorant and neural input, we will use a longitudinal experimental design in which each patient's olfactory ability and sniff characteristics are measured before surgery and at several points in time after surgery. In addition, we will extend our tests of olfactory ability to include a confusion matrix, magnitude estimations and the UPSIT. We will determine whether olfactory ability is related to the elapsed time since laryngectomy and/or proficiency at esophageal speech. We will explore the possibility that olfactory deficits in laryngectomees can be prevented or reversed by repeated exposures to the nasal flow of odorized air and we will begin looking at the possibility of a """"""""memory"""""""" component in the olfactory dysfunction of long-term laryngectomees. Finally, we will assess whether laryngectomy leads to any morphological changes in the olfactory mucosa.
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