Effects of Nasal Airflow-Inducing Maneuver in Total Laryngectomy Patients Based on Changes to Olfactory Test Results: A Retrospective Study

Abstract

<b><i>Introduction:</i></b> This study aims to retrospectively examine temporal changes in three aspects, i.e., olfactory threshold test, olfactory identification test, and olfactory perception on daily living test, caused by the use of the nasal airflow-inducing maneuver (NAIM). <b><i>Methods:</i></b> The olfactory threshold test (Sniffin’ Sticks test), olfactory identification test (Open Essence [OE]), and olfactory perception on daily living test (self-administered odor question; SAOQ) were administered to 46 patients who had undergone a total laryngectomy (NAIM Start group: 17; Using group: 19; and Nonuse group: 10). The tests were immediately performed after the NAIM and again after an average of 8 months. <b><i>Results:</i></b> In the NAIM Start group, all olfactory functions significantly improved in the second test compared with the first test (Sniffin’ Sticks test and OE, <i>p</i> < 0.01 for both; self-administered, <i>p</i> < 0.05). Additionally, in terms of the intergroup changes among scores for the Sniffin’ Sticks test and OE, the NAIM Start group showed a significant difference compared with all of the other groups (Start group > Using and Nonuse group, <i>p</i> < 0.01). The NAIM Using group did not exhibit any significant changes. In the NAIM Nonuse group, olfactory identification function was lower in the second test compared with the first test and showed a trend toward a significant difference (OE, <i>p</i> < 0.1). Temporal changes in SAOQ showed a significant increase in all intragroup comparisons. However, there were no significant differences observed in terms of the changes between the groups. <b><i>Conclusion:</i></b> The results demonstrated that even in those who were not using NAIM and undergoing olfactory rehabilitation after laryngectomy (NAIM Start group), the subsequent daily use of NAIM and voluntary rehabilitation aided in the recovery of olfactory function to the same level as that in the already using NAIM group. SAOQ results were considered because of the experimenter effect and they appeared to be unrelated to use NAIM. This study showed that in total laryngectomy patients who did not receive olfactory rehabilitation, olfactory identification was reduced.