THE MAGNITUDE OF RANDOM ERRORS IN ACOUSTIC RHINOMETRY AND REINTERPRETATION OF THE ACOUSTIC PROFILE

By measuring the effect of incomplete acoustic seal and increasing nos epiece insertion depth on the derived nasal acoustic profile, this stu dy quantifies the random errors that may arise in the course of the cl inical practice of acoustic rhinometry using the insert nosepiece. The relative movement of the nose and nosepiece also enables us to separa te the contribution of each to the acoustic curve. Sixteen volunteers were tested using a commercial rhinometer. As a consequence of this st udy we are able Co formulate the following conclusions: (1) The first minimum of the nasal acoustic profile is due to the end of the nosepie ce, but mag; be further diminished by the position of the nosepiece ti p on or within the nose. (2) The second minimum is due to the nasal va lve, to which the head of the inferior turbinate contributes. (3) Acou stic rhinometry is extremely sensitive to acoustic leaks and results o btained without a fluid acoustic sealant cannot be considered valid. ( 4) The errors associated with the nosepiece insertion technique are ve ry small unless the nosepiece is forced into the nasal vestibule.