title: The use of the startle reflex measurement in patients with various types of fixation of the ossicular chain.
abstract: The results of startle and acoustic stapedius reflex measurements can be used to subclassify various types of fixation of the ossicular chain. Reflex measurements were performed on a group of subjects with normal hearing and on a group of patients with surgically verified ossicular chain fixation. In 97% of the subjects with normal hearing (n = 30), reproducible impedance changes were observed as part of a startle reaction and four different reaction patterns could be distinguished. In a subgroup of subjects with normal hearing who had a relatively, statistically significant, high acoustic reflex threshold, a characteristic response was found which was most probably caused by contraction of the tensor tympani muscle only. The same response was detected in 77% of the patients (n = 22) with otosclerosis. In the remaining 23%, no middle ear impedance changes occurred as part of a startle reaction. In five out of six patients with fixation of the malleus, no response was observed. Although the startle reflex measurement is a valuable tool for distinguishing between stapes fixation and multiple ossicular chain fixations, the results are not conclusive.
authors.affiliation: ENT Department, University Hospital, Nijmegen, The Netherlands.
authors.forename: J J
authors.initials: JJ
authors.lastname: Mulder
authors.forename: G
authors.initials: G
authors.lastname: Vantrappen
authors.forename: A F
authors.initials: AF
authors.lastname: Snik
authors.forename: J J
authors.initials: JJ
authors.lastname: Manni
mesh_terms: D000158:Acoustic Impedance Tests; D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000368:Aged; D001299:Audiometry; D004427:Ear Diseases / Q000151:congenital / Q000503:physiopathology*; D004429:Ear Ossicles / Q000503:physiopathology*; D004432:Ear, Middle / Q000502:physiology / Q000503:physiopathology*; D005072:Evoked Potentials, Auditory; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012022:Reflex, Acoustic / Q000502:physiology*; D013216:Reflex, Startle / Q000502:physiology*; D013199:Stapes / Q000503:physiopathology