%0 Journal Article
%T Sound Sensitivity of the Saccule for Low Frequencies in Healthy Adults
%A Seyede Faranak Emami
%A Akram Pourbakht
%A Ahmad Daneshi
%A Kianoush Sheykholeslami
%A Hessamedin Emamjome
%A Mohammad Kamali
%J ISRN Otolaryngology
%D 2013
%R 10.1155/2013/429680
%X Approximately 80 years ago John Tait speculated about a possible auditory role for the otolith organs in humans those days, there was no direct evidence for that idea. This time is for us to review and research. Then, the objective of our study was to investigate saccular hearing in healthy adults. We selected twenty healthy controls and twenty-four dizzy cases. Assessment comprised of audiologic evaluations, cervical vestibular evoked myogenic potentials (cVEMPs), and recognition of spoken phonemes in white noise (Rsp in wn). In the case group (a total of 48 ears), the cVEMPs abnormalities were all unilateral (24 affected ears and 24 contralateral unaffected ears). Affected ears with decreased vestibular excitability as detected by abnormal cVEMPs had decreased Rsp in wn ( ), whereas both unaffected ( ) and control ears ( ) presented normal results. The correlation between RSP in wn and p13 latencies was significant ( , ). The peak-to-peak amplitudes showed significant correlation to RSP in wn ( , ). The correlation between RSP in wn and the latencies of n23 was significant ( , ). We concluded in presence of severe competing noise, saccule has a facilitating role for cochlea and can improve to detection of loud low-frequencies. 1. Introduction There are afferent fibers in the vestibular nerve of amniotes (reptiles, birds, and mammals) that respond to sound at levels within the normal range of hearing. The ascending auditory pathway (inner ear, cochlear nucleus, medulla, midbrain, thalamus, and cerebrum) of amniotes is organized similarly to those of anamniotes (fish and amphibians). Convergent neuroanatomical specializations in two species may reflect common functional requirements [1, 2]. These structures have retained sound sensitivity in man and primates [3, 4]. Intense air-conducted stimulations with low frequencies (between 50 and 800 Hz) may evoke the continuous responses in the human saccular neurons. The range of acoustic sensitivity of the sacculus happens to coincide with the range of voice pitch, for male voices between 80 and 200£¿Hz and up to 400£¿Hz for females. Also, the first formant of our voice falls within the range of saccular sensitivity [4¨C6]. Thus, given the proximity of the ear to the larynx, it is possible that saccular responses may be obtained to an individual¡¯s own vocalisations, particularly for singing. Another possibility is that responses are obtained when there are large groups of individuals vocalising together, such as in a choir or a crowd at a concert or sporting event [6¨C8]. On the other hand, most acoustically
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