Hindawi Publishing Corporation ISRN Otolaryngology Volume 2013, Article ID 429680, 6 pages http://dx.doi.org/10.1155/2013/429680 Research Article Sound Sensitivity of the Saccule for Low Frequencies in Healthy Adults Seyede Faranak Emami,1 Akram Pourbakht,2 Ahmad Daneshi,3 Kianoush Sheykholeslami,4 Hessamedin Emamjome,5 and Mohammad Kamali6 1 Department of Audiology, School of Rehabilitation, Iran University of Medical Sciences, Mirdamad Street, 98, Tehran 1545913187, Iran 2 Department of Audiology, Rehabilitation Research Center, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran 3 ENT-Head and Neck Research Center, Hazrat Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran 4 Department of Surgery, University of Illinois, Rockford, USA 5 Audiology Research Center, Hazrat Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran 6 Rehabilitation Research Center, School of Rehabilitation Sciences, Iran Univessity of Medical Sciences, Tehran, Iran Correspondence should be addressed to Ahmad Daneshi; [email protected] Received 18 June 2013; Accepted 12 July 2013 Academic Editors: G. G. Ferri, S. L. Halum, and S. C. Winter Copyright © 2013 Seyede Faranak Emami et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 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 (mean = 60.78 ± 8.33), whereas both unaffected (mean = 96.24 ± 2.4) and control ears (mean = 96.24 ± 2.4)presented normal results. The correlation between RSP in wn and p13 latencies was significant ( < 0.05, = −0.551). The peak-to-peak amplitudes showed significant correlation to RSP in wn ( < 0.05, = 0.307). The correlation between RSP in wn and the latencies of n23 was significant ( < 0.05, = −0.493). 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 Intense air-conducted stimulations with low frequen- cies (between 50 and 800 Hz) may evoke the continuous There are afferent fibers in the vestibular nerve of amniotes responsesinthehumansaccularneurons.Therangeof (reptiles, birds, and mammals) that respond to sound at levels acoustic sensitivity of the sacculus happens to coincide with within the normal range of hearing. The ascending auditory the range of voice pitch, for male voices between 80 and pathway (inner ear, cochlear nucleus, medulla, midbrain, 200Hzandupto400Hzforfemales.Also,thefirstformant thalamus,andcerebrum)ofamniotesisorganizedsimilarly of our voice falls within the range of saccular sensitivity to those of anamniotes (fish and amphibians). Convergent [4–6]. Thus, given the proximity of the ear to the larynx, neuroanatomical specializations in two species may reflect it is possible that saccular responses may be obtained to common functional requirements [1, 2]. These structures an individual’s own vocalisations, particularly for singing. have retained sound sensitivity in man and primates [3, 4]. Another possibility is that responses are obtained when there 2 ISRN Otolaryngology are large groups of individuals vocalising together, such as in completed for the one test, subjects were given a short break a choir or a crowd at a concert or sporting event [6–8]. and the whole procedure repeated for another. The study was On the other hand, most acoustically responsive fibers approved by the IRAN university ethics committee. in the inferior vestibular nerve have irregular spontaneous activity and originate in the saccule. These fibers traced 2.2. Ethical Considerations. Our study was on human sub- centrally arborized extensively in vestibular nuclei and ven- jects, so to minimize harms and risks and maximize benefits tromedial to the cochlear nucleus. Then, mammalian saccule and respect human dignity, privacy, autonomy, immunity, responds to sound and sends acoustic information to the safety, respectability, and satisfaction, we took human precau- central nervous system [2–9], including bulbospinal, brain- tions with our case-control groups and strived to distribute stem, cerebellum, higher centres up to the hypothalamus [2, the benefits and burdens of research fairly. In addition, our 6, 7], and medial and superior temporal gyrus [10]. Therefore, research did not present the work of others as their own or the objective of this study was to investigate saccular hearing did not fail to give appropriate credit for the work of others in healthy adults. through citations. 2.3. Assessments. Evaluation for screening of case group, 2. Materials and Methods consisted of pure tone audiometry, tympanometry and acous- 2.1. Participants. This case-control study consisted of twenty tic reflex test, auditory brainstem response, electronystagmog- healthy controls (11 females, 9 males) and twenty-four dizzy raphy, word recognition scores (Rsp) in quiet, and cervical patients (14 females and 10 males), which were screened from vestibular evoked myogenic potentials (cVEMPs), which were of sixty-seven patients with benign paroxysmal positional employed for reviewing our inclusion criteria. Recognition of vertigo and migraineurs. They were presented to the Audi- spoken phonemes in white noise (Rsp in wn) and cVEMPs ology Department of Hazrat Rasoul Akram hospital of IRAN involved assessment of our main variables. university of medical sciences (Tehran, Iran), from May 2012 The devices were diagnostic pure tone audiometry toDecember2012.Wescreenedallvolunteereligiblepatients (Madsen:OB-822), impedance acoustic metr (Maico MI 34), about seven months (we could not find previous collected full system of auditory-vestibular evoked potentials (Labat Epic-plus). works and used of censes method for sampling strategy). − The diagnose of patients with benign paroxysmal posi- Pure tone thresholds in the normal range ( 10 to tional vertigo was based on medical history and findings 25 dBHL) were obtained from each person’s over the fre- of characteristic nystagmus (torsional up beating nystagmus quency range of 250–8000 Hz [13]. Tympanometry served to with latency and fatigue lasting less than 1 min) and subjective evaluate the middle ear status [14]. Acoustic reflex test (Ipsi- vertigointheDix-Hallpiketest[11, 12]. lateral and contralateral) was conducted to eliminate the pos- In migraineurs vestibular dysfunctions were connected sibility of any additional auditory olivocochlear pathology. with nystagmus, and with episodic vertigo, or a variety of The normal range considered from about 85 to 100 dB SPL combinations of headache/vertigo. A number of patients for pure tone stimuli [15]. Auditory brainstem response was reported that their symptoms were worse with achieved head done to exclude the probability of any additional brainstem status, but this is not confused with BPPV,since patients with pathology. We considered the responses to be abnormal when migrainous vertigo were nauseated or phonophobic during peaks III and/or V were absent or when the peak to peak I– attacks [11, 12]. V exceeded the normal limits of our laboratory (4.40 ms for The exclusion criteria consisted of history of ear infections females, 4.58 ms for males). Electronystagmography used to and middle ear diseases, which can interfere with cVEMPs reject the possibility of any additional vestibular pathology. measurements, and conditions that can cause abnormal The battery of electronystagmography tests included assess- auditory function. To this list were included history of head ment of the central vestibular and vestibulocular systems trauma, ototoxic drugs, otosclerosis, labyrinthitis, cardiac with evaluation of gaze [12]. Word recognition scores in and metabolic diseases, heart failure, anemia, hypothy- quiet presented by one female (monitoring of live voice). The roidism, hyperthyroidism, diabetes mellitus, hypertension, normal scores were 96–100% [16]. and various neurological diseases (vertebrobasilar insuffi- ciency, temporal lobe epilepsy, multiple sclerosis, central 2.3.1. Cervical Vestibular Evoked Myogenic Potentials nervous system tumors, and cerebellar infarction, among (cVEMPs). During the cVEMPs, recording patients were others). instructed to turn and hold their heads as far as possible The inclusion criteria involved normal function of hear- toward the side contralateral to the stimulated ear. At ing, middle ear pressure, olivocochlear and auditory brain- that point, the overall electromyogenic activity of the stem pathway, with abnormal function of saccule. sternocleidomastoid muscle was set as the reference level A handedness questionnaire was also administered. All of the tonic contraction. Patients were asked to maintain