Is All Human Hearing Cochlear?

Abstract

The objective of this cross-sectional study was to investigate the possibility that the saccule may contribute to human hearing. The forty participants included twenty healthy people and twenty other subjects selected from patients who presented with benign paroxysmal positional vertigo to Audiology Department of Hazrat Rasoul Akram hospital (Tehran, Iran). Assessments comprised of audiological evaluations, cervical vestibular evoked myogenic potentials (cVEMPs), recognition of spoken phonemes in white noise (Rsp in wn), and auditory brainstem response to 500 Hz tone burst (ABR500 HZ). Twenty affected ears with decreased vestibular excitability as detected by abnormal cVEMPs revealed decreased scores of Rsp in wn and abnormal findings of ABR500 HZ. Both unaffected and normal ears had normal results. Multiple comparisons of mean values of cVEMPs and ABR500 HZ between three groups were significant (P < 0.05, ANOVA). 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. In high-level of noisy competing situations, healthy human saccular sensation can mediate the detection of low frequencies and possibly help in cochlear hearing for frequency and intensity discrimination. So, all human hearing is not cochlear.

Saccular Dysfunction in Low-Frequency Age-Related Sensorineural Hearing Loss

“…The recent articles show that acoustical activation of the saccule in human enhanced temporal fine arrangement signals of the sound and has very important starring role in recognition of harmonic pitch data to separate the message and maskers, which are essential for audible function in noise [14]. The latest reports discuss about a novel finding, which confirms saccular projection activations make the cues in human brainstem to cortex and can possibly contribute to auditory processing [13][14][15][16].…”

“…A number of investigators have recently explored the air and bone conducted acoustic activation of the saccule among human {the best frequencies did not exceed 1000 Hz to sound and 500 Hz to vibration [11,12]. They reported conservational sounds (voice pitch in speaking, singing, crowd actions, vocalisations and musicalnoises) can stimulate the saccule [13]. The recent articles show that acoustical activation of the saccule in human enhanced temporal fine arrangement signals of the sound and has very important starring role in recognition of harmonic pitch data to separate the message and maskers, which are essential for audible function in noise [14].…”

“…Previous studies have focused on the possibility that saccule has auditory sensitivity in human and in the clamor environments may contribute to the hearing of low frequency high-intensity sounds. Indeed, the saccule has a compensatory role for the hearing of aloud low frequencies (90 dB spl<) and allows to phonemic selfregulation [12][13][14][15][16]. More probability of this sacculocochlear comorbidity in elderly is that reduced output from the impaired sensory systems, due in part to a-SNHL changes, decreases the value of the input to the central auditory-vestibular system and eventually the communication challenges concomitant with age related hearing loss [9], it may well be that impaired hearing statuses more necessity on consideration sharing, thus, making mobility further of a challenge.…”

Hypersensitivity of Vestibular System to Sound and Pseudoconductive Hearing Loss in Deaf Patients

“…Of these organs, the cochlea is involved in hearing, while the otolith organs (saccule and utricle) serve to detect linear acceleration [ 1 ]. Recent evidences from human show that the saccule has acoustic sensitivity to sound [ 2 – 4 ], which can contribute to the affective quality of loud low frequencies [ 4 ]. Saccular stimulation to air-conducted sound has a compensatory role for cochlear hearing in noisy conditions [ 3 ].…”

“…Saccule not only responds best to low frequency high-intensity air-conducted sound, but also, in clamor conditions, may contribute to the hearing of this frequency band [ 2 ]. Saccular hearing is an effective reinforcer for cochlear hearing [ 4 ]. It can cooperate to frequency and intensity discrimination [ 5 , 6 ].…”