Air conduction, bone conduction, and soft tissue conduction audiograms in normal hearing and simulated hearing losses.

Pure-tone audiometry is a standard clinical test for hearing diagnosis. Air–bone gaps derived from the difference between air conduction (AC) and bone conduction (BC) thresholds are important indicators to distinguish between different types of hearing losses. Even though BC thresholds are typically unaffected in conductive hearing loss (CHL) cases, a notch or depression at 2 kHz frequency (i.e., Carhart notch) could occur, which could be mistakenly considered as the involvement of sensorineural hearing loss (SNHL). In this article, it was clearly demonstrated that the BC notch at 2 kHz (that could exceed the normal limit) was in fact related to CHL (not SNHL). That is, in this case, both AC and BC thresholds became “perfectly” normal after the treatment (and the notch at 2 kHz disappeared). Several useful points were highlighted from the present case report to guide clinicians, medical trainees, and respective students to avoid misdiagnosis in clinical practice.

Patients with elevated bone conduction (BC) thresholds are not considered a good candidate for otosclerosis surgery. Sometimes, it might be difficult to decide to operate these patients considering relatively poor cochlear function. However, viewpoints may vary among otologists. This study was undertaken to compare hearing outcome following otosclerosis surgery in patients who had bone conduction (BC) thresholds >or= 30 dB, and to investigate whether BC thresholds >30 dB has a negative impact on hearing outcome. Medical records of 111 patients who had undergone otosclerosis surgery were reviewed. Of 111 patients, 83 had undergone stapedotomy, and 28 stapedectomy. The patients were grouped based on preoperative four-tone BC threshold. Eighty-seven patients had average BC threshold <or= 30 dB, and were assigned to good-cochlear reserve group. The remaining 24 patients had average BC > 30 dB, and constituted poor-cochlear reserve group. Pre- and postoperative air conduction (AC) and BC thresholds, air-bone (AB) gap, vocal audiometry results and amount of deterioration in BC were determined. Mean postoperative AB gap was almost the same in both groups (14 and 15 dB) (P > 0.05). Percentage of AB gap = 10 dB favored good-cochlear reserve group (41 vs 29%)(P > 0.05). Analysis of mean hearing gain was slightly in favor of good-cochlear reserve group (19 vs 15 dB) (P > 0.05). Better BC thresholds were obtained postoperatively in good-cochlear reserve group (P < 0.001). Deterioration > 10 dB in BC was observed in 5.7 and 12.5% of the patients with good- and poor-cochlear reserve, respectively (P > 0.05). Based on the results of this small sample-size study, even though BC threshold of 30 dB was not considered a negative factor for hearing gain, otosclerosis surgery might have detrimental effects on postoperative BC thresholds in patients who had BC thresholds >30 dB.

Background: Two different pathways of sound transmission to the inner ear are differentiated; air conduction (AC) and bone conduction (BC). The transmission pathway of AC, which is physiological for human hearing, implies the transmission of sound to the cochlea via the ear canal, eardrum, and middle-ear ossicles, while BC bypasses the Pinna, the external auditory canal and the middle ear. The transmission pathway by BC has not been fully understood and many aspects still remain questionable. The aim of this study is to characterize two ways of direct transmission of vibrations to the inner ear by measuring hearing thresholds and vibrations of the skull. The bone-vibrator, which is usually used to measure the BC hearing thresholds in contact with the mastoid, can also be used to simulate other contents of skull, such as the eye. Methods: Ten adults (age range of 25-40) with normal hearing and five patients (age range of 21-31) with single sided profound deafness (SSD) were included in this study. The AC audiometry by pure tones was measured using insert earphones and the BC audiometry was measured by stimulating four different locations of the skull; the forehead, the temporal region, the mastoid, and the ipsilateral eyeball with two different contact pressure magnitudes of 2N and of 5N. The vibrations of the skull bones induced by air and bone conduction stimuli were measured by an accelerometer positioned between an upper and lower front incisor tooth. Results: The BC hearing thresholds by stimulating the temporal region and the mastoid were the lowest in both of normal hearing and SSD subjects and the values by both stimulations were similar. Thresholds were significantly higher for stimulations on the forehead and the eye (p<0.05). The difference between the thresholds by stimulation at the mastoid or temporal region and at the eye was more pronounced in SSD subjects (p<0.01). The averaged BC thresholds of normal subjects by stimulation on the contralateral temporal region were significantly lower than the averaged BC thresholds of SSD subjects only at the frequency of 0.25 kHz (p<0.01). The BC thresholds by stimulation on the contralateral mastoid of the normal hearing subjects were significantly lower in 5 N headband than in 2 N headband at the whole frequency range (p<0.05). The BC thresholds by stimulation on the ipsilateral mastoid of the normal hearing subjects showed significant differences between the contact pressure forces of 5 N and 2 N at the frequencies of 1, 2, and 3 kHz (p<0.5). The stimulation on the contralateral mastoid with the 5 N headband resulted in a significantly lower BC threshold than the stimulation with 5 the 2 N headband at the entire frequency range (p<0.05). In SSD subjects, the stimulation on the ipsilateral mastoid side with the 5 N headband had a significantly lower BC thresholds than stimulation with the 2 N headband at all frequencies except for 0.5 and 4 kHz (p<0.05). The BC thresholds in normal hearing subjects were significantly lower with the ipsilateral temporal stimulation than with a corresponding contralateral stimulation for the all frequencies except for 0.5 and 1 kHz (p<0.01). For the SSD subjects, the BC thresholds with the ipsilateral temporal stimulation were significantly lower at 2, 3 and 4 kHz than those with the corresponding contralateral stimulation. Skull vibrations in the normal hearing subjects showed similar behaviors at low frequencies up to 2 kHz for all stimulations except for stimulation on the eye, where vibrations were smaller. In contrast, skull vibrations measured from stimulation at the eye were increasing with higher frequencies. Under 2 kHz skull vibrations at eye were significantly smaller than those from stimulation of the mastoid, but above 2 kHz, they were significantly bigger (p<0.05). Skull vibrations between stimulation at the ipsilateral mastoid and forehead were significantly different at 0.25, 3 and 4 kHz (p<0.05). The subjects with SSD showed similar patterns. Conclusion: The patterns of BC hearing thresholds were similar in normal subjects and subjects with SSD. Hearing thresholds in all subjects were significantly better for mastoid and temple stimulation compared to eye stimulation. One reason for that may be the different pressures applied. Skull vibrations as measured at teeth did not match the same pattern as the hearing thresholds. Eye stimulation induced low vibrations below 2 kHz, but high vibrations above 2 kHz. This finding demonstrates special acoustic properties of the living organism, the distance from stimulation might also contribute. Skull-bone vibrations decreased with increasing frequency for mastoid and temple stimulation. Stimulation of soft tissue, presumably including skull contents, seems to induce high frequency skull vibrations. That might be involved with the distance form the front teeth. The transcranial attenuation of vibration should be considered especially in high frequencies.

Distinct audiometric patterns in congenital round window atresia: A comparative study with common congenital middle ear anomalies

Although human air conduction (AC) and bone conduction (BC) hearing are well investigated, there is a lack of information about BC hearing in most other species, the normal BC hearing thresholds have not been established. And animal model is vital for understanding the physiology of bone conduction hearing. Hence, in our study, the hearing thresholds in the guinea pigs were estimated by a regression of the amplitude of the compound action potential (CAP) with stimulation level and was found robust and gave a high resolution of the threshold level in the frequency range between 2 kHz and 20 kHz. The reference for the BC thresholds was the cochlear promontory bone velocity. This reference enables comparison of BC hearing in animals, both intra and inter species, which is independent on the vibrator and stimulation position. According to our comparable BC threshold, we can do some further research. The vibration was measured in three orthogonal directions where the dominating vibration directions was in line with the stimulation direction, here the ventral direction. The BC thresholds lay between -10 and 3 dB re 1 μm/s. The slopes of CAP growth function were similar for AC and BC at low and high frequencies, but slightly lower for BC than AC at frequencies between 8 and 16 kHz. This was attributed to differences in the stimulus levels used for the slope estimation and not a real difference in CAP slopes between the stimulation modalities. At the same time, the effect of a middle ear lesion, here modelled by severing the ossicles (ossicular discontinuity) and gluing the ossicles to the bone (otosclerosis), is investigated for both AC and BC. Two kinds of middle ear lesions, ossicular discontinuity and stapes glued to the surrounding bone, gave threshold shifts of between 23 and 53 dB for AC while it was below 16 dB when the stimulation was by BC. Statistically different threshold shifts between the two types of lesions were found where the AC threshold shifts for a glued stapes at 2 and 4 kHz were 9 to 18 dB greater than for a severed ossicular chain, and the BC threshold shifts for a glued stapes at 4 and 12 kHz were 8 to 9 dB greater than for a severed ossicular chain. Moreover, the direction of the vibration influences BC hearing also is investigated in our study. This direction sensitivity was investigated guinea pigs by providing BC stimulation in five different directions at the vertex of the guinea pig skull. The hearing thresholds for BC stimulation was obtained in the frequency range of 2 to 20 kHz by measurements of the guinea pigs’ compound action potential. During the stimulation by BC, the vibration of the cochlear promontory was measured with a three-dimensional laser Doppler vibrometer resulting in a set of unique three-dimensional vibration combinations for each threshold estimation. The sets of three-dimensional vibration at threshold were used to investigate six different predictors of BC hearing based on cochlear promontory vibration, three single direction (x, y and z directions in isolation), one linear combination of the three-dimension vibrations, one square-rooted sum of the squared vibration magnitudes, and one sum of the weighted three-dimensional vibrations based on a restricted minimum mean square error (MMSE) estimation. The MMSE gave the best predictions of the hearing threshold based on the cochlear promontory vibration while using only a single direction gave the worst predictions of the hearing thresholds overall. According to the MMSE estimation, at frequencies up to 8 kHz the vibration direction between the right and left side gave the greatest contribution to BC hearing in the guinea pig while at the highest frequencies measured, 16 and 20 kHz, the anteroposterior direction of the guinea pig head gave the greatest contribution. We do the further research to compare the vibrational patterns of human and guinea pig cochleae accurately, we developed and validated a novel finite element model of the guinea pig, leveraging it to analyze vibrational patterns in the cochlea. This approach is mirrored in our examination of the human cochlear model, providing granular insights into the nuances of human bone conduction hearing. The comparative analysis reveals that the guinea pig cochlea mirrors human cochlear vibrational patterns, thus serving as an efficient proxy for exploring human cochlear function. The convenient and comparable sites for bone conduction stimulation are identified as the human mastoid and the upper region of the guinea pig's skull. The cochlear vibration pattern encompasses a mix of rigid, rotational, and compressive motion.

This study was designed to investigate bone Conduction (BC)/auditory steady state response (ASSR) in children with normal hearing, together with various types of hearing loss, to find out an objective method to differentiate between different types of hearing loss. A total of 80 children (with ages ranging between 3 and 6 years) were subjected to history taking, otological examination, and basic audiological evaluation in the form of pure-tone audiometry (air Conduction (AC), BC). Single monotic ASSR (AC, BC) was tested at 0.5, 1, 2, and 4 kHz. They were classified on the basis of hearing status into three categories (20 children each): category I, normal hearing; category II, sensorineural hearing Loss (SNHL) (subdivided into two groups: group 1, mild-to-moderate SNHL; and group 2, severe-to-profound SNHL), and category III, conductive hearing loss. BC thresholds were poorer for ASSR testing compared with thresholds obtained with behavioral testing in normal category using 9, 7.5, 5.5, and 10.5 dBHL at 0.5, 1, 2, and 4 kHz, respectively. In category II, in the mild-to-moderate SNHL group, it was poorer using 16.25, 5.75, 12.25, and 11.75 dBHL at the same measured frequencies. Minimum levels at which spurious BC/ASSR occurred were established in the group with severe-to-profound SNHL as 52, 66.5, 69, and 64 dBHL at 0.5, 1, 2, and 4 kHz, respectively (no BC/pure tone audiometry (PTA) could be measured). In conductive hearing loss (CHL) category, it was poorer using 12.5, 8.5, 9.5, and 9 dBHL at 0.5, 1, 2, and 4 kHz, respectively. Preliminary normal levels for BC/ASSR at 0.5, 1, 2, and 4 kHz were 23.5, 22.5, 20, and 25 dBHL, respectively. In children with conductive hearing loss, the average BC/ASSR thresholds corresponded closely to those in the normal-hearing group. BC/ASSR thresholds could be recorded reliably in children with normal hearing and conductive hearing losses. Meanwhile, BC/ASSR may not provide a reliable measure in cases of SNHL, especially cases with moderate or greater loss due to the low levels at which spurious responses may occur.

The objective was to assess audiological results after total ossicular reconstruction for stapes fixation. The study is a retrospective evaluation conducted in a tertiary referral centre. The patients were 16 adults with conductive or mixed hearing loss and stapes fixation due to tympanosclerosis or otosclerosis. A total or partial stapedectomy with perichondrium interposition on the oval window and ossicular reconstruction with titanium total prosthesis were done. To assess pre- and post-operative (1 and 4 years) air and bone-conduction thresholds (frequencies 0.5, 1, 2, 3 kHz), pure-tone average air and bone conduction, and air-bone gaps were measured and the number of decibels of closure of the air-bone gap at 1 year and at 4 years were compared. One year after surgery, air conduction thresholds and pure-tone average air conduction were improved for all frequencies, and there were no significant differences in bone conduction thresholds or in pure-tone average bone conduction. There were no differences in air and bone conduction thresholds, pure-tone average air or bone conduction between 1 and 4 years. The air-bone gap was significantly reduced 1 year after surgery and remained so at 4 years. (Preoperative air-bone gap, 34.04 dB; at 1 year, 16.40 dB; at 4 years, 17.3 dB. Decibels of closure of the air-bone gap at 1 year, 17.64 dB; at 4 years, 16.74 dB.) No differences were found between otosclerosis subjects and all other cases combined. Total ossicular reconstruction in stapes fixation due to tympanosclerosis or otosclerosis produces satisfactory short- and long-term auditory results.

Conclusion: Active middle ear implant (AMEI) implantation in children and adolescents is safe and provides improved hearing results. No statistical difference in hearing outcomes was shown in the group of patients affected by chronic middle ear diseases versus aural atresia. Also, the transducer location (round window versus oval window placement) did not lead to different outcomes in hearing abilities. Objectives: (1) To assess the hearing outcomes with the active implant Vibrant Soundbridge (VSB) in children and adolescents. (2) To evaluate whether functional results of the subjects in the study could depend on the hearing loss etiology (chronic middle ear diseases versus aural atresia) or on transducer location (round window versus oval window placement). Methods: The study was carried out with a retrospective, single-subject, repeated measures design, and included 22 children and adolescents with conductive or mixed hearing loss due to aural atresia or chronic middle ear diseases. Preoperative and postoperative pure tone air conduction (AC) and bone conduction (BC) thresholds were measured to demonstrate implantation safety. Free-field warble tone and speech audiometry were performed to assess postoperative hearing abilities with and without the VSB. Results: No significant changes in mean BC or AC thresholds between preoperative and postoperative conditions were seen in the 22 patients. Mean PTA4 functional gain was 30.7 dB. Averaged over all 22 patients, word recognition at 65 dB SPL changed from an average of 19% in the unaided postoperative condition to 97% in the VSB-aided condition. Functional results were independent of hearing loss etiology and transducer location.

We investigated whether cholesteatoma is associated with sensorineural hearing loss (SNHL) and the effects of a lateral semicircular canal (LSCC) fistula, destruction of stapes, localization of cholesteatoma, and air-bone gap (ABG) size on SNHL. The charts of 159 patients who had received surgery for unilateral cholesteatoma were examined retrospectively. In all patients, air conduction and bone conduction (BC) thresholds in both ears were measured at 500, 1000, 2000, and 4000 Hz. Differences in BC thresholds between ears with cholesteatoma and contralateral ears were calculated. Demographics, localization of cholesteatoma, presence of LSCC fistula, condition of stapes, and ABG size on the affected ear were evaluated. There were significantly greater BC thresholds in ears with cholesteatoma than in normal ears for each frequency. Comparing the average BC differences at the different cholesteatoma locations, there were significant differences between the tympanic cavity + all mastoid cell group and attic, attic + antrum, and tympanic cavity + antrum groups. The BC differences at 4000 Hz were significantly high in patients with LSCC fistula. There were no significant relationships between the condition of the stapes and BC differences at any frequencies. There were significant correlations between average ABG and BC threshold differences at all frequencies. A significant relationship was found between cholesteatoma and SNHL. Patients with advanced cholesteatoma had significantly higher levels of SNHL. The BC threshold differences increased with increases in the ABG.

To improve understanding of normal responses in infants by comparing air conduction (AC) and bone conduction (BC) auditory thresholds using both the auditory steady state response (ASSR) and behavioral testing methods in normal-hearing infants (6 to 18 months of age) and adults. At present, there are no correction factors available for estimating BC behavioral thresholds from BC ASSR thresholds, which is a barrier to clinical implementation of the ASSR. In addition, previous studies have reported infant-adult differences in AC and BC sensitivity, which suggest a "maturational" air-bone gap (ABG) that is not attributable to a conductive pathology; no study has yet compared AC and BC thresholds for either ASSR or behavioral methods in the same individuals. The objectives of the present study are: (1) to compare BC thresholds between methods and provide the initial step toward positing correction factors to predict BC behavioral thresholds, (2) to directly compare AC and BC thresholds to provide an accurate estimate of the maturational ABG, (3) to determine preliminary normal levels for BC and AC ASSRs to exponentially amplitude modulated stimuli, and (4) to investigate infant-adult differences in AC and BC thresholds using ASSRs and behavioral assessment tools. Participants were 23 infants (6.5 to 19.0 months of age) and 12 adults (17 to 50 years of age) with normal hearing. Thresholds were estimated at 500, 1000, 2000, and 4000 Hz using air- and bone-conducted stimuli for ASSRs and behavioral testing. The ASSR stimuli were exponential envelope modulated (amplitude modulation [AM]) at modulation frequencies of 78, 85, 93, and 101 Hz for 500, 1000, 2000, and 4000 Hz, respectively, presented simultaneously. Frequency-modulated (warble tone) stimuli were used for behavioral testing for both infants and adults, respectively. All stimuli were calibrated in dB HL. Thresholds were compared across frequency and between stimulus presentation modes, between age groups and assessment method. Normal levels for AC and BC ASSRs to AM stimuli were also calculated. The findings indicated that BC thresholds were, on average, 7 to 16 dB poorer for ASSR compared with visual reinforcement audiometry (VRA), but varied widely across infants. For infants, mean ABGs of 14 to 17 dB were found for low-frequency ASSR thresholds but mean ABGs for VRA thresholds were less than 10 dB. The preliminary normal levels for ASSR AM stimuli at 500, 1000, 2000, and 4000 Hz, respectively, were: (i) AC: 30, 30, 20, and 20 dB HL, and (ii) BC: 20, 20, 30, and 30 dB HL. There was a tendency for infant and adult ASSR thresholds to differ for BC, but not for AC. Behavioral thresholds for AC and BC were similar between infants and adults and across frequency. Infant-adult and AC-BC threshold differences are greater for ASSRs compared with behavioral measures. The results support the presence of a clinically significant maturational ABG in the low frequencies for infant ASSRs but not for VRA. The findings also show a significant offset between BC ASSR and BC VRA thresholds and large intersubject variability.

Background Vestibular evoked myogenic potential (VEMP) test is an electrophysiological testing that can assess dysfunction of otolithic organs and the integrity of their pathways precisely. Aim Compare amplitude and latency of ocular and cervical vestibular evoked myogenic potentials evoked by air- and bone-conducted stimuli in three different groups. Materials and methods The control group (group 1) included ten healthy volunteers adults (20 ears) with normal hearing thresholds. Group 2 consisted of ten patients (20 ears) with conductive hearing loss (CHL) and group 3 comprised 10 patients (20 ears) with sensorineural hearing loss (SNHL). All participants underwent pure tone audiometry, immittancemetry ocular vestibular evoked myogenic potential (oVEMPs) and cervical vestibular evoked myogenic potential (cVEMPs) by air and bone conduction stimuli. Results The response rate of cVEMPs and oVEMPs elicited by both types of stimuli was 100% in control group and SNHL group. In the group of conductive hearing loss, air conduction(AC) (c VEMPs and o VEMPs) response rate was 60%. There was a statistically significant positive correlation between latencies of oVEMPs and cVEMPs evoked by AC and BC methods and degrees of hearing loss in SNHL group. Conclusion Ocular and cervical VEMPs elicited by bone conduction (BC) stimuli aren’t vulnerable to conductive hearing loss. Bc VEMPs provides assessment of vestibular system in patients with conductive hearing loss. Significant correlation was found between cVEMPs and oVEMPs abnormalities and severity of sensorineural hearing loss.

This study aimed to investigate the factors affecting permanent sensorineural hearing loss (SNHL) and causing changes in bone conduction (BC) thresholds over time in patients after receiving radiotherapy (RT) or chemoradiotherapy (CRT) to the head and neck region. A total of 63 patients with irradiated HNC that were admitted to the Radiation Oncology Department between 2011 and 2018 were included in the study. All patients were assessed with pure tone audiometry at eight different time points (first before RT and last five years after completion of RT). A chi-square test was used to analyze the variables that affected permanent SNHL occurrence. Repeated measure analysis of variance was conducted to investigate the factors affecting change in the BC threshold at pure-tone average (0.5-2 kHz) and the air conduction (AC) threshold at 4 and 6 kHz frequencies over time. Median follow-up was 52 months (range, 12-110 months). SNHL was found in 18 (14%) of the 126 ears. According to the receiver operating characteristic analysis, the cut-off values of cochlear Dmean and Dmax radiation doses were 40 Gy [p=0.017, area under the curve (AUC): 0.676] and 45 Gy (p=0.008, AUC: 0.695). Dmean (≤40 Gy vs. >40 Gy) and Dmax (≤45 Gy vs. >45 Gy) cochlear doses and age (≤40 vs. >40 years) were determined as factors affecting SNHL in the chi-square test. Repeated measures showed that BC thresholds between 0.5-2 kHz and AC thresholds at 4 and 6 kHz increased over time. Age (≤40 vs. >40 years), treatment of head and neck cancer (RT vs. CRT), cisplatin use, and Dmean (≤40 Gy vs. >40 Gy) and Dmax cochlear dose (≤45 Gy vs. >45 Gy) were important factors affecting the course of BC threshold over time. Dmean and Dmax cochlear doses and age were found to be associated with permanent SNHL. Conduction thresholds worsened over time at all frequencies, and this trend was affected by cochlear doses, age, CRT, and cisplatin use.

Air-conduction (AC) and bone-conduction (BC) thresholds were measured to evaluate standard reference thresholds and recommend revisions to audiometer standards. AC and BC thresholds were measured from listeners with normal hearing (NH) and sensorineural hearing loss (SNHL) at three sites. NH participants (n = 53) were selected based on age (18-25 years old), normal AC thresholds, tympanometry, otoscopy, and absence of otologic disease. SNHL participants (n = 49) were selected based on AC thresholds, tympanometry, otoscopy, and absence of otologic disease. AC thresholds obtained from NH listeners averaged 3.7 dB hearing level (HL). Air-bone gaps (ABGs) occurred in NH and SNHL listeners above 2000 Hz and in SNHL listeners at 250 Hz. Corrections to standard reference equivalent threshold sound pressure levels are recommended. ABGs in listeners without conductive pathology result from incorrect reference threshold levels for frequencies above 2000 Hz. False ABGs increase with hearing-loss magnitude, probably the result of the effects of ambient and internal noise for low-level BC stimuli. False ABGs place patients at risk for unnecessary medical and surgical intervention. Reference threshold levels should achieve two objectives: (1) AC thresholds from young NH listeners should average 0 dB HL; and (2) ABGs from listeners with normal middle-ear function should average 0 dB.

Differences between air conduction (a–c) and bone conduction (b–c) thresholds are commonly used to determine the presence and magnitude of a middle ear abnormality in the human audiotory system, making the tacit assumption that b–c directly stimulates the cochlea. Animal experiments have long established that b–c transmission is a complex phenomenon [J. Tonndorf, in Foundations of Modern Auditory Theory, Vol. 2 (Academic, New York, 1972)] with significant contributions from middle and external ear components. An artificial reversible middle ear abnormality may be induced in man by maintaining an air pressure in the external meatus. The shifts in a–c and b–c thresholds provide a means to evaluate the relative importance of the external and middle ear components. At the lower frequencies of 250 and 500 Hz, these components predominate; at 500 Hz there is an a–c shift of 15.9 dB accompanied by a b–c shift of 15.8 dB. These results have important implications for the interpretation of air and bone conduction thresholds.

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Masking dilemma is a condition prevalent whenever there is significant hearing loss in non-test ear and conductive hearing loss in test ear resulting into narrow or non-existent plateau width. Three feasible ways are divulged to circumvent this condition namely, Sensorineural acuity level testing, Fusion Inferred at threshold and use of insert type transducers. Different circumstances encountered when using insert type transducers and Fusion Inferred at threshold test has made it peril to use. Thus, administration of sensorineural acuity level test has been preferred. Sensorineural acuity level test involves computation of individual threshold shifts and its comparison with normal threshold shifts when a maximum level of bone conducted noise is presented at the centre of forehead via bone conduction vibrator. This research study aims to document normal threshold shifts and its validation in individual with bilateral symmetrical sensorineural hearing loss.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; A prospective study was carried out among 50 normal individuals and 50 patients with bilateral symmetrical sensorineural hearing loss. Pertinent measures were taken to ensure fulfilment of all-inclusive and exclusive criteria. In addition, air conduction and bone conduction threshold were computed using conventional methods followed by administration of sensorineural acuity level test. Necessary comparison was made among the threshold shifts. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Inferences drawn showed closer correlation between sensorineural acuity level threshold and bone conduction thresholds during puretone audiometry.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Sensorineural acuity level test has shown to be effectual in both rehabilitation and medical interventions. Besides, imperative role of an audiologist can be recognized in its administration and elucidation for better prognostication.&lt;/p&gt;