Protective effect of trimetazidine on amikacin-induced ototoxicity in rats

Objective

Aminoglycoside antibiotics are known to have ototoxic effects and may induce sensorineural hearing loss. This study investigated the protective effect of trimetazidine, which has antioxidant and cytoprotective properties, against amikacin ototoxicity.

Methods

Thirty-two male rats were divided into four groups – amikacin, amikacin + trimetazidine, trimetazidine, and control groups. Trimetazidine, 10 mg/kg per day, was given for 14 days by oral gavage. Amikacin, 600 mg/kg per day, was also given for 14 days, by the intramuscular route. Distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) tests were applied to the rats for hearing assessment. At the termination of the study, the biochemical parameters were calculated to evaluate the oxidative status.

Results

The DPOAE values of the amikacin group were significantly lower on the 7th and 14th days than those of the trimetazidine + amikacin group and there was an increase in the ABR thresholds. The ABR thresholds for the amikacin group on the 7th and 14th days were significantly higher than the levels on the first day of the study, while there was no significant increase in those values in the trimetazidine + amikacin group. The total oxidant status (TOS) and oxidant status index (OSI) values of the amikacin group were significantly higher than those of the trimetazidine + amikacin group. The total antioxidant status (TAS) values of the amikacin group were lower than those of the trimetazidine + amikacin group.

Conclusions

The audiologic tests and biochemical parameters investigated in this study both point to the protective effect of trimetazidine against amikacin-induced ototoxicity.     

Are Systemic Voriconazole and Caspofungin Ototoxic? An Experimental Study with Rats

Objectives

To determine whether systemic administration of voriconazole and caspofungin causes ototoxicity.

Methods

This study was conducted on 32 healthy male Wistar albino rats. The baseline auditory brainstem response (ABR) thresholds of all animals were obtained under general anesthesia. Then, the rats were randomly divided into 4 groups (groups I-IV), each group consisting of 8 rats. Rats in group I were injected intraperitoneally with voriconazole 10 mg/kg/day for 7 days, and the rats in the group II were injected intraperitoneally with caspofungin 5 mg/kg/day for 7 days. Group III received 120 mg/kg/day gentamicin for 7 days. Group IV received saline for 7 days. The animals were then observed for 7 days, and on 14th day of the trial, posttreatment ABRs of both ears were recorded.

Results

We did not find any significant differences between pretreatment and posttreatment median ABR thresholds in the voriconazole, caspofungin, or saline groups. In the gentamicin group, there was a statistically significant difference between pretreatment and posttreatment ABR thresholds.

Conclusion

Caspofungin and voriconazole did not change ABR thresholds in speech frequencies after a 7-day-period of their administration. We believe that further animal studies must be performed after administration of these agents for a longer time period, and these findings must be consolidated with histopathological investigations.     

The protective role of thymoquinone in the prevention of gentamicin ototoxicity

Objective

To investigate the potential protective effect of thymoquinone in gentamicin-induced ototoxicity through auditory brain stem responses (ABR) testing and histomorphological evaluation of the cochlea.

Methods

This study was conducted on 48 adult female Sprague–Dawley rats that were randomized into 4 groups. Group 1 received intraperitoneal gentamicin; group 2 received intraperitoneal gentamicin plus corn oil solution; group 3 received intraperitoneal thymoquinone; and group 4 received intraperitoneal gentamicin plus thymoquinone. All groups received the drugs (once daily) in the above-mentioned protocols over 15 days. After conducting repeated ABR measurements, the rats were sacrificed, and their cochleae were isolated.

Results

ABR thresholds were preserved in the gentamicin plus thymoquinone group when compared with the group receiving gentamicin alone. There were fewer TUNEL-positive cells and caspase-3 and caspase-9 expressions were weaker in the inner and outer hairy cells of the organ of Corti in the gentamicin plus thymoquinone group compared with the group receiving gentamicin alone.

Conclusion

The ABR values and number of apoptotic cells did not significantly increase in the group receiving gentamicin plus thymoquinone when compared to the group receiving gentamicin alone. Again, the cochlear histomorphological findings were supportive of the auditory findings. In light of these findings, we conclude that gentamicin-induced ototoxicity may be prevented by thymoquinone use in rats.     

Protective effect of thymoquinone against cisplatin-induced ototoxicity

The aim of this study was to investigate the potential protective effect of thymoquinone against cisplatin-induced ototoxicity. This study is a prospective, controlled experimental animal study. Experiments were performed on 30 healthy female Sprague-Dawley rats. Thirty animals were divided into three groups of 10 animals each. Group 1 received an intraperitoneal (i.p.) injection of cisplatin 15 mg/kg. Group 2 received i.p. thymoquinone 40 mg/kg/day for 2 days prior to cisplatin injection and third day i.p. cisplatin 15 mg/kg was administered concomitantly. Group 2 continued to receive i.p. thymoquinone until fifth day. Group 3 received i.p. thymoquinone 40 mg/kg/day for 5 days. Pretreatment distortion product otoacoustic emissions (DPOAE) and auditory brain stem responses (ABR) testing from both ears were obtained from the animals in all groups. After the baseline measurements, drugs were injected intraperitonally. After an observation period of 3 days, DPOAE measurements and ABR testing were obtained again and compared with the pretreatment values. There was no statistically significant difference between pre and post-treatment DPOAE responses and ABR thresholds group 2 and 3. However, group 1 demonstrated significant deterioration of the ABR thresholds and DPOAE responses. Our results suggest that DPOAE responses and ABR thresholds were preserved in the cisplatin plus TQ-treated group when compared with the group receiving cisplatin alone. According to these results, cisplatin-induced ototoxicity may be prevented by thymoquinone use in rats.     

Evaluation of the Protective Effect of Beta Glucan on Amikacin Ototoxicity Using Distortion Product Otoacoustic Emission Measurements in Rats

Objectives

This experimental study investigated the possible protective effect of beta glucans on amikacin ototoxicity.

Methods

Thirty-eight rats with normal distortion product otoacoustic emissions (DPOAEs) were divided into four groups. Group K was the control group. Group A was injected intramuscularly (i.m.) with amikacin 600 mg/kg/day between days 1-15. Group AB was given beta glucan gavage 1 mg/kg/day on days 0-15 and given amikacin 600 mg/kg/day i.m. on days 1-15. Group B was administered only beta glucan gavage, 1 mg/kg/day, on days 0-15. The DPOAEs were elicited in different frequency regions between 2,003 and 9,515 Hz, as distortion product diagrams (DPgrams), before and after the medication was administered, in all groups, on days 1, 5, 10, and 15.

Results

No significant changes in the DPgrams were observed in group K. In group A, significant deterioration was observed at the 8,003 and 9,515 Hz frequencies on day 10, and at the 3,991, 4,557, 5,660, 6,726, 8,003, and 9,515 Hz frequencies on day 15. For group AB, statistically significant deterioration was observed at the 2,824, 8,003, and 9,515 Hz frequencies on day 15. The results for group B showed a significant improvement of hearing at the 2,378, 2,824, 3,363, and 3,991 Hz frequencies on day 1, at the 3,363, 3,991, and 8,003 Hz frequencies on day 10, and at the 8,003 Hz frequency on day 15.

Conclusion

This study suggests that amikacin-induced hearing loss in rats may be limited to some extent by concomitant use of beta glucan.     

Comparison of cochlear morphology and apoptosis in mouse models of presbycusis

Objectives

Morphological studies on presbycusis, or age-related hearing loss, have been performed in several different strains of mice that demonstrate hearing loss with auditory pathology. The C57BL/6 (C57) mouse is a known model of early onset presbycusis, while the CBA mouse is characterized by relatively late onset hearing loss. We performed this study to further understand how early onset hearing loss is related with the aging process of the cochlea.

Methods

We compared C57 cochlear pathology and its accompanying apoptotic processes to those in CBA mice. Hearing thresholds and outer hair cell functions have been evaluated by auditory brainstem response (ABR) recordings and distortion product otoacoustic emission (DPOAE).

Results

ABR recordings and DPOAE studies demonstrated high frequency hearing loss in C57 mice at P3mo of age. Cochlear morphologic studies of P1mo C57 and CBA mice did not show differences in the organ of Corti, spiral ganglion, or stria vascularis. However, from P3mo and onwards, a predominant early outer hair cell degeneration at the basal turn of the cochlea in C57 mice without definitive degeneration of spiral ganglion cells and stria vascularis/spiral ligament, compared with CBA mice, was observed. Additionally, apoptotic processes in the C57 mice also demonstrated an earlier progression.

Conclusion

These data suggest that the C57 mouse could be an excellent animal model for early onset ''sensory'' presbycusis in their young age until P6mo. Further studies to investigate the intrinsic or extrinsic etiologic factors that lead to the early degeneration of organ of Corti, especially in the high frequency region, in C57 mice may provide a possible pathological mechanism of early onset hearing loss.     

Apoptotic Pattern of Cochlear Outer Hair Cells and Frequency-specific Hearing Threshold Shift in Noise-exposed BALB/c Mice

Objectives

Apoptosis of outer hair cell (OHC) can be identified through nuclear staining by specific nuclear changes. The change of filamentous actin (F-actin) is also involved in early cell death process. The study was designed to investigate OHC death along the whole length of the organ of Corti.

Methods

BALB/c hybrid mice were used in this study. The noise group was exposed to white noise of 120 dB SPL for 3 hr per day for 3 consecutive days. The tone burst auditory brainstem response (ABR) test was conducted and cochleas from each group were obtained for the immunostaining of FITC phalloidin for F-actin and propidium iodide (PI) for nuclei.

Results

ABR threshold of the noise group significantly increased after noise exposure (P<0.001). No threshold shift was found in the control group. Threshold shift of the noise group constantly increased from 4 to 16 kHz, but threshold shifts at 16 kHz and 32 kHz were similar. Patterns of OHC staining were subclassified as FITC+PI- cells, FITC+ PI+ cells, FITC-PI+ cells and missing cells. Proportion of normal live OHCs (FITC+PI-) rapidly decreased from the apex to the base. In the basal turn, FITC-PI+ cells and vacancy OHC (missing cells) were observed easily. Apoptotic and missing cells were most abundant at 60% of the whole length of the Corti organ.

Conclusion

We could subclassify morphologic changes in OHC death after noise exposure. Quantitative changes in OHCs along the whole Corti organ showed a plateau pattern similar to that of a frequency-specific threshold shift.     

Audiological Follow-up Results after Newborn Hearing Screening Program

Objectives

To investigate the validity of newborn hearing screening protocol using automated auditory brainstem response (AABR) with a confirmation method using click auditory brainstem response (ABR) and to evaluate changes in hearing status of infants with confirmed congenital hearing loss.

Methods

Neonates in the well-baby nursery were screened by staged AABR. Subjects whose final AABR result was "refer" were tested by diagnostic click ABR and 226 Hz tympanometry within 3 months of age. Changes in hearing status of subjects with confirmed hearing loss were analyzed by follow-up ABR at 3-6 month intervals.

Results

Of the 12,193 healthy babies born during this period, 10,879 (89.22%) were screened by AABR. Of 10,879 neonates screened by AABR, 148 (1.36%) were "referred"; of these, 45 subjects showed ABR thresholds over 30 dB nHL in at least one ear. Thirty-four subjects underwent serial follow-up ABR tests, with 11 (32.4%) found to have normal ABR thresholds. Most subjects with mild to moderate hearing loss were found to be normal before 1 year of age, whereas all infants with severe or profound hearing loss were identified as having congenital hearing loss.

Conclusion

The referral rate and the positive predictive value of our protocol were acceptable. We have also found here that substantial temporary hearing loss can be included in the first confirmative diagnosis. Temporary hearing loss of our study on follow-up give emphasis to need of further differentiation using the testing for bone conduction and middle ear status.     

Early Sensorineural Hearing Loss in Ob/Ob Mouse, an Animal Model of Type 2 Diabetes

Objectives

There have been many studies on the relationship between diabetes mellitus and presbycusis. Microangiopathy and neuropathy that''s caused by chronic hyperglycemia may lead to damage to the inner ear. Several clinical studies on humans and animal studies have been performed to investigate the association between diabetes and hearing loss, however, this relationship is still a matter of debate. We investigated the association of diabetes and sensorineural hearing loss in an animal model of type-2 diabetes and obesity (the ob/ob mouse [OM]).

Methods

The auditory brainstem response (ABR) thresholds were obtained in the OM and the wild type mice (C57BL/6J mice) up to 25 weeks after birth. After the animals were sacrificed, their cochleae were retrieved and then subjected to histopathologic observations.

Results

The OM exhibited significantly elevated ABR thresholds at 21 weeks of age, yet the C57BL/6J mice exhibited no significant change until 25 weeks of age. On the histological findings, outer hair cell degeneration and loss of spiral ganglion cells were observed in the middle and basal turns of the OM. On the contrary, no degenerative change was observed until 25 weeks of age in the C57BL/6J mice.

Conclusion

This study suggests that chronic hyperglycemia and obesity may lead to early sensorineural hearing loss.     

Medical ozone therapy for the inner ear acoustic trauma

Objectives

The goal of the study was to look at the potential protective effect of ozone therapy by studying its antioxidant and vasodilatation effects against hearing loss caused by acoustic trauma.

Methods

Thirty-two male Wistar Albino rats were divided into four groups of eight. The 1st group was exposed to acoustic trauma, the 2nd group was treated with ozone initially, and was exposed to acoustic trauma 24 h later, the 3rd group received ozone without trauma, while the 4th group was the control group. The 1st and 2nd groups were exposed to acoustic trauma with 105 dB SPL white band noise for 4 h. DPOAE and ABR tests were conducted in all groups on the 1st, 5th, and 10th days after trauma.

Results

In the 1st group, the effects of acoustic trauma continued on days 1, 5 and 10. The 2nd group's DPOAE and ABR results on days 5 and 10 showed significant improvement at all frequencies compared to deterioration on day 1, and the readings were comparable to baseline measurements.

Conclusion

Acoustic trauma is a pathology that is experienced frequently and leads to many problems in terms of health and cost. Ozone was demonstrated to be a reparative substance against acoustic trauma and, in addition, it can be supplied and applied easily.     

Potentiation of noise-induced hearing loss by amikacin in guinea pigs.

Noise and aminoglycosides initially attack cochlear outer hair cells (OHCs). Distortion product otoacoustic emissions (DPOAEs) are used for the early diagnosis of damage to OHCs. The effects of sub-damaging doses of amikacin, an aminoglycoside antibiotic agent, on noise-induced hearing loss (NIHL) were examined in guinea pigs. Animals were grouped by gender and exposed to broadband noise at 105 dB SPL for 12 h and/or injected i.m. with either amikacin (100 mg/kg/day) or saline for 10 days. Auditory brainstem response (ABR) thresholds, along with DPOAE amplitudes, were measured serially before and after noise exposure. DPOAE amplitudes decreased and ABR thresholds elevated immediately after noise exposure and then gradually recovered. At all frequencies, the emission amplitudes recovered completely to pre-exposure baseline values by 4 days after noise exposure. There was no effect of amikacin on either the ABR threshold or DPOAE amplitudes, in animals treated with amikacin only. However, amikacin significantly prolonged the effect of noise exposure on DPOAE amplitude but not on the noise-induced temporary threshold shift (TTS) of the ABR. In animals treated with a combination of noise and amikacin, significant changes in DPOAE amplitudes were still observed at 4 weeks after cessation of noise exposure. No gender difference in the responses to noise and/or amikacin could be demonstrated. The present findings indicate that even sub-damaging dosages of amikacin might impair recovery from NIHL in guinea pigs.     

Factors Affecting the Variation of Maximum Speech Intelligibility in Patients With Sensorineural Hearing Loss Other Than Apparent Retrocochlear Lesions

Objectives

To examine the relationship between speech intelligibilities among the similar level of hearing loss and threshold elevation of the auditory brainstem response (ABR).

Methods

The relationship between maximum speech intelligibilities among similar levels of hearing loss and relative threshold elevation of the click-evoked ABR (ABR threshold - pure tone average at 2,000 and 4,000 Hz) was retrospectively reviewed in patients with sensorineural hearing loss (SNHL) other than apparent retrocochlear lesions as auditory neuropathy, vestibular schwannoma and the other brain lesions.

Results

Comparison of the speech intelligibilities in subjects with similar levels of hearing loss found that the variation in maximum speech intelligibility was significantly correlated with the threshold elevation of the ABR.

Conclusion

The present results appear to support the idea that variation in maximum speech intelligibility in patients with similar levels of SNHL may be related to the different degree of dysfunctions of the inner hair cells and/or cochlear nerves in addition to those of outer hair cells.     

Utilizing prestin as a predictive marker for the early detection of outer hair cell damage

Purpose

To evaluate prestin as a biomarker for the identification of early ototoxicity.

The effect of various durations of noise exposure on auditory brainstem response, distortion product otoacoustic emissions and transient evoked otoacoustic emissions in rats

This study was designed to investigate the effect of various durations of noise exposure in animals on physiological responses from the cochlea which are also used clinically in humans: auditory brainstem response (ABR), transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs). Rats were exposed to 113 dB SPL broad-band noise (12 h on/12 h off) for durations of 3, 6, 9, 12, 15 and 21 days, and tested 24 h after cessation of the noise and again after a period of 6 weeks. ABR threshold to click stimuli and to a 2-kHz tone burst (TB), TEOAE energy content and DPOAE amplitude in the exposed rats were compared to those in a group of control rats not exposed to noise. ABR thresholds (click and TB) were significantly elevated in all exposure duration groups compared to control rats. DPOAE amplitudes and TEOAE energy content were significantly reduced. The mean ABR thresholds following 21 days exposure were significantly greater (click = 100 dB pe SPL; TB = 115 dB pe SPL) than those following 3 days exposure (click = 86 dB pe SPL; TB = 91 dB pe SPL). Linear regression analysis between recorded responses and duration of noise exposure (days) showed a significant increase in ABR thresholds of approximately 0.8-- 1.4 dB/day. TEOAE and DPOAE responses showed no such dependence on noise duration and were already maximally reduced after only 3 days of exposure. This can be explained by the possibility that short noise exposures may cause damage to the early, more active stages of cochlear transduction (as shown by TEOAEs and DPOAEs). As the noise exposure continues, further damage may be induced at additional, later stages of the cochlear transduction cascade (as shown by ABR). Thus, ABR seems more sensitive to noise duration than OAE measures.     

Clinical Comparison of the Auditory Steady-State Response with the Click Auditory Brainstem Response in Infants

Objectives

Our goal was to determine the effectiveness of using the auditory steady state response (ASSR) as a measure of hearing thresholds in infants who are suspected of having significant hearing loss, as compared with using the click-auditory brainstem response (C-ABR).

Methods

We retrospectively analyzed the audiologic profiles of 76 infants (46 boys and 30 girls, a total of 151 ears) who ranged in age from 1 to 12 months (average age: 5.7 months). The auditory evaluations in 76 infants who were suspected of having hearing loss were done via the C-ABR and ASSR. In addition, for reference, the mean ASSR thresholds were compared to those of 39 ears of infants and 39 ears of adults with normal hearing at 0.5, 1, 2, and 4 kHz.

Results

The highest correlation between the C-ABR and ASSR thresholds was observed at an average of 2-4 kHz (r=0.94). On comparison between the hearing of infants and adults at 0.5, 1, 2, and 4 kHz, the mean ASSR threshold in infants was 12, 7, 8, and 7 dB higher, respectively, than that in adults.

Conclusion

ASSR testing may provide additional audiometric information for accurately predicting the hearing sensitivity, and this is essential for the management of infants with severe to profound hearing loss.     

Effects of GSM-like Radiofrequency on distortion product otoacoustic emissions of rabbits: Comparison of infants versus adults

Objectives

The aim of this study is to investigate the potential hazardous effects of 1800 MHz Global System for Mobile Communications-like (GSM-like) Radiofrequency (RF) exposure on the cochlear functions of female infant and adult rabbits by measuring Distortion Product Otoacoustic Emission (DPOAE) response amplitudes.

Methods

Eighteen each one-month-old New Zealand White female rabbits and eighteen each 13-month-old adult rabbits were included into the study. They were randomly divided into four groups. Nine infant rabbits (Group 1) were not exposed to 1800 MHz GSM-like RF (Infant Control, C-In). Nine infant rabbits (Group 2) were exposed to 1800 MHz GSM-like RF, 15 min daily for 7 days after they reached one-month of age (Infant RF, RF-In). Nine adult rabbits were not exposed to 1800 MHz GSM-like RF, 15 min daily for 7 (Adult Control, C-Ad). Nine adult rabbits were exposed to 1800 MHz GSM-like RF, 15 min daily for 7 days (Adult RF, RF-Ad). Cochlear functions were assessed by DPOAEs at 1.0-8.0 kHz.

Results

At 1.0-2.0 and 6.0 kHz, the mean DPOAE values of Group 2 were significantly higher than that of Group 1. At 3.0-8.0 kHz, the mean DPOAE values of Group 4 were significantly lower than that of Group 1. At 6.0-8.0 kHz, the mean DPOAE values of Group 2 were significantly higher than that of Group 3. At 1.0-8.0 kHz, the mean DPOAE values of Group 4 were significantly lower than that of Group 2. At 1.0-8.0 kHz, the mean DPOAE values of Group 4 were significantly lower than that of Group 3.

Conclusion

Harmful effects of GSM-like 1800 MHz RF exposure was detected more in the adult female rabbits than infant female rabbits by DPOAE measurement. Prolonged exposure and hyperthermia related to the power density of applied RFR, increasing the temperature in the ear canal, may decrease the DPOAE amplitudes. Water containing medium in the middle ear of infant rabbits may play the protective role **from the RF damage.     

Hearing Abilities at Ultra-High Frequency in Patients with Tinnitus

Objectives

To compare tinnitus patients who have normal hearing between 250 Hz and 8 kHz with normal controls with regard to the ability of each group to hear extended high-frequency pure tone thresholds.

Methods

We enrolled 18 tinnitus patients, each of whom had a threshold of HL <25 dB and threshold differences of <10 dB between ears at frequencies of 250 and 500 Hz and 1, 2, 4, and 8 kHz. We also enrolled age- and gender-matched normal volunteers (10 ears), for each patient. Extended high frequency pure tone audiometry was performed, and the mean hearing thresholds at 10, 12, 14, and 16 kHz of each tinnitus ear were compared with those of the 10 age- and sex-matched normal ears.

Results

Of the 18 patients with tinnitus, 12 had significantly increased hearing thresholds at more than one of the four high frequencies, compared with the normal group. When we assessed results according to frequency, we found that 8 patients had decreased hearing ability at 10 kHz, 10 at 12 kHz, 8 at 14 kHz, and 4 at 16 kHz.

Conclusion

Some patients with tinnitus who have normal hearing below 8 kHz have decreased hearing ability at extended high-frequencies. Thus, the proportion of patients with tinnitus who have normal hearing over the entire audible range is smaller than in previous reports.     

Dexmedetomidine Preconditioning Attenuates Cisplatin-Induced Ototoxicity in Zebrafish

Objectives

Utilisation of high-frequency drills is known to increase noise induced hearing loss due to increasing the damages of inner ear cells. This study aimed to investigate whether preconditioning by using dexmedetomidine (DEX) decreased the occurrence of ischemia in inner cells of the ear.

Methods

We utilised a transgenic zebrafish line Brn3C, and the embryos were collected from breeding adult zebrafish. Five-day-old larvae were cultured at the density of 50 embryos, and the larvae were classified into 4 groups: control, cisplatin group, DEX group, and DEX+yohimbine; adrenoreceptor blocker group. The DEX group was categorised into 3 subgroups by dosage; 0.1, 1, and 10 µM. Preconditioning was performed for 150 minutes and then exposed to cisplatin for 6 hours. The experiment was performed in 7 replicates for each group and the number of hair cells in 3 parts of the neuromasts of each fish was determined.

Results

Hair cell apoptosis by cisplatin was attenuated more significantly in the DEX preconditioning group than in the control group. However, the preconditioning effects were not blocked by yohimbine.

Conclusion

The results of this study suggest that hearing loss caused by vibration-induced noise could be reduced by using DEX and may occur through other mechanisms rather than adreno-receptors.     

Effects of intratympanic dexamethasone on noise-induced hearing loss: An experimental study

Aim

Aim of the study was to evaluate the effect of intratympanic steroid treatment on hearing based on oto-acoustic emission.

Threshold prediction in children with sensorioneural hearing loss using the auditory steady-state responses and tone-evoked auditory brain stem response

Objective

The purpose of this study was to compare ASSRs to tone-evoked ABR and to behavioral thresholds obtained on follow-up audiometry at 500, 1000, 2000, and 4000 Hz in infants and young children.

Methods

The study included 17 infants and young children ages between 2 months and 3 years old, with sensorineural hearing loss. The ASSRs thresholds were compared with the tone-evoked ABR thresholds, and with the behavioral thresholds obtained on follow-up audiometry.

Results

The correlation of tone-evoked ABR and ASSRs thresholds at 500, 1000, 2000 and 4000 Hz was 0.91, 0.76, 0.81, 0.89, respectively. ASSRs and behavioral hearing thresholds obtained on follow-up were highly correlated, with Pearson r values exceeding 0.94 at each of the test frequencies.

Conclusions

Multiple ASSRs have strong correlations to tone-evoked ABR and to behavioral thresholds obtained during follow-up in hearing impaired infants and young children. These results might be useful in order to provide further evidence for the use of multiple ASSRs, as an alternative tool to tone-evoked ABR, although further data are still required.