The auditory steady state response is a modern test for estimating hearing thresholds، especially in difficult to test individuals. However، there are few bone conduction auditory steady state response data، particularly for individuals with hearing loss. The objective of this study was to investigate bone conduction auditory steady state response thresholds in individuals with sensorineural hearing loss and normal hearing. In a cross-sectional study، 10 individuals with normal hearing and 10 with sensorineural hearing loss at the age of 15-30 years were selected by non-probability sampling. Auditory steady state response and pure tone audiometry to bone conduction stimuli in 500 and 2000 Hz were recorded in two groups. Paired and independent t-test were used to compare data between the groups. There was low correlation between bone conduction auditory steady state response and pure tone audiometry in both groups (p>0. 05 for both). The difference of behavioral thresholds and auditory steady state response in 500 Hz was higher than 2000 Hz in both groups (p=0. 033 for normal hearing and p=0. 017 for sensorineural hearing loss groups). Comparison of these results showed significant differences between the two groups (p<0. 001). In both groups، there was low correlation between bone conduction auditory steady state response and pure tone audiometry thresholds. In individuals with sensorineural hearing loss and in higher frequencies، bone conduction auditory steady state response thresholds was closer to pure tone audiometery thresholds.

Among all auditory assessment tools، auditory steady state response (ASSR) is a modern test. Modulation frequency for this test is usually 80 Hz. The purpose of this study، was to examined adult subjects with 40 Hz and 80 Hz ASSR and compare the results. Thirty adult (60 ears) were evaluated by ASSR and PTA test، Results were divided into three groups: normal hearing، mild and moderate sensorineural hearing loss. In all groups، forty hertz ASSR thresholds were relatively closer to behavioral threshold than those of 80 Hz ASSR (p<0. 05). Besides، the more severe hearing loss، the lower the difference between those two thresholds. Correlation coefficients were also higher in 40 Hz ASSR (p<0. 05). Frequency modulation thresholds with 40 Hz are more likely to be closer to the behavioral thresholds. Moreover، it has better results than the thresholds with 80 Hz.

Many of the current brain-computer interface systems rely on the patient`s ability to control voluntary eye movements. Some diseases can lead to defects in the visual system. Due to the intactness of these patients` auditory system, researchers moved towards the auditory paradigms. Attention can modulate the power of auditory steady-state response. As a result, this response is useful in an auditory brain-computer interface.
As humans intrinsically enjoy listening to rhythmic sounds, this project was carried out with the aim of extraction and classification of the EEG signal patterns in response to simple and rhythmic auditory stimuli to investigate the possibility of using the rhythmic stimuli in brain-computer interface systems.
Two three-membered simple and rhythmic groups of auditory sinusoidally amplitude-modulated tones were generated as the stimuli. Corresponding EEG signals were recorded and classified by means of five-fold cross-validated naïve Bayes classifier on the basis of power spectral density at message frequencies.
There was no significant difference between the classification performances of the responses to each group of the stimuli. All the classification accuracies, even without any noise reduction and artifact rejection, was greater than the acceptable value for being used in brain-computer interface systems (70%).
Like the common sinusoidally amplitude-modulated tones, the novel proposed rhythmic stimuli in this project have a promising discrimination for being used in brain-computer interface systems. In addition, Power spectral density has provided an appropriate discrimination for within- and between-subject EEG classification.

Hyperbilirubinemia during the neonatal period is known to be an important risk factor for neonatal auditory impairment, and may reveal as a permanent brain damage, if no proper therapeutic intervention is considered. In the present study some electroacoustic and electrophysiologic tests were used to evaluate function of auditory system in a group of children with severe neonatal Jaundice. Forty five children with mean age of 16.1 14.81 months and 17 mg/dl and higher bilirubin level were studied, and the transient evoked otoacoustic emission, acoustic reflex, auditory brainstem response and auditory steady-state response tests were performed for them. The mean score of bilirubin was 29.37 8.95 mg/dl. It was lower than 20 mg/dl in 22.2%, between 20-30 mg/dl in 24.4% and more than 30 mg/dl in 48.0% of children. No therapeutic intervention in 26.7%, phototherapy in 44.4%, and blood exchange in 28.9% of children were reported. 48.9% hypoxia and 26.6% preterm birth history was shown too. TEOAEs was recordable in 71.1% of cases. The normal result in acoustic reflex, ABR and ASSR tests was shown just in 11.1% of cases. The clinical symptoms of auditory neuropathy were revealed in 57.7% of children. Conducting auditory tests sensitive to hyperbilirubinemia place of injury is necessary to inform from functional effect and severity of disorder. Because the auditory neuropathy/ dys-synchrony is common in neonates with hyperbilirubinemic, the OAEs and ABR are the minimum essential tests to identify this disorder.

Auditory steady state response(ASSR) is an auditory evoked response that has received a lot of attention nowadays. At present, ASSR is mostly used to estimate pure-tone thresholds. Clinical evidence of ASSR in combination with findings for auditory middle latency response (AMLR) and 40 Hz response support the assumption that based on stimulus modulation rate, the ASSR anatomic generators are sub-cortical and/or cortical. The goal of the present study was to investigate ASSR findings in a group of young adults with auditory neuropathy/dys-synchrony(AN/AD). Patients and This cross-sectional analytical study was performed on 16 adults with AN/AD (mean age: 20 5.30 years) and 28 subjects with normal hearing(mean age: 22 3.80 years). ASSR test with high rate modulated stimulus was done at four octave frequencies of 500, 1000, 2000 and 4000 Hz on each ear individually in both AN/AD and control groups. Independent t-test was used to compare hearing thresholds obtained by behavioral evaluation and ASSR recording in each studied group individually. Average pure-tone thresholds revealed moderate hearing loss in AN/AD individuals with focus on low frequencies so that the low-tone loss seen in audiograms was observed in almost two-thirds of the subjects, a finding which is common in adults with AN/AD. However, ASSR revealed profound hearing loss at four studied frequencies in all AN/AD patients regardless of behavioral hearing thresholds, and a significant difference was shown between hearing thresholds gained by these two methods, namely PTA and ASSR. Although in clinical setting ASSR is usually used to estimate hearing thresholds in different populations and degrees of hearing loss, its findings are different in AN/AD patients and can be used for differential diagnosis of this disorder. Using high rate modulated stimulus, severe and profound hearing loss or no ASSR is expected in AN/AD. Considering the fact that ABR also leads to the same abnormal results in AN/AD, it seems that the brain generators of both ABR and ASSR are the same and the concordance between their findings can confirm a defect in auditory brainstem function in patients with suspected AN/AD.

Mild Cognitive Impairment (MCI), a disorder of the elderly people, is difficult to diagnose and often progresses to Alzheimer Disease (AD). Temporal region is one of the initial areas, which gets impaired in the early stage of AD. Therefore, auditory cortical evoked potential could be a valuable neuromarker for detecting MCI and AD.
In this study, the thresholds of Auditory Steady-State Response (ASSR) to 40 Hz and 80 Hz were compared between Alzheimer Disease (AD), MCI, and control groups. A total of 42 patients (12 with AD, 15 with MCI, and 15 elderly normal controls) were tested for ASSR. Hearing thresholds at 500, 1000, and 2000 Hz in both ears with modulation rates of 40 and 80 Hz were obtained.
Significant differences in normal subjects were observed in estimated ASSR thresholds with 2 modulation rates in 3 frequencies in both ears. However, the difference was significant only in 500 Hz in the MCI group, and no significant differences were observed in the AD group. In addition, significant differences were observed between the normal subjects and AD patients with regard to the estimated ASSR thresholds with 2 modulation rates and 3 frequencies in both ears. A significant difference was observed between the normal and MCI groups at 2000 Hz, too. An increase in estimated 40 Hz ASSR thresholds in patients with AD and MCI suggests neural changes in auditory cortex compared to that in normal ageing.
Auditory threshold estimation with low and high modulation rates by ASSR test could be a potentially helpful test for detecting cognitive impairment.

Behavioral audiometry is the best method of hearing evaluation. Hearing thresholds are estimated with auditory evoked responses in patients who are not able to cooperate in behavioral audiometry. Because rehabilitative decisions are based on behavioral thresholds, it is essential to determine the amount of difference between behavioral and evoked response thresholds. The purpose of this study was to evaluate the difference between functional and auditory steady-state response (ASSR) gains. Twenty six moderate to severe hearing impaired adolescents and adults (age range: 14 to 55 years) participated in this interventional-comparative study. Audiometery and ASSR testing was performed (without hearing aid and then with hearing aid). Finally, functional gain with ASSR gain, and behavioral thresholds with ASSR thresholds were compared using paired t-test and correlation statistical methods. All tests were performed in the sound field. The mean difference was 6.19 dB between unaided behavioral and ASSR thresholds, 4.33 dB between aided thresholds, and 2.43 dB between functional and ASSR gains. There was no significant difference between functional and ASSR gains (p>0.05). The difference between functional and ASSR gains is less than the difference between behavioral and ASSR thresholds and it has less variability between different frequencies. So, it may be better to use ASSR gain instead of ASSR thresholds in hearing aid fitting in difficult-to-test population.

One of the most important applications of electrode physiological tests is early diagnosis of hearing loss and estimating of hearing threshold in neonate and children for early auditory intervention. Auditory Steady–State Response (ASSR) is modern technology for threshold detection in audiology. Measurement of Auditory brainstem response (ABR) is most common method of detection auditory threshold in neonates. The goal of this article was to correlate the results between thresholds obtained from ASSR and click-ABR. Subjects and In this descriptive-analytic design، 32 children with mild and moderate hearing loss، aged between birth to 7 years، were studied. All children were evaluated by both ASSR and C-ABR. The correlation coefficients for frequencies of 0. 5، 1، 2، 4، mean of 2-4، and mean of 1-4 kHz were between 0. 40- 0. 87 in mild hearing loss and 0. 52-0. 91 in moderate hearing loss (P<0. 05). C-ABR and ASSR thresholds in mean frequencies had a greater correlation than single-frequency (P-Value< 0. 001<0. 002-0. 015). This correlation was higher in greater degrees of hearing loss and higher frequencies.

The Auditory steady-state response (ASSR) is a scalp-recorded auditory evoked potential that is captured by far-field electrodes. It is elicited by periodic, transient or modulated acoustic stimuli. The possible effects of shifting the response recording channel on 40Hz ASSR thresholds and their recording times were evaluated and compared in this study. Thirty subjects with normal hearing (thresholds of 500 to 4000 Hz ≤ 15 dB HL), with ages ranged from 18 to 30 years, gave written informed consent were enrolled in this study. Right-handed subjects were selected. New chirp stimuli using a two-channel EP recording system, the Eclipse, were presented only to the right ear via insert earphones. Thresholds for central frequencies (0.5, 1, 2 and 4 KHz) and their total recording time in the ipsilateral- (recording from the right-EEG channel) and contralateral-array (recording from the left-EEG channel) relative to the stimulus ear were evaluated at 40Hz repetition rate. The mean contralateral ASSR thresholds to 40 Hz rate were about 2.25 dB HL better than the ipsilateral mean (that only significant at 2000 Hz central frequency; P.value=0.03). Also, the mean contralateral ASSR recording time was about 5.31 minutes better than the ipsilateral mean (Pvalue=0.0005). In awaking adults with normal hearing, the contralateral 40Hz ASSR is slightly more accurate in threshold estimation and shorter in recording time than the ipsilateral one. This method is promising despite these differences may clinically be significant.

Auditory steady-state response (ASSR) has widespread usage in the clinical hearing assessment of infants and young children. The present study evaluated the effect of restricting maximum possible intensity to 100 dB HL on ASSR thresholds. This retrospective study was conducted in multiple audiology centers. ASSR thre sholds with restricted settings were evaluated in 58 infants (116 ears). They had absent otoacoustic emissions and click-evoked auditory brainstem response waveforms and bilateral severe to profound hearing loss in behavioral evaluations. ASSR thresholds were absent in 28 %, 25%, 60 %, and 70 % of ears in 500, 1000, 2000, and 4000 Hz, respectively. The mean value of remained thresholds was approximately 90−95 dB HL. Restricted ASSR settings are prevalent; however, they fail to provide extensive additional information about hearing sensitivity. Thus, manufacturers are suggested to improve ASSR setting and transducers and resolve the intensity restrictions. ASSR settings should be able to test auditory thresholds to level of 120 dB HL.