Speech induced binaural beats: Electrophysiological assessment of binaural interaction.

This paper introduces and evaluates a speech signal manipulation scheme that generates transient speech induced binaural beats (SBBs). These SBBs can only be perceived when different signals are presented dichotically (to both ears). Event-related potentials were recorded in 22 normal-hearing subjects. Dichotic stimulus presentation reliably evoked auditory late responses (ALRs) in all subjects using such manipulated signals. As control measurements, diotic stimulation modalities were presented to confirm that the ALRs were not evoked by the speech signal itself or that the signal manipulation scheme created audible artifacts. Since diotic measurements evoked no ALRs, responses from dichotic stimulation are a pure correlate of binaural interaction. While there are several auditory stimuli (mostly modulated sinusoids or noise) that share this characteristic, none of them are based on running speech. Because SBBs can be added to any arbitrary speech signal, they could easily be combined with psychoacoustic tests, for example speech reception thresholds, adding an objective measure of binaural interaction.

A BCI Gaze Sensing Method Using Low Jitter Code Modulated VEP.

Visual evoked potentials (VEPs) are used in clinical applications in ophthalmology, neurology, and extensively in brain-computer interface (BCI) research. Many BCI implementations utilize steady-state VEP (SSVEP) and/or code modulated VEP (c-VEP) as inputs, in tandem with sophisticated methods to improve information transfer rates (ITR). There is a gap in knowledge regarding the adaptation dynamics and physiological generation mechanisms of the VEP response, and the relation of these factors with BCI performance. A simple, dual pattern display setup was used to evoke VEPs and to test signatures elicited by non-isochronic, non-singular, low jitter stimuli at the rates of 10, 32, 50, and 70 reversals per second (rps). Non-isochronic, low-jitter stimulation elicits quasi-steady-state VEPs (QSS-VEPs) that are utilized for the simultaneous generation of transient VEP and QSS-VEP. QSS-VEP is a special case of c-VEPs, and it is assumed that it shares similar generators of the SSVEPs. Eight subjects were recorded, and the performance of the overall system was analyzed using receiver operating characteristic (ROC) curves, accuracy plots, and ITRs. In summary, QSS-VEPs performed better than transient VEPs (TR-VEP). It was found that in general, 32 rps stimulation had the highest ROC area, accuracy, and ITRs. Moreover, QSS-VEPs were found to lead to higher accuracy by template matching compared to SSVEPs at 32 rps. To investigate the reasons behind this, adaptation dynamics of transient VEPs and QSS-VEPs at all four rates were analyzed and speculated.

Fast acquisition of full-range auditory event-related potentials using an interleaved deconvolution approach.

This work relates to recent advances in the field of auditory event-related potentials (ERP), specifically deconvolution-based ERP acquisition and single-trial processing. An efficient stimulus sequence optimization method for ERP deconvolution is proposed, achieving consistent noise attenuation within a broad designated frequency range. Furthermore, a stimulus presentation paradigm for the fast, interleaved acquisition of auditory brainstem, middle-latency and late responses featuring alternating periods of high-rate deconvolution sequences, and subsequent low-rate stimulation is investigated in 20 normal hearing subjects. Deconvolved sequence responses containing early and middle-latency ERP components are fused with subsequent late responses using a time-frequency resolved weighted averaging method based on cross-trial regularity, yielding a uniform signal-to-noise ratio of the full-range auditory ERP across investigated timescales. Obtained average ERP waveforms exhibit morphologies consistent with both literature values and reference recordings acquired in 15 normal hearing subjects using a prior art approach to full-range auditory ERP acquisition, with all prominent waves being visible in the grand average waveforms. Results suggest the proposed interleaved stimulus presentation and associated ERP processing methodology to be suitable for the fast, reliable extraction of full-range auditory processing correlates in future ERP studies.

Auditory brainstem, middle and late latency responses to short gaps in noise at different presentation rates.

OBJECTIVE: The effects of rate on auditory-evoked potentials (AEP) to short noise gaps (12 ms) recorded at high sampling rates using wide-band filters were investigated. DESIGN: Auditory brainstem (ABR), middle latency (MLR), late latency (LLR) and steady-state (ASSR) responses were simultaneously recorded in adult subjects at four gap rates (0.5, 1, 5 and 40 Hz). Major components (V, Na, Pa, Nb, Pb, N1 and P2) were identified at each rate and analysed for latency/amplitude characteristics. Gap responses at 40 Hz were recovered from Quasi-ASSRs (QASSR) using the CLAD deconvolution method. STUDY SAMPLE: Fourteen right ears of young normal hearing subjects were tested. RESULTS: All major components were present in all subjects at 1 Hz. P1 (P50) appeared as a low-pass filtered component of Pa and Pb waves. At higher rates, N1 and P2 disappeared completely while major ABR-MLR components were identified. Peak latencies were mostly determined by noise onsets slightly delayed by offset responses. CONCLUSIONS: Major AEP components can be recorded to short gaps at 1 Hz using high sampling rates and wide-band filters. At higher rates, only ABR and MLRs can be recorded. Such simultaneous recordings may provide a complete assessment of temporal resolution and processing at different levels of auditory pathways.

Next Generation PERG Method: Expanding the Response Dynamic Range and Capturing Response Adaptation.

PURPOSE: To compare a new method for steady-state pattern electroretinogram (PERGx) with a validated method (PERGLA) in normal controls and in patients with optic neuropathy. METHODS: PERGx and PERGLA were recorded in a mixed population (n = 33, 66 eyes) of younger controls (C1; n = 10, age 38 ± 8.3 years), older controls (C2; n = 11, 57.9 ± 8.09 years), patients with early manifest glaucoma (G; n = 7, 65.7 ±11.6 years), and patients with nonarteritic ischemic optic neuropathy (N; n = 5, mean age 59.4 ± 8.6 years). The PERGx stimulus was a black-white horizontal grating generated on a 14 × 14 cm LED display (1.6 cycles/deg, 15.63 reversals/s, 98% contrast, 800 cd/m2 mean luminance, 25° field). PERGx signal and noise were averaged over 1024 epochs (∼2 minutes) and Fourier analyzed to retrieve amplitude and phase. Partial averages (16 successive samples of 64 epochs each) were also analyzed to quantify progressive changes over recording time (adaptation). RESULTS: PERGLA and PERGx amplitudes and latencies were correlated (Amplitude R2 = 0.59, Latency R2 = 0.39, both P < 0.0001) and were similarly altered in disease. Compared to PERGLA, however, PERGx had shorter (16 ms) latency, higher (1.39×) amplitude, lower (0.37×) noise, and higher (4.2×) signal-to-noise ratio. PERGx displayed marked amplitude adaptation in C1 and C2 groups and no significant adaptation in G and N groups. CONCLUSIONS: The PERGx high signal-to-noise ratio may allow meaningful recording in advanced stages of optic nerve disorders. In addition, it quantifies response adaptation, which may be selectively altered in glaucoma and optic neuropathy. TRANSLATIONAL RELEVANCE: A new PERG method with increased dynamic range allows recording of retinal ganglion cell function in advanced stages of optic nerve disorders. It also quantifies the response decline during the test, an autoregulatory adaptation to metabolic challenge that decreases with age and presence of disease.

Signal-to-noise ratio improvement of swept-tone-generated transient otoacoustic emissions.

In this study, we utilized the swept-tone (ST) deconvolution method for comparing the signal-to-noise ratio (SNR) characteristics of ST otoacoustic emissions (OAE) to conventionally acquired click, or transient-evoked (TE), OAE. We generated a hearing-level equalized (HLeq) ST stimulus based on normative loudness metrics at the different frequencies present in the ST. Due to noise-shaping properties of the ST deconvolution method, we anticipated a theoretical SNR gain of +4.26 dB in STOAE compared to TEOAE acquired under comparable settings. This prediction was confirmed by computer simulation. HLeq STOAE and TEOAE were then acquired from each of the 22 ears that were tested at five stimulation levels from 5 to 45 dB HL, and analyzed responses in terms of their overall SNR. We found that the overall SNR of the HLeq STOAE responses at stimulation levels at or above 15 dB HL was significantly higher than that of TEOAE by an average of +3.6 dB. Importantly, this leads to recording quality and time-saving improvements in clinical hearing screenings.

Estimating audiometric thresholds using simultaneous acquisition of ASSR and ABR from QASSR in patients with sensorineural hearing loss.

OBJECTIVES: To evaluate the accuracy with which the innovative QASSR method predicts behavioral thresholds in adult patients with sensorineural hearing loss. DESIGN: Subjects were tested at four carrier frequencies (500, 1000, 2000, and 4000 Hz).The resulting QASSR recordings were analyzed for thresholds and magnitude/phase characteristics. Tone-burst ABR was recovered from QASSR signal using CLAD method and analyzed in the time domain. The electrophysiological estimates were compared to hearing thresholds determined behaviorally. STUDY SAMPLE: Sixteen ears of nine volunteer subjects recruited from a clinical population. RESULTS: All mean threshold estimates differed less than 3 dB for QASSR and less than 5 dB for ABR at 1000, 2000 and 4000Hz (carrier or pure-tone test frequencies). The largest differences were observed for both at 500 Hz (5.63 and 11.56 dB respectively).The audiometric configurations of QASSR and ABR estimates followed those of the respective behaviorally determined configurations across ears tested. CONCLUSIONS: QASSR method merges two dissimilar stimulation techniques, transient and steady-state, to create a hybrid stimulation-and-analysis paradigm that seems to improve the overall performance of the electrophysiological threshold estimation. The unique feature of the QASSR technique is the additional information afforded by the transient ABR, recovered from the same recording. The QASSR thus holds promise to be a very useful tool for practical clinical applications.

Effects of rate (0.3-40/s) on simultaneously recorded auditory brainstem, middle and late responses using deconvolution.

OBJECTIVE: Auditory evoked potentials (AEPs) are typically acquired in either transient (low-rate) or steady state (high-rate) conditions. This study utilizes deconvolution to obtain transient responses over a range of rates from 0.3 to 40/s, to establish a rate profile of transient responses employing uniform recording conditions. METHODS: Deconvolution is used to obtain transient responses from quasi steady state recordings for rates 3.5-40/s, and components are scored and waveform morphologies are compared across rates. RESULTS: All component latencies remain stable across all rates other than P2, which decreases for rates up to 3.5/s. Amplitudes for brainstem (V, Na), middle latency (Pa, Nb), and late (Pb/P1, N1 and P2) responses increased for rates below 1, 2 and 3.5/s, respectively. Rates between 3.5 and 25/s undergo a gradual morphology transition, above which oscillations begin to occur after 100 ms. CONCLUSIONS: Auditory brainstem, middle and late latency components other than P2 show stable latencies across 0.3-40/s with varying amplitude rate dependencies. SIGNIFICANCE: Obtaining a transient response rate profile utilizing uniform acquisition parameters is useful for an improved understanding of how individual AEP components interact with stimulation rate, and can provide a more comprehensive assessment of the ascending auditory pathway and primary auditory cortices.

Relationship between transient and steady-state pattern electroretinograms: theoretical and experimental assessment.

PURPOSE: We determined if the overlap of transient (tr) pattern electroretinograms (PERG(tr)) can explain the generation of the steady-state (SS) pattern electroretinogram (PERG(SS)), and investigated the relationship between the two types of responses. METHODS: Slightly jittered pattern reversals were used to generate quasi SS (QSS) PERG(SS) responses from eight normal subjects, recorded using lower eyelid skin electrodes, at rates between 6.9 and 26.5 reversals per second (rps). Jittered quasi PERG(SS) were deconvolved using the frequency domain continuous loop averaging deconvolution method. Additionally, conventional PERG(tr) at 2.2 rps and PERG(SS) at each of the QSS stimulation rates were obtained from all subjects. Two synthetic PERG(SS) responses were constructed at each stimulation rate, one using the PERG(tr) obtained at that rate, and the other using the conventional 2.2 rps PERG(tr). Synthetic responses then were compared to the recorded PERG(SS) using amplitude, latency, and spectral measurements. RESULTS: Findings indicate that the PERG(SS) obtained at SS rates can be predicted using the superposition of deconvolved tr PERGs at each particular rate. Although conventional PERG(tr) can explain PERG(SS) obtained at rates below 15.4 rps (≥ 97% correlation), for higher reversal rates only deconvolved responses obtained at that rate can produce the recorded SS responses (96% vs. 65% correlation at 26.5 rps). CONCLUSIONS: The study shows that PERG(SS) results from the overlapping of tr PERG(tr) waveforms generated at that reversal rate. The first two peaks (N(SS) and P(SS)) of the PERG(SS) reflect N35 and P50 waves of the tr PERG(tr). The N95 amplitude is reduced at conventional (16 rps) SS rates, but contributes to the overall PERG(SS) amplitude.

Unwrapping of transient responses from high rate overlapping pattern electroretinograms by deconvolution.

OBJECTIVE: Due to overlapping, temporal information is mostly lost in high rate steady-state pattern electroretinograms (PERGSS). This study develops a deconvolution method and a display/recording system to "unwrap" PERGSS and obtain a transient, "per stimulus" response (PERGtr) regardless of reversal rate. METHODS: Processing and instrumentation, including high temporal resolution display and acquisition were developed for deconvolving PERGs acquired at high rates by slight jittering of reversal onsets at a given mean rate. RESULTS: The system was successfully tested at eight rates from 2.2 to 78.1rps. At medium rates (17.4-41.2rps) recordings with conventional morphology (N35-P50-N95) but earlier peaks and higher amplitudes were extracted up to 40rps. At higher rates, smaller triphasic responses were obtained, exhibiting similar peak latencies, but reversed polarity. Oscillating potentials (OPs) were also recorded at all rates after deconvolution. CONCLUSIONS: Transient PERGs and OPs can be extracted from quasi steady-state PERG recordings obtained at high rates with a deconvolution algorithm using high temporal resolution display and acquisition systems. SIGNIFICANCE: The methodology to extract transient and oscillatory responses from steady-state PERGs could be useful in understanding high rate responses and diagnosis of various retinal diseases by revealing temporal information on waveform components which cannot be normally observed.

Robust mouse pattern electroretinograms derived simultaneously from each eye using a common snout electrode.

PURPOSE: We recorded pattern electroretinograms (PERGs) simultaneously from each eye in mice using binocular stimulation and a common noncorneal electrode. METHODS: The PERG was derived simultaneously from each eye in 71 ketamine/xylazine anesthetized mice (C57BL/6J, 4 months old) from subcutaneous needles (active, snout; reference, back of the head; ground, root of the tail) in response to contrast-reversal of gratings (0.05 cycles/deg, >95% contrast) generated on two custom-made light-emitting diode (LED) tablets alternating at slight different frequencies (OD, 0.984 Hz; OS, 0.992 Hz). Independent PERG signals from each eye were retrieved using one channel continuous acquisition and phase-locking average (OD, 369 epochs of 492 ms; OS, 372 epochs of 496 ms). The PERG was the average of three consecutive repetitions. RESULTS: Binocular snout PERGs had high amplitude (mean, 25.3 µV, SD 6.6) and no measurable interocular cross-talk. Responses were reliable (test-retest variability within-session, 14%, SD 7; between sessions, 25%, SD 9; interocular asymmetry within-session, 9%, SD 7; between sessions, 13%, SD 5). Retinal ganglion cells (RGCs) were the main source of the binocular snout PERG, as optic nerve crush in three mice abolished the signal. CONCLUSIONS: The PERG, a sensitive measure of RGC function, is used increasingly in mouse models of glaucoma and optic nerve disease. Compared to current methods, the binocular snout PERG represents a substantial improvement in terms of simplicity and speed. It also overcomes limitations of corneal electrodes that interfere with invasive procedures of the eye and facilitates experiments based on comparison between the responses of the two eyes.

Effects of single cycle binaural beat duration on auditory evoked potentials.

Binaural beat (BB) illusions are experienced as continuous central pulsations when two sounds with slightly different frequencies are delivered to each ear. It has been shown that steady-state auditory evoked potentials (AEPs) to BBs can be captured and investigated. The authors recently developed a new method of evoking transient AEPs to binaural beats using frequency modulated stimuli. This methodology was able to create single BBs in predetermined intervals with varying carrier frequencies. This study examines the effects of the BB duration and the frequency modulating component of the stimulus on the binaural beats and their evoked potentials. Normal hearing subjects were tested with a set of four durations (25, 50, 100, and 200 ms) with two stimulation configurations, binaural dichotic (binaural beats) and diotic (frequency modulation). The results obtained from the study showed that out of the given durations, the 100 ms beat, was capable of evoking the largest amplitude responses. The frequency modulation effect showed a decrease in peak amplitudes with increasing beat duration until their complete disappearance at 200 ms. Even though, at 200 ms, the frequency modulation effects were not present, the binaural beats were still perceived and captured as evoked potentials.

Simultaneous acquisition of high-rate early, middle, and late auditory evoked potentials.

Auditory evoked potentials (AEPs) are typically acquired at rates that facilitate their study as segregated by epochs relative to stimulus onset: early (ABR, 1.5-15 ms), middle (MLR, 15-60 ms), and late (LAEP, ≥60 ms) potentials. In particular, late AEPs are often acquired with stimulus repetition rates between 0.1 Hz and 1 Hz, and are bandpass filtered to contain information only within 1-30 Hz. These low repetition rates, filtering and low SNRs eliminate much of the potential contributions of the early and middle-latency responses in AEP recordings. This study aims to demonstrate a method for acquiring whole-AEP responses at higher stimulus repetition rates of 0.5 Hz to 10 Hz, by utilizing the Continuous Loop Averaging Deconvolution (CLAD) method, increasing the bandwidth of the recordings to 1-300 Hz to include early components, and using short-duration chirps to increase synchronous firing of the cochlear and auditory pathway neurons. Such a method may facilitate diagnostic or functional assessment of single AEP recordings for detection, identification, or evaluation of early, middle and late components of auditory responses.

A preliminary investigation of the deconvolution of auditory evoked potentials using a session jittering paradigm.

OBJECTIVE: In the high stimulus rate studies of auditory evoked potentials (AEPs), deconvolution techniques have been developed to unwrap the overlapped responses based on the jittering strategy of stimulus onset asynchronies (SOAs). This study investigates an alternative deconvolution method (multi-rate steady-state averaging deconvolution, MSAD) using a session-jittering strategy where steady-state responses recorded at different SOAs can be adequate to derive the transient-AEP. APPROACH: A linear transform model was developed to solve the deconvolution problem, and the mathematical properties of the transform matrix were explored by singular value decomposition, which indicates the need for regularization techniques to solve the ill-conditioning of the matrix. MAIN RESULTS: The performance evaluated by both synthetic and experimental data is satisfactory compared with the classic SOA-jittering method commonly known as the continuous loop averaging deconvolution. SIGNIFICANCE: Our initial investigations suggest that the MSAD method is promising in terms of SOA insensitivity, sequence robustness and recording flexibility. However, more evaluation is needed to make the method suitable for a general application of the high stimulus rate paradigm.

Biomedical engineering principles of modern cochlear implants and recent surgical innovations.

This review covers the most recent clinical and surgical advances made in the development and application of cochlear implants (CIs). In recent years, dramatic progress has been made in both clinical and basic science aspect of cochlear implantation. Today's modern CI uses multi-channel electrodes with highly miniaturized powerful digital processing chips. This review article describes the function of various components of the modern multi-channel CIs. A selection of the most recent clinical and surgical innovations is presented. This includes the preliminary results with electro-acoustic stimulation or hybrid devices and ongoing basic science research that is focused on the preservation of residual hearing post-implantation. The result of an original device that uses a binaural stimulation mode with a single implanted receiver/stimulator is also presented. The benefit and surgical design of a temporalis pocket technique for the implant's receiver stimulator is discussed. Advances in biomedical engineering and surgical innovations that lead to an increasingly favorable clinical outcome and to an expansion of the indication of CI surgery are presented and discussed.

Simultaneous acquisition of 80 Hz ASSRs and ABRs from quasi ASSRs for threshold estimation.

OBJECTIVES: Both 80 Hz auditory steady state responses (ASSRs) and tone burst auditory brainstem responses (ABRs) have been shown to provide reasonable estimates of the behavioral thresholds. Although ASSRs provide statistically objective estimates that can be easily automated by computers, they present no information for the neurophysiological interpretation of the results. ABRs, on the other hand, do not provide easily automated information and usually need expert interpretation of the recorded waveforms. A recently developed continuous loop averaging deconvolution algorithm offers an alternative solution by acquiring slightly jittered 80 Hz quasi auditory steady state responses (QASSRs), thus enabling the acquisition of both recordings simultaneously. The purpose of this study is to investigate a specially developed 80 Hz QASSR paradigm for simultaneous acquisition for both responses for threshold detection purposes. DESIGN: Sixteen ears from eight adults with normal hearing were tested. Amplitude modulated QASSRs were obtained using slightly jittered temporal sequences of tone bursts presented at a mean rate of 78.125 Hz. Four carrier frequencies (500, 1000, 2000, and 4000 Hz) at several stimulus intensity levels were monaurally presented and QASSRs to 128 sweeps blocks were recorded. The ABRs were extracted using the CLAD algorithm. Wave V was visually identified and analyzed in the time domain as in everyday clinical practice. In addition, statistically objective ƒMP computation method was used to automatically detect ABR threshold as well. The QASSRs were analyzed in the frequency domain and magnitudes, phase delays, and thresholds were obtained. Phasor (polar plot) diagrams were constructed. QASSR and ABR hearing thresholds were obtained and compared with behavioral thresholds. RESULTS: Study reveals that the QASSR method provides accurate objective estimation of the audiometric thresholds from extracted ASSRs and latency/amplitude information from extracted ABRs. The largest mean threshold difference for QASSR was within 5 dB for all carrier frequencies including 500 Hz. For auditory threshold estimation in adults with normal hearing, the Hotelling's T-Square test in four dimensions in the frequency domain was more accurate than the ƒMP or visual ABR threshold detection in the time domain. CONCLUSIONS: Simultaneously recorded ASSR and ABR from QASSRs provide accurate and effective method for frequency-specific hearing threshold estimation with neurophysiological information in adults with normal hearing. Further research is required for hearing-impaired adults, newborns, and infants.

Simultaneously extracted transient and steady-state evoked responses during general anesthesia: variability of different rates.

Unintended intraoperative awareness occurs in one to two individuals out of every one thousand treated with general anesthesia. Patients that experience intraoperative awareness have significant post-operative psychological sequelae. The ability to detect intraoperative awareness is currently suboptimal because the mechanism employed by anesthetic drugs to impair consciousness remains poorly understood. Studies have suggested that evoked potentials (EP) may be used to monitor the depth of anesthesia. Both transient and steady state responses can be simultaneously extracted using the Continuous Loop Averaging Deconvolution (CLAD) method with specially designed CLAD sequences. 20 Hz and 30 Hz jittered CLAD sequences in addition to 5 Hz isochronic and 40 Hz jittered CLAD sequences were applied in baseline awake and general anesthesia conditions. A qualitative method to assess the extracted EPs was developed in this study, termed Randomized Split Set Average (RSSA). The results showed that EPs extracted during general anesthesia require a greater number of sweeps to obtain a signal-to-noise ratio comparable to that observed in EPs extracted during the awake state. Therefore, the development of a real time or quasi real time EP monitoring system for anesthesia provides an increased challenge. The RSSA employed in this study is a useful method for assessing the signal quality of EP responses.

Hearing level equalized otoacoustic emissions acquired by swept-tones: intensity characteristics.

Otoacoustic emissions (OAE), which are acoustic responses produced by the cochlea, can be recorded with a microphone in the ear canal to give diagnostic information regarding cochlear functioning. Recently, the researchers developed a novel stimulus for the acquisition of OAE using a hearing-level equalized (HL(eq)) swept-tone signal. The objective of this study was to observe OAE characteristics at a multitude of intensities to track the changes in temporal and spectral morphology. An increase in high-frequency emissions was found as stimulation intensity decreased. Furthermore, it was found that hearing level equalized swept-tone OAEs (HL(eq) sTEAOE) can be acquired at very low intensities, which is not typical under current acquisition modalities. This may result in clinical improvements by providing a fast and cheap method for contributing to the detection of auditory thresholds.

Auditory evoked responses to binaural beat illusion: stimulus generation and the derivation of the Binaural Interaction Component (BIC).

Electrophysiological indices of auditory binaural beats illusions are studied using late latency evoked responses. Binaural beats are generated by continuous monaural FM tones with slightly different ascending and descending frequencies lasting about 25 ms presented at 1 sec intervals. Frequency changes are carefully adjusted to avoid any creation of abrupt waveform changes. Binaural Interaction Component (BIC) analysis is used to separate the neural responses due to binaural involvement. The results show that the transient auditory evoked responses can be obtained from the auditory illusion of binaural beats.

Design of a clinically viable pneumatic system for the acquisition of pressure compensated otoacoustic emissions.

Otoacoustic emission (OAE) screening is perhaps one of the most common diagnostic tools used on both adults and children alike to clinically asses hearing health. However small to moderate middle ear pressures (both positive and negative), which are quite prevalent among the general population, are known to significantly reduce the OAE response specifically among frequencies below 2 kHz. This study focuses on the design and development of a software controlled syringe pump which will be used for the automatic compensation of middle ear pressure. This study reports validating test results which confirm the feasibility of using this system for future clinical trials.