WO2013183009A2

WO2013183009A2 - A system for auditory impairment screening

Info

Publication number: WO2013183009A2
Application number: PCT/IB2013/054624
Authority: WO
Inventors: Nitin SISODIA; Pragun GOYAL; Mayank Kumar; Rakesh LODHA; Ramesh Agarwal; Shouri Chatterjee; Gita HANDA; Ritu KAMAL; Pushkar V INGALE
Original assignee: Secretary, Department Of Biotechnology
Priority date: 2012-06-05
Filing date: 2013-06-05
Publication date: 2013-12-12
Also published as: WO2013183009A3; WO2013183009A9; WO2013183009A4

Abstract

The present invention relates to a hearing impairment screening system having fast test screening for neonates. The system comprises of a head frame (17) having microphone (13), audio transducer and at least three surface electrodes, a signal amplification unit (10), a signal filtering unit (11), an analog to digital converter (12) and fed to a digital processing and control unit (15). A display unit (16) can display the ABR in digital format which can be evaluated by an expert. The head frame (17) which comprises of integrated speaker and at least three surface electrodes to get a good contact on the above forehead (on the vertical axis) and on mastoid behind the ear (horizontal axis) and a convenient point on the baby which provides a good ground source on the body to detect waveform recordings. The head frame of the system enables quick and stable positioning of the electrodes, reduced length of the connecting wires from the electrodes to the signal amplification unit (10) reduces the impedance, and the loop formed between inverting electrode with ground and non- inverting electrode with ground being same balances the impedance which reduces the noise.

Description

A SYSTEM FOR AUDITORY IMPAIRMENT SCREENING

FIELD OF INVENTION:

The present invention relates to the field of hearing impairment screening and in particular to a hearing impairment screening system having fast screening test for neonates.

PRIOR ART / BACKGROUND OF INVENTION:

Congenital hearing loss is the most common disorder at birth. The ability to hear is also essential in developing language. A child develops significant auditory perception skills before the age of six months. However, it may take four years before he starts to speak clear sentences. In certain cases, a child may suffer from congenital hearing impairment which can have devastating, detrimental impact on their development. Early detection and intervention can save the child from speech and linguistic loss, can avoid cognitive impairment and difficulties in education and employment.

For hearing impairment screening in newborns, Automated Auditory Brainstem response (AABR) is accepted as standard of care for early identification of hearing impairment (Joint Committee of Infant Hearing Guidelines, 2007).

Over the last two decades, various instruments and applications have been developed for AABR. However, current neonatal auditory screening approaches, do not account for many different types and degrees of auditory abnormalities that are encountered with present screening approaches. Because of this, individual screening tests based on single measurement can be influenced negatively by interaction among various independent auditory abnormalities. The current screening approaches have not considered the critical factors that impact the functioning and utility of such devices, such as (i) physical characteristics of the measurement device i.e., portability, physical size, ease of use, (ii) operational characteristics of the device i.e., battery life, amount of record stage, required operational training, etc. and/or (iii) program logistics i.e., retesting mechanisms, referral mechanisms, record processing, patient tracking, report writing and other practical aspects. These factors can interact negatively to increase the total cost of auditory screening program. There are many drawbacks with disposable electrodes such as impedance mismatch is difficult to control and only way to control it is to remove them and restick it which destroys the adhesive. Also, temperature and handling have diverse effects and positioning is difficult (the person applying the electrodes needs to know where to apply them). Further, disposables are reused to reduce cost which leads to contamination and affect the results. Cost of disposables is high and availability of disposables is scarce.

There are many drawbacks with reusable electrodes such as long application time, messy application of conductive gel, post test cleaning is messy, chances of infection are high, more low frequency (<100Hz) electrode electrolyte noise is induced and practitioner doesn't know where to apply stick the electrodes. Figure 4 shows reusable electrodes of prior art and messy placement of such electrodes in prior art.

Auditory evoked potential (AEP) are very small electrical voltage potentials originating from the brain recorded from the scalp in response to an auditory stimulus (such as different tones, speech sounds etc.) the AEPs that are recorded from the top of the head originate from structures within the brain (e.g. the auditory cortex, the auditory brain stem structures, the auditory VIII cranial nerve). They are very low in voltage: from 0.1 microvolt to 1 microvolt. Their low voltage combined with relatively high background electrical noise requires the use of highly sensitive amplifiers and computer averaging component.

Further, the test time which comprises subject preparation, data acquisition and algorithm time is prohibitively high in many contemporary devices which hinders their widespread use in non-institutional setups such as vaccination camps due to demand-supply inequality.

Thus there is a need to develop an effective auditory screening device which provides more accurate results, is easy to use and is hand-held so that can be used in a non- institutional setup. The present invention provides a system which enables the hearing testing to be achieved very quickly and accurately. The present invention allows hearing test to be performed in the brief periods when an infant is sleeping and allows many infants to be tested in a short time.

The present invention significantly reduces the time for screening. In the present invention, the test time is reduced by reducing time to place the electrode. The placement of electrodes is crucial in deciding the time it takes to test the baby. The placement of electrodes involves positioning of electrode at the right place and position stability of electrodes in one place. The present invention electrode system helps the caregiver to position the electrode accurately and in less time and provides better position stability to it. In the present invention, the impedance is reduced and balanced by providing contact stability, effectively increasing the electrode surface area.

SUMMARY OF THE INVENTION

The present invention relates to a hearing impairment screening system having fast test screening for neonates. The system comprises of a head frame (17) having microphone (13), audio transducer and at least three surface electrodes, a signal amplification unit (10), a signal filtering unit (11), an analog to digital converter (12) and fed to a digital processing and control unit (15). A display unit (16) can display the ABR in digital format which can be evaluated by an expert. The head frame (17) which comprises of integrated speaker and at least three electrodes to get a good contact on the above forehead (on the vertical axis) and on mastoid behind the ear (horizontal axis) and a convenient point on the baby which provides a good ground source on the body to detect waveform recordings. The head frame of the system enables quick and stable positioning of the electrodes, reduced length of the connecting wires from the electrodes to the signal amplification unit (10) reduces the impedance, and the loop formed between inverting electrode with ground and non- inverting electrode with ground being same balances the impedance which reduces the noise. This system provides pillow- shaped head frame, head frame with extendable electrodes, head frame with adjustable electrodes, head frame which fits different head sizes, head frame shaped as flexible bands and caps.

BRIEF DESCRIPTION OF FIGURES:

Figure 1 is a block diagram of one of the embodiments of the present invention.

Figure 2 is the ABR signal acquired from the preferred embodiment of the present invention.

Figure 3 shows disposable electrodes of prior art.

Figure 4 shows reusable electrodes of prior art and messy placement of such electrodes in prior art.

Figure 5 shows pillow shaped head frame as one of the embodiment of the present invention. Figure 6 shows head frame with extendable electrodes and integrated speakers in one of the embodiment of the present invention.

Figure 7 shows head frame with adjustable electrodes in one of the embodiment of the present invention.

Figure 8 shows head frame which fits different head sizes in one of the embodiment of the present invention.

Figure 9 shows knob adjustment (modification) details in head frame to fit different head sizes in one of the embodiment of the present invention.

Figure 10 shows head frame as flexible bands and flexible caps with flexible electrodes in one of the embodiment of the present invention.

Figure 11 shows detail structure of head frame with extendable electrodes and integrated speaker.

Figure 12 shows electrode of the present invention which are worn on the fingers and enables healthcare provider to control the impedance value by applying pressure and changing position of his fingers.

Figure 13 shows complete device configuration as one of the embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a hearing impairment screening system having fast test screening for neonates. The system comprises of a head frame (17) having microphone (13), audio transducer and at least three surface electrodes, a signal amplification unit (10), a signal filtering unit (11), an analog to digital converter (12) and fed to a digital processing and control unit (15). A display unit (16) can display the ABR in digital format which can be evaluated by an expert. The head frame (17) which comprises of integrated speaker and at least three electrodes to get a good contact on the above forehead (on the vertical axis) and on mastoid behind the ear (horizontal axis) and a convenient point on the baby which provides a good ground source on the body to detect waveform recordings. The head frame of the system enables quick and stable positioning of the electrodes, reduced length of the connecting wires from the electrodes to the signal amplification unit (10) reduces the impedance, and the loop formed between inverting electrode with ground and non- inverting electrode with ground being same balances the impedance which reduces the noise.

In the prior art, while using disposable electrodes one needs to spend time to find the right placement every time one conducts the test and this requires skill to place it. The wrong lacement of electrodes can lead to false results and also sometimes require test to repeat. In the prior art, it is difficult to place the electrodes stable at one place because of movement of baby or movement of electrode wires. Figures 3 & 4 show disposable and reusable electrodes of prior art and messy placement of these electrodes in prior art.

The present invention provides a system which enables the hearing testing to be achieved very quickly and accurately. The present invention allows hearing test to be performed in the brief periods when an infant is sleeping and allows many infants to be tested in a short time. This system provides pillow- shaped head frame, head frame with extendable electrodes, head frame with adjustable electrodes, head frame which fits different head sizes, head frame shaped as flexible bands and caps.

A hearing impairment screening system having fast test screening for neonates, the system comprising:

(a) a head frame (17) comprising a microphone (13) for providing auditory stimulus, an audio transducer (14) and at least three surface electrodes placed above forehead on vertical axis and on mastoid behind the ear on horizontal axis and on a convenient point on the baby for providing ground source on the body and said surface electrodes sense auditory brainstem responses (ABR in response to the auditory stimulus;

(b) signal amplification unit (10) for amplifying the ABR signals;

(c) signal filtering unit (11) for filtering the signals received from signal amplification unit;

(d) analog to digital converter (12) for digitizing the analog signals received from the signal filtering unit;

(e) processing control unit (15) for receiving the digitized signals from analog to digital converter and processing these signals to enhance signal-to-noise ratio by averaging method; and

(f) display unit (16) for displaying the results; wherein the head frame of the system enables quick and stable positioning of the electrodes, reduced length of the connecting wires from the electrodes to the signal amplification unit (10) reduces the impedance, and the loop formed between inverting electrode with ground and non- inverting electrode with ground being same balances the impedance which reduces the noise.

In one of the embodiment, any one or more of units selected from signal amplification unit (10), signal filtering unit (11), analog to digital converter (12), processing control unit (15) and display unit (16) can be housed in the head frame (17) of the system.

Referring now to the drawings, there is shown an illustrative embodiment of the system for auditory impairment screening. It should be understood that the invention is susceptible to various modifications and alternative forms; specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It will be appreciated as the description proceeds that the invention may be realized using different embodiments.

Before describing in detail embodiments it may be observed that the novelty and inventive step that are in accordance with the present invention reside in the mechanism of the system for auditory impairment screening, accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

Figure 1 of the present invention illustrates a block diagram of auditory impairment screening system. Broadly, the system comprises of a data acquisition unit and an auditory stimulus device. A processing and control unit is connected to the data acquisition unit and the auditory stimulus device. The processing and control unit may further be connected to a user interface unit which can comprise of a display unit.

As shown in figure 1, the head frame (17) comprises of a microphone (13) for providing auditory stimulus, an audio transducer (14) and at least three electrodes which are placed above forehead on vertical axis and on mastoid behind the ear on horizontal axis and on a convenient point on the baby for providing ground source on the body and said surface electrodes sense auditory brainstem responses (ABR in response to the auditory stimulus. The surface electrodes sense signals which are in response to the auditory stimulus provided by a microphone (13) placed in the subject's ears. For newborns, various stimulus types like click, tone, chirp, pip etc. are used to generate responses, but click evoked Auditory Brainstem Response (ABR) is generally considered as a standard. In one embodiment, a click sound stimulus is repetitively applied to subject's ears through a transducer earphone. Screening ABR requires 3 to 27 minutes of testing.

The head frame (17) records a very weak signal from the surface electrodes. The signals are fed to a signal amplification unit (10) for amplification. The signals are then filtered by a signal filtering unit (11) to remove any background noise and those signals which are not applicable to the ABR such as power line noise and RF noise. These analog signals are then digitized by an analog to digital converter (12) and fed to a digital processing and control unit (15).

ABR elicited by a single acoustic stimulus has very small amplitude. It cannot be detected in the presence of huge EEG background noise which also is recorded from the scalp electrodes. To enhance the signal-to-noise ratio, averaging method is implemented in the digital processing and control unit (15). In this method a large number of stimuli are applied in a short period of time, and the post stimulus responses are averaged synchronously to enhance signal-to-noise ratio. As the interfering EEG noise has random characteristics, its contribution become smaller and smaller with progressive averaging.

The preferred embodiment described herein could be used to acquire ABR response of patients by placing the electrode system onto the head and connecting it to the ABR acquisition hardware. The digital processing and control unit (15) helps in processing and representation of ABR in digital format.

As shown in figure 2, a display unit (16) can display the ABR in digital format which can be evaluated by an expert. In another embodiment, the resultant ABR can be sent to an expert over a communication channel. Also, a report can be generated which will help the specialist to re-analyze the subjects hearing condition.

The present invention uses a signal acquisition system, and an application with reduced processing time, that saves time, requires less skill and expertise to detect hearing loss in newborns in a resource constrained environment n the present invention, the screening ABR utilizes click stimuli ranging from 70 db to 35 db and below. At least three surface electrodes are placed to get a good contact on the above forehead (on the vertical axis) and on mastoid behind the ear (horizontal axis) and a convenient point on the baby which provides a good ground source on the body to detect waveform recordings generated by the auditory brainstem response to the click stimuli. The characteristics of the waveform (morphology, latency, energy, spectral information) are compared to normal or analyzed independently for the presence of brainstem evoked signal. Delayed or absent waves suggest a neurologic or cochlear deficit.

In one of the embodiment of the present invention, the system is easy to clean, and the system can be dis-assembled and re-assembled again.

In one of the embodiment of the present invention, head frame is shaped as pillow-like structure, the speaker is integrated in the pillow structure which provides the stimuli and there will be flexible electrodes which can get attached to the forehead mastoid and earlobe of the subject. The head frame is pillow shaped and the head frame provides stability to the baby' s head, stable positioning of the electrodes and reduced motion artifacts. This pillow frame comprises of hardware electronics assembled inside the pillow structure. In one of the embodiment, any one or more of units selected from signal amplification unit (10), signal filtering unit (1 1), analog to digital converter (12), processing control unit (15) and display unit (16) can be housed in the head frame (17) of the system. Further, this pillow shaped head frame with electrodes provides cushion and is comfortable to neonates. A small display unit will give indication about the impedance match and starting/completion of the test. Figure 5 shows pillow structure embodiment of the present invention.

There are many advantages of the above-mentioned pillow like structure of the present invention. Main advantage of the above system is that the length of the wires used from electrodes to the hardware will be reduced which reduces the impedance, also the loop formed between inverting electrode with ground and non- inverting electrode with ground will be same which will help in balancing the impedance and thus will reduce the noise. Secondly, this system provides a better contact and more stability to the baby's head which provides a better contact stability to the electrode. In addition, this system provides a more comfortable posture for baby to lie down and thus reduces motion artifacts. Hence, this system is user friendly and helps healthcare worker to conduct the test in less time.

In yet another embodiment of the present invention, head frame is provided with extendable electrodes and integrated speaker. The mechanism will allow it to extend or compress. In this system, the electrodes system is integrated with the speaker. The surface electrodes of the head frame are extendable, at least one electrode (top electrode) is capable of extending to come on forehead and said electrode is flexible to be pressed on the forehead. At least two electrodes are extendable to the earlobes. There are two extendable clips shown in figure 6 which can be clipped to the earlobes. These two clips will act as electrode, it is very easy to apply them and maintain their stability while conducting the test. This unit may also enclose hardware/ software or combination of hardware and software electronics. Figure 6 shows head structure with extendable electrodes and integrated speakers of the present invention. The electrodes are extendable and spring action or any other suitable mechanism makes it fit different head sizes. Figure 11 shows detail structure of head frame with extendable electrodes and integrated speaker. Hence, the electrodes can comfortably fit to different head sizes of the neonates which save time, efforts and require less skill while conducting hearing impairment screening test.

In one of the other embodiment of the present invention, head structure is provided with adjustable electrodes. The head frame is having groove for the movement of the surface electrodes. The electrodes will move along the grove to adjust to different head sizes and also the get the best impedance match. The top unit which is compact in size and comprises of hardware/ software or combination of hardware and software electronics. The display and processing is performed by a wireless display unit and data is transmitted via bluetooth or other means. Figure 7 shows head structure with adjustable electrodes in one of the embodiment of the present invention.

In yet another embodiment of the present invention, head frame is able to fit different head sizes. Figure 8 shows head structure which fits different head sizes in one of the embodiment of the present invention. As shown in figure 8, knobs are provided to change the pressure of the sensor and grooves are provided to adjust the size of the structure to ensure better fit and stability. The head frame is having knobs and grooves to adjust the size of the head frame structure to fit with head size of the neonate for stable positioning of the electrodes. Figure 9 shows details about the modifications possible in the head frame which fits different head sizes in one of the embodiment of the present invention. In one of the other embodiment of the present invention, flexible bands and caps are provided with integrated electrodes. The flexible bands and caps are made from combination of hard and soft materials. Figure 10 shows flexible bands and caps with integrated electrodes in one of the embodiment of the present invention. Figure 10(c) shows material property of the electrode system and head frame. The material of the head frame and electrodes are such that it is comfortable, can be stretched and can fit different head sizes. Material of the structure is such that it can be stretched to fit different head sizes, it is gelly type so won't give discomfort and can mould and fit different head sizes to form like a cap or band. It also has the capability of enclosing a circuitry and provides a display for the test results.

In one of the other embodiment of the present invention, as shown in Figure 12, electrode of the present invention are worn on the fingers and enables healthcare provider to control the impedance value by applying pressure and changing position of his fingers. Figure 12 shows electrode points in the hand of healthcare provider/mother.

Figure 13 shows complete device configuration as one of the embodiment of the present invention. Figure 13 shows easily adjustable electrodes, preamplifier, processor and display in one of the embodiment of the present invention.

The present invention significantly reduces the time for screening. In the present invention, the test time is reduced by reducing time to place the electrode. The placement of electrodes is crucial in deciding the time it takes to test the baby. The placement of electrodes involves: a) Positioning of electrode at the right place:

The head frame of the system as claimed in the present invention enables positioning of electrodes at right place in less time and requires less skill. This avoids repetition of testes and also prevents false results. This system provides pillow- shaped head frame, head frame with extendable electrodes, head frame with adjustable electrodes, head frame which fits different head sizes, head frame shaped as flexible bands and caps. Figures 5 to 10 shows embodiments of the head frame of the system of the present invention. b) Position stability of electrodes in one place:

The head frame of the system as claimed in the present invention enables stable positioning of electrodes. Our electrode system helps the caregiver to position the electrode accurately and in less time and provides better position stability to it. The difficulties arising due to movement of baby or movement of electrode wires are avoided. This system provides pillow- shaped head frame, head frame with extendable electrodes, head frame with adjustable electrodes, head frame which fits different head sizes, head frame shaped as flexible bands and caps. Figures 5 to 10 shows embodiments of the head frame of the system of the present invention.

In the present invention, the impedance is reduced and balanced by:

1) providing contact stability,

2) effectively increasing the electrode surface area.

An electrolyte gel, paste or cream is applied to improve the conductivity of the dead skin layer which also reduces time of placing the electrode.

Further, in the present invention, testing of both the ears at same time reduces testing time by half. Hence, this results in reducing time to collect data.

Quick data analysis: In the present invention, data acquisition and processing boards are used. The hardware devices which can be used are mobile phones, laptops, tablets and other processing devices.

Enhancement in signal to noise ratio: The present invention provides enhancement in signal to noise ratio. The algorithm constitutes of selecting the separate sweeps and averaging them to improve the SNR. This technique helps in improving the signal to noise ratio (S/N ratio) of weak signals buried in noise. Averaging N data samples improves the S/N ratio by a factor of root of N. This value is obtained if each of the data samples contain a signal and additive noise and if the noise samples are zero mean, uncorre!ated and have identical variances. In some applications, however, these conditions are not met. This is especially true for electric response audiometry (ERA), where the superimposed noise is generally non-stationary, due to changing EEG and myogenic activities.

In one of the embodiment, the processing control unit (15) of the screening device is configured for enhancing signal -to-noise ratio by selective data rejection and averaging techniques. In yet other embodiment, the averaging techniques employed by the processing control unit (15) comprises of one or more of the weighted averaging, latency corrected averaging, and techniques for deciding when to stop averaging.

Selective data rejection and weighted averaging: First step taken to overcome noise was the rejection of individual, stimulus-related epochs during which the noise level exceeded and adjustable limit (artifact rejection). The next step was the introduction of preamplifiers with automatic gain control (AGC). Individual epochs which were not rejected were amplified, depending on the noise level present, and so contributed to the average with different weights.

Weighted averaging: weighted averaging techniques have been introduced to improve the signal to noise ratio by taking into account the non-stationarity of the EEG.

Detection of ABR waves: Latency corrected averaging techniques have been employed to overcome some BAEP non-stationarity. Other method is focused on the decision of when to stop averaging i.e. stopping criterion or on the development of high speed stimulation techniques in order to reduce the acquisition time necessary to extract the BAEPs. Signal stationarity is used for detection of signal.

The system may be based on statistical methods to detect the presence or absence of ABR, therefore removing the discrepancies arising due to the judgment of the person conducting the test procedure.

Different algorithms and strategy are generally used for detection of ABR waves - matching an infant's ABR with a template obtained from normalized data, computing statistical energy measure to ascertain the presence or absence of ABR response, or application of statistical coherence test to determine the presence of ABR response. Such algorithm could be implemented on the computing devices easily.

The manner in which the processor is implemented will depend on the particular application and the design constraints imposed on the overall system. Those skilled in the art will recognize the interchangeability of hardware, firmware, and software configurations under these circumstances, and how best to implement the described functionality for each particular application. Method of Conducting Hearing Screening Test in Neonates:

The present invention provides a method of conducting hearing screening Test in Neonates and this method saves time and requires less skill and less expertise to detect hearing loss in newborns in a resource constrained environment. The skin is prepared by applying the gel and at least three electrodes are placed to get a good contact on the above forehead (on the vertical axis) and on mastoid behind the ear (horizontal axis) and a convenient point on the baby which provides a good ground source on the body to detect waveform recordings. Click stimuli ranging from 70 db to 35 db or below is provided to the neonates and ABR signal is generated by the auditory brainstem response to the click stimuli. The characterstics of the waveform (morphology, latency, energy, spectral information) are compared to normal or analyzed independently for the presence of brainstem evoked signal. Delayed or absent waves suggest a neurologic or cochlear deficit. A display unit (16) can display the ABR in digital format which can be evaluated by an expert. In another embodiment, the resultant ABR can be sent to an expert over a communication channel. Also, a report can be generated which will help the specialist to reanalyze the subject's hearing condition.

The manner in which the processor is implemented will depend on the particular application and the design constraints imposed on the overall system. Those skilled in the art will recognize the interchangeability of hardware, firmware, and software configurations under these circumstances, and how best to implement the described functionality for each particular application.

The various illustrative logical blocks, modules, circuits, elements, and/or components described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, or other programmable logic component, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The methods described in connection with the embodiments disclosed herein may be embodied directly in hardware, in one or more instructions executed by a processor, or in a combination of the two. The software may reside as one or more instructions in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.

The previous description is provided to enable any person skilled in the art to practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments. Thus, the claims are not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more." Structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims.

Advantages of the present invention:-

1. This system has reduced screening time by quick placement of electrodes at correct position and by stable positioning of electrodes.

2. This system provides head frame comprising at least three surface electrodes with integrated speaker in the shape of pillow, head frame with extendable electrodes, head frame with adjustable electrodes to fit different head sizes and head frame shaped as flexible bands and flexible caps.

3. This is a low cost system for auditory impairment screening in neonates and saves time, efforts of the health care provider.

4. This system is easy to use, requires less skill and it is useful in resource constraint environment such as remote places.

5. This system is easy to clean, and the system can be dis-assembled and reassembled again

Claims

The Claim:

1. A hearing impairment screening system having fast test screening for neonates, the system comprising:

(a) a head frame (17) comprising a microphone (13) for providing auditory stimulus, an audio transducer (14) and at least three surface electrodes placed above forehead on vertical axis and on mastoid behind the ear on horizontal axis and on a convenient point on the baby for providing ground source on the body and said surface electrodes sense auditory brainstem responses (ABR) in response to the auditory stimulus;

(b) signal amplification unit (10) for amplifying the ABR signals;

(f) display unit (16) for displaying the results;

wherein the head frame of the system enables quick and stable positioning of the electrodes, reduced length of the connecting wires from the electrodes to the signal amplification unit (10) reduces the impedance, and the loop formed between inverting electrode with ground and non- inverting electrode with ground being same balances the impedance which reduces the noise.

2. The system as claimed in claim 1, wherein the surface electrodes of the head frame are extendable, at least one electrode is capable of extending to come on forehead and said electrode is flexible to be pressed on the forehead, at least two electrodes are extendable to the earlobes and said two electrodes are clipped to the earlobes.

3. The system as claimed in claim 2, wherein the electrodes are extendable by spring action or any other suitable mechanism to fit different head sizes of the neonates.

4. The system as claimed in claim 1, wherein the surface electrodes of the head frame are adjustable and the head frame is having groove for the movement of the surface electrodes along the groove to adjust to different head sizes and to match the impedance.

5. The system as claimed in claim 1, wherein the head frame is having knobs and grooves to adjust the size of the head frame structure to fit with head size of the neonate for stable positioning of the electrodes.

6. The system as claimed in claim 1, wherein the head frame is shaped as flexible band or flexible cap and the head frame is made from combination of hard and soft materials.

7. The system as claimed in claim 6, wherein the material of the head frame & electrodes enables stretching of the head frame & electrodes to fit different head sizes, and preferably the material of the head frame & electrodes is soft polymer.

8. The system as claimed in claim 1, wherein the head frame is pillow shaped and the head frame provides stability to the baby's head, stable positioning of the electrodes and reduced motion artifacts.

9. The system as claimed in claim 1, wherein the system is capable of screening both the ears simultaneously.

10. The system as claimed in claim 1, wherein the electrodes are worn on the fingers of health care provider and enable controlling the impedance value by applying pressure and by changing the position of his fingers.

11. The system as claimed in claim 1, wherein the processing control unit (15) is configured for enhancing signal-to-noise ratio by selective data rejection and averaging techniques.

12. The system as claimed in claim 1, wherein the time duration for detection ranges from three minutes to twenty seven minutes.