BERA STUDY IN 150 CHILDREN UNDER 5 YRS AGE
Dr. K. K. Desarda
Professor Emeritus & Head, Otolaryngology.KEM Hospital Pune.
&
Dr. A. N. Sangekar
Audiologist and Speech Pathologist,
KEM Hospital, Pune
BERA (BSER OR BAEP)
Abstract
OBJECTIVES: The brainstem evoked response audiometry (BERA) is an objective neurophysiological method for the evaluation of the hearing threshold and diagnosing retrocochlear lesions. The aim of the study was to investigate the hearing level in children with suspected hearing loss or pathological speech development. PATIENTS AND METHODS: The BERA diagnostic procedure was applied in 150 children ranging from 1 to 5years of age at KEM Hospital Pune.. RESULTS: We found profound hearing loss (deafness) in 15 children, severe hearing loss in 10 children, moderate hearing loss in 35 children, mild hearing loss in 30 children, and normal hearing level in 60 children. Out of the children suspected for hearing loss, 42% actually had some level (mild-moderate) of hearing loss. Out of the children with delayed speech, 63% had some level (mild-profound) of hearing loss which actually caused the delay in speech development; 37% had normal hearing, but inadequate verbal communication affected their language acquisition and speech development. CONCLUSIONS: These results illustrate the necessity to test children hearing even with the slightest suspicion by the parent or doctor of hearing loss.
INTRODUCTION
BERA has proved to be a useful tool in diagnosing hearing impairments in children which could be conductive or sensorineural in nature. Thanks to early detection, rehabilitative procedures could be started early which will help speech and language development.
We have studied 150 cases below five years of age, and our observations are recorded with case history profiles like high risks, referral for adaptions, congenital malformations and delayed speech. We feel BERA is the only tool which can present an accurate picture of hearing sensitivity.
BERA (Brainstem evoked response audiometry), ABR (Auditory brain stem response), BAER (Brainstem auditory evoked response audiometry).
BERA is an electro-physiological test procedure which studies the electrical potential generated at the various levels of the auditory system starting from cochlea to cortex. This investigation was first described by Jewett and Williston in 1971.
Procedure: The stimulus either in the form of click or tone pips is transmitted to the ear via a transducer placed in the insert ear phone or head phone. The waves of impulses generated at the level of brain stem are recorded by the placement of electrodes over the scalp.
Electrode placement: Since the electrodes should be placed over the head, the hair must be oil free. The patient should be instructed to have shampoo bath before coming for investigation. The standard electrode configuration for BERA involves placing a non inverting electrode over the vertex of the head, and inverting electrodes placed over the ear lobe or mastoid prominence. One more earthing electrode is placed over the forehead. This earthing electrode is important for proper functioning of preamplifier.
BERA is resistant to the effects of sleep, sedation, sleep and anesthesia. Its threshold has been found to be within 10dB as elicited by conventional audiometry.
The waves detected in BERA tests
1. Auditory nerve
2. Cochlear nucleus
3. Superior olivary complex
4. Lateral lemniscus
5. Inferior colliculus
6 and 7. Medical geniculate body
.
Hearing problems are common among the children which could be conductive or sensorineural in nature. Early diagnosis of hearing impairment is important as the rehabilitative procedure can be started early which will help speech and language development.
Various audiological test procedures are used to assess the hearing sensitivity of children. Some of the common ones are: Behavioral Observation.
• Free Field Audiometry.
• Peep Show.
• Pediatric Tester.
All the above techniques are useful in estimating hearing sensitivity but have their own limitations. The major difficulties involved in the use of these techniques are:
• Co–operation of children.
• Consistency of responses.
• Subjectivity on the part of the tester.
• Assessment of children with multiple handicaps.
BERA, (BSER or BAEP) has proved to be a useful objective tool in diagnosing hearing impairments in children. The use of Auditory Brainstem Response (ABR) (1) audiometry as an audiological tool focused on two principal areas:
• The assessment of hearing sensitivity and slope of loss, (if any) in patients, who are unable or unwilling to participate in standard psychoacoustic test procedures.
• To study the neurological integrity of acoustic nerve and brainstem pathway.
To achieve this objective, the paradigm employed is to collect appropriate ABR data for a case, analyze it and compare the data with relevant norms and draw inferences.
Material and Methods
In this study, an attempt is made to study the findings of BERA in children below the age of five years. These children reported to us or were referred to us for the following reasons:
• Delay in speech and language development.
• Inconsistent responses to sound or inability to respond to sound.
• History of high risk factors – Deafness in the family, consanguineous marriage, difficult/obstructed labor, pre–term/premature labor, administration of antibiotic drugs during pregnancy, diseases contracted by the mother such as Rubella, Meningitis or Hyperbilirubinemia.
• To rule out hearing impairment before adoption.
• To rule out the extent of malformation anomalies especially in Atresia.
Test Procedure
All patients were administered the test procedures with prior appointment. An ENT check up was done to rule out the possibility of wax, ear infection, middle ear problems etc. The parents were instructed to wash the scalp of the child thoroughly as a requirement of the test. Prior to the test, each child was examined by the pediatrician and the dosage for sedation was prescribed. Drugs used for sedation were Trichloryl and Phenergan in combination.
Test was carried out in pre–cooled, quiet (not treated) room. The instrument used was Nicolet EP Four Compact which is a fully computerized machine with the facility of artifact rejection. The skin was cleaned with spirit and OMEN abrasive skin preparatory paste. The silver electrode were placed as follows: Cz–vertex, A–1 LF mastoid, A–2 values was not more than 1ohms. Electrode electrolyte gel was used and electrodes were fixed. Acoustically shielded THD 32 ear phones were placed on the ear and head bands were adjusted. The clicks of 11.4/sec duration were used as stimulus. The filter settings used were a 50Hz–300Hz. The polarity used was alternate and the analysis time was 10m/sec. About 4,000 responses were averaged. First, stimulus was given at 105 dBnHL level (i.e. maximum intensity level available). If peak V was detected at a particular level, intensity was increased by 5dB. The existence of peak V was considered as sound stimulus heard and perceived by the auditory mechanism. The threshold for each ear was confirmed. The guidelines used for the confirmation of peak V were as follows:
1.Peak V occurs around latency of 5.7 m/sec with S.D. of 0.25 (as per our norms).
2.With decrease, an intensity level latency of peak V increases and its amplitude decreases.
3.Reproduction of peak in re–run.
4.Peculiar in shape.
5.Use of a neutral run.
Since the measurement of hearing sensitivity in children under five years of age was the only aim of this study, the latency values and interpeak intervals even though measured, are not considered. Each child's hearing sensitivity was assessed, and they were sub–grouped in the following categories.
Normal hearing sensitivity. Hg. thresholds up to 25dB level and below.
Mild hearing impairment. Hg. thresholds between 30dB to 45dB.
Moderate hearing impairment Hg. thresholds between 50dB to 65dB.
Severe hearing impairment. Thresholds between 70dB to 85dB.
Profound hearing impairment. Thresholds above 90dB.
Observation
We have studies BERA findings of 150 children (below the age of five yrs) for this study.
Given below is the age–wise distribution of these children:
AGE No.
0–1 52
1–2 52
2–4 24
4–5 22
The case history profile of these cases is as follows:
High risk clinics. 82 cases
Referred for adoption. 31 cases
Patients with ear anamolies (congenital). 3 cases
Patients brought by atresia. 34 cases
Patients with complaint of delayed speech or inability to respond to sound.
The BERA findings of 15 cases studied:
Normal hearing sensitivity. 53
Mild hearing impairment. 12
Moderate hearing impairment. 21
Severe hearing impairment. 30
Profound hearing impairment. 34
Total 150
Out of 53 patients with normal hearing sensitivity, 33 were sent for adaption, 26 patients were found to be mentally subnormal and 5 patients had multiple anomalies. Out of 12 patients with mild hearing impairment nine patients had history of ear discharge and out of 21 patients with moderate hearing loss 10 had history of ear discharge either in one ear or in both ears and three patients had congenital anomalies of the ear and four had a history of high risk factors. Out of 30 patients with severe hearing impairment 22 had high risk factors contributing to their history and of 34 patients of profound hearing loss, 23 had high risk factors contributing to their history.
Out of 82 high risk cases, 22 had severe hearing loss, 23 had profound hearing loss, four had moderate hearing loss, 33 had normal hearing sensitivity. All the above cases were sent for further rehabilitative procedures as per their requirement.
Conclusion
BERA is a very useful in early detection of hearing loss and planning rehabilitative procedures. In case of multiple handicaps, BERA is the only test which can give accurate picture of hearing sensitivity. In cases of high risk babies, BERA should be carried out as a routine procedure to detect hearing loss. BERA test helps us to conclude regarding the cause of delay in speech and language development. BERA is the only tool which can confirm the normal sensitivity of hearing whenever required.
References
• Chaturvedi V. N., Chaturvedi P. (1980): Assessment of hearing in small children. Indian Journal of Paediatrics. 27: 827–831.
• Jerger J and Hall (1980): Effects of age and sex on Auditory Brainstem response. Archives of otolaryngology.
• Jerger and Mauldin. (1978): Prediction of S N Hearing loss from BERA. Archives of otolaryngology.
• awson S., Mc Cromic B., Wood S. (1995): BERA in children and normative study.
• Kilney (1982): Auditory brainstem responses as indicators of hearing aid performance. Annals of otology, Rhinology and Laryngology pp 91.
• Alberti P. W., Hyde M. L., Riko K., Corbin H., Abramovich S. (1984): Laryngoscope BERA in high risk neonates.
Contributed by Dr. K. K. Desarda(This paper was read in AOI conference.)
Dr. K. K. Desarda
Professor Emeritus & Head, Otolaryngology.KEM Hospital Pune.
&
Dr. A. N. Sangekar
Audiologist and Speech Pathologist,
KEM Hospital, Pune
BERA (BSER OR BAEP)
Abstract
OBJECTIVES: The brainstem evoked response audiometry (BERA) is an objective neurophysiological method for the evaluation of the hearing threshold and diagnosing retrocochlear lesions. The aim of the study was to investigate the hearing level in children with suspected hearing loss or pathological speech development. PATIENTS AND METHODS: The BERA diagnostic procedure was applied in 150 children ranging from 1 to 5years of age at KEM Hospital Pune.. RESULTS: We found profound hearing loss (deafness) in 15 children, severe hearing loss in 10 children, moderate hearing loss in 35 children, mild hearing loss in 30 children, and normal hearing level in 60 children. Out of the children suspected for hearing loss, 42% actually had some level (mild-moderate) of hearing loss. Out of the children with delayed speech, 63% had some level (mild-profound) of hearing loss which actually caused the delay in speech development; 37% had normal hearing, but inadequate verbal communication affected their language acquisition and speech development. CONCLUSIONS: These results illustrate the necessity to test children hearing even with the slightest suspicion by the parent or doctor of hearing loss.
INTRODUCTION
BERA has proved to be a useful tool in diagnosing hearing impairments in children which could be conductive or sensorineural in nature. Thanks to early detection, rehabilitative procedures could be started early which will help speech and language development.
We have studied 150 cases below five years of age, and our observations are recorded with case history profiles like high risks, referral for adaptions, congenital malformations and delayed speech. We feel BERA is the only tool which can present an accurate picture of hearing sensitivity.
BERA (Brainstem evoked response audiometry), ABR (Auditory brain stem response), BAER (Brainstem auditory evoked response audiometry).
BERA is an electro-physiological test procedure which studies the electrical potential generated at the various levels of the auditory system starting from cochlea to cortex. This investigation was first described by Jewett and Williston in 1971.
Procedure: The stimulus either in the form of click or tone pips is transmitted to the ear via a transducer placed in the insert ear phone or head phone. The waves of impulses generated at the level of brain stem are recorded by the placement of electrodes over the scalp.
Electrode placement: Since the electrodes should be placed over the head, the hair must be oil free. The patient should be instructed to have shampoo bath before coming for investigation. The standard electrode configuration for BERA involves placing a non inverting electrode over the vertex of the head, and inverting electrodes placed over the ear lobe or mastoid prominence. One more earthing electrode is placed over the forehead. This earthing electrode is important for proper functioning of preamplifier.
BERA is resistant to the effects of sleep, sedation, sleep and anesthesia. Its threshold has been found to be within 10dB as elicited by conventional audiometry.
The waves detected in BERA tests
1. Auditory nerve
2. Cochlear nucleus
3. Superior olivary complex
4. Lateral lemniscus
5. Inferior colliculus
6 and 7. Medical geniculate body
.
Hearing problems are common among the children which could be conductive or sensorineural in nature. Early diagnosis of hearing impairment is important as the rehabilitative procedure can be started early which will help speech and language development.
Various audiological test procedures are used to assess the hearing sensitivity of children. Some of the common ones are: Behavioral Observation.
• Free Field Audiometry.
• Peep Show.
• Pediatric Tester.
All the above techniques are useful in estimating hearing sensitivity but have their own limitations. The major difficulties involved in the use of these techniques are:
• Co–operation of children.
• Consistency of responses.
• Subjectivity on the part of the tester.
• Assessment of children with multiple handicaps.
BERA, (BSER or BAEP) has proved to be a useful objective tool in diagnosing hearing impairments in children. The use of Auditory Brainstem Response (ABR) (1) audiometry as an audiological tool focused on two principal areas:
• The assessment of hearing sensitivity and slope of loss, (if any) in patients, who are unable or unwilling to participate in standard psychoacoustic test procedures.
• To study the neurological integrity of acoustic nerve and brainstem pathway.
To achieve this objective, the paradigm employed is to collect appropriate ABR data for a case, analyze it and compare the data with relevant norms and draw inferences.
Material and Methods
In this study, an attempt is made to study the findings of BERA in children below the age of five years. These children reported to us or were referred to us for the following reasons:
• Delay in speech and language development.
• Inconsistent responses to sound or inability to respond to sound.
• History of high risk factors – Deafness in the family, consanguineous marriage, difficult/obstructed labor, pre–term/premature labor, administration of antibiotic drugs during pregnancy, diseases contracted by the mother such as Rubella, Meningitis or Hyperbilirubinemia.
• To rule out hearing impairment before adoption.
• To rule out the extent of malformation anomalies especially in Atresia.
Test Procedure
All patients were administered the test procedures with prior appointment. An ENT check up was done to rule out the possibility of wax, ear infection, middle ear problems etc. The parents were instructed to wash the scalp of the child thoroughly as a requirement of the test. Prior to the test, each child was examined by the pediatrician and the dosage for sedation was prescribed. Drugs used for sedation were Trichloryl and Phenergan in combination.
Test was carried out in pre–cooled, quiet (not treated) room. The instrument used was Nicolet EP Four Compact which is a fully computerized machine with the facility of artifact rejection. The skin was cleaned with spirit and OMEN abrasive skin preparatory paste. The silver electrode were placed as follows: Cz–vertex, A–1 LF mastoid, A–2 values was not more than 1ohms. Electrode electrolyte gel was used and electrodes were fixed. Acoustically shielded THD 32 ear phones were placed on the ear and head bands were adjusted. The clicks of 11.4/sec duration were used as stimulus. The filter settings used were a 50Hz–300Hz. The polarity used was alternate and the analysis time was 10m/sec. About 4,000 responses were averaged. First, stimulus was given at 105 dBnHL level (i.e. maximum intensity level available). If peak V was detected at a particular level, intensity was increased by 5dB. The existence of peak V was considered as sound stimulus heard and perceived by the auditory mechanism. The threshold for each ear was confirmed. The guidelines used for the confirmation of peak V were as follows:
1.Peak V occurs around latency of 5.7 m/sec with S.D. of 0.25 (as per our norms).
2.With decrease, an intensity level latency of peak V increases and its amplitude decreases.
3.Reproduction of peak in re–run.
4.Peculiar in shape.
5.Use of a neutral run.
Since the measurement of hearing sensitivity in children under five years of age was the only aim of this study, the latency values and interpeak intervals even though measured, are not considered. Each child's hearing sensitivity was assessed, and they were sub–grouped in the following categories.
Normal hearing sensitivity. Hg. thresholds up to 25dB level and below.
Mild hearing impairment. Hg. thresholds between 30dB to 45dB.
Moderate hearing impairment Hg. thresholds between 50dB to 65dB.
Severe hearing impairment. Thresholds between 70dB to 85dB.
Profound hearing impairment. Thresholds above 90dB.
Observation
We have studies BERA findings of 150 children (below the age of five yrs) for this study.
Given below is the age–wise distribution of these children:
AGE No.
0–1 52
1–2 52
2–4 24
4–5 22
The case history profile of these cases is as follows:
High risk clinics. 82 cases
Referred for adoption. 31 cases
Patients with ear anamolies (congenital). 3 cases
Patients brought by atresia. 34 cases
Patients with complaint of delayed speech or inability to respond to sound.
The BERA findings of 15 cases studied:
Normal hearing sensitivity. 53
Mild hearing impairment. 12
Moderate hearing impairment. 21
Severe hearing impairment. 30
Profound hearing impairment. 34
Total 150
Out of 53 patients with normal hearing sensitivity, 33 were sent for adaption, 26 patients were found to be mentally subnormal and 5 patients had multiple anomalies. Out of 12 patients with mild hearing impairment nine patients had history of ear discharge and out of 21 patients with moderate hearing loss 10 had history of ear discharge either in one ear or in both ears and three patients had congenital anomalies of the ear and four had a history of high risk factors. Out of 30 patients with severe hearing impairment 22 had high risk factors contributing to their history and of 34 patients of profound hearing loss, 23 had high risk factors contributing to their history.
Out of 82 high risk cases, 22 had severe hearing loss, 23 had profound hearing loss, four had moderate hearing loss, 33 had normal hearing sensitivity. All the above cases were sent for further rehabilitative procedures as per their requirement.
Conclusion
BERA is a very useful in early detection of hearing loss and planning rehabilitative procedures. In case of multiple handicaps, BERA is the only test which can give accurate picture of hearing sensitivity. In cases of high risk babies, BERA should be carried out as a routine procedure to detect hearing loss. BERA test helps us to conclude regarding the cause of delay in speech and language development. BERA is the only tool which can confirm the normal sensitivity of hearing whenever required.
References
• Chaturvedi V. N., Chaturvedi P. (1980): Assessment of hearing in small children. Indian Journal of Paediatrics. 27: 827–831.
• Jerger J and Hall (1980): Effects of age and sex on Auditory Brainstem response. Archives of otolaryngology.
• Jerger and Mauldin. (1978): Prediction of S N Hearing loss from BERA. Archives of otolaryngology.
• awson S., Mc Cromic B., Wood S. (1995): BERA in children and normative study.
• Kilney (1982): Auditory brainstem responses as indicators of hearing aid performance. Annals of otology, Rhinology and Laryngology pp 91.
• Alberti P. W., Hyde M. L., Riko K., Corbin H., Abramovich S. (1984): Laryngoscope BERA in high risk neonates.
Contributed by Dr. K. K. Desarda(This paper was read in AOI conference.)
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