BAEP / ABR (Auditory Brainstem Response)
Waves I-V recorded from the auditory nerve and brainstem pathways; wave V latency in adults is 5.5-6 ms, I-V interwave interval 4 ms; applicable without sedation.
General reading about BAEP / ABR (Auditory Brainstem Response) does not replace a otology and ear disease examination; meaning comes from personal findings. Waves I-V recorded from the auditory nerve and brainstem pathways; wave V latency in adults is 5.5-6 ms, I-V interwave interval 4 ms; applicable without sedation. Age, expectations, symptom duration, side pattern and previous procedures change the weight of assessment. this entry assessment interprets hearing level, the clinical point ear pressure, the dictionary entry discharge history, this topic dizziness pattern and this term daily communication impact together. This entry organizes the the finding details that belong in consultation notes. The first message for this entry is that the finding becomes meaningful through history, examination and selected tests: ABR measures brainstem electrical responses to auditory stimulation, recorded with scalp electrodes. This keeps online information from replacing personal diagnosis.
A the clinical point visit gathers the current complaint, previous treatment experience and patient expectation into one clinical file. The key question is whether examination supports that story or suggests another explanation. this topic review may gather otoscopy, this term microscopic examination, the finding audiometry-tympanometry and this entry temporal bone imaging inside the the clinical point file. the dictionary entry interpretation separates hearing type, this topic eardrum mobility, this term ossicular chain status, the finding vestibular findings and this entry prior infection history. When this term is assessed, the short definition, patient wording and objective findings are read together: The main clinical uses of ABR are: determining hearing threshold in newborns who do not pass OAE, detection of acoustic neuroma and retrocochlear lesions, intraoperative monitoring and brainstem function assessment in intensive care patients. Higher-risk possibilities are considered first, then the next clinical step is chosen. Conclusions rely on coherent evidence rather than one isolated finding.
Observation, medication, supportive care, procedures and surgery are treated as stepwise options in the finding. Each step is matched with diagnostic certainty and patient safety. this entry planning discusses medication or drops, the clinical point hearing aids, the dictionary entry vestibular rehabilitation, this topic tympanoplasty-stapes surgery or this term implant options by finding. Before a care path is chosen for the finding, expected benefit, alternatives, recovery, possible complications and the later review plan are discussed in the same visit. The aim is a proportionate decision that preserves function.
Follow-up for this entry varies from patient to patient. Age, overall health, medication, previous operations, comorbidities and functional expectations influence review timing. the clinical point follow-up tracks hearing change, the finding ear discharge, this entry dizziness, the clinical point tinnitus burden and the dictionary entry quality-of-life impact together. Patient counselling for this topic aims to prepare the right questions without replacing personal diagnosis with online information, recognize safety signals and decide with examination findings. During this term care, the finding follow-up with rapidly reduced hearing, weak facial movement or severe dizziness is recorded as a warning-sign note.
Assessment of this entry is more efficient when the patient separates what changed, what limits daily life and which symptom may be a warning sign; the final conclusion still depends on personal examination and current findings.
In this guide
Interpreting ABR Testing
ABR interpretation evaluates wave latencies, amplitudes and interwave intervals. If the right-left difference in wave V latency exceeds 0.3 ms, the asymmetry is considered significant and a retrocochlear lesion is investigated. Determination of wave V threshold is used to estimate audiometric threshold in newborns and patients who cannot cooperate.
Typical findings in retrocochlear lesions (acoustic neuroma): prolongation of wave V latency, prolongation of interwave I-III or I-V interval and disappearance of wave V despite the presence of wave I. Demyelinating diseases (MS) prolong interwave delays while largely preserving amplitudes.
Clinical Applications of ABR
As an objective test, ABR together with OAE forms the basis of newborn hearing screening and diagnostic protocol. Intraoperative ABR monitoring reduces the risk of nerve damage in acoustic neuroma surgery, posterior fossa mass and cochlear implant surgery. It is also applied as supporting evidence in brain death assessment in intensive care.
In children where behavioural audiometry cannot obtain a threshold, the standard approach is objective threshold determination with ABR. In suspected functional (non-organic) hearing loss, ABR and OAE can be used together to confirm a threshold better than reported.
ABR Reliability and Limitations
ABR is an objective test requiring no cooperation and has high reliability in terms of accuracy. However, it cannot measure all hearing frequencies with equal precision; tone-burst ABR or ASSR are more appropriate alternatives for low frequencies at 500 Hz and below. Electrical artefact, muscle activity and depth of sleep can affect results.
ABR is not a standalone diagnosis but part of clinical assessment. A negative ABR in suspected retrocochlear lesion does not definitively exclude acoustic neuroma; gadolinium-enhanced MRI is mandatory in this situation. ABR latency norms vary according to age, sex and body temperature.
When Should ABR Be Done?
Diagnostic ABR within 1 month is mandatory in every newborn who does not pass OAE screening; early diagnosis enables timely initiation of hearing aid and language development interventions. In unilateral tinnitus or progressive asymmetric hearing loss, ABR and MRI should be evaluated together to exclude acoustic neuroma.
Continuous intraoperative ABR monitoring during acoustic neuroma surgery under anaesthesia is standard practice. ABR is the first option for objective threshold determination in children where behavioural cooperation cannot be achieved and in high-risk infants and children for ototoxicity.
Frequently asked questions
What is BAEP / ABR (Auditory Brainstem Response)?
When is BAEP / ABR (Auditory Brainstem Response) clinically important?
When is ENT assessment relevant for BAEP / ABR (Auditory Brainstem Response)?
What information helps assessment of BAEP / ABR (Auditory Brainstem Response)?
Learn more about this procedure
Detailed guide from Prof. Dr. Özdoğan's clinic
Related terms
References
- AAO-HNSFClinical Practice Guideline: Sudden Hearing Loss (Update)
- AAO-HNSFClinical Practice Guideline: Benign Paroxysmal Positional Vertigo (Update)
- AAO-HNSFClinical Practice Guideline: Meniere's Disease
- NCBI BookshelfAcute Otitis Media
- NCBI BookshelfTympanoplasty
This glossary entry is for informational purposes only and does not constitute medical advice. Consult a qualified specialist for diagnosis and treatment.