Ear Treatment


Definition: Brainstem Evoked Response Audiometry (BERA) is an objective electrophysiological test measuring response in the brain waves that are stimulated by a clicking sound to check the central auditory pathways (hearing) of the brainstem. It is a non-invasive technique to find the integrity of central auditory pathways through the VIIIth nerve, pons and midbrain.

  • Nervous system abnormalities
  • Children with hearing loss
  • To assess neurological functions
  • Malingering patients
  • Suspected acoustic neuroma
  • Central pontine myelinolysis

Bera test Procedure
  • The test is done in an air-conditioned room.
  • Patient is asked to wash the hair the night before the test.
  • Infants and small children need to be administered sedatives like triclofos sodium in a dose of 50 mg per kg of body weight or promethazine hydrochloride in a dose of 0.5mg per kg of body weight so that the child is deeply sedated during the test.
  • Electrodes are placed on the patient’s scalp, along the vertex and on each earlobe.
  • Patient in lying down position, eyes closed and preferably asleep.
  • Earphones are put on the ear. The patient hears a clicking sound between 10 and 40 clicks per second through the earphones.
  • The electrodes pick up the brain’s response and record it on the graph.
  • It measures hearing sensitivity in the range of 1000–4000 Hz.
  • In a normal person, seven waves are produced in the first 10 ms.
  • The first, third and fifth waves are most stable and are used in measurements.
  • The waves are studied for absolute latency, inter-wave latency (usually between wave I and V) and the amplitude.
  • Wave V is the most reliable and easily identifiable wave in the BERA tracing.
BERA waves Interpretation
  • Wave I - Distal part of CN VIII
  • Wave II - Proximal part of CN VIII near the brainstem
  • Wave III - Cochlear nucleus
  • Wave IV - Superior olivary complex
  • Wave V - Lateral lemniscus
  • Waves VI - Inferior colliculus
  • Waves VII - Medial geniculate body
Absolute latency:
Wave Latency (ms)
Wave I 1.55 - 1.75
Wave III 3.8
Wave IV 5.5 - 5.85
Interaural latency:
Parameter measured Normal value (milliseconds) Criteria for abnormality (milliseconds)
Interaural latency difference of wave V Less than 0.3 More than 0.3