Detecting Hearing Loss Early: Brainstem Evoked Response Audiometry
As parents we want our children to grow up with every advantage in life. We bring them home from the hospital and begin the teaching of life’s lessons, but if we aren’t paying attention, we might miss signs pointing to subtle hearing loss. A child with unnoticed hearing loss may not be able to develop normal language and speech or obtain the cognitive abilities (knowing, thinking, and judging) needed for learning. However, with early identification and treatment, the impact can be lessened. Current technology now permits the accurate assessments of hearing in children starting within a few hours of birth. Brainstem evoked response audiometry (BERA), is a physiological screening test designed to detect hearing loss or deafness, and is safe for use with newborn infants. Since approximately 1-6 of every 1000 children is born deaf, the evoked response test provides a safe and painless method of detection.
The brainstem evoked response audiometry test assesses the functions of the ears, cranial nerves, and various brain functions of the lower part of the auditory system. The procedure involves headphones being placed on the infant’s head and a tiny tone (or click) being released into the ear, eliciting an evoked response. Similar to electroencephalography (EEG), surface electrodes are placed on the earlobes and scalp and the signals (in microvoltage) are averaged and charted against the time (in milliseconds). This information is recorded simultaneously for use by the audiologist.
The evoked response method tests the integrity of the hearing system from the ear to the brainstem. Audiologists and doctors have begun evaluating the results to track differences between normal children and children with learning problems, proving that information from the BERA can serve as a biological marker for auditory function in children with language-based learning problems, like dyslexia.