CORTICAL AUDITORY EVOKED POTENTIALS PORTAL

WHAT IS A CORTICAL AUDITORY EVOKED POTENTIAL:

Cortical auditory evoked potentials are EEG responses that are specific to auditory stimuli and record responses at the level of the cortex.

WHY DO WE NEED NEW TECHNIQUES FOR ASSESSING CHILDREN’S SPEECH PERCEPTION IN INFANCY?

Infants all over the United States and the world are being screened for hearing loss shortly after birth. They can be fit with hearing aids within a few weeks after birth. At the present time, we can determine through cortical auditory evoked potentials (P1) that specific sounds reach the cortex of the brain, but there has not been a clinical technique for assessing speech discrimination in infants or toddlers. Determination of whether hearing aids are providing access to sounds of the native language so that the infant/toddler can discriminate one sound from another cannot be done until 2.5 to 3 years of age after the child has established spoken language.

WHY USE PHYSIOLOGICAL ASSESSMENT PROCEDURES?

In infancy, although a newborn can provide behavioral responses, these responses are not conditioned responses with a specific behavioral outcome, such as a head turn. Infants can be observed to alter breath patterns, heart rate, can blink eyes, move limbs or increase sucking in response to sound. However, because of the variability of responses, the reliability of observing these responses requires significant training of the observer. To date, no clinical behavioral technique has been developed for discrimination of speech sounds. Studies have focused on detection of sound not discrimination of sounds.
A reliable and valid assessment technique is needed in the first six months of life. For the same reason that EEG recordings, Auditory Brainstem Responses (ABR) testing is used to diagnose hearing loss in newborns, EEG recordings elicited from auditory stimuli in an oddball paradigm provide the best opportunity to create a viable clinical diagnostic physiological assessment procedure.