Early ear infection and trauma, age birth to 12 years are known to have a significant effect on sensory and cognitive development. This effect can be demonstrated through fMRI study of children who have a history of ear infection compared to a control group. A second research question is the extent to which brain plasticity at an early age can reduce the impact of infection on hearing and cognitive development.

Functional Magnetic Resonance Imaging (fMRI) provides a mapping of brain activity in cognitive and sensory regions by recording the oxygenation state of the local cerebral blood flow.

The gradient coils of fMRI scanners generate intense acoustic noise (GCN)—to which the subject is in close proximity—in the range of 90 to 140 dB SPL during the imaging process. Clearly this noise will impress its signature on low level brain response patterns. An Active Noise Canceller (ANC) system can suppress the effect of GCN on the subject's perception of a phonetic stimulus at the phoneme, word or phrase level.

The frequency and time domain components of the test signal and GCN are superimposed so simple filtering procedures such as band-pass and band-eliminate are not acceptable.

The filtering system is that it performs its function in real time—we must capture the brain's response to the test signal AFTER the noise has been removed. This goal is achieved through application of Field Programmable Gate Array (FPGA) technology of NI LabVIEW.

The presentation (in the noisy fMRI environment) of test words and phrases to hearing impaired children can identify sources of distortion to their perceptual processes associated with GCN. Once this distortion has been identified, learning strategies may be introduced to replace the hearing function distorted by early infection as well as the short term effect of GCN. A first research strategy is to allow the study of speech cognition without the confounding effect of GCN Second, the varying level of GCN that is allowed to remain in the test signal can lead to a measure of recovery through brain plasticity when the test is repeated at a later age.