Development of Tone Burst ABR in Infants

Abstract

Frequency-specific ABR is universally recommended to determine the thresholds in infants who do not pass new born hearing screening. However important variable in the interpretation of ABR tracings, especially in premature infants, is the effect of maturation on the waveforms. The present study was carried out with the aim of studying the effect of age on tone burst evoked ABR in infants and to see the maturational changes of tone burst evoked ABR in infants. Infants were divided into two groups; group I with age range of 0 to 6 months (15 ears) and group II with age range of 6 to 12 months (15 ears). Wave V latency changes of 500 Hz and 4000 Hz at intensity levels of 70 dB nHL, 50 dB nHL, 40 dB nHL and 30 dB nHl were analysed in both the groups. There was significant correlations f or wave V latency across age groups for 500 Hz at all the intensities, and for 4000 Hz correlation was present only for 70 dB nHL and 50 dB nHL. Significant difference in latency was observed within age groups across 2 frequencies at different intensity levels. Use of tone burst ABR is helpful in. finding the frequency specific threshold in infants. Also by seeing the latency change, maturation of the auditory system can be easily understood.