The Effect of Stimulus Polarity on Auditory Brainstem Responses Elicited by Level-Specific CE-Chirp in Young Adults...

This study investigated the effect of stimulus polarity on the auditory brainstem response (ABR) elicited by level-specific Claus Elberling Chirp (LS CE-Chirp) stimuli in young adults with normal hearing.

Thirty-one healthy participants (23 females, eight males; M_age = 20.6 ± 1.4 years; range: 18-25 years) underwent LS CE-Chirp ABR recordings at 70 dB nHL using three polarities: rarefaction, condensation, and alternating. Right and left ear values were averaged per participant. Absolute latencies of Waves I, III, and V; interpeak latencies (IPLs) I-III, III-V, and I-V; and wave amplitudes were compared across polarities using the Friedman test, with Wilcoxon signed-ranks test post hoc comparisons and Bonferroni correction applied where warranted.

No statistically significant differences were observed among the three polarity conditions for any of the nine ABR parameters (all ps > .05). The largest Friedman statistics were obtained for Wave I latency (χ² = 5.193, p = .075) and IPL III-V (χ² = 5.600, p = .061), neither of which reached significance. Mean values were numerically similar across all polarity conditions.

Stimulus polarity does not exert a statistically significant or clinically meaningful influence on LS CE-Chirp ABR measures in young normal-hearing adults. The traveling-wave delay compensation inherent to the LS CE-Chirp stimulus appears to attenuate polarity-related phase sensitivity, suggesting that all three polarities are clinically equivalent under the conditions examined (70 dB nHL, young adults with normal hearing). Caution is warranted before extending this conclusion to other intensity levels or clinical populations.

Clinicians recording LS CE-Chirp ABR at suprathreshold levels may select any of the three standard polarities without compromising the validity or accuracy of measurements under the specific conditions described in this study. Consistent application of a single polarity within a laboratory setting is recommended to maintain comparability with internally established normative data.