BackgroundTo investigate the characteristics of mismatch negativity (MMN) in terms of latency and amplitude in children with bilateral congenital microtia using a Bone conduction implant (Bonebridge), and to explore the relationship between cortical level auditory discrimination, speech perception, and psychosocial well-being. MethodsThis descriptive, observational, cross-sectional study compared three groups: eight children with bilateral congenital microtia and Bonebridge implants (bilateral group), eight children with unilateral congenital microtia and no hearing aids (unilateral group), and eight children with normal hearing (NH group). Participants underwent MMN evaluation using a classic oddball paradigm with a pure tone burst stimulus, featuring a 1000 Hz standard stimulus and a 1200 Hz deviant stimulus, presented in a sound field at 65 dBHL. Additionally, speech perception tests, the Meaningful Use of Speech Scale (MUSS), and psychosocial status questionnaires, including the Social Anxiety Scale for Children (SASC) and the Children’s Loneliness Scale (CLS), were administered to all subjects. ResultsThe bilateral group’s average MMN latency was 241.23 ± 29.47 ms, and the unilateral group’s was 209.96 ± 54.32 ms, both significantly longer than the NH group’s 146.05 ± 15.73 ms (p < 0.0001, F=3.509, 95 % CI 68.09 to 122.3 and p = 0.0097, F=11.92, 95 % CI 18.07 to 109.8, respectively). However, no significant difference was found in MMN latency between the bilateral and unilateral groups (p = 0.202, F=3.397, 95 % CI −18.84 to 81.36). The unilateral group scored significantly higher on the MUSS (38.63 ± 1.41 vs. 30.75 ± 3.80, p = 0.0001, F=7.276, 95 % CI −11.16 to −4.590), had lower CLS scores (47.13 ± 8.13 vs. 58.25 ± 8.39, p = 0.024, F=1.065, 95 % CI 1.652 to 20.60), and lower SASC scores (4.13 ± 2.09 vs. 6.50 ± 2.25, p = 0.062, F=1.204, 95 % CI −0.138 to 4.89) compared to the bilateral group. MMN latency in the bilateral group correlated with SASC scores. ConclusionThe MMN latency in congenital microtia patients may serve as an indicator of central auditory discrimination capabilities. In children with bilateral congenital microtia and Bonebridge implants, MMN latency can reflect social anxiety conditions to a certain degree.