Auditory Middle Latency Response in Children with and Without Dichotic Deficits

Area of Science:

• Auditory Neuroscience
• Neurophysiology
• Developmental Psychology

Background:

• Amblyaudia (AMB) and dichotic dysaudia (DD) are distinct dichotic listening deficits with differing behavioral profiles.
• AMB is characterized by significant interaural asymmetry, while DD presents with bilaterally poor but symmetric performance.
• The auditory middle latency response (MLR) is an objective measure of auditory pathway function.

Purpose of the Study:

• To investigate if MLR patterns reflect the behavioral distinctions between AMB and DD in children.
• To determine if children with AMB exhibit asymmetric MLR and if children with DD show more symmetric responses compared to typically performing peers.

Main Methods:

• Thirty-seven children (9-12 years) with normal hearing were classified as AMB, DD, or typically performing (TYP).
• MLRs were recorded using monaural click stimulation at slow and fast rates.
• Peak-to-peak Na-Pa amplitude and latency were analyzed for ear- and electrode-specific effects.

Main Results:

• Children with AMB showed greater Na-Pa amplitudes with left-ear stimulation, reflecting behavioral asymmetry.
• The DD group exhibited minimal amplitude asymmetry but had prolonged Na-Pa latencies for right-ear stimulation at faster rates.
• TYP children displayed minor asymmetries without significant latency delays.

Conclusions:

• MLR findings paralleled behavioral performance, differentiating AMB and DD subtypes.
• Amplitude asymmetry in MLR is characteristic of AMB, while rate-dependent latency differences are associated with DD.
• The MLR offers objective insights for characterizing distinct dichotic listening profiles in children.