Increasing Cognitive Interference Modulates the Amplitude of the Auditory Brainstem Response.

BACKGROUND

Despite the presence of efferent neural pathways from the cortex to brainstem, evidence for cognitive inhibition and sensory gating on the auditory brainstem has been mixed. Some previous studies have suggested auditory brainstem responses (ABR) can be affected by cognitive load whereas others have not.

PURPOSE

The present study explores if the ABR recorded from adults with normal hearing was affected by increased cognitive load involving cognitive interference.

RESEARCH DESIGN

Within-subject repeated measures.

STUDY SAMPLE

Twenty young adults with normal hearing (ten females and ten males, aged 21-26 yr).

DATA COLLECTION AND ANALYSIS

ABRs were collected with and without cognitive load (a visual Stroop task). Two measures of cognitive interference, that is, the ability to suppress task-irrelevant input, were derived from the performance on the Stroop task.

RESULTS

No main effect of cognitive load on ABR wave V amplitudes was found. Participants with higher cognitive interference showed increased response times and larger decreases in ABR wave V amplitudes from the no cognitive load to cognitive load conditions.

CONCLUSIONS

The present study showed that ABR wave V amplitudes did not change with increased overall cognitive load (cognitive load with and without cognitive interference), but ABR amplitude was related to cognitive interference. Increased cognitive load in the form of increased cognitive interference could trigger cognitive inhibition and/or sensory gating to suppress the processing of task-irrelevant information at the level of the brainstem. This suppression could present as reduced ABR wave V amplitudes.