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Updated: Aug 10, 2026
Data Acquisition and Analysis In Brainstem Evoked Response Audiometry In Mice
Published on: May 10, 2019
Auditory brain-stem, middle- and long-latency evoked potentials in mild cognitive impairment
R Irimajiri1, E J Golob, A Starr
1Department of Neurology, Institute for Brain Aging and Dementia, University of California, Irvine, CA 92627, USA.
Objective:
Mild cognitive impairment (MCI) is a selective episodic memory deficit in the elderly with a high risk of Alzheimer's disease. The amplitudes of a long-latency auditory evoked potential (P50) are larger in MCI compared to age-matched controls. We tested whether increased P50 amplitudes in MCI were accompanied by changes of middle-latency potentials occurring around 50 ms and/or auditory brain-stem potentials.
Methods:
Auditory evoked potentials were recorded from age-matched controls (n = 16) and MCI (n = 17) in a passive listening paradigm at two stimulus presentation rates (2/s, 1/1.5 s). A subset of subjects also received stimuli at a rate of 1/3 s.
Results:
Relative to controls, MCI subjects had larger long-latency P50 amplitudes at all stimulus rates. Significant group differences in N100 amplitude were dependent on stimulus rate. Amplitudes of the middle-latency components (Pa, Nb, P1 peaking at approximately 30, 40, and 50 ms, respectively) did not differ between groups, but a slow wave between 30 and 49 ms on which the middle-latency components arose was significantly increased in MCI. ABR Wave V latency and amplitude did not differ significantly between groups.
Conclusions:
The increase of long-latency P50 amplitudes in MCI reflects changes of a middle-latency slow wave, but not of transient middle-latency components. There was no evidence of group difference at the brain-stem level.
Significance:
Increased slow wave occurring as early as 50 ms may reflect neurophysiological consequences of neuropathology in MCI.
Insights
In mild cognitive impairment (MCI), larger auditory evoked potential (P50) amplitudes are linked to a middle-latency slow wave increase, not transient potentials. This suggests early neurophysiological changes in MCI.
Area of Science:
- Neuroscience
- Gerontology
- Auditory Electrophysiology
Background:
- Mild cognitive impairment (MCI) is characterized by episodic memory deficits and increased Alzheimer's disease risk.
- Individuals with MCI exhibit larger long-latency P50 auditory evoked potential amplitudes compared to controls.
Purpose of the Study:
- To investigate if increased P50 amplitudes in MCI are associated with alterations in middle-latency potentials (around 50 ms) or auditory brain-stem potentials.
- To explore the neurophysiological underpinnings of auditory processing changes in MCI.
Main Methods:
- Auditory evoked potentials were recorded in individuals with MCI (n=17) and age-matched controls (n=16) using passive listening.
- Stimuli were presented at rates of 2/s, 1/1.5 s, and a subset at 1/3 s.
Main Results:
- MCI subjects showed significantly larger long-latency P50 amplitudes across all stimulus rates.
- While transient middle-latency components (Pa, Nb, P1) did not differ, a slow wave between 30-49 ms was significantly increased in MCI.
- Auditory brain-stem response (ABR) Wave V latency and amplitude showed no significant group differences.
Conclusions:
- The elevated P50 amplitudes in MCI are attributed to an underlying middle-latency slow wave increase, not changes in transient middle-latency components.
- No auditory brain-stem level differences were observed between MCI and control groups.
- The early increase in the slow wave (around 50 ms) may indicate neurophysiological consequences of MCI-related neuropathology.
