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Auditory brain-stem, middle- and long-latency evoked potentials in mild cognitive impairment.
- Author(s): Irimajiri, R;
- Golob, EJ;
- Starr, A
- et al.
Published Web Locationhttps://doi.org/10.1016/j.clinph.2005.04.010
ObjectiveMild 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.
MethodsAuditory 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.
ResultsRelative 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.
ConclusionsThe 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.
SignificanceIncreased slow wave occurring as early as 50 ms may reflect neurophysiological consequences of neuropathology in MCI.
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