Cognitive Event related potentials (ERPs) are very small voltages that are generated in the brain structures in response to specific events or stimuli (sensory, cognitive or motor). They have been widely used either alone or combined with neuropsychometric or other tests for the assessment of cognitive functions in neurological disorders such as Alzheimer's disease (AD), Mild Cognitive Impairment (MCI), Epilepsy and Multiple sclerosis.
In this systematic review by Paitel et al., the authors focus on the value of ERPs in detecting early signs of neurodegenerative disease as well as differentiating MCI, AD patients and healthy subjects that pose increased AD risk due to the presence of APOE4 allele from healthy elderly. The total number of studies included in the systematic review were 100 and the total number of participants was 3922 (2359 MCI patients, 1445 AD patients; 118 APOEε4 carriers). Most studies have used the oddball auditory paradigm and ERPs were measured in midline EEG electrodes (mostly Fz,Cz, Pz).
The authors then provide an extensive review on the various ERP components and their characteristics (latency, amplitude) in MCI, AD patients and APOE4 carriers. The most frequently studied ERP components were N200 and P300 waves. A pattern of delayed latency and reduced amplitude of ERP components was observed in MCI and AD patients compared to controls. ERPs hold promise as a neurophysiological biomarker for early and accurate diagnosis of MCI and AD, however further studies with larger study groups and more complex cognitive tasks are needed in order to confirm this potential.
Key Points:
- ERPs is a non-invasive and test low-cost test, with high temporal resolution (in the level of msec) in assessing neural activity.
- ERPs holds promise as early and accurate neurophysiological biomarker of AD.
- ERPs might be able to assess early changes indicative of future cognitive impairment in healthy elderly.
- The auditory oddball paradigm is most often used.
- Increased ERP latency and reduced amplitude are associated with brain atrophy and cognitive impairment
References:
- Paitel ER, Samii MR, Nielson KA. A systematic review of cognitive event-related potentials in mild cognitive impairment and Alzheimer's disease. Behav Brain Res. 2021 Jan 1;396:112904. doi: 10.1016/j.bbr.2020.112904. Epub 2020 Sep 15. PMID: 32941881. Link https://pubmed.ncbi.nlm.nih.gov/32941881/
- Papaliagkas, V., Kimiskidis, V., Tsolaki, M. Anogeianakis G. Usefulness of event-related potentials in the assessment of mild cognitive impairment. BMC Neurosci. 2008 Nov 5;9:107. doi: 10.1186/1471-2202-9-107. PMID: 18986528; PMCID: PMC2613153. Link https://pubmed.ncbi.nlm.nih.gov/18986528/