Presented by Mauricio Gonzalez-Lopez, MSc: Age is the main risk factor for the incidence of neurocognitive disorders. Past research has shown that quantitative electroencephalography (qEEG) might be a good tool to assess the risk of developing future cognitive decline in a healthy elderly population, and specifically an excess of theta activity (4.0-8.0 Hz) has been observed (Prichep, et al., 2006, Prichep, 2007).
Based on this rationale we have explored whether an excess of theta activity, even when all neuropsychological variables seem normal, might discriminate in neurobiological terms between two populations of healthy elderly. For this reason, we explored with several neurobiological tools, such as event-related potentials and magnetic resonance imaging, whether these two populations would differ, in order to provide: a) a rationale for a neurofeedback treatment and b) neurophysiological tools to assess the efficacy of a specific neurofeedback protocol.
Therefore, with this two-fold objective in mind, we present two sets of comparisons: 1) the results of the neurophysiological comparison between a group considered to be at risk of cognitive decline (i.e., those that presented an excess of theta activity compared to a normative database) and a control group with normal EEG; and 2) the neuropsychological results and EEG changes after a neurofeedback protocol that aimed to normalize these theta excesses, as well as the comparison with a placebo group. We observed a difference in psychophysiological terms between the Risk Group (before treatment) and the Control group, when considering biological measures but not psychometric and neuropsychological tools.
Moreover, we observed differences post-treatment between the Neurofeedback and the Placebo (Sham) Group. We also present preliminary results of a sLORETA treatment, which aimed to normalize the most abnormal current sources in the theta band.
This evidence contributes to the idea that normalizing an abnormal excess of theta activity might have beneficial effects on cognition in this elderly subgroup, and quantitative and normative EEG might be a low-cost and viable tool for the early identification of risk of cognitive decline.
Acknowledgements: Catalina Alatorre, Susana Castro, Sergio Sánchez, Francisca Salcedo, Carolina Villada, Rodrigo Flores, Monserrat Palacios, Saulo Hernández and Hector Belmont for technical support and Teresa Alvarez for personal assistance. This work was funded by grants IN225414 and IN200817 from PAPIIT DGAPA, as well as scholarship 608617 from CONACyT.
