Background: Peak individual alpha frequencies (IAF) extracted from an EEG exam can provide novel sources of information regarding brain function. This information can help measure and track changes in cognition arising from conditions such as concussion or unhealthy aging. Objective 1: To validate a method for combining eyes-closed EEG with eyes-closed audio P300 ERP in order to streamline testing times involved in IAF extraction. Objective 2: To validate age-stratified target ranges of IAF collected in clinic against published research Objective 3: To validate the stability of IAF for data collected in routine clinical settings. Participants: Two thousand twenty-five subjects aged 13-90. Methods: EEG with audio P300 was collected as part of a health screening exam for studies through Colorado University, Children’s Hospital Colorado, Boone Heart Institute, WAVi Co., and various clinics alongside other clinical evaluations. Results: (1) No differences were seen between IAF extracted during an eyes-closed resting and the P300 protocol. (2) The age-related AF trends measured in clinic match the age-related trends from previous research. (3) IAF remained stable over the course of 0-2 years in a test-retest dataset. Conclusion: In-clinic measures of peak EEG frequency corroborate the age-related trends of published research taken over the last several decades and IAF. These results also confirm that IAF is a stable trait, making it useful for within-person longitudinal tracking. By following changes in IAF over time, deviations from normal CNS functioning, such as onset or progression of disease, can be monitored.

Background Evoked potential (ERP) markers extracted from an EEG exam can provide novel sources of information regarding brain function allowing changes in cognition, from conditions such as concussion or unhealthy aging, to be measured and tracked over time. Age-related targets can provide useful guides for practitioners, trainers, and patients seeking to optimize and track brain function over time. Objective 1: To compare age-related changes in auditory P300 metrics of latencies and amplitudes collected in the course of routine clinical evaluations with published trends from research. Objective 2: To establish within-person test-retest variances for these P300 metrics. Objective 3: To validate a method for presenting age-stratified target ranges of P300 metrics. Participants One thousand seven-hundred and seventy-eight reference subjects aged 13-90. Methods Audio P300 was measured as part of a health screening exam for studies through Colorado University, Children’s Hospital Colorado, Boone Heart Institute, WAVi Co., and various clinics alongside other clinical evaluations. Results The age-related trends in both the P300 latency and amplitude measured in clinic match the age-related trends from previous research. In particular, the 2 control group endpoints at 20 and 90 years match the linear slopes predicted for age-related decline from early studies, and the inclusion of all ages produces a maturation prediction of a recent meta analysis where metrics peak near 20 years of age. Large between-person variances are observed across all studies but within-person variances remain consistent with previous studies. Conclusion In-clinic measures of P300 latency and amplitude corroborate the age-related trends of published research taken over the last several decades. Large between-person variance remains, leaving P300 best suited for within-person comparison.

Background: Cardiovascular disease and dementia represent two health problems that may be causally connected. Studies have shown patients with dementia to have reduced cardiovascular health measures, where patients with dementia also have reduced electrophysiological brain activity as measured by event-related potentials (ERP’s). Few studies have attempted to correlate the two: cardiovascular health and ERP brain activity. The objective of this study is to determine if there are ERP differences between patients with lower versus higher measures of cardiovascular risk. Methods: For 180 patients ages 53 (16) years, Audio P300 ERP amplitudes and latencies (speeds) were measured upon initial patient visit alongside other clinical evaluations. Cardiovascular risk was categorized into good versus poor levels for blood pressure resting and stressed, E/A Ratio, atherosclerosis, and carotid intima-media thickness. Results: Groups with good levels had lower latencies (faster P300′s) and higher amplitudes than those with poor levels across all cardiovascular risk measures, significant to p < 0.05 for most parameters. While both cardiovascular health and P300 metrics decline with age, poor blood pressure and plaque was seen to affect P300 performance across all age groups in this study. Conclusion: These data suggest correlation between brain activity, as measured by the P300, and five standard measures of cardiovascular health and this correlation may begin at an early age. While further explorations are warranted, these results could have implications on the management of preventative medicine by bringing preventative cardiology and brain health together.

In 1972, Robert May showed that diversity is detrimental to an ecosystem since, as the number of species increases, the ecosystem is less stable. This is the so-called diversity-stability paradox, which has been derived by considering a mathematical model with linear interactions between the species. Despite being in contradiction with empirical evidence, the diversity-stability paradox has survived the test of time for over 40+ years. In this paper we first show that this paradox is a conclusion driven solely by the linearity of the model employed in its derivation which allows for the neglection of the fixed point solution in the stability analysis. The linear model leads to an ill-posed solution and along with it, its paradoxical stability predictions. We then consider a model ecosystem with nonlinear interactions between species, which leads to a stable ecosystem when the number of species is increased. The saturating non linear term in the species interaction is analogous to a Hill function appearing in systems like gene regulation, neurons, diffusion of information and ecosystems The exact fixed point solution of this model is based on k -core percolation and shows that the paradox disappears. This theoretical result, which is exact and non-perturbative, shows that diversity is beneficial to the ecosystem in agreement with analyzed experimental evidence