Executive functions empowerment in healthy aging: what about electrophysiological markers?

Objective: Age-related changes in information-processing and executive control are accompanied by the alteration of electrophysiological components mirroring those processes. Such electrophysiology markers may also offer useful information for the evaluation of experimental empowerment protocols and may help in overcoming the limitations of behavioural outcome measures. We then designed a longitudinal study and compared behavioural and electrophysiological modulations induced by a cognitive- and a neuromodulation-based empowerment protocol. In particular, we focused on the N2 event-related potential (ERP) - associated to basic information-processing and investigated as biomarker of the progression to pathological decline. Participants and methods: 28 healthy elderly were divided into two experimental and a control group. A standardized assessment procedure was performed at the beginning of the study, after the intervention period and at follow-up. Besides neuropsychological testing, we also recorded resting EEG and ERP responses during a Stroop-like task. The empowerment protocols lasted eight weeks and included three sessions per week. Results: Firstly, statistical analyses of neuropsychological data suggested that the experimental protocols lead to partially different improvement profiles, and such improvements were still partially present at the follow-up. Secondly, we observed an increase of N2 deflection at the end of the neuromodulation protocol. Interestingly, that effect was localized consistently with the stimulation montage. Conclusions: Due to their remarkable sensitivity to changes in cognitive functioning and their temporal resolution, ERPs are valuable candidates as markers of decline progression for specific processes. Present evidences begin to highlight their potential also as objective indices of intervention effects even in healthy elderly.