FUNCTIONAL NEUROMARKERS OF COGNITIVE IMPAIRMENT IN VASCULAR DEMENTIA: A CASE STUDY

Background: Early diagnosis and monitoring of disease progression in patients with Vascular Dementia (VaD) have become vital in clinical practice, as disease modifying treatments for VaD become available. The goal of our research was to study cognitive impairment in a patient at an early stage of VaD. We evaluated latencies of the P3 GO and NOGO components of event-related potentials (ERPs), elicited in cued GO/NOGO tasks, as potential neuromarkers of cognitive impairment, as suggested by previous research. Case study: The patient, a right-handed, 53-year-old male with a college education, suffered a transient ischemic attack (TIA) in 2011. During this attack, which lasted for a few minutes, he was confused and had trouble speaking, trouble seeing in both eyes, difficulty walking, problems with balance and coordination, and strange behavior. Seven years later, in 2018, he was assessed using the HBI methodology, which consisted of recording (1) a 19-channel EEG in resting state (with eyes open and eyes closed), and (2) a cued GO/NOGO task, and then comparing the results with EEG spectra and Event-Related Potentials (ERPs) data from normative and patient databases. The patient died in 2019. Post-mortem studies confirmed cortical microhaemorrhages neuropathological criteria for VaD. We did not found deposits of hyperphosphorylated tau (HPT) and A beta, which fulfil the neuropathological criteria for AD. Results: The parietal-temporal-occipital EEG power was significantly higher in all conditions in this subject in comparison to healthy controls, indicating idling of the corresponding areas. The amplitude and latency of the P3 GO wave were found to be intact in the subject, indicating normal posterior cortical functioning in the cognitive task. The latency of the P3 GO wave was found to be significantly higher in the subject, indicating impairment of engagement operations. Conclusions: In a GO/NOGO task, ERPs provide a useful tool for assessment of brain functioning in clinical settings.