NCT05710549

Understanding Brain Mechanisms Involved in Autobiographical Memory

Understanding Brain Mechanisms Involved in Autobiographical Memory Using High-density Electroencephalography and Transcranial Alternating Current Stimulation

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 120 (estimated)
• Sponsor: Lucie Bréchet · Academic / Other
• Sex: All
• Age: 18 Years – 85 Years
• Healthy volunteers: Accepted

Summary

The overall objective of this project is to characterize the spatiotemporal dynamics of brain oscillations underpinning autobiographical memory (ABM) and the modulation of the memory network using non-invasive brain stimulation.

Detailed description

Accumulating evidence suggests that activity in distributed networks supporting ABM is altered even decades before the expected onset of clinical symptoms in Alzheimer's disease (AD). Robust network alterations associated with age-related memory and cognitive decline have been linked to abnormal oscillatory brain rhythmic activity and functional dysconnectivity. However, the detailed neural mechanisms are still poorly understood. The investigators propose to precisely characterize the underlying neurophysiological mechanisms that lead to behavioral and cognitive disturbances in ABM of MCI patients. Specifically, hdEEG will be used to characterize the sources and spatiotemporal dynamics of the neuronal activity involved in the ABM network of 40 mild cognitive impairment (MCI) patients and compare it to 40 age-matched, older healthy participants and 40 healthy young participants. The investigators will then apply non-invasive brain stimulation in the form of transcranial alternating current stimulation (tACS) to gain novel insights into the causal role of brain oscillations in the ABM network of MCI patients.

Conditions

• Mild Cognitive Impairment
• Alzheimer Disease
• Memory Loss

Interventions

Type	Name	Description
DEVICE	high-density electroencephalography (hdEEG)	EEG will be recorded with a 257-channel EEG system (Geodesic Sensor Net, MegStim). An EEG net is applied at once on the head with evenly spaced sensors that provide full scalp coverage, including the cheek, Ag/Ag-Cl electrodes that are interconnected by thin rubber bands and contain small sponges soaked with saline water that touches the participant's scalp surface directly. Net application takes about 10 min to derive impedances to \<30 kOhms. EEG is recorded with 1 kHz and band-pass filtered between 0.1-200 Hz. Vertex electrode Cz is used as an acquisition reference.
DEVICE	Transcranial alternating current stimulation (tACS)	tACS will be delivered by a battery-driven current stimulator Starstim SS32 (Neuroelectrics) through surface Ag/AgCl electrodes placed into holes of a neoprene cap corresponding to the international 10/20 EEG system. Gel (Parker Lab, Inc.) will be applied to optimize signal conductivity and lower impedance.

Timeline

• Start date: 2022-04-25
• Primary completion: 2027-05-01
• Completion: 2027-08-01
• First posted: 2023-02-02
• Last updated: 2025-07-15

Locations

1 site across 1 country: Switzerland