protocolSection identificationModule nctId: NCT06284720, orgStudyIdInfo id: Project number 144, briefTitle: Transcranial Alternating Current Stimulation for the Improvement of Episodic Memory in Healthy Older Adults, statusModule overallStatus: NOT_YET_RECRUITING, startDateStruct date: 2024-03-01, primaryCompletionDateStruct date: 2024-10-31, completionDateStruct date: 2024-10-31, studyFirstPostDateStruct date: 2024-02-29, lastUpdatePostDateStruct date: 2024-03-12, sponsorCollaboratorsModule leadSponsor name: Universidade Católica Portuguesa, class: OTHER, collaborators name: Clínica NeuroVida (Portugal), descriptionModule briefSummary: Memory complaints are a common symptom among Subjective Cognitive Decline, Mild Cognitive Impairment and Alzheimer disease. Indeed, episodic memory and Alzheimer disease are highly sensitive to aging. Many brain areas become active when we remember an event from the past. The precuneus, part of the posterior system of default mode network, has been identified as a central node of episodic memory retrieval and a central node in various psychiatric and neurological disorders, such as Alzheimer disease. Age-related changes have been consistently found in the default mode network connectivity, occurring within its posterior areas and with the reduction of connectivity between anterior and posterior subnetwork. It has also been found that aging is associated with decreased functional connectivity in the precuneus and posterior cingulate of the default mode network. Furthermore, γ-Aminobutyric acid (GABA), which plays an essential role in regulating brain activity and modulating the default mode network, shows a decrease throughout the normal course of aging, in Mild Cognitive Impairment and Alzheimer disease. It was also verified a link between cognitive decline and the dysfunction of the inhibitory activity of GABAergic interneurons, particularly parvalbumin-positive interneurons, that play a role in control local circuitry, brain networks and memory processing. Parvalbumin interneurons are the fast-spiking interneurons that generate and maintain gamma frequency. Gamma band has been associated with the encoding and retrieval of episodic memory. Impairments of gamma oscillations have been observed in healthy aging, Mild Cognitive Impairment and Alzheimer disease.By identifying these functional connectivity changes, non-invasive neuromodulation techniques may offer a new strategy for improving cognitive functions. Transcranial Alternating Current Stimulation (tACS) is a form of non-invasive brain stimulation that modulates cortical activity by applying weak, oscillating electrical currents to the cortex via two or more scalp electrodes. By using alternating currents, it is possible to simulate the rhythmic pattern of electrophysiological activity of the brain. tACS can interact with neural firing at behaviorally relevant frequencies linked to memory.In this randomized, double-blind, sham-controlled, cross-over study, the investigators will evaluate whether stimulation with gamma tACS on the precuneus can improve episodic memory in healthy older adults., conditionsModule conditions: Healthy Older Adults, designModule studyType: INTERVENTIONAL, phases: NA, designInfo allocation: RANDOMIZED, interventionModel: CROSSOVER, primaryPurpose: PREVENTION, maskingInfo masking: QUADRUPLE, whoMasked: PARTICIPANT, whoMasked: CARE_PROVIDER, whoMasked: INVESTIGATOR, whoMasked: OUTCOMES_ASSESSOR, enrollmentInfo count: 16, type: ESTIMATED, armsInterventionsModule interventions name: Gamma tACS (40 Hz) over the precuneus, interventions name: Sham tACS over the precuneus, outcomesModule primaryOutcomes measure: Changes in immediate and delayed free recall Auditory Verbal Learning Test scores, primaryOutcomes measure: Changes in immediate free recall and delayed recognition Face-Name Memory Test scores, secondaryOutcomes measure: Change in functional connectivity, eligibilityModule sex: ALL, minimumAge: 65 Years, stdAges: OLDER_ADULT, contactsLocationsModule locations facility: Filipa Ribeiro, city: Lisbon, country: Portugal, contacts name: Filipa Ribeiro, PhD, role: CONTACT, phone: +351 217214147, email: filipa.nc.ribeiro@ucp.pt, contacts name: Joana Macedo, MSc, role: PRINCIPAL_INVESTIGATOR, contacts name: Filipa Ribeiro, PhD, role: PRINCIPAL_INVESTIGATOR, geoPoint lat: 38.71667, lon: -9.13333, hasResults: False