tES Effects on Associative Memory Performance

University of Bern

Status: Completed

Conditions: Alzheimer Disease; Healthy; Mild Cognitive Impairment

Treatments: Device: sham transcranial electric current stimulation; Device: real transcranial alternating current stimulation; Device: real anodal transcranial direct current stimulation

Study type: Interventional

Funder types: Other

Identifiers

NCT03351452

2017-01197

Details and patient eligibility

About

Previous studies showed that transcranial electric stimulation (tES) applied over the prefrontal cortex improves cognitive performance in healthy elderly adults as well as in patients suffering from mild cognitive impairment or early Alzheimer's disease. Therefore, tES methods might be a useful intervention tool for patients suffering from memory impairment in early terms of the disease.

The present study aims at establishing a connection between the stimulation-induced changes on associative memory performance and its underlying neurophysiological parameters. tES effects and their underlying mechanisms will be compared between healthy elderly controls and clinical study populations receiving either real or sham tES over the left ventrolateral prefrontal cortex during an associative memory task.

Enrollment: 28 patients

Sex: All

Ages: 60 to 85 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Written informed consent
• Non-smokers
• Right-handedness
• Native German speakers or comparable level of fluency
• Normal or corrected-to-normal vision

Exclusion criteria

• Neurological or psychiatric condition (other than diagnosed cognitive impairment)
• Past head injuries
• Magnetizable implants
• History of seizures
• Current or life-time alcohol or drug abuse
• Skin diseases

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

---

28 participants in 3 patient groups

Real tDCS

Experimental group

Description:

20 min of 2 mA real anodal transcranial direct current stimulation applied via 5x7 cm rubber electrode over the VLPFC (current density: 0.057 mA/cm2) and cathodal 10x10 rubber electrode over supraorbital region (current density: 0.02 mA/cm2). Additional ramp-up and ramp-down phase of 15 s at the beginning and the end of stimulation.

Treatment:

Device: real anodal transcranial direct current stimulation

Real tACS

Experimental group

Description:

20 min of 2 mA real transcranial alternating current stimulation in theta frequency applied via 5x7 cm and 10x10 cm rubber electrodes over the VLPFC (current density: 0.057 mA/cm2) and supraorbital region (current density: 0.02 mA/cm2). Additional ramp-up and ramp-down phase of 15 s at the beginning and the end of stimulation.

Treatment:

Device: real transcranial alternating current stimulation

Sham tES

Sham Comparator group

Description:

30 s of 2 mA sham transcranial electric current stimulation applied via 5x7 cm and 10x10 cm rubber electrodes over the VLPFC (current density: 0.057 mA/cm2) and supraorbital region (current density: 0.02 mA/cm2). Additional ramp-up and ramp-down phase at beginning and end of stimulation lasting for 15 s. Electrodes remain attached to the participant's head for the duration of the encoding phase of the memory task.

Treatment:

Device: sham transcranial electric current stimulation