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Completed

NCT Number: NCT04882527

Modulating Prospective Memory in Older Adults With Non-invasive Brain Stimulation

Prospective memory is the ability to remember to carry out intentions with a certain delay (e.g. remember to buy stamps when passing a postal office). Prospective memory tasks require a large degree of self-initiated retrieval and in the absence of a prompt to recall, people must 'remember to remember' by their own volition. Thus, prospective memory is a challenge - especially in old age with increasing health-related prospective memory demands.

Previous studies reported links between neural activity in specific brain regions and prospective memory performance. Yet, the mere occurrence of a change in brain activity in concomitance with performance of a behavioral task is not sufficient to confirm a causal relationship between the two phenomena. Therefore, this study aims to apply non-invasive brain stimulation to facilitate or inhibit activity in different brain regions presumed to be functionally associated with prospective memory. Additional to the prospective memory tasks, the investigators will implement control tasks (i.e., attention) to assess whether stimulation will specifically enhance prospective memory performance or whether other cognitive functions will be modulated additionally.

It is hypothesized that stimulation will lead to changes in prospective memory functioning. Further, the investigators expect that facilitation of attentional processes might be linked to prospective memory improvements.

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Key information

Conditions

Healthy Aging

Age range

60 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Universitätsklinik für Alterspsychiatrie und Psychotherapie

Bern, 3008, Switzerland

About this study

This study aims to modulate neural activity in the left and right inferior frontal lobe as well as in the right superior parietal lobe via high-definition transcranial direct current stimulation (HD-tDCS) in older adults. There is evidence from functional magnetic resonance imaging (fMRI) studies that these areas are involved in prospective memory performance in younger and older adults but a causal relation between activity in these areas and responses in prospective memory tasks has not been established so far.

A double blind, sham-controlled, parallel group design will be applied. Healthy older adults (n=105) will participate in two separate sessions: During the first baseline session, no stimulation is applied. For the second session, participants will then be randomly assigned to one of seven experimental groups (cathodal vs. anodal right inferior frontal lobe (rIFL); cathodal vs. anodal left inferior frontal lobe (lIFL); cathodal vs. anodal right superior parietal lobe (rSPL); or sham). Real stimulation will be applied during 20 minutes with one Milliamp (mA). In case of sham stimulation (i.e., control intervention), the electrode positions and the attachment procedures correspond to those of real tDCS but the electrical current will only be ramped up to one mA and switched off completely after 30 s of stimulation.

The primary objective of this study is the modulation of prospective memory performance in a computer-based task via tDCS. Further, this study aims to clarify the role of attentional control for prospective memory performance, as both processes seem to recruit similar neural structures. Additionally, naturalistic and self-rated prospective memory performance will be assessed.

It is hypothesized that stimulation of the right inferior frontal lobe will lead to changes in prospective memory performance and attentional processes. Whether cathodal or anodal stimulation will enhance performance is not clear yet, since previous fMRI studies were inconsistent about activity changes in older adults. Further, the investigators expect that anodal stimulation of the left inferior frontal cortex may lead to faster responses to prospective memory stimuli, whereas cathodal stimulation of the same area may lead to prolonged reaction times. It is hypothesized that attentional control will not be affected by stimulation of the left inferior frontal lobe. Finally, the investigators expect that anodal stimulation of the right superior parietal cortex will lead to better prospective memory and attentional control performance, whereas cathodal stimulation will have detrimental effects on both functions.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • No cognitive impairments
  • Fluent in German
  • Right-handed
  • Normal or corrected-to-normal vision
  • Non-smokers
  • Written informed consent

Exclusion criteria

  • Current/lifetime severe psychiatric or neurological disorder
  • Metal implants in the head area
  • Psychotropic medication
  • Dermatosis
  • Current/lifetime alcohol abuse
  • Magnetisable implants

Treatment and study plan

Non-invasive brain stimulation

Device

Stimulation will be applied once per subject with one mA for 20 minutes over either the left inferior frontal lobe, the right inferior frontal lobe or the right superior parietal lobe.

Other names: high-definition transcranial direct current stimulation, HD-tDCS, Soterix medical

Sham stimulation

Device

The electrode positions and the attachment procedures correspond to those of real tDCS but the electrical current will only be ramped up to 1 mA and switched off completely after 30 s of stimulation.

Primary outcomes

  1. Prospective memory performance

    Time frame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes

    Assessed with a computer task. Number of correct answers given to prospective memory stimuli.

    Change from baseline to intervention session, difference between intervention groups.

  2. Prospective memory reaction time

    Time frame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes

    Assessed with a computer task. Reaction times of answers given to prospective memory stimuli.

    Change from baseline to intervention session, difference between intervention groups.

  3. Executive controlling functioning

    Time frame: During both sessions (for stimulation session: during intervention), task fixed to 6 minutes

    Assessed with a computer task (ANT - Attentional Network Task). Interference between answers given to congruent and incongruent stimuli.

    Change from baseline to intervention session, difference between intervention groups.

  4. Flexibility performance

    Time frame: During both sessions (for stimulation session: directly after intervention), 3 minutes

    Assessed with a computer task (TAP- Test of Attentional Performance). Number of correct answers.

    Change from baseline to intervention session, difference between intervention groups.

  5. Inhibition errors

    Time frame: During both sessions (for stimulation session: directly after intervention), 2 minutes

    Assessed with a computer task (Test of Attentional Performance). Sum of incorrect responses to no-go stimuli.

    Change from baseline to intervention session, difference between intervention groups.

  6. Divided attention misses

    Time frame: During both sessions (for stimulation session: directly after intervention), 3 minutes 30 seconds

    Assessed with a computer task (TAP - Test of Attentional Performance). Sum of missed target stimuli.

    Change from baseline to intervention session, difference between intervention groups.

  7. Flexibility reaction-time

    Time frame: During both sessions (for stimulation session: directly after intervention), 3 minutes

    Assessed with a computer task (TAP - Test of Attentional Performance). Mean/ median of reactions times of correct responses.

    Change from baseline to intervention session, difference between intervention groups.

  8. Inhibition reaction time

    Time frame: During both sessions (for stimulation session: directly after intervention), 2 minutes

    Assessed with a go/no-go computer task (TAP -Test of Attentional Performance). Mean/ median of reactions times to correct responses.

    Change from baseline to intervention session, difference between intervention groups.

  9. Divided attention reaction time

    Time frame: During both sessions (for stimulation session: directly after stimulation), 3 minutes 30 seconds

    Assessed with a computer-based task (Test of Attentional Performance). Median reaction time of correct answers.

    Change from baseline to intervention session, difference between intervention groups.

Secondary outcomes

  1. Alerting network functioning

    Time frame: During both sessions (for stimulation session: during intervention), task fixed to 6 minutes

    Assessed with a computer task (ANT - Attentional Network Task). Contrasting reaction times of answers given to stimuli with alerting cues to those without alerting cues.

    Change from baseline to intervention session, difference between intervention groups.

  2. Orienting network functioning

    Time frame: During both sessions (for stimulation session: during intervention), task fixed to 6 minutes

    Assessed with a computer task (ANT - Attentional Network Task). Contrasting reaction times of answers given to stimuli with reliable spatial cues to those without spatial cues.

    Change from baseline to intervention session, difference between intervention groups.

  3. Ongoing-task performance

    Time frame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes

    Assessed with a computer task. Number of correctly answered ongoing task stimuli in the course of the prospective memory task.

    Change from baseline to intervention session, difference between intervention groups.

  4. Ongoing-task reaction time

    Time frame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes

    Assessed with a computer task. Mean/median response time of correct ongoing task answers in the course of the prospective memory task.

    Change from baseline to intervention session, difference between intervention groups.

  5. Ongoing-task intra-individual coefficient of variation

    Time frame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes

    Assessed with a computer task. Variability of response times (i.e., within-person fluctuation in response latency) to ongoing task stimuli in the course of the prospective memory task.

    Change from baseline to intervention session, difference between intervention groups.

Other outcomes

  1. Self-rated prospective memory

    Time frame: Only at baseline session, after computer-based tasks, 10 minutes

    Assessed with a questionnaire (PRMQ - Prospective Retrospective Memory Questionnaire).

    Comparison to performance in other tasks.

  2. Self-rated metacognitive prospective memory

    Time frame: Only at stimulation session, after intervention, 10 minutes

    Assessed with a questionnaire (MPMI - Metacognitive Prospective Memory Inventory).

    Comparison to performance in other tasks.

  3. Stimulation Side-Effects

    Time frame: Only at stimulation session, after intervention, 3 minutes

    Self-rating about adverse side effects during and after stimulation are assessed with a questionnaire.

  4. Naturalistic prospective memory

    Time frame: 5 minutes per session; retrieval within five days after each session

    Assessed with a behavioral task. Number of correctly retrieved naturalistic prospective memory intentions.

    Change from baseline to intervention session, difference between intervention groups.

  5. Inhibition intra-individual coefficient of variation

    Time frame: During both sessions (for stimulation session: directly after intervention), 2 minutes

    Assessed with a go/no-go computer task (TAP -Test of Attentional Performance). Variability of response times (i.e., within-person fluctuation in response latency) to go-stimuli.

    Change from baseline to intervention session, difference between intervention groups.

  6. Flexibility intra-individual coefficient of variation

    Time frame: During both sessions (for stimulation session: directly after intervention), 3 minutes

    Assessed with flexibility computer task (TAP -Test of Attentional Performance). Variability of response times (i.e., within-person fluctuation in response latency).

    Change from baseline to intervention session, difference between intervention groups.

  7. Divided attention intra-individual coefficient of variation

    Time frame: During both sessions (for stimulation session: directly after stimulation), 3 minutes 30 seconds

    Assessed with a computer-based task (Test of Attentional Performance). Variability of response times (i.e., within-person fluctuation in response latency).

    Change from baseline to intervention session, difference between intervention groups.

Sponsors and collaborators

Lead sponsor

University of Bern

Other

Registry information

Official study title

Modulating Prospective Memory in Older Adults With Noninvasive Brain Stimulation

Important dates

Study start
2021
Primary completion
2023
Study completion
2023
First posted
May 12, 2021
Registry last updated
Dec 12, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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