Clinical trial NCT04882527: Modulating Prospective Memory in Older Adults With Non-invasive Brain Stimulation
Official title: Modulating Prospective Memory in Older Adults With Noninvasive Brain Stimulation
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Healthy Aging
Lead sponsor: University of Bern
Sponsor class: OTHER
First posted: 2021-05-12
Enrollment: 106
Sex: ALL
Minimum age (years): 60
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: 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.

Detailed description: 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.

Eligibility criteria: 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

Primary outcomes:
measure: Prospective memory performance
timeFrame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes
measure: Prospective memory reaction time
timeFrame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes
measure: Executive controlling functioning
timeFrame: During both sessions (for stimulation session: during intervention), task fixed to 6 minutes
measure: Flexibility performance
timeFrame: During both sessions (for stimulation session: directly after intervention), 3 minutes
measure: Inhibition errors
timeFrame: During both sessions (for stimulation session: directly after intervention), 2 minutes
measure: Divided attention misses
timeFrame: During both sessions (for stimulation session: directly after intervention), 3 minutes 30 seconds
measure: Flexibility reaction-time
timeFrame: During both sessions (for stimulation session: directly after intervention), 3 minutes
measure: Inhibition reaction time
timeFrame: During both sessions (for stimulation session: directly after intervention), 2 minutes
measure: Divided attention reaction time
timeFrame: During both sessions (for stimulation session: directly after stimulation), 3 minutes 30 seconds
Secondary outcomes:
measure: Alerting network functioning
timeFrame: During both sessions (for stimulation session: during intervention), task fixed to 6 minutes
measure: Orienting network functioning
timeFrame: During both sessions (for stimulation session: during intervention), task fixed to 6 minutes
measure: Ongoing-task performance
timeFrame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes
measure: Ongoing-task reaction time
timeFrame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes
measure: Ongoing-task intra-individual coefficient of variation
timeFrame: During both sessions (for stimulation session: during intervention), fixed to 14 minutes
Other outcomes:
measure: Self-rated prospective memory
timeFrame: Only at baseline session, after computer-based tasks, 10 minutes
measure: Self-rated metacognitive prospective memory
timeFrame: Only at stimulation session, after intervention, 10 minutes
measure: Stimulation Side-Effects
timeFrame: Only at stimulation session, after intervention, 3 minutes
measure: Naturalistic prospective memory
timeFrame: 5 minutes per session; retrieval within five days after each session
measure: Inhibition intra-individual coefficient of variation
timeFrame: During both sessions (for stimulation session: directly after intervention), 2 minutes
measure: Flexibility intra-individual coefficient of variation
timeFrame: During both sessions (for stimulation session: directly after intervention), 3 minutes
measure: Divided attention intra-individual coefficient of variation
timeFrame: During both sessions (for stimulation session: directly after stimulation), 3 minutes 30 seconds
Locations:
city: Bern
country: Switzerland
facility: Universitätsklinik für Alterspsychiatrie und Psychotherapie
Study officials:
affiliation: University of Bern
name: Stefan Klöppel, Prof. Dr.
role: PRINCIPAL_INVESTIGATOR
affiliation: University of Bern
name: Jessica Peter, PD Dr.
role: STUDY_CHAIR
affiliation: University of Geneva
name: Matthias Kliegel, Prof. Dr.
role: STUDY_CHAIR
affiliation: University of Bern
name: Nadine Schmidt, MSc.
role: STUDY_CHAIR
References: