Effects of Individualized Theta-tACS on a Working Memory Training at SCD

NCT ID: NCT06501755

Last Updated: 2024-07-15

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Clinical Phase

NA

Total Enrollment

36 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-07-19

Study Completion Date

2025-07-31

Brief Summary

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The aim of the study is to investigate the effects and mechanisms of action of an individualized transcranial alternating current stimulation in the theta-range (ITF-tACS) on a three day spatial working memory training in healthy older adults with subjective cognitive decline (SCD).

Detailed Description

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This study uses a randomized, double-blind, two-armed, sham-controlled between-subjects design. It is conducted at the University Hospital for Psychiatry and Psychotherapy Tübingen, Germany. Participants older than 60 years and with subjective cognitive decline (SCD) will be included. Other inclusion and exclusion criteria are displayed under "Eligibility". Participants are recruited via email-newsletters at the University of Tübingen, flyers and newspaper advertisement. Participants will receive financial compensation. A stratified block randomization is applied after the inclusion of the participants and before the baseline-session. The person generating the randomization list is not involved with data collection. Operators do not have access to the randomization list during the data collection.

Sample size is N = 36 with n = 18 participants in each group. As a phase 2 study, the aim of this study is the determination of effect sizes which can be used for further investigations. Thus due to a lack of comparable studies, no power analysis could be conducted. The group size is therefore based on the most frequently found group size (n = 18) observed in a systematic review regarding the effects of tACS targeting the memory in healthy adults.

The study includes seven time points: screening-session, baseline-session (in the end of the first week of data-collection), three training sessions (within the second week of data-collection, each session two days apart), post-session (10-12 days after the baseline-session; in the beginning of the third week of data-collection) and follow-up session (one month after the post-session). Online tACS is applied during the training sessions while the participants will conduct an adaptive spatial n-back task (online stimulation). Resting-state EEG as well as EEGs during the spatial 2-, 3-, 4-back at the baseline- and the post-session are conducted. Two groups are compared: one group with individualized theta-tACS (ITF-tACS) and one with sham-tACS.

Hypothesis H1 contains the effect on the trained task (spatial 2-, 3-, 4-back) at the post-session. The investigators expect a higher performance in the group with ITF-tACS compared to sham-tACS. To test this hypothesis, two ANCOVAs (dependent variable = performance at post-session (Reaction time and d prime, Covariate = performance at baseline-session) will be conducted.

Hypothesis H2.1 contains the effect on the trained task in the training sessions concurrent to the tACS. The investigators expect a higher performance in the group with ITF-tACS compared to sham-tACS in all sessions. To test the hypothesis, a linear mixed model will be conducted.

Hypothesis H2.2 contains the long-term effect on the trained task at the follow-up session. The investigators expect a higher performance in the group with ITF-tACS compared to sham-tACS. To test the hypothesis, two ANCOVAs will be conducted.

Hypothesis H2.3 contains the transfer effects on the verbal working memory (digit span task) at the post-session. The investigators expect a higher performance in the group with ITF-tACS compared to sham-tACS. To test the hypothesis, three ANCOVAs will be conducted.

Hypothesis H2.4 contains the effect of the training on the subjective cognitive decline (10-point Likert-scale) at the post-session. The investigators expect a lower scoring in the group with ITF-tACS compared to sham-tACS. To test the hypothesis, an ANCOVA will be conducted.

Hypothesis H2.5 contains the effect of neurophysiological measures of the spatial working memory (EEG). The investigators expect a higher theta-power and fronto-parietal connectivity in the group with ITF-tACS compared to sham-tACS.

Exploratively measures for the accuracy in the trained task, transfer effect at follow-up session for the transfer task, subjective cognitive decline (subjective cognitive decline questionnaire), quality of live (WHO-5), side effects and for sleep (Karolinska sleepiness scale, Insomnia Severity Index) are evaluated.

For all analyses the alpha level for significance is set to p \< 0.05. Because reaction times \< 150 ms are regarded as unintended and \> mean reaction time + 3 SD per participant are regarded as additionally including different processes than only working memory, reaction times \< 150 ms and \> mean reaction time + 3 SD per participant per session are excluded from the analyses. Participants who did not complete the post-session or will miss \> 1/3 of the training sessions are excluded from analyses. We test model assumptions in all analyses and control for multiple testing in the primary analyses. An interim analysis is conducted in 09/2024.

The study will provide important implications for the usage of multi-session ITF-tACS in the context of healthy aging.

Conditions

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Subjective Cognitive Decline

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

DOUBLE

Participants Investigators

Study Groups

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Sham tACS

Intensity: 2 mA (peak-to-peak), localisation: F4/P4, phase-shift between the electrodes: 0°,duration: 20s at the begin and the end of the task (adaptive spatial n-back) with additionally each time 15 s fade-in and fade-out, frequency: 6Hz.

Group Type SHAM_COMPARATOR

transcranial alternating current stimulation (tACS)

Intervention Type DEVICE

Transcrainal alternating current stimulation (tACS) is a non-invasive brain-stimulation where weak sinusoidal electric current with frequencies within the EEG-range is applied over electrodes on the scalp. In the study we use the DC-Stimulator MC, neuroConn, Ilmenau for the stimulation.The device is authorized as medical device for the application on humans in Germany with a CE-Identification. We use two circular (area each = ca. 7.07 cm\^2) and two ring-shaped (area each = 40 cm\^2) rubber electrodes. Impedances are kept \< 15 kOhm.

Individualized Theta-Frequency tACS

Intensity: 2 mA (peak-to-peak), localisation: F4/P4, phase-shift between the electrodes: 0°, duration: 27 min with 15 s fade-in and fade-out, frequency: peak theta-frequency at the baseline measurement during the execution of the spatial 2-, 3-, and 4-back.

Group Type EXPERIMENTAL

transcranial alternating current stimulation (tACS)

Intervention Type DEVICE

Transcrainal alternating current stimulation (tACS) is a non-invasive brain-stimulation where weak sinusoidal electric current with frequencies within the EEG-range is applied over electrodes on the scalp. In the study we use the DC-Stimulator MC, neuroConn, Ilmenau for the stimulation.The device is authorized as medical device for the application on humans in Germany with a CE-Identification. We use two circular (area each = ca. 7.07 cm\^2) and two ring-shaped (area each = 40 cm\^2) rubber electrodes. Impedances are kept \< 15 kOhm.

Interventions

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transcranial alternating current stimulation (tACS)

Transcrainal alternating current stimulation (tACS) is a non-invasive brain-stimulation where weak sinusoidal electric current with frequencies within the EEG-range is applied over electrodes on the scalp. In the study we use the DC-Stimulator MC, neuroConn, Ilmenau for the stimulation.The device is authorized as medical device for the application on humans in Germany with a CE-Identification. We use two circular (area each = ca. 7.07 cm\^2) and two ring-shaped (area each = 40 cm\^2) rubber electrodes. Impedances are kept \< 15 kOhm.

Intervention Type DEVICE

Eligibility Criteria

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Inclusion Criteria

* age \>/= 60 years
* subjective cognitive decline with a duration \> 6 month and without a concrete cause
* right-handedness (score \> 48 in the Edinburgh Handedness Inventory (EHI; Oldfield, 1971))
* corrected or sufficient eyesight
* sufficient knowledge in German
* ability to consent

Exclusion Criteria

* neuropsychiatric diagnose
* score \> 13 in the DemTect (Kalbe et al., 2019)
* score \> 4 in the Geriatric Depression Scale Short Form (GDS-SF; Sheikh \& Yesavage, 1986)
* score \> 16 Geriatric Anxiety Scale German version(GAS-G; Gottschling et al., 2016)
* substance abuse or dependence
* epileptic seizure in medical history
* metall in skalp-area
* pacemaker
* gravidity
* psychiatric medication
* benzodiazepines in a dosage \> 1 mg Lorazepam
* participation in a tACS in history
Minimum Eligible Age

60 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University Hospital Tuebingen

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Prof. Dr. Christian Plewnia

Role: PRINCIPAL_INVESTIGATOR

Universitätsklinik für Psychiatrie und Psychotherapie Tübingen, Tübingen, DE

Locations

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Universitätsklinik für Psychiatrie und Psychotherapie Tübingen, Neurophysiologie & Interventionelle Neuropsychiatrie, Tübingen, DE

Tübingen, Baden-Wurttemberg, Germany

Site Status

Countries

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Germany

Central Contacts

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M.Sc. Selina Galefskii

Role: CONTACT

004917655188703

Dr. Tobias Schwippel

Role: CONTACT

004917684090293

References

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Akerstedt T, Gillberg M. Subjective and objective sleepiness in the active individual. Int J Neurosci. 1990 May;52(1-2):29-37. doi: 10.3109/00207459008994241.

Reference Type BACKGROUND
PMID: 2265922 (View on PubMed)

Gottschling, J, Segal, D. L., Häusele C., Spinath, F. M., & Stoll, G. Assessment of Anxiety in Older Adults: Translation and Psychometric Evaluation of the German Version of the Geriatric Anxiety Scale (GAS). Journal of Psychopathology and Behavior Assessment. 2016; 38: 136-148. doi: 10.1007/s10862-015-9504-z

Reference Type BACKGROUND

Kalbe, E., Calabrese, P., & Kessler, J. (2019). DemTect® Zur Unterstützung der Demenz-Diagnostik (1. Auflage.). Hogrefe.

Reference Type BACKGROUND

Morin, C.M. (1993). Insomnia: Psychological assessment and management. Guilford Press.

Reference Type BACKGROUND

Rami L, Mollica MA, Garcia-Sanchez C, Saldana J, Sanchez B, Sala I, Valls-Pedret C, Castellvi M, Olives J, Molinuevo JL. The Subjective Cognitive Decline Questionnaire (SCD-Q): a validation study. J Alzheimers Dis. 2014;41(2):453-66. doi: 10.3233/JAD-132027.

Reference Type BACKGROUND
PMID: 24625794 (View on PubMed)

Sheikh, R.L. & Yesavage, J.A. Geriatric Depression Scale (GDS). Clinical Gerontologist. 1986; 5: 165-173.

Reference Type BACKGROUND

Topp CW, Ostergaard SD, Sondergaard S, Bech P. The WHO-5 Well-Being Index: a systematic review of the literature. Psychother Psychosom. 2015;84(3):167-76. doi: 10.1159/000376585. Epub 2015 Mar 28.

Reference Type BACKGROUND
PMID: 25831962 (View on PubMed)

Booth SJ, Taylor JR, Brown LJE, Pobric G. The effects of transcranial alternating current stimulation on memory performance in healthy adults: A systematic review. Cortex. 2022 Feb;147:112-139. doi: 10.1016/j.cortex.2021.12.001. Epub 2021 Dec 24.

Reference Type BACKGROUND
PMID: 35032750 (View on PubMed)

Other Identifiers

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tACOSenior

Identifier Type: -

Identifier Source: org_study_id

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