Cognitive FlexibilityNCT06267521
The STRENGTHEN Study
A study testing Healthy Minds Program, Stimulation in Lab and MRI Scanner in people with Cognitive Flexibility and Emotional Regulation, run by University of Wisconsin, Madison at 1 site in United States.
Trial summary
This study uses two different types of interventions including electrical brain stimulation delivered during sleep, and brief, daily meditation training. The investigators are trying to figure out whether these techniques, either alone or in combination with each other, can positively impact the brain networks that… Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Cognitive Flexibility, Emotional Regulation
- What is being tested?
- Healthy Minds Program, Stimulation in Lab and MRI Scanner
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 64 participants
- Where
- 1 siteUnited States
- Study dates
- 6 Mar 2024to 24 Apr 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Medically healthy
- English-speaking (able to provide consent and complete questionnaires)
- Citizen or legal resident
Who cannot join
- Any current or recent history (6 months) of any mental health diagnosis (Examples include major depression, hypomania, psychosis, schizophrenia, and bipolar disorder)
- Any current or recent (past 6 months) history of treatment for mental illness (including anti-depressant/anti anxiety medications, therapy)
- Scoring above Moderate range for Anxiety or Depression - Patient Health Questionnaire-9 (PHQ-9) greater than or equal to 15 or General Anxiety Disorder (GAD7) greater than or equal to 15
- At risk for suicide (PHQ item 9 greater than 0)
- Any current or past history of neurological disorders or acquired neurological disease (e.g. stroke, traumatic brain injury), including intracranial lesions and obstructive sleep apnea
- History of head trauma resulting in prolonged loss of consciousness; or a history of greater than 3 grade I concussions
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- Current history of poorly controlled headaches including intractable or poorly controlled migraines
- Any systemic illness or unstable medical condition that may cause a medical emergency in case of a provoked seizure (cardiac malformation, cardiac dysrhythmia, asthma, etc.)
- History of fainting spells of unknown or undetermined etiology that might constitute seizures
- History of seizures, diagnosis of epilepsy, history of abnormal (epileptiform) electroencephalogram, or family history of treatment resistant epilepsy with the exception of a single seizure of benign etiology (e.g. febrile seizures) in the judgment of a board-certified neurologist
- Possible pregnancy or plan to become pregnant in the next 6 months.
- Any metal in the brain, skull or elsewhere
- Any hair braid, dreadlocks, hair pieces, or extensions which cannot be taken out before the MRI scans and/or sleep stimulation sessions
- Any head coverings or headdress that participant feels uncomfortable removing for the purposes of the MRI scans and/or sleep stimulation sessions
- Any medical devices or implants (i.e. cardiac pacemaker, medication infusion pump, cochlear implant, vagal nerve stimulator) unless otherwise approved by the responsible physician
- Dental implants containing metal (titanium or titanium alloys) surgically implanted post and core
- Substance use disorder within the past six months
- Any medication that may alter seizure threshold i.e., Attention-deficit/hyperactivity disorder (ADHD) stimulants (Adderall, amphetamine); Tricyclic/atypical antidepressants (amitriptyline, doxepine, imipramine, maprotiline, nortriptyline, bupropion); Antipsychotics (chlorpromazine, clozapine), Bronchodilators (theophylline, aminophylline); Antibiotics (fluoroquinolones, imipenem, penicillin, cephalosporins, metronidazole, isoniazid); Antivirals (valacyclovir, ritonavir); Over the Counter (OTC) (diphenhydramine, Benadryl)
- Claustrophobia (a fear of small or closed places)
- Back problems that would prevent lying flat for up to two hours
- Regular night-shift work (second or third shift)
- Do not have access to a smartphone or the internet
- Regular meditation practice and/or prior use of the Healthy Minds Program app
- Cannot visit the lab in-person for 7 consecutive weeks in the next year
- Permanent retainers
- Additional Exclusion Criteria (Phase 2):
- Any current or recent history (6 months) of bipolar disorder, psychosis, schizophrenia. A history of stable depression or anxiety is not exclusionary.
- Mental health treatment (e.g, psychotherapy) is no longer exclusionary, although all the medication exclusions outlined above still apply
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Hybrid Interventions to Optimize Neural Plasticity and Enhance Well-being: Mental Exercise, and Transcranial Electrical Stimulation With Temporal Interference: The STRENGTHEN Study - Phase 1 and 2
This study uses two different types of interventions including electrical brain stimulation delivered during sleep, and brief, daily meditation training. The investigators are trying to figure out whether these techniques, either alone or in combination with each other, can positively impact the brain networks that support our ability to think flexibly and to regulate our emotions. 48 participants will be enrolled into each of 2 phases and can expect to be on study for up to 9 months.
Read the detailed description
The investigators will evaluate the independent and synergistic effect of Cognitive Flexibility (CF)/Emotional Regulation (ER) - targeted meditation and CF/ER-targeted Transcranial Electrical Stimulation with Temporal Interference (TES-TI) during sleep in low-risk participants (n = 48).
After informed consent, all participants will undergo a set of baseline assessments, including self-report measures, behavioral tasks, functional and structural MRI, and a baseline in-laboratory sleep study.
Following these assessments, participants undergo four weeks of the study intervention. The participants will be assigned into one of four groups. Each group consists of 12 participants.
After completing the 4-week intervention, participants will repeat the behavioral, self-report, and imaging assessments given at baseline. Participants will also complete a 7-day ecological momentary assessment (EMA) at baseline, the week after intervention, and at 4-months following intervention. At the 4-month follow-up, participants may complete another round of self-report and behavioral measures.
The Primary Objectives are to:
- Evaluate the effects of the following on CF and ER networks:
- meditation practice alone
- meditation practice and high-dose TES-TI
- meditation practice and low-dose TES-TI
- TES-TI alone
The Secondary Objectives are to:
- Evaluate the differential synergies between Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM) sleep TES-TI intervention and the restoration of CF verses ER circuits
For Phase 2, an additional 48 participants will be recruited and will eliminate TES-TI once per week. All participants will come to the sleep laboratory for 2 nights over the 4 week intervention period.
Planned interim analysis of slow wave activity data from N=20 participants is adequately powered to evaluate whether TES-TI produces the anticipated modulation of deep sleep.
- Conditions
- Cognitive Flexibility, Emotional Regulation
- Being tested
- Healthy Minds Program, Sham Meditation Didactic Material, Sham Stimulation in Lab, Stimulation in Lab, MRI Scanner
- Medical subject headings
- Emotional Regulation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Healthy Minds ProgramOther
Also called Health Minds App
Participants will follow daily instructions from the Healthy Minds Program at home for four weeks, including guided meditation exercises.
Sham Meditation Didactic MaterialOther
Participants will listen to lessons from the Healthy Minds Program at home for four weeks, which will not include any actual meditation exercises.
Sham Stimulation in LabDevice
On two nights each week during the four weeks of the intervention, participants will sleep in the lab and undergo sham TES-TI stimulation for approximately 10 hours per night
Stimulation in LabDevice
Also called TES-TI, Transcranial Electrical Stimulation with Temporal Interference
Participants will sleep in the lab and undergo active TES-TI stimulation for approximately 10 hours per night.
MRI ScannerDevice
Also called 3 Tesla MAGNUS, Microstructure Anatomy Gradient for Neuroimaging with Ultrafast Scanning
Imaging protocol will include: structural T1-weighted and T2-weighted images, resting-state functional MRI, task-based functional MRI, and multi-shell diffusion weighted MRI, total scan time will be approximately 2 hours
| Study group | Role | What they receive |
|---|---|---|
| Group 1: Mediation Only (Phase 1 and Phase 2) | Experimental | * Baseline measures including imaging
* Meditation plus Sham Stimulation 2 nights per week for 4 weeks
* Post Intervention (week 5) measures including imaging
* Follow up measures (week 20) Receives: Other: Healthy Minds Program; Device: Sham Stimulation in Lab; Device: MRI Scanner |
| Group 2: Stimulation Only (Phase 1 and Phase 2) | Experimental | * Baseline measures including imaging
* Sham Meditation plus Stimulation in Lab 2 nights per week for 4 weeks
* Post Intervention (week 5) measures including imaging
* Follow up measures (week 20) Receives: Other: Sham Meditation Didactic Material; Device: Stimulation in Lab; Device: MRI Scanner |
| Group 3: Combined, Low Frequency (Phase 1) | Experimental | * Baseline measures including imaging
* Meditation plus Stimulation in Lab 1 night per week for 4 weeks
* Post Intervention (week 5) measures including imaging
* Follow up measures (week 20) Receives: Other: Healthy Minds Program; Device: Stimulation in Lab; Device: MRI Scanner |
| Group 4: Combined, High Frequency (Phase 1 and Phase 2) | Experimental | * Baseline measures including imaging
* Meditation plus Stimulation in Lab 2 nights per week for 4 weeks
* Post Intervention (week 5) measures including imaging
* Follow up measures (week 20) Receives: Other: Healthy Minds Program; Device: Stimulation in Lab; Device: MRI Scanner |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Patient Health Questionnaire-9 (PHQ-9) Score
The PHQ-9 is a 9-item inventory asking participants to rate from 0 (not at all) to 3 (nearly everyday) the frequency and intensity of depressive symptoms experienced by the respondent over the preceding two-week period. Scores range from 0 to 27 where higher scores indicate poorer patient health. Participants with scores greater than 15 will be excluded from study.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
Change in General Anxiety Disorder (GAD-7) Score
This 7-item inventory measures the severity of generalized anxiety disorder symptoms in individuals by asking participants to rate from 0 (not all at) to 3 (nearly everyday) the frequency and intensity of various anxiety-related symptoms experienced by the participant in the past two weeks. Scores range from 0-21 where higher scores indicate more anxiety. This study will exclude any participants who have a total score of 15 or above.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
Change in Single-item Suicide Question
This single-item suicide question assesses participant's suicidal ideation to respond yes or no to "Since the last time we saw you, did you seriously consider attempting suicide?".
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
Change in Healthy Minds Index (HM Index)
The HM Index is a 17-question, 5-point scale well-being assessment that measures the four pillars of Wellbeing - Awareness, Connection, Insight, and Purpose. Means scores are from 1 to 5 with higher scores indicative of increased wellbeing.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in the Perceived Stress Scale (PSS) Score
This is a 10-item inventory asking participants to rate from 0 (never) to 4 (very often) the frequency with which they have felt various kinds of stress in the last month. Scores range from 0 to 40 with higher score indicative of higher stress.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Emotional Styles Questionnaire (ESQ) Score
This is a 24-item inventory asking participants to rate from 1 (strongly disagree) to 7 (strongly agree). Scores range from 24 - 168, higher scores are indicative of less Healthy Emotionality
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Cognitive Flexibility Inventory (CFI) Score: Alternatives Subscale
The CFI is a 20-item self-report measure to monitor how often individuals engage in cognitive behavioral thought challenging interventions. Participants rate each item from 1 (strongly disagree) to 7 (strongly agree). Scores range from 13 - 91, higher scores are indicative of increased ability to perceive multiple alternative explanations.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Cognitive Flexibility Inventory (CFI) Score: Control Subscale
The CFI is a 20-item self-report measure to monitor how often individuals engage in cognitive behavioral thought challenging interventions. Participants rate each item from 1 (strongly disagree) to 7 (strongly agree). Scores range from 7 - 49, higher scores are indicative of increased ability to perceive difficult situations as controllable.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Difficulties in Emotion Regulation Scale-18 (DERS-18) Score
The DERS-18 is a 18-item self-report measure which assesses various aspects of emotion regulation, including emotional awareness, acceptance of emotional responses, impulse control, and effective goal-directed behavior during emotional experiences using a 5-point scale from 1 (almost never) to 5 (almost always). Higher scores suggest greater problems with emotion regulation.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in PROMIS Sleep Disturbance Score
This validated assessment tool asks participants to rate 8 items that measure sleep-related difficulties using a 5-point Likert scale. Scores range from 8 to 40 with higher scores indicative of more sleep disturbance.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in PTSD Checklist for DSM-5 (PCL-5)
This 20-item self-report questionnaire is a widely used self-report questionnaire which assesses symptoms of post-traumatic stress disorder (PTSD). Participants rate from 0 (not at all) to 4 (extremely) the severity of their symptoms. Scores range from 0 to 80 with higher scores indicative of more severe PTSD symptoms.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in World Health Organization-5 (WHO-5)
This 5-item scale is a global measure of Well-Being, where higher scores reflect greater overall wellbeing (range 0-25).
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Restorative Sleep Questionnaire (RSQ) Score
This validated assessment measuring subjective perceptions of the restorative or inadequate properties of sleep will be given the morning after every sleep lab visit. The questionnaire includes 9 items rated on a 5 point scale given at the time of awakening. Scores range from 0 to100, where higher scores are indicative of better restorative sleep.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4)
Change in Sleep Depth Question (SDQ) Score
Participants will be asked to rate the depth of their prior night's sleep using 5-point Likert-type scale. How deep was your sleep? from 1 (light) to 5 (deep) after every sleep laboratory visit.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4)
Change in Pittsburgh Sleep Quality Index (PSQI) Score
This validated questionnaire evaluates subjective sleep quality. Each of the questionnaire's 19 self-reported items belongs to one of seven subcategories: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Five additional questions rated by the respondent's roommate or bed partner are included for clinical purposes and are not scored. Each component is scored 0 (no difficulty) to 3 (severe difficulty), scores ranging from 0 to 21. Higher scores are indicative of worse sleep quality.
Measured: baseline, post-intervention (week 5)
Change in Suicide Risk Survey
This battery assesses known suicide risk factors. The 13 items ask participants about their sociodemographic characteristics; past experiences with mental health symptoms; thoughts of self-harm, and self-harming actions; psychological traits. Scores range from < 0.39408955691660219 to >= 0.67215170692043313 with higher scores indicative of increased suicidality.
Measured: baseline, post-intervention (week 5)
Change in Brief Suicide Cognitions Scale (B-SCS) Score
This self-report measure assesses the suicide belief system. Using a 5-point likert scale, participants rate 6 items measuring their enduring or identity-based hopelessness rooted in their beliefs about being undesirable, their emotional state as intolerable, and life challenges as insurmountable. Scores range from 6 to 30 where higher scores are indicative of increased suicidality.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Passive and Active Suicidal Ideation Scale (PASIS) Score
This 17-item validated tool assesses participants' passive and active suicidal ideation in the past seven days using a six-point Likert scale, from 0 (Not in the past 7 days) to 5 (several times every day). Higher score reflects greater suicidal ideation.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in NIH Toolbox Loneliness Score
The NIH Toolbox Loneliness consists of 5 self-report items assessing participants' feelings of loneliness and social isolation on a 5-point Likert scale ranging from 1-5 where higher scores indicate increased loneliness.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
Change in Five Facet Mindfulness Questionnaire (FFMQ) Score
The FFMQ is a widely used self-report inventory that assesses mindfulness across five facets: observing, describing, acting with awareness, non-judging of inner experience, and non-reactivity to inner experience. Participants rate their agreement level with 39 items using a 5-point Likert scale. Scores range from 39 to 195 with higher scores indicative of increased mindfulness.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
Change in Drexel Defusion Scale (DDS) Score
This self-report measure evaluates the ability to create a mental separation or distance from one's internal experiences by asking participants to rate 10 items assessing defusion across a spectrum of internal thoughts and emotions on a 6-point scale, ranging from 0-5. Total scores range from 0 to 50 with higher scores indicative of increased defusion.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
Change in PROMIS Meaning and Purpose Score
This is a 37-item inventory asks participants to rate their sense of life with purpose and perceived reasons for living using a 5-point Likert scale. The current study will administer the computer adaptive test (CAT) version of the instrument, in which subsequent item choice of the system will be based on participants' previous responses. Scores range from 37 to 185 with higher scores indicative of higher feelings of meaning and purpose.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
Change in Digital Working Alliance Inventory (D-WAI) Score
The inventory consists of 6 items which measures the quality of the therapeutic alliance between a user and a digital mental health intervention, which is the HMP in this study. Participants rate their experience using the HMP on a 7-point scale, ranging from 1 (strongly disagree) to 7 (strongly agree). Scores range from 6 to 42 where higher scores indicate better user experience with the app.
Measured: post-intervention (week 5), follow-up (week 20)
Change in Perseverative Thinking Questionnaire (PTQ) Score
The PTQ is a self-report instrument assessing repetitive and uncontrolled thinking by asking participants to rate 15 items about the frequency, duration, and perceived uncontrollability of repetitive thoughts on a scale of 0-4. Scores range from 0 to 60. The higher the score, the higher the level of perseverative thinking or repetitive thoughts experienced by the individual.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Experiences Questionnaire's Decentering subscale (EQ-D) Score
This subscale is an 11-item scale of decentering originally developed to assess mechanisms of Mindfulness Based Cognitive Therapy (e.g., "I can separate myself from my thoughts and feelings."). The EQ-D is originally scored on a 5-point Likert scale (1 = never to 5 = all the time) where higher scores indicate increased decentering.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Experience Sampling / Ecological Momentary Assessment
The experience sampling method assesses present moment experience using a short series of questions administered on a smart phone 6 times a day for 7 days. Questions measure current emotional and cognitive state. Score range from 1-5 where higher scores indicate increased emotional state
Measured: 6 times per day for 7 days
Change in Death Implicit Association Test Score
This task involves participants viewing words on a screen. Words are either related to self (e.g., "I"), others (e.g., "They"), life (e.g., "survive") or death (e.g., "die"). Like other Implicit Association Tests, participants are asked to indicate which category each word belongs to. Across the trials, self and other are paired with either life or death. The measure can be scored as an implicit marker of how easily participants associated death with themselves. Scores are greater than 2 or less than 2, with more positive values indicating a stronger association between self and death.
Measured: baseline, post intervention (5 weeks)
Change in Reversal Learning Task Score
This task involves participants viewing and choosing between two abstract visual stimuli (i.e., geometric shapes). After each choice they receive feedback that is either positive (+10) or negative (-10) feedback devoid of monetary value. Stimulus-outcome pairings are reversed over the course of the experiment.
Measured: baseline, post intervention (5 weeks)
Change in Multi-Source Interference Task Score
This task involves viewing a series of numbers and letters. Participants are asked to indicate using a button press which number was different from the other numbers. Scores are reported as percentage correct.
Measured: baseline, post intervention (5 weeks)
Change in Emotional Stroop Score: Reaction Time
This task involves viewing a series of faces and words. Participants are asked to identify the emotional expression of the faces. Percent change in reaction time is reported.
Measured: baseline, post intervention (5 weeks)
Change in Emotional Stroop Score: Percent Correct
This task involves viewing a series of faces and words. Participants are asked to identify the emotional expression of the faces. Percent correct is reported.
Measured: baseline, post intervention (5 weeks)
Change in Meteor Mission Score: Mean Reaction Time
This is a mobile measure of attention, based on the Sustained Attention to Response Task (SART), a validated, standardized laboratory task. This task lasts five minutes and measures attention regulation and sustained attention, as assessed based on reaction time, reaction time variability, and accuracy.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Meteor Mission Score: Coefficient of Variation
This is a mobile measure of attention, based on the Sustained Attention to Response Task (SART), a validated, standardized laboratory task. This task lasts five minutes and measures attention regulation and sustained attention, as assessed based on reaction time, reaction time variability, and accuracy.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Meteor Mission Score: Percent Correct
This is a mobile measure of attention, based on the Sustained Attention to Response Task (SART), a validated, standardized laboratory task. This task lasts five minutes and measures attention regulation and sustained attention, as assessed based on reaction time, reaction time variability, and accuracy.
Measured: baseline, post-intervention (week 5), follow-up (week 20)
Change in Emotional Persistence Task Score
This task involves viewing pictures categorized as neutral, positive, or negative. Participants may be asked to press a button indicating the valence category of the picture. Positive and negative affect ratings will be made on a continuous sliding scale ranging from 0 to 6.
Measured: baseline, post intervention (5 weeks)
Change in Change Your Mind Task Score: Mean Change
This task involves viewing a series of letters and numbers. Participants are asked to determine whether a target letter was a certain letter (e.g., "T"). Participants receive feedback on their choices. The feedback is not always accurate and participants are informed of this. Change range is from 0 to 1.
Measured: baseline, post intervention (5 weeks)
Change in Change Your Mind Task Score: Accuracy
This task involves viewing a series of letters and numbers. Participants are asked to determine whether a target letter was a certain letter (e.g., "T"). Participants receive feedback on their choices. The feedback is not always accurate and participants are informed of this. Accuracy is from 0 to 1.
Measured: baseline, post intervention (5 weeks)
Change in Change Your Mind Task Score: Response Time
This task involves viewing a series of letters and numbers. Participants are asked to determine whether a target letter was a certain letter (e.g., "T"). Participants receive feedback on their choices. The feedback is not always accurate and participants are informed of this. Response time is reported.
Measured: baseline, post intervention (5 weeks)
Psychomotor Vigilance Task (Phase 2 only)
Psychomotor vigilance performance will be measured with the visual psychomotor vigilance task (PVT) a portable, easily usable reaction-time test with a that can yield rapid and reliable assessments of psychomotor vigilance impairment. Participants will take a 3 minute version of the PVT on a tablet or laptop every morning after an in-laboratory sleep visit to assess alertness. Reaction time is reported.
Measured: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4)
Secondary outcomes (2)
Change in Spectral Power Density During Stimulation-Free Sleep
Change in individual participant spectral power density during stimulation free sleep will be measured and reported separately for NREM sleep (in the 1-4 Hz frequency range) and REM sleep (in the approximately 50hz frequency range) at circadian time-matched periods of baseline sleep and time-matched, stimulation free periods on each of the intervention nights.
Measured: baseline and up to 8 nights (4 nights for the low frequency group) over the 4 week intervention period following the baseline assessment
Resting-state fMRI Connectivity Z-Scores
Resting-state fMRI connectivity will be assessed based on the Fisher-Z transformed (FZT) correlation of each seed region with all other voxels in the brain. In order to test for intervention effects, difference maps will be computed and a voxelwise analysis of the difference maps across the whole brain will be used to identify regions that might differ in connectivity between groups over time. A z-score is the number of standard deviations away from the mean.
Measured: baseline, post intervention (5 weeks)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Feb 2024
- Study start6 Mar 2024
- Primary completion24 Apr 2026
- Study completion24 Apr 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Cognitive FlexibilityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- N= 48 into Phase 1, N=48 into Phase 2
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 64 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Wisconsin, Madison
- Sponsor type
- University, hospital or other
- Collaborators
- United States Department of Defense
- Responsible party
- Sponsor
- Investigators
- Richard Davidson, PhD, Principal investigator, University of Wisconsin, MadisonGiulio Tononi, MD, PhD, Principal investigator, University of Wisconsin, Madison
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06267521
- Sponsor's protocol ID
- 2023-1473
- Other IDs
- Protocol Version 2/28/2025, L&S/PSYCHOLOGY/PSYCHOLOGY, A487400, AWD00000302
- Status last verified
- Apr 2026
- First submitted
- 12 Feb 2024
- Last updated
- 29 Apr 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Yes: Data from this study will be kept for an indefinite period. Banked data will be kept in a secure location for use by researchers. The data may be shared with other researchers at the University of Wisconsin-Madison and outside the University. Outside researchers may be at other universities, private companies, or other kinds of organizations. The banked data will be labeled with a code instead of a participant's name. When the data is shared with other investigators for research projects, they will not be able to use the code to figure out which data belongs to a particular subject. The research team will maintain a link between the data and subject identifiable information kept by the study team. This link will not be shared with anyone outside of the study team. Participants will be able to request to have their data removed from the bank by contacting the research team at any time.
Publications
Schaeffer EL, Haber I, Fan Z, Bruno S, Mat B, Alauddin T, Vigueras G, Neumann L, Smith R, Missey F, Williamson A, Achermann P, Beerli S, Capstick M, Neufeld E, Kuster N, Goldman RI, Davidson RJ, Marshall W, Albantakis L, Jones SG, Cirelli C, Boly M, Tononi G. Enhancement of sleep slow wave activity using transcranial electrical stimulation with temporal interference: an interim analysis of the STRENGTHEN study. Commun Med (Lond). 2026 Jul 1. doi: 10.1038/s43856-026-01744-x. Online ahead of print.
PubMed 42386897
Study at a glance
From the registry record, last updated by the sponsor on 29 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Hybrid Interventions to Optimize Neural Plasticity and Enhance Well-being: Mental Exercise, and Transcranial Electrical Stimulation With Temporal Interference: The STRENGTHEN Study - Phase 1 and 2
- ClinicalTrials.gov ID
- NCT06267521
- Acronym / sponsor ID
- 2023-1473
- Conditions
- Cognitive Flexibility, Emotional Regulation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 64 participants (actual)
- Lead sponsor
- University of Wisconsin, MadisonUniversity, hospital or other
- Collaborators
- United States Department of Defense
- Study start
- 6 Mar 2024 (actual)
- Primary completion
- 24 Apr 2026 (actual)
- Study completion
- 24 Apr 2026 (actual)
- First posted
- 20 Feb 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study uses two different types of interventions including electrical brain stimulation delivered during sleep, and brief, daily meditation training. The investigators are trying to figure out whether these techniques, either alone or in combination with each other, can positively impact the brain networks that support our ability to think flexibly and to regulate our emotions. 48 participants will be enrolled into each of 2 phases and can expect to be on study for up to 9 months.
Detailed description
The investigators will evaluate the independent and synergistic effect of Cognitive Flexibility (CF)/Emotional Regulation (ER) - targeted meditation and CF/ER-targeted Transcranial Electrical Stimulation with Temporal Interference (TES-TI) during sleep in low-risk participants (n = 48).
After informed consent, all participants will undergo a set of baseline assessments, including self-report measures, behavioral tasks, functional and structural MRI, and a baseline in-laboratory sleep study.
Following these assessments, participants undergo four weeks of the study intervention. The participants will be assigned into one of four groups. Each group consists of 12 participants.
After completing the 4-week intervention, participants will repeat the behavioral, self-report, and imaging assessments given at baseline. Participants will also complete a 7-day ecological momentary assessment (EMA) at baseline, the week after intervention, and at 4-months following intervention. At the 4-month follow-up, participants may complete another round of self-report and behavioral measures.
The Primary Objectives are to:
- Evaluate the effects of the following on CF and ER networks:
- meditation practice alone
- meditation practice and high-dose TES-TI
- meditation practice and low-dose TES-TI
- TES-TI alone
The Secondary Objectives are to:
- Evaluate the differential synergies between Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM) sleep TES-TI intervention and the restoration of CF verses ER circuits
For Phase 2, an additional 48 participants will be recruited and will eliminate TES-TI once per week. All participants will come to the sleep laboratory for 2 nights over the 4 week intervention period.
Planned interim analysis of slow wave activity data from N=20 participants is adequately powered to evaluate whether TES-TI produces the anticipated modulation of deep sleep.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 4
- Model description
- N= 48 into Phase 1, N=48 into Phase 2
| Arm | Type | Receives |
|---|---|---|
| Group 1: Mediation Only (Phase 1 and Phase 2) | Experimental | Other: Healthy Minds Program, Device: Sham Stimulation in Lab, Device: MRI Scanner* Baseline measures including imaging * Meditation plus Sham Stimulation 2 nights per week for 4 weeks * Post Intervention (week 5) measures including imaging * Follow up measures (week 20) |
| Group 2: Stimulation Only (Phase 1 and Phase 2) | Experimental | Other: Sham Meditation Didactic Material, Device: Stimulation in Lab, Device: MRI Scanner* Baseline measures including imaging * Sham Meditation plus Stimulation in Lab 2 nights per week for 4 weeks * Post Intervention (week 5) measures including imaging * Follow up measures (week 20) |
| Group 3: Combined, Low Frequency (Phase 1) | Experimental | Other: Healthy Minds Program, Device: Stimulation in Lab, Device: MRI Scanner* Baseline measures including imaging * Meditation plus Stimulation in Lab 1 night per week for 4 weeks * Post Intervention (week 5) measures including imaging * Follow up measures (week 20) |
| Group 4: Combined, High Frequency (Phase 1 and Phase 2) | Experimental | Other: Healthy Minds Program, Device: Stimulation in Lab, Device: MRI Scanner* Baseline measures including imaging * Meditation plus Stimulation in Lab 2 nights per week for 4 weeks * Post Intervention (week 5) measures including imaging * Follow up measures (week 20) |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Medically healthy
- English-speaking (able to provide consent and complete questionnaires)
- Citizen or legal resident
Key exclusion criteria (28 listed)
- Any current or recent history (6 months) of any mental health diagnosis (Examples include major depression, hypomania, psychosis, schizophrenia, and bipolar disorder)
- Any current or recent (past 6 months) history of treatment for mental illness (including anti-depressant/anti anxiety medications, therapy)
- Scoring above Moderate range for Anxiety or Depression - Patient Health Questionnaire-9 (PHQ-9) greater than or equal to 15 or General Anxiety Disorder (GAD7) greater than or equal to 15
- At risk for suicide (PHQ item 9 greater than 0)
- Any current or past history of neurological disorders or acquired neurological disease (e.g. stroke, traumatic brain injury), including intracranial lesions and obstructive sleep apnea
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Healthy Minds ProgramAlso: Health Minds AppParticipants will follow daily instructions from the Healthy Minds Program at home for four weeks, including guided meditation exercises. | Other | Group 1: Mediation Only (Phase 1 and Phase 2), Group 3: Combined, Low Frequency (Phase 1), Group 4: Combined, High Frequency (Phase 1 and Phase 2) |
| Sham Meditation Didactic MaterialParticipants will listen to lessons from the Healthy Minds Program at home for four weeks, which will not include any actual meditation exercises. | Other | Group 2: Stimulation Only (Phase 1 and Phase 2) |
| Sham Stimulation in LabOn two nights each week during the four weeks of the intervention, participants will sleep in the lab and undergo sham TES-TI stimulation for approximately 10 hours per night | Device | Group 1: Mediation Only (Phase 1 and Phase 2) |
| Stimulation in LabAlso: TES-TI, Transcranial Electrical Stimulation with Temporal InterferenceParticipants will sleep in the lab and undergo active TES-TI stimulation for approximately 10 hours per night. | Device | Group 2: Stimulation Only (Phase 1 and Phase 2), Group 3: Combined, Low Frequency (Phase 1), Group 4: Combined, High Frequency (Phase 1 and Phase 2) |
| MRI ScannerAlso: 3 Tesla MAGNUS, Microstructure Anatomy Gradient for Neuroimaging with Ultrafast ScanningImaging protocol will include: structural T1-weighted and T2-weighted images, resting-state functional MRI, task-based functional MRI, and multi-shell diffusion weighted MRI, total scan time will be approximately 2 hours | Device | Group 1: Mediation Only (Phase 1 and Phase 2), Group 2: Stimulation Only (Phase 1 and Phase 2), Group 3: Combined, Low Frequency (Phase 1), Group 4: Combined, High Frequency (Phase 1 and Phase 2) |
Primary outcome
Change in Patient Health Questionnaire-9 (PHQ-9) Score
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
The PHQ-9 is a 9-item inventory asking participants to rate from 0 (not at all) to 3 (nearly everyday) the frequency and intensity of depressive symptoms experienced by the respondent over the preceding two-week period. Scores range from 0 to 27 where higher scores indicate poorer patient health. Participants with scores greater than 15 will be excluded from study.
Change in General Anxiety Disorder (GAD-7) Score
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
This 7-item inventory measures the severity of generalized anxiety disorder symptoms in individuals by asking participants to rate from 0 (not all at) to 3 (nearly everyday) the frequency and intensity of various anxiety-related symptoms experienced by the participant in the past two weeks. Scores range from 0-21 where higher scores indicate more anxiety. This study will exclude any participants who have a total score of 15 or above.
Change in Single-item Suicide Question
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
This single-item suicide question assesses participant's suicidal ideation to respond yes or no to "Since the last time we saw you, did you seriously consider attempting suicide?".
Change in Healthy Minds Index (HM Index)
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
The HM Index is a 17-question, 5-point scale well-being assessment that measures the four pillars of Wellbeing - Awareness, Connection, Insight, and Purpose. Means scores are from 1 to 5 with higher scores indicative of increased wellbeing.
Change in the Perceived Stress Scale (PSS) Score
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This is a 10-item inventory asking participants to rate from 0 (never) to 4 (very often) the frequency with which they have felt various kinds of stress in the last month. Scores range from 0 to 40 with higher score indicative of higher stress.
Change in Emotional Styles Questionnaire (ESQ) Score
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This is a 24-item inventory asking participants to rate from 1 (strongly disagree) to 7 (strongly agree). Scores range from 24 - 168, higher scores are indicative of less Healthy Emotionality
Change in Cognitive Flexibility Inventory (CFI) Score: Alternatives Subscale
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
The CFI is a 20-item self-report measure to monitor how often individuals engage in cognitive behavioral thought challenging interventions. Participants rate each item from 1 (strongly disagree) to 7 (strongly agree). Scores range from 13 - 91, higher scores are indicative of increased ability to perceive multiple alternative explanations.
Change in Cognitive Flexibility Inventory (CFI) Score: Control Subscale
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
The CFI is a 20-item self-report measure to monitor how often individuals engage in cognitive behavioral thought challenging interventions. Participants rate each item from 1 (strongly disagree) to 7 (strongly agree). Scores range from 7 - 49, higher scores are indicative of increased ability to perceive difficult situations as controllable.
Change in Difficulties in Emotion Regulation Scale-18 (DERS-18) Score
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
The DERS-18 is a 18-item self-report measure which assesses various aspects of emotion regulation, including emotional awareness, acceptance of emotional responses, impulse control, and effective goal-directed behavior during emotional experiences using a 5-point scale from 1 (almost never) to 5 (almost always). Higher scores suggest greater problems with emotion regulation.
Change in PROMIS Sleep Disturbance Score
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This validated assessment tool asks participants to rate 8 items that measure sleep-related difficulties using a 5-point Likert scale. Scores range from 8 to 40 with higher scores indicative of more sleep disturbance.
Change in PTSD Checklist for DSM-5 (PCL-5)
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This 20-item self-report questionnaire is a widely used self-report questionnaire which assesses symptoms of post-traumatic stress disorder (PTSD). Participants rate from 0 (not at all) to 4 (extremely) the severity of their symptoms. Scores range from 0 to 80 with higher scores indicative of more severe PTSD symptoms.
Change in World Health Organization-5 (WHO-5)
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This 5-item scale is a global measure of Well-Being, where higher scores reflect greater overall wellbeing (range 0-25).
Change in Restorative Sleep Questionnaire (RSQ) Score
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4)
This validated assessment measuring subjective perceptions of the restorative or inadequate properties of sleep will be given the morning after every sleep lab visit. The questionnaire includes 9 items rated on a 5 point scale given at the time of awakening. Scores range from 0 to100, where higher scores are indicative of better restorative sleep.
Change in Sleep Depth Question (SDQ) Score
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4)
Participants will be asked to rate the depth of their prior night's sleep using 5-point Likert-type scale. How deep was your sleep? from 1 (light) to 5 (deep) after every sleep laboratory visit.
Change in Pittsburgh Sleep Quality Index (PSQI) Score
Time frame: baseline, post-intervention (week 5)
This validated questionnaire evaluates subjective sleep quality. Each of the questionnaire's 19 self-reported items belongs to one of seven subcategories: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Five additional questions rated by the respondent's roommate or bed partner are included for clinical purposes and are not scored. Each component is scored 0 (no difficulty) to 3 (severe difficulty), scores ranging from 0 to 21. Higher scores are indicative of worse sleep quality.
Change in Suicide Risk Survey
Time frame: baseline, post-intervention (week 5)
This battery assesses known suicide risk factors. The 13 items ask participants about their sociodemographic characteristics; past experiences with mental health symptoms; thoughts of self-harm, and self-harming actions; psychological traits. Scores range from < 0.39408955691660219 to >= 0.67215170692043313 with higher scores indicative of increased suicidality.
Change in Brief Suicide Cognitions Scale (B-SCS) Score
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This self-report measure assesses the suicide belief system. Using a 5-point likert scale, participants rate 6 items measuring their enduring or identity-based hopelessness rooted in their beliefs about being undesirable, their emotional state as intolerable, and life challenges as insurmountable. Scores range from 6 to 30 where higher scores are indicative of increased suicidality.
Change in Passive and Active Suicidal Ideation Scale (PASIS) Score
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This 17-item validated tool assesses participants' passive and active suicidal ideation in the past seven days using a six-point Likert scale, from 0 (Not in the past 7 days) to 5 (several times every day). Higher score reflects greater suicidal ideation.
Change in NIH Toolbox Loneliness Score
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
The NIH Toolbox Loneliness consists of 5 self-report items assessing participants' feelings of loneliness and social isolation on a 5-point Likert scale ranging from 1-5 where higher scores indicate increased loneliness.
Change in Five Facet Mindfulness Questionnaire (FFMQ) Score
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
The FFMQ is a widely used self-report inventory that assesses mindfulness across five facets: observing, describing, acting with awareness, non-judging of inner experience, and non-reactivity to inner experience. Participants rate their agreement level with 39 items using a 5-point Likert scale. Scores range from 39 to 195 with higher scores indicative of increased mindfulness.
Change in Drexel Defusion Scale (DDS) Score
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
This self-report measure evaluates the ability to create a mental separation or distance from one's internal experiences by asking participants to rate 10 items assessing defusion across a spectrum of internal thoughts and emotions on a 6-point scale, ranging from 0-5. Total scores range from 0 to 50 with higher scores indicative of increased defusion.
Change in PROMIS Meaning and Purpose Score
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)
This is a 37-item inventory asks participants to rate their sense of life with purpose and perceived reasons for living using a 5-point Likert scale. The current study will administer the computer adaptive test (CAT) version of the instrument, in which subsequent item choice of the system will be based on participants' previous responses. Scores range from 37 to 185 with higher scores indicative of higher feelings of meaning and purpose.
Change in Digital Working Alliance Inventory (D-WAI) Score
Time frame: post-intervention (week 5), follow-up (week 20)
The inventory consists of 6 items which measures the quality of the therapeutic alliance between a user and a digital mental health intervention, which is the HMP in this study. Participants rate their experience using the HMP on a 7-point scale, ranging from 1 (strongly disagree) to 7 (strongly agree). Scores range from 6 to 42 where higher scores indicate better user experience with the app.
Change in Perseverative Thinking Questionnaire (PTQ) Score
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
The PTQ is a self-report instrument assessing repetitive and uncontrolled thinking by asking participants to rate 15 items about the frequency, duration, and perceived uncontrollability of repetitive thoughts on a scale of 0-4. Scores range from 0 to 60. The higher the score, the higher the level of perseverative thinking or repetitive thoughts experienced by the individual.
Change in Experiences Questionnaire's Decentering subscale (EQ-D) Score
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This subscale is an 11-item scale of decentering originally developed to assess mechanisms of Mindfulness Based Cognitive Therapy (e.g., "I can separate myself from my thoughts and feelings."). The EQ-D is originally scored on a 5-point Likert scale (1 = never to 5 = all the time) where higher scores indicate increased decentering.
Change in Experience Sampling / Ecological Momentary Assessment
Time frame: 6 times per day for 7 days
The experience sampling method assesses present moment experience using a short series of questions administered on a smart phone 6 times a day for 7 days. Questions measure current emotional and cognitive state. Score range from 1-5 where higher scores indicate increased emotional state
Change in Death Implicit Association Test Score
Time frame: baseline, post intervention (5 weeks)
This task involves participants viewing words on a screen. Words are either related to self (e.g., "I"), others (e.g., "They"), life (e.g., "survive") or death (e.g., "die"). Like other Implicit Association Tests, participants are asked to indicate which category each word belongs to. Across the trials, self and other are paired with either life or death. The measure can be scored as an implicit marker of how easily participants associated death with themselves. Scores are greater than 2 or less than 2, with more positive values indicating a stronger association between self and death.
Change in Reversal Learning Task Score
Time frame: baseline, post intervention (5 weeks)
This task involves participants viewing and choosing between two abstract visual stimuli (i.e., geometric shapes). After each choice they receive feedback that is either positive (+10) or negative (-10) feedback devoid of monetary value. Stimulus-outcome pairings are reversed over the course of the experiment.
Change in Multi-Source Interference Task Score
Time frame: baseline, post intervention (5 weeks)
This task involves viewing a series of numbers and letters. Participants are asked to indicate using a button press which number was different from the other numbers. Scores are reported as percentage correct.
Change in Emotional Stroop Score: Reaction Time
Time frame: baseline, post intervention (5 weeks)
This task involves viewing a series of faces and words. Participants are asked to identify the emotional expression of the faces. Percent change in reaction time is reported.
Change in Emotional Stroop Score: Percent Correct
Time frame: baseline, post intervention (5 weeks)
This task involves viewing a series of faces and words. Participants are asked to identify the emotional expression of the faces. Percent correct is reported.
Change in Meteor Mission Score: Mean Reaction Time
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This is a mobile measure of attention, based on the Sustained Attention to Response Task (SART), a validated, standardized laboratory task. This task lasts five minutes and measures attention regulation and sustained attention, as assessed based on reaction time, reaction time variability, and accuracy.
Change in Meteor Mission Score: Coefficient of Variation
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This is a mobile measure of attention, based on the Sustained Attention to Response Task (SART), a validated, standardized laboratory task. This task lasts five minutes and measures attention regulation and sustained attention, as assessed based on reaction time, reaction time variability, and accuracy.
Change in Meteor Mission Score: Percent Correct
Time frame: baseline, post-intervention (week 5), follow-up (week 20)
This is a mobile measure of attention, based on the Sustained Attention to Response Task (SART), a validated, standardized laboratory task. This task lasts five minutes and measures attention regulation and sustained attention, as assessed based on reaction time, reaction time variability, and accuracy.
Change in Emotional Persistence Task Score
Time frame: baseline, post intervention (5 weeks)
This task involves viewing pictures categorized as neutral, positive, or negative. Participants may be asked to press a button indicating the valence category of the picture. Positive and negative affect ratings will be made on a continuous sliding scale ranging from 0 to 6.
Change in Change Your Mind Task Score: Mean Change
Time frame: baseline, post intervention (5 weeks)
This task involves viewing a series of letters and numbers. Participants are asked to determine whether a target letter was a certain letter (e.g., "T"). Participants receive feedback on their choices. The feedback is not always accurate and participants are informed of this. Change range is from 0 to 1.
Change in Change Your Mind Task Score: Accuracy
Time frame: baseline, post intervention (5 weeks)
This task involves viewing a series of letters and numbers. Participants are asked to determine whether a target letter was a certain letter (e.g., "T"). Participants receive feedback on their choices. The feedback is not always accurate and participants are informed of this. Accuracy is from 0 to 1.
Change in Change Your Mind Task Score: Response Time
Time frame: baseline, post intervention (5 weeks)
This task involves viewing a series of letters and numbers. Participants are asked to determine whether a target letter was a certain letter (e.g., "T"). Participants receive feedback on their choices. The feedback is not always accurate and participants are informed of this. Response time is reported.
Psychomotor Vigilance Task (Phase 2 only)
Time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4)
Psychomotor vigilance performance will be measured with the visual psychomotor vigilance task (PVT) a portable, easily usable reaction-time test with a that can yield rapid and reliable assessments of psychomotor vigilance impairment. Participants will take a 3 minute version of the PVT on a tablet or laptop every morning after an in-laboratory sleep visit to assess alertness. Reaction time is reported.
2 secondary outcomes
Change in Spectral Power Density During Stimulation-Free Sleep
Time frame: baseline and up to 8 nights (4 nights for the low frequency group) over the 4 week intervention period following the baseline assessment
Resting-state fMRI Connectivity Z-Scores
Time frame: baseline, post intervention (5 weeks)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Apr 2026.
- Derived from this study: PubMed 42386897Schaeffer EL, Haber I, Fan Z, Bruno S, Mat B, Alauddin T, Vigueras G, Neumann L, Smith R, Missey F, Williamson A, Achermann P, Beerli S, Capstick M, Neufeld E, Kuster N, Goldman RI, Davidson RJ, Marshall W, Albantakis L, Jones SG, Cirelli C, Boly M, Tononi G. Enhancement of sleep slow wave activity using transcranial electrical stimulation with temporal interference: an interim analysis of the STRENGTHEN study. Commun Med (Lond). 2026 Jul 1. doi: 10.1038/s43856-026-01744-x. Online ahead of print.
- Center for Healthy MindsLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Data from this study will be kept for an indefinite period. Banked data will be kept in a secure location for use by researchers. The data may be shared with other researchers at the University of Wisconsin-Madison and outside the University. Outside researchers may be at other universities, private companies, or other kinds of organizations. The banked data will be labeled with a code instead of a participant's name. When the data is shared with other investigators for research projects, they will not be able to use the code to figure out which data belongs to a particular subject. The research team will maintain a link between the data and subject identifiable information kept by the study team. This link will not be shared with anyone outside of the study team. Participants will be able to request to have their data removed from the bank by contacting the research team at any time.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Richard Davidson, PhD principal investigator
University of Wisconsin, Madison
Giulio Tononi, MD, PhD principal investigator
University of Wisconsin, Madison
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Healthy Minds Program, Stimulation in Lab and MRI Scanner in people with Cognitive Flexibility and Emotional Regulation, run by University of Wisconsin, Madison at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 28 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Patient Health Questionnaire-9 (PHQ-9) Score (time frame: baseline, visit 3 (week 1), visit 4 (week 1), visit 5 (week 2), visit 6 (week 2), visit 7 (week 3), visit 8 (week 3), visit 9 (week 4), visit 10 (week 4), post-intervention (week 5), follow-up (week 20)). The study lists 39 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06267521, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Apr 2026.