Acoustic Stimulation, Sleep, and Cognitive-Emotional Processes in Young Adults With Anxiety and Depression Symptoms

When interested participants are identified through recruitment methods, they will be directed to complete an online screening survey. The aim of this screening is to ensure that participants meet minimal study inclusion/exclusion criteria and to avoid an unnecessary in-person visit to the lab.

Based on the online screening, eligible participants will be contacted by study personnel for scheduling for the in-lab baseline visit. During the baseline visit, informed consent will be obtained. The investigators will also perform additional screening, a hearing test, and an audio recording of the participant singing in preparation for the karaoke task (described below). Finally, participants will be given a wrist actigraphy device and will be sent a daily electronic sleep diary with which to track their sleep at home for approximately 1-week before each overnight session. Participants will be told to maintain a consistent sleep schedule (+/- 1hr around wake and bedtimes) for one week before each overnight. Sleep diary and actigraphy will be used to verify compliance. Participants will also be asked to refrain from alcohol and recreational drug use for 48hrs before each in-lab overnight session and will be asked to refrain from consuming caffeine after Noon on the day of their overnight visits. Participants will also be asked to wear the headband device for one night at home prior to each overnight visit to get acclimated to the feel.

Approximately 1-2 weeks later, participants will return for their first overnight visit. They will be screened for drug/alcohol use through a subjective questionnaire. Prior to sleep, participants will complete a set of tasks and questionnaires assessing mood, sleepiness, cognition, and emotional processing. The primary tasks will include a modified AX-CPT cognitive control task and a karaoke task.

After completing these tasks, participants will be randomized in counterbalanced order to receive acoustic stimulation during sleep (STIM) or a control night with no acoustic stimulation (SHAM). Participants will remain blind to condition. During STIM, participants will wear a headband device (Philips SmartSleep or Dreem 2), which presents sub-arousal tones during slow-wave sleep to boost underlying slow-wave activity. During SHAM, participants will wear the same device, but no tones will be administered. During both nights, participants will also be set up with standard polysomnography to objectively assess sleep and slow-wave activity.

Post-sleep, participants will again complete a set of tasks and questionnaires assessing mood, sleepiness, cognition, and emotional processing. The primary tasks will include a modified AX-CPT task, an International Affective Picture Stimuli (IAPS) task, and the Karaoke task which will be competed in an fMRI scanner.

After a 1-2-week washout period at home, participants will return for their second overnight session to complete the other experimental condition. For at least one week before the second overnight, participants will maintain a consistent sleep schedule (+/- 1hr around wake and bedtimes), verified with wrist actigraphy and sleep diary. Participants will again be asked to refrain from alcohol and recreational drugs use for 48hrs before the overnight session and will be asked to refrain from consuming caffeine after Noon on the day of their overnight visit. Participants will again be asked to wear the headband device at home for one night prior to their overnight visit.

After completing the second overnight session, participants will take a headband device home and wear it each night for approximately 2 weeks. Participants will be asked to maintain a consistent sleep schedule (+/- 1hr around wake and bedtimes). Half of the participants will be randomly assigned to receive tones each night (Stim2) and half will not (Sham2). Participant will be blind to condition. Participants will complete daily assessments of their mood, anxiety/depression symptoms, and sleep quality. After the ~2 weeks at home, participants will return for a final testing visit. Participants will complete assessments of their mood, anxiety/depression symptoms, cognition, and emotional processing.

Below is a description of the primary tasks:

AX-CPT task: participants view cue-probe pairings, displayed as two letters presented one at a time on a computer screen. The first letter is the cue and the second letter is the probe. Participants are instructed to press a button when they encounter the valid cue-probe pairing and a different button for non-valid cue-probe pairings.

IAPS task: participants will be presented with neutral and negative images from the International Affective Picture System. Participants may be asked to rate their affect, valence, and arousal after each image.

Karaoke task: this task is intended to assess emotional processes, particularly self-referential emotions (i.e., shame, embarrassment). During the baseline visit, participants will sing while being audio recorded. Participants may be asked to wear headphones, which will present the song audio, but will mask their own singing, to promote out-of-tune singing. During the overnight visits, participants will listen to audio snips of their own singing and the same song sung by a professional singer. Participants will rate the intensity of different emotions.

Inclusion criteria

• Age 18-25. Equal numbers of men and women will be included.
• Normal hearing.
• Elevated anxiety or depression symptoms. This will be determined using the PROMIS anxiety and PROMIS depression scales. Participants with T-scores ≥ 60 (i.e., ≥ than 1 standard deviation above the mean) on either or both scales will be eligible for participation.
• Elevated sleep disturbance. This will be determined using the PROMIS sleep disturbance scale. Participants with T-scores ≥ 55 on the PROMIS sleep disturbance scale will be eligible for participation.

Exclusion criteria

• Presence of a severe chronic or psychiatric condition including psychosis, bipolar disorder, developmental disorders, or substance use disorder.
• Current use of psychotropic medications or medications affecting sleep/wake function, such as antidepressants, antipsychotic medications, steroids, and stimulants. Rationale: These medications may affect sleep and cognitive-emotional function.
• Substance abuse. Rationale: Substance abuse may affect sleep and cognitive-emotional function.
• Consumption of > 14 standard alcoholic drinks per week. Rationale: excessive alcohol consumption may interfere with sleep and cognitive-emotional function.
• Consumption of > 400mg of caffeine per day, which is roughly equivalent to 3-4 8oz cups of coffee per day.
• Drug or alcohol use < 48 hours before the in-lab overnight sessions. Rationale: Recent drug or alcohol use could affect sleep, cognitive-emotional processes, and poses a safety risk.
• Severe insomnia or sleep apnea symptoms. Insomnia symptoms will be determined using the Insomnia Severity Index. Participants with severe insomnia (i.e., scores > 21) will not be eligible. Sleep apnea symptoms will be determined using the STOP-Bang questionnaire. Participants with scores ≥ 3 will not be eligible. Rationale: Sleep disturbances which result in low sleep efficiency and frequent awakenings during the night may reduce the effectiveness of acoustic stimulation which targets the deepest stage of sleep (i.e., slow-wave sleep).
• Extreme bedtimes (< 10:00pm, > 1:00am) or wake times (< 6:00am, > 10:00am). Rationale: Participants with extreme bed or wake times may have difficulty falling asleep, waking up, or obtaining a sufficient amount of sleep during the in-lab overnight sessions.
• Short (<5hrs) or long (>9hrs) average sleep duration. Rationale: short or long sleepers may have different sleep profiles which could impact the effectiveness of the acoustic stimulation intervention.
• Uncorrected vision problems.
• Claustrophobia. Rationale: MRI safety criteria.
• Metal in body. Rationale: MRI safety criteria.
• Body Mass Index (BMI) > 40. Rationale: MRI safety criteria.
• Pregnancy. Rationale: MRI safety criteria.
• Left handedness. Rationale: Left-handed people may have different lateralization of neural functioning which could affect the fMRI results.
• Formal vocal training and Good/Very Good at singing in tune. Rationale: The purpose of the karaoke task is to induce negative self-referential emotions via out-of-tune singing.
• Does not own a smartphone or tablet. Rationale: Participants may need to download an app (SleepMapper or Alfin) to download their sleep data from the headband device when wearing it at home.
• Inability or unwillingness to complete study procedures.
• Hairstyles that prevent access to the scalp (e.g., weave). Rationale: Polysomnography for the in-lab overnights cannot be applied with hairstyles which prevent access to the scalp to apply electrodes.