Yoga Nidra: Yogic Relaxation for Mental Health, Brain and Immunity

About the study

The project evaluates the feasibility of yoga nidra as an intervention to improve mental health. We want to understand if the study methodology is sound and appropriate to measure neuroinflammation. We want to comprehend if the selected biomarkers and neuroimaging markers are appropriate and acceptable. This study is the groundwork for our larger control study. This future study will investigate the biological mechanisms responsible for mental health improvements after a yoga nidra intervention in depression.

Yoga nidra is a guided relaxation practice. Participants lie down during the experience, which induces a sleep-like state. Studies found yoga nidra effective at reducing perceived stress, insomnia and anxiety. While traditional forms of yoga nidra included a rigid scripted format, recent innovations include script co-creation with the participant. This method allows the participant to control the hypnotic experience and avoid triggering or unpleasant experiences. The recordings are short (between 15 and 30 minutes) and can be done safely at home without a therapist. Currently, there are few non-pharmacological therapies for reducing stress and depression approved for clinical use. This study will set the foundations to bring mind-body therapies, such as yoga, to the table of evidence-based care. No studies have investigated the psychological, neurological and immunological effects of yoga nidra in chronic stress.

This investigation is the first of its kind to use neuroimaging and biological markers and offer one-to-one yoga nidra co-creation sessions. The study will validate the usability of salivary samples to screen participants with higher systemic inflammation. Neuroimaging scans are expensive and require significant time investment from participants. We want to effectively select the right participants to observe if yoga nidra influences neuroinflammation. We will run an exploratory analysis to evaluate yoga nidra's effect on mental health and identify the potential biological mechanisms
responsible for these effects.

What will it involve?

We need strict selection methods since we are looking for a specific subgroup of individuals. If you do not meet the inclusion criteria for this study but would still like to be involved in future studies, you can indicate it in the consent form. We are recruiting healthy participants reporting high-stress levels and showing sub-clinical (not high enough to be a diagnosis) levels of inflammation.

If you choose to participate in the study, we will first confirm your eligibility with an online questionnaire, and then we will ask you to complete three questionnaires online to evaluate your reported stress levels. You must respond to these questionnaires as truthfully as you can. If your questionnaire responses indicate high-stress levels, we will share a consent form to sign. If you reach the questionnaires’ high-stress threshold, you can take a salivary collection to check your physiological stress levels.

We will invite you to Denmark Hill’s Institute of Psychiatry, Psychology and Neuroscience (IoPPN) to collect your saliva. You will share your availability via email, and we will find a good time for you to come in to collect your saliva. Please note that this saliva sample is for screening purposes. You will be invited to participate in the actual study if we find a significant level of inflammation in your saliva sample.

If your salivary sample indicates enough inflammation, you will be invited to participate in the study. You must sign a second consent form to process your neuroimaging and further salivary sampling. When you come to your first data collection session, we will explain the procedures we follow and confirm the eligibility criteria again. You will have the opportunity to ask any questions you have.

All participants will undergo a short EEG data collection session and provide salivary samples. A randomly selected subset of participants will undergo a brain scan session via an MRI.

The first session will last between 1 and one-half and two- and one-half hours (depending if you do the MRI or not) will either take place in the Institute of Psychiatry, Psychology and Neuroscience (IoPPN), De Crespigny Park, Camberwell, or at the Clinical Research Facility of the King’s College Hospital at Denmark Hill. We will collect a new saliva sample to measure additional biomarkers for stress levels.

We will place a cap with EEG electrodes on your head for the EEG. We will apply EEG gel on your head/in your hair. When the electrodes have good conductivity, you will complete a 5-minute resting-state task in which you need to look at a fixation cross in the middle of the screen and rest. Two- and one-half minutes will be with your eyes open and two and-one-half with your eyes closed. Once you have completed the task, you will complete a second task, the heartbeat counting task. You will be given 25/35/45/100 seconds to count how many heartbeats you can feel. Once you have completed this task, we ask you to complete three questionnaires. These should take less than 10 minutes to complete. Upon completion, you will have time to clean your hair. We have shampoo, towels and a hairdryer available. Afterwards, you will receive a kit with 6 vials to collect your saliva on six occasions for one day. We will give you a printout to record the time of the sample collection. The first sample is taken immediately upon waking. No food or fluid should be consumed before the sample. The sampling will be repeated 15 minutes after waking, 30 minutes after waking, 60 minutes after waking, at noon and 8 pm. Samples need to be stored in the fridge after collection. Upon completion, these samples will be returned to us via a pre-paid Royal Mail service. When you collect the samples, you must keep a diary of the exact time and how you felt during the collection (we will give you a handout).

If you are selected to do an additional MRI, you will undergo a 45-minute structural brain scan via an MRI scanner. The scans will happen at the Clinical Research Facility in the King’s College Hospital at Denmark Hill either after or before you do the EEG, which is described above. You should wear comfortable clothes without metallic zippers on your jumper and trousers. We will record structural and functional scans, which will last around 30 minutes in total, but we account for 45 minutes to give time to rest and ask questions before and in between the scans. You must try to stay as still as possible during the scans so that we acquire high-quality structural scans of your brain.

After you have completed the saliva collection at home and we have received it at the lab, you can book a session with your yoga therapist. You will meet your yoga therapist on two occasions. Once for 50 minutes and once for 30 minutes online.

You will be randomly assigned to a yoga nidra or music control group. Running a study with a control population increases the data quality.

Yoga Nidra
In the first session, you will have a 15–20-minute discussion and 30 minutes to experience a yoga nidra. While lying on your back, the therapist will guide you to bring your awareness to different body parts, your breath and visualisation practice. During the conversation, you will specify to the therapist which visualisation you want to do (this could be a specific place in nature or a particular memory). While the therapist guides you through the relaxation, she will record her voice. The recordings can be between 15 and 25 minutes, depending on your preference. We will send you the recording via email. You will play this recording on your own for two to three weeks. You will meet again online with the therapist to discuss how you found the experience, if you liked it or if you’d like to change the visualisation part of the recording. If you’d like to change it, we will discuss what you want to change. The therapist will guide you again and record the new experience. You will be able to use both recordings for the entirety of the study. You should practice at least three times per week for three months.

Music
In the first session, you will have a 15–20-minute discussion and 30 minutes to experience a music-guided relaxation. The therapist will share with you a playlist you can use. She will help you to find a comfortable position to lie in while you listen to relaxing music. You will practice the relaxing pose while listening to the music.
You will receive a follow-up session as in the yoga nidra group. In the follow-up session, you will discuss how you found the practice, and the therapist will respond to any questions you may have.

In either case, you must email us on a Sunday or Monday how many times you have practised that week. You will receive a word document each week to note how you felt before and after each session. You can use keywords or send us a full sentence. Please let us know how many times you have practised. This information will help us improve our intervention.

After three months, you will come for a final time to repeat all the above measurements (EEG and saliva). If you were selected for the MRI before, we ask you to complete the same brain scans again. This collection will help us measure if the intervention impacted your brain, mind and immune system.


Below, you can find a description of each of the questionnaires we ask you to complete on our online data platform:
The eligibility questionnaire will cover the eligibility criteria outlined in the part ‘Why have I been invited to take part?’. Example questions: How old are you? Do you have a pacemaker? With this questionnaire, we want to ensure you meet the inclusion criteria.
The demographic questionnaire will cover additional demographic information. Example questions: What is your gender? Have you ever had a serious illness or any reason to be hospitalised? Do you have any chronic illness?
The Ethnic Group Questionnaire. This questionnaire was requested in the past by the research committee for similar studies.
The Hamilton Depression Rating Scale (HDRS) measures depressive symptoms.
Quick Inventory of Depressive Symptomatology (QIDS) measures depressive symptoms.
Beck Depression Inventory (BDI) measures depressive symptoms.
The Rumination Response Scale (RRS) measures whether you experience rumination.
State-Trait Anxiety Inventory (STAI) measures your current levels of anxiety.
Perceived Stress Scale (PSS) measures your perceived stress levels
Kupfer Detre Scale (KDS) can indicate if you are likely to have a particular depression subgroup

This study is part of Carola Chiarpenello’s PhD, assessing the psychoneuroimmunological mechanisms of yoga nidra in stress and depression.