Meditation and Yogic Breathing-driven Modulation of Neurofluid Coupling and Brain Clearance

The glymphatic system is a brain waste-clearance pathway that facilitates the movement of cerebrospinal fluid (CSF) and interstitial fluid and is thought to play an important role in maintaining brain homeostasis. Emerging evidence suggests that respiration, autonomic activity, and changes in cerebral blood flow may influence CSF dynamics and related neurofluid processes. However, the effects of voluntary breathing practices and meditation on these physiological mechanisms in humans remain incompletely understood.

The SPANDHA study will investigate whether structured yogic breathing (Pranayama; specifically Nadi Shuddhi) and/or meditation (Shoonya meditation) are associated with changes in neurofluid dynamics and related physiological measures. The study will use the GLYMPHOMETER, a forehead-mounted multimodal device designed to measure physiological signals associated with neurofluid coupling during naturalistic meditation and breathing practices. The system incorporates multi-wavelength electroencephalography (EEG) and near-infrared spectroscopy (NIRS) to characterize changes in cerebral electrical activity, cerebral hemodynamics, and neurofluid-related dynamics while participants engage in the interventions.

The study will enroll approximately 100 participants, including 50 novice and 50 experienced practitioners. Using a 2-sequence crossover, participants will complete two study visits involving meditation and yogic breathing conditions. The study will evaluate changes in measures of neurofluid dynamics, cerebral compliance, autonomic regulation including heart-rate variability (HRV), and EEG-derived brain states associated with the interventions. Participants will be stratified by experience level (novice/advance) and randomized within each stratum to one of the two intervention sequences.

A subset of participants will undergo additional validation assessments using phase-contrast magnetic resonance imaging (MRI) and blood-based biomarkers. These assessments will be used to examine the relationship between measurements obtained with the GLYMPHOMETER and established measures of CSF and cerebrovascular physiology.

The primary objective of the study is to characterize the acute physiological effects of meditation and yogic breathing on neurofluid dynamics and related brain and autonomic measures. The findings may provide preliminary evidence regarding the feasibility of using voluntary breathing and meditation practices to modulate physiological processes associated with glymphatic function and may inform future studies of non-pharmacological approaches to brain health.

Less than 1 year of consistent meditation practice.

Behavioral: Nadi Shuddhi · Behavioral: Shoonya Meditation

More than 5 years or a minimum of 2500 hours of consistent meditation practice

Behavioral: Nadi Shuddhi · Behavioral: Shoonya Meditation

Nadi Shuddhi is a structured yogic breathing practice involving slow, alternating respiration through the left and right nostrils in a prescribed sequence.

Shoonya meditation is a structured contemplative practice characterized by conscious non-doing, in which participants maintain a relaxed, alert state while minimizing deliberate attentional selection, cognitive elaboration, and engagement with internal or external stimuli.

Time frame: At each study visit while the meditation is being practiced. Expected acquisition window: 20 minutes; Total number of visits: 2

Participants meeting threshold for analyzable device recordings.

Time frame: At each study visit while the meditation is being practiced. Expected acquisition window: 20 minutes; Total number of visits: 2

Changes in GLYMPHOMETER-derived measures of neurofluid coupling, during Shoonya meditation and Nadi Shuddhi breathing.

(Measurement device: Glymphometer; Measure: Neurofluid coupling aka Fluid dynamics in brain)

Time frame: At each study visit while the meditation is being practiced. Expected acquisition window: 20 minutes; Total number of visits: 2

Changes in heart-rate variability (HRV) during Shoonya meditation and Nadi Shuddhi breathing.

Time frame: At each study visit while the meditation is being practiced. Expected acquisition window: 20 minutes; Total number of visits: 2

Changes in predefined very-low-frequency (0.001-0.1 Hz) signal characteristics derived from GLYMPHOMETER medical™ recordings and their relationship to neurofluid-related measures.

Time frame: From date of enrollment until end of both study visits; assessed up to 4 weeks from enrollment.

Comparison of changes in GLYMPHOMETER-derived measures of neurofluid coupling between novice and advanced meditators.

Time frame: Once at Baseline. Estimated acquisition window: 5-8 minutes

We assess for change in Mindfulness levels by using a validated scale for this purpose namely, Mindfulness Attention Awareness Scale (MAAS). The scale measures the individuals' ability for receptive awareness and attention to present. This aids in evaluating any change on the individual's awareness levels after the Inner engineering intervention. We compute the MAAS scores for each participant which is a mean score for 15 item questionnaires and compare the pre \& post intervention results to look for change. Participants are asked to rate on a scale of 1 (Almost Always) to 6 (Almost Never) to assess the frequency of occurrence of each experience. Mean is then computed using items from each of the 15 questions to create a MAAS score, ranging from 0 to 6. Higher MAAS scores indicate better mindfulness state.

Time frame: At each study visit after the meditation practice is completed. Expected acquisition window: 10-15 minutes; Total number of visits: 2

This 30-item measure assesses the subjective depth of meditation across progressively deeper experiential states. Items are typically rated on a 5-point Likert scale and are grouped into five empirically derived domains: hindrances, relaxation, personal-self/concentration, essential/transpersonal qualities, and transpersonal-self/non-duality. Together, these domains capture experiences ranging from obstacles and relaxation during meditation to focused concentration, transpersonal qualities, and experiences of diminished self-boundaries or non-dual awareness.

Time frame: From date of enrollment until end of both study visits; assessed up to 4 weeks from enrollment.

This outcome evaluates the concurrent validity of the portable device against the gold standard. The statistical method will be a correlation analysis (Pearson or Spearman, as appropriate based on data distribution).

• Measurement 1 (Variable A): Neurofluid coupling oscillations measured via the GLYMPHOMETER medical™ device (measured as relative changes in HbO, HbR, HbT, and CSF/H2O proportional signal including interhemispheric correlation coefficient across these neurofluid compartments while gating each of them to very low frequency, respiratory and cardiac frequency bands).
• Measurement 2 (Variable B): Global neurofluid dynamics and CSF flow measured via 3T MRI using fast fMRI and phase-contrast sequences (measured as BOLD-CSF coupling magnitude and CSF stroke volume in mL).
• Assessment: The study will assess the correlation between the magnitude of oscillatory coupling in Measurement 1 with the absolute flow dynamics in Measurement 2 during the designated validation windows.

Time frame: From date of enrollment until end of both study visits; assessed up to 4 weeks from enrollment.

This outcome evaluates the relationship between neurofluid dynamics and blood-based markers of brain clearance. The statistical method will be a correlation analysis (Pearson or Spearman).

• Measurement 1 (Variable A): Neurofluid coupling oscillations measured via the GLYMPHOMETER medical™ device (measured as relative changes in HbO, HbR, HbT, and CSF/H2O proportional signal including interhemispheric correlation coefficient across these neurofluidic compartments while gating each of them to very low frequency, respiratory and cardiac frequency bands).
• Measurement 2 (Variable B): Plasma concentrations of brain-derived proteins/peptides (Aβ40, Aβ42, total/phosphorylated tau, NF-L, GFAP) measured via ultra-sensitive Simoa immunoassay (measured in pg/mL).
• Assessment: The study will assess the correlation between acute GLYMPHOMETER-derived neurofluid changes and plasma biomarker concentrations before and after intervention.

Time frame: At each study visit after the meditation practice is completed. Expected acquisition window: 30 minutes; Total number of visits: 2

Qualitative characterization of participant experiences using one-on-one micro-phenomenological interviews.

Meditation and Yogic Breathing-driven Modulation of Neurofluid Coupling and Brain Clearance