Meditation, EEG and Brain Waves: What Is Known

EEG (electroencephalography) records tiny electrical signals from the scalp. Researchers sort the signals into "waves" by speed: delta, theta, alpha, beta and gamma. Articles about meditation often say it "increases alpha waves" or produces "gamma". This page looks at what the reviews actually found. It is information only and does not diagnose or treat anything.

What EEG can and cannot measure

EEG is good at timing: it shows changes within fractions of a second. It is poor at pinpointing which brain structure a signal comes from. fMRI is better at location but slower. Both describe what the brain is doing during an activity, which is different from whether the activity helps your health.

What the reviews found

Mindfulness meditation. A systematic review covered 56 papers and 1,715 participants (1,358 healthy people and 357 with psychiatric diagnoses). [1] Studies reported increases, decreases and no differences in EEG oscillations compared with rest and various tasks. [1] The most common finding was greater alpha and theta power compared with an eyes-closed resting state, though not uniformly reported. [1] No consistent pattern appeared for beta, delta or gamma. [1] The authors suggested the combination of alpha and theta may signify a state of relaxed alertness, which is their interpretation and not a proven mechanism. [1]

Earlier overview. A 2006 review of EEG, event-related potential and imaging studies reported an overall slowing of EEG activity after meditation, with theta and alpha activity related to proficiency of practice, and noted that state and trait effects were variable. [2]

Across styles. A more recent review concluded that oscillatory EEG studies are not conclusive, likely because meditation styles and practitioners are so varied. [3] It also said meditation classification types remain varied and largely subjective. [3]

1. Mindfulness increases alpha and theta power

   Mixed

   Most common finding versus eyes-closed rest, not uniform [1]

2. Meditation raises gamma waves

   Insufficient evidence

   No consistent pattern for gamma in mindfulness EEG studies [1]

3. EEG patterns show how deep or good your meditation is

   Insufficient evidence

   Not established; results vary with style and practitioner [3]

4. Brain-wave changes explain benefit for symptoms

   Insufficient evidence

   Mechanisms remain unclear [4]

Why results vary

• Different practices. "Meditation" includes focused attention, open monitoring, mantra and compassion practices. fMRI work found that these show distinct activation patterns. [5]
• Different comparison states. Compared with an eyes-closed rest, almost any calm activity might change the signal. This is a reasoning point: the review only reports comparisons with rest and tasks. [1]
• Different people. The reviewed studies mixed healthy people and people with psychiatric diagnoses, [1] and the practitioners studied are heterogeneous. [3]

Brain-wave devices and apps

Consumer headbands and apps that show your "calm score" or "brain-wave state" are covered in meditation tracking and apps. The reviews above studied research-grade recordings; they do not show that a consumer reading predicts whether you are benefiting. Proper evidence not found: the reviews cited here do not cover the accuracy of consumer scores.

How to use this information

If you meditate, you do not need to chase a particular brain-wave pattern. The reviews above describe averages across groups, not a target for any one person, and they do not link a specific wave to a specific benefit. If a product or teacher promises a brain-wave "state" as a health outcome, treat it as a marketing claim unless it points to trials of symptoms, not just recordings.

Bottom line

EEG studies find measurable signal differences during meditation, and alpha and theta changes are the most reported. But the findings are inconsistent, and there is no brain-wave pattern you need to achieve. Judge practice by how you feel and function, and read does meditation work? for symptom evidence. For imaging beyond EEG, see meditation and the brain and default mode network and amygdala claims.