Neurophysiological Effects of Meditation Based on Evoked and Event Related Potential Recordings

Table 2

Details of the evoked potential studies.

S. number	Reference	Modality auditory/visual/somatosensory and latency	Type of meditation	Meditation experience, duration	Components altered and brain area	Sample and design
1	Electroencephalogr Clin Neurophysiol. 1978, 45 (5): 671–673 [1]	Auditory; Long latency	Transcendental meditation	18 months to 6 years	No significant change	Single group
2	Intern J Neuroscience. 1980, 10 (2-3): 165–170 [14]	Auditory; Short latency	Transcendental meditation	6 to 9 years	Wave V latency increased in moderate intensity stimuli and wave V latency decreased in high intensity stimuli	Single group
3	Am J Chin Med. 1990, 18 (3-4): 95–103 [15]	Auditory; Short latency, middle latency, and long latency	Qigong meditation which involves the initial “concentrating,” a subsequent “circulating,” and finally the “dispersion” of Qi	1 to 20 years	There was a significant increase in amplitude in wave I-V of BAER, Na and Pa wave of MLR decreased, and P2 wave of LLAER also decreased during meditation	3 groups: BAER, MLAER, and LLAER
4	Am J Chin Med. 1993, 21 (3-4): 243–249 [16]	Visual; Cortical evoked potentials	Qigong meditation in which the practitioner concentrates on the “Dantian”	2.3 years for the experienced group, 1.9 months for the learning group	Peak-to-peak amplitude of N80-P115-N150 and N150-P200-N280 increased in the experienced group	3 groups: practitioner group learning group, and control group
5	Int J Neurosci. 1994; 76 (1-2): 87–93 [18]	Auditory; Middle latency evoked potentials	“OM” meditation in which the participants meditated with effortless absorption in the single-thought state of the object of meditation, that is, “OM.”	10 years	Experienced meditators had significant increase in peak amplitude of Na wave during meditation and significant reduction in Na wave peak amplitude during control session	Two-group study (experienced meditators and nonexperienced)
6	Indian J Med Res. 1993; 98: 237–9 [19]	Auditory; Middle latency evoked potentials	“OM" meditation in which the participants meditated with effortless absorption in the single-thought state of the object of meditation, that is, “OM.”	5–20 years	Experienced meditators had a significant reduction in the peak latency of the Nb wave	Two-group study (experienced meditators and nonexperienced)
7	Appl Psychophysiol Biofeedback. 2000, 25 (1): 1–12 [17]	Auditory; BAEP; MLAEP	Sahaja yoga in which the participants make certain mental assertions by placing the hand on different parts of the body.	Not experienced = 10 (Sahaja yoga group), = 10 (mimicking exercise group), and = 12 (control group)	Significant increase in Na-Pa amplitude of MLR following meditation practice	Randomized controlled study
8	Clin EEG Neurosci. 2009, 40 (3): 190–195 [5]	Auditory; Mid latency	Cyclic meditation in which a series of asanas (postures interspersed with relaxation techniques) are practiced with awareness.	6–48 months	After cyclic meditation there was a significant increase in the peak latency of the Pa wave and of the Nb wave; peak amplitude of the Nb wave also increased	Self as control design
9	Int J Yoga. 2010 3 (2): 37–41 [11]	Auditory; Brainstem auditory-evoked potentials (BAEPs)	“OM” meditation in which the participants meditated with effortless absorption in the single-thought state of the object of meditation, that is, “OM.”	6 months	Wave V peak latency significantly increased in cancalata, ekagrata, and dharana, but no change occurred during the dhyana session	Self as control
10	Clin EEG Neurosci. 2012, 43 (2): 154–60 [12]	Auditory; Mid latency	“OM” meditation participants were instructed to keep their eyes closed and dwell on thoughts of OM, without any effort, particularly on the subtle (rather than physical) attributes and connotations of the syllable.	6–60 months	Significant increase in the peak latencies of Na and Pa waves during meditation and the peak amplitude of Pa wave was significantly decreased during meditation	Self as control design
11	Clin EEG Neurosci. 2014, pii: 1550059414544737 [13]	Auditory; Long Latency	“OM” meditation in which participants were instructed to keep their eyes closed and dwell on thoughts of OM, without any effort, particularly on the subtle (rather than physical) attributes and connotations of the syllable.	6–60 months	Decrease in the peak latency of the P2 wave during and after meditation	Self as control design