Effect of long-term meditation on cognitive status and selected neurophysiological parameters

Abstract

Meditation is a self-entrainment of the mind impacting overall health. We evaluated the effect of long-term meditation on the cognitive status and selected neurophysiological parameters.Thirty experienced long-term meditators (LTM) and thirty matched meditation naïve controls (MNC) were selected. A validated Sinhala-version of the repeatable battery for the assessment of neuropsychological status (RBANS) was used to assess the cognitive status. EEG with 10-20 system was recorded for 20 min. EEG frequencies were analysed from six regions. Latencies of N75, P100, N145 were measured on visual evoked potentials (VEP) while median and tibial nerve conduction velocities and amplitudes were recorded via nerve conduction study (NCS).Sum of index scores of cognitive domains were higher among LTM (mean age 42.8; SD = 4.4 years) than MNC (mean age 42.6; SD = 4.4 years): immediate memory, LTM = 106.7 ± 12.4SD, MNC = 81.3 ± 17.9SD (p < 0.001); visuospatial, LTM = 116.2 ± 8.9SD, MNC = 78.3 ± 14.7SD (p < 0.001); language, LTM = 117 ± 9.35SD, MNC = 104 ± 8.5SD (p < 0.001); attention, LTM = 119.8 ± 16.8SD, MNC = 97.2 ± 17.2SD (p < 0.001); delayed memory, LTM = 112.5 ± 10.6SD, MNC = 81.5 ± 13.7SD (p < 0.001).In EEG, significantly higher alpha activity was observed among LTM (mean rank 36.8) at rest in right temporal region compared to MNC (mean rank 24.2) (p = 0.005). During meditation bilateral frontopolar region had most significant changes with LTM having predominant higher frequency wave activity compared to MNC.LTM had significantly higher conduction velocity (LTM 41.9 m/s, MNC 33.8 m/s, p < 0.001) and amplitude (LTM 6.7 mV, MNC 5.6 mV, p = 0.007) in tibial nerve NCS and significantly shorter latencies on VEP for all deflections.Long-term meditation enhances cognitive domains and produces significant changes in EEG frequencies, VEP and NCS.