YOGA BREATHING THROUGH A PARTICULAR NOSTRIL INCREASES SPATIAL MEMORY SCORES WITHOUT LATERALIZED EFFECTS1
K. V. Naveen, R. Nagarathna, H. R. Nagendra and Shirley Telles*
Vivekananda Kendra Yoga Research Foundation,
9, Appajappa Agrahara, 1st Main, Chamarajpet, Bangalore - 560 018
(Accepted July 17, 1997.)
Summary- Uninostril breathing facilitates the performance on spatial and verbal cognitive tasks, said to be right and left brain functions, respectively. Since hemispheric memory functions are also known to be lateralized, the present study assessed the effects of uninostril breathing on the performance in verbal and spiritual memory tests. School children (N= 108 whose ages ranged from 10 to 17 years) were randomly assigned to four groups. Each group practised a specific yoga breathing technique: (i) right nostril breathing, (ii) left nostril breathing, (iii) alternate nostril breathing, or (iv) breath awareness without manipulation of nostrils. These techniques were practised for 10 days. Verbal and spatial memory was assessed initially and after 10 days. An age-matched control group of 27 were similarly assessed. All 4 trained groups showed a significant increase in spatial test scores at retest, but the control group showed no change. Average increase in spatial memory scores for the trained groups was 84%. It appears yoga breathing increases spatial rather than verbal scores, without a lateralized effect.
The nasal cycle is an ultradian rhythm characterized by alternating patency of the left and right nostrils with a periodicity of 1 to 8 hours (Keuning, 1968). Some reports suggested a connection between the phases of the nasal cycle and the cerebral hemisphere which is dominant, mediated through a neural reflex (Werntz, Bickford, Bloom, & Shannahoff-Khalsa, 1983).
This was based on studies using the electroencephalogram (EEG). Forced unilateral nostril breaching modified EEG activity over the two hemispheres, with a greater amplitude on the side contralateral to the patent nostril. This was also believed to influence performance on specific tasks (Beubel, 1977; Klein, Pilon, Prossner, & Shannahoff-Khalsa, 1986; Jella & Shannahoff-Khalsa, 1993). In the report by Klein, et al (1986) adult volunteers tended to exhibit right-nostril dominance during normal breathing, to perform better on simple perceptual tasks with verbal information and known to be carried out by the left hemisphere, compared with subjects whose left nostril was dominant. Similarly during the left nostril-dominant phase subjects performed better on simple perceptual tasks using spatial information inferred to activate the right hemisphere. Both verbal and spatial tasks involved deciding whether stimulus pairs were same or different. For the verbal tasks stimuli were pairs of upper and lower case letters, while for the spatial task the stimuli were pairs of random seven dot patterns. There was no significant effect of forced uninostril breathing on performance of these tasks. In contrast, a subsequent study of undergraduate students whose group average age was 20.7 yr. (Jella & Shannahoff-Khalsa, 1993) showed that forced left-nostril breathing increased spatial performance on a cognitive task. This paper and pencil task tested mental rotation, manipulation and twisting of two-and three- dimensional stimulus objects; however, it did not validate that forced right-nostril breathing increased verbal performance on a task modeled after the Miller Analogies and SAT tests. Perhaps the difference in results obtained with normal breathing and with forced uninostril breathing may be related to forced uninostril breathing using an uncomfortable nose plug.
There are specific yoga breathing practices (pranayamas) which involve breathing selectively through a particular nostril. These techniques can be practiced effortlessly for prolonged periods and allow the effects of unilateral nostril breathing to be studied. The effects of three pranayama practices (which involve left nostril, right nostril, and alternate nostril breathing) on autonomic functions and metabolism have been reported to be similar to the effects of forced uninostril breathing (Shannahoff-Khalsa, 1991; Telles, Nagarathna, & Nagendra, 1994). The present study was carried out to assess whether practicing these three pranayama practices, i.e., left, right, or alternate nostril breathing pranayamas, or breath awareness four times a day for ten days would alter the performance of school children on verbal and spatial memory tests, compared to those of a control group who did no specific practice.