New Zealand Rhythm Centre - Rhythm and Healing - Research on composite effects of group drumming, page 5
Rhythm Centre :: Rhythm and Healing :: Research and Studies
"Composite effects of group drumming music therapy on modulation of neuroendocrine-immune parameters in normal subjects." - Page 5


Table 1


      Prior to initiating the experimental protocol, 6 groups of normal subjects were studied to determine the drumming approach to be used for the treatment group. Tests of proportions (Figure 1 and Table 1) were used to determine the proportion of subjects whose measured parameters were modulated in the predicted direction. The binomial test was performed to elucidate statistically significant trends of post-pre cortisol, NK cell activity, and DHEA-cortisol changes that occurred in a direction opposite to that expected to be associated with the classic stress response. NK cell activity was calculated as an arithmetic average of the post- minus pre- differences for all NK cell activity and LAK cell activity measures as well as E:T ratios to demonstrate a combined trend. Although all parameters reported in the actual study also were analyzed in the preliminary groups, it was determined that the "composite drumming" intervention was the only protocol that demonstrated NK cell activity enhancement in conjunction with appropriate hormonal responses (Table 1), and would thereby be used as the treatment protocol for the actual study.
      The purpose of this study was to compare the biological effects of a single group-drumming intervention on normal subjects compared with controls. Hypothetical differences between treatment and control groups were tested across 12 biological markers, first globally across all 12 biological

markers with a Hotelling T2 (P<.0005), then individually with independent t tests adjusted for multiple comparisons (Table 2).
      Although measures for affective change (ie, anxiety and depression), volume shifting (ie, hematocrit), and cell demargination (ie, white blood cell count) showed pre-post differences, these changes were in the same direction and magnitude for both the experimental and control groups. This finding suggests that the unique experimental milieu, rather than the treatment per se, affected these results. Therefore, random assignment of subjects to the treatment and control groups was successful in controlling for sampling bias in these areas. In addition, the Sense of Coherence Scale by Antonovsky/25 (measured once at the end of the experiment on each subject) showed no significant difference between the treatment group (mean=158) and control group (mean=150).
      Serum cortisol and, to a lesser extent, DHEA—2 of the 12 designated biological markers—exhibited a similar pattern of reaction to the general milieu (within-groups effect), but not to the treatment (between-groups effect). However, for plasma DHEA there was a notable trend toward a difference between the treatment and control groups (P=.073). The DHEA-to-cortisol ratio showed a significant increase for within-group effects in the experimental subjects (P=.036).
      Six of 10 NK cell assays, when expressed as mean normalized change, were significant for alpha levels adjusted for multiple comparisons (Table 2). Specifically, NK cell activity at E:T ratios of 6:1, 12:1, and IFN-y-stimulated LAK cell activity with associated baselines for E:T ratios of 12:1 and 25:1 were significantly increased in the treatment group compared with the control group (Table 2). The other 4 assays (ie, NK cell activity at E:T ratios of 25:1 and 50:1 and IL-2-stimulated LAK cell activity at E:T ratios of 12:1 and 25:1) showed a similar pattern of normalized change (to a lesser degree of significance) in response to treatment. In fact, each of the 10 NK cell measures with differing E:T ratios increased above the preexperimental level (ie, the mean normalized change >0) in the treatment group; 8 of 10 declined slightly (ie, mean normal-ized change <0) in the control group (Figure 2).
      Comparison of baselines for IFN-y-stimulated LAK cell activi-ty at E:T ratios of 12:1 and 25:1 and for NK cell activity at E:T ratios of 12:1 and 25:1 showed an enhanced sensitivity effect for the 2 baselines due to their extended incubation times. Also, changes in natural killing ability, especially when activated by IFN-y (eg, LAK with IFN-Y at E:T 12:1), were highly significant and clearly associated with the drumming activity. Although enhanced lymphokine activation of NK cell activity was evident in vitro, no significant in vivo changes in plasma cytokine levels were detected. Although it is possible that the time points selected in this study may not have
reflected in vivo cytokine level alterations, it should also be noted that marked variability in measurements of plasma IL-2 and IFN-y may have precluded accurate in vivo assessments.

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