رد: إطلالة على التوحد (موضوع متجدد)
was not significant, thereby seriously calling into question whether HBOT produced a meaningful treatment effect.
Recently
Rossignol et al. (2009) published a double-blind placebo-controlled trial of HBOT. The study compared a group
that received 40 sessions of 24% oxygen at 1.3 atm to a group that received regular room air at 1.03 atm (control group). In an
unusual statistical methodology, only within-group changes were contrasted and the authors found a greater degree of what
they described as significant improvement within the treatment group. However, when data are analyzed for differences
between the treatment and placebo groups, very few are found. Specifically, the difference between groups on the Aberrant
Behavior Checklist (ABC; Aman & Singh, 1994), for total scores and subscales, are not statistically significant. The authors
point out that the change from pre- to post-scores for the treatment group on the ABC total score was significant, and the
control group was not, however the mean change within the treatment group was 8.8 points whereas the control group
changed by 7.8 points, with standard deviations ranging from 17.3 to 28.7 points on these measures. A difference of one point
between groups appears unlikely to be clinically significant. Analyses of the other described significant effects reveal similar
findings. In particular, when the level of significance is corrected for alpha inflation, none of the numerous contrasts appear
significant. Essentially, both groups improved as a function of participating in the study but the difference between groups
that received 40 sessions of 24% oxygen at 1.3 atm to a group that received regular room air at 1.03 atm (control group). In an
unusual statistical methodology, only within-group changes were contrasted and the authors found a greater degree of what
they described as significant improvement within the treatment group. However, when data are analyzed for differences
between the treatment and placebo groups, very few are found. Specifically, the difference between groups on the Aberrant
Behavior Checklist (ABC; Aman & Singh, 1994), for total scores and subscales, are not statistically significant. The authors
point out that the change from pre- to post-scores for the treatment group on the ABC total score was significant, and the
control group was not, however the mean change within the treatment group was 8.8 points whereas the control group
changed by 7.8 points, with standard deviations ranging from 17.3 to 28.7 points on these measures. A difference of one point
between groups appears unlikely to be clinically significant. Analyses of the other described significant effects reveal similar
findings. In particular, when the level of significance is corrected for alpha inflation, none of the numerous contrasts appear
significant. Essentially, both groups improved as a function of participating in the study but the difference between groups
was not significant, thereby seriously calling into question whether HBOT produced a meaningful treatment effect.
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