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Examining a Controversial PPS Publication*

Professor Edward Bollenbach
Marcia Falconer, PhD

Date: Mon, 29 August 2006

Recently a controversial article, "Electrophysiological findings in a cohort of old polio survivors" by Sorenson, Daube and Windebank was published in the Journal of the Peripheral Nervous System, Volume 11, pages 241-246, September 2006. The findings in this article are the subject of heated discussion in the PPS world. Let us examine this article.

A scientific article usually is divided into parts; an abstract, which gives a brief overview of the article; the introduction, where related findings are discussed; the methods, which tell how the work was done; the results, which tell what was found in the study and the discussion in which the results are put into context with previous findings. In this final section the authors can speculate on wider implications of their findings.

The discussion section is often the source of intellectual debate. On occasion this debate can be vigorous, particularly when data from different studies point toward very different conclusions.

Another controversial part of the article is the suggestion by Sorenson that there are two models to explain new muscle weakness in PPS. One is "linear loss" where the loss of neurons (and hence of strength) is a constant decline for everyone as happens in normal aging. The other model is "proportional decline" where the loss is related to the amount of damage from acute polio. In the discussion, the authors say that the proportional model best explains their findings. However the authors also say that neither model closely fits their data! This strongly suggests that neither model is correct. Therefore, the pattern for new muscle weakness is not related to a slow general loss (as is found in everybody with aging) and it is not (solely) related to the amount of original paralysis. There are other rate laws which could describe the way new muscle weakness is appearing. It might have been illustrative if these had been explored. It appears that the model preferred by the authors does not support their hypothesis that muscle weakness (loss) is related to normal aging (the first model).

Sorenson et. al. tell us that "The large degree of variation seen in both models may be a reflection of the underlying variation known to occur with most MUNE techniques available currently." This means that the method used to obtain this data may not be adequate for the job asked of it. In other words, be a bit skeptical about the results.

On a different topic, the authors say that "There was no association between the magnitude of decline in either the summated CMAP amplitude or the summated MUNE and the presence of symptomatic progression." One interpretation of this data is that a decline in the function of the two muscles they tested does not correlate with symptoms of new muscle weakness elsewhere in the body. If there is a significant relationship between the muscles tested and those generally reported as becoming weaker, this should be demonstrated or referenced.

This article is controversial not because of its actual findings, but because of the interpretation of its findings. The authors were poorly served by reviewers whose job was to point out all of the inconsistencies described above. This article has many statements that are not supported by the evidence. Unfortunately the popular press found a critical one and sensationalized it.

Marcia Falconer – PhD in neuronal cell biology from University of Ottawa, Ottawa, Canada. Post-doctoral study in molecular biology at Massachusetts Institute of Technology, Cambridge, Mass. Led virology laboratory with biotechnology applications at the Centre for Food and Animal Research, Agriculture Canada, Ottawa. Also holds MSc in cell biology from Carleton University, Ottawa, Canada and BSc from Simmons College, Boston, Mass. Speaker at many PPS conferences and meetings in Canada, Australia and Britain. Now retired, she researches and writes about post-polio syndrome. Has numerous publications in peer-reviewed journals and on the Web. She is currently writing a book about inflammation and PPS. Contact information:

Edward Bollenbach – Emeritus Professor of Biology. Full Professor of Biology since the age of 39, won first Educational Excellence and Distinguished Service Award in the Connecticut Community College System, Specialized in the Teaching of Microbiology and Chemistry at Northwestern Connecticut Community College for 32 years. Holds an Master of Arts in Biology from the State University of New York at New Paltz, New York. and graduate certificates in Cryptogamic Botany, Origins of Life, and Holistic Health. He currently writes about and researches the post-polio syndrome and has several articles in print and on the Web. Contact information:

Published with permission of the authors.