WriteClick contributors this week address the issues of certainty and error in scientific publications. In reference to “Pattern of brain tissue loss associated with freezing of gait in PD” by Filippi et al., Dr. Montgomery reiterates the importance of setting forth alternatives when discussing a hypothesis in order to avoid inadvertently providing a false sense of validity. Dr. Walker calls attention to a genetic sequencing error made in a report published by Saiki et al. in 2003 which significantly alters the emphasis of the original publication. The authors acknowledge the error in a letter that will be linked to their original article. Megan Alcauskas, MD, and Robert C. Griggs, MD
We thank Dr. Montgomery1 for his stimulating comments on our article. Our study showed that a specific pattern of brain network damage involving frontal and parietal cortices occurs in patients with Parkinson disease (PD) and freezing of gait (FOG).2 Although voxel-based morphometry may not be sensitive enough to depict damage to subcortical and brainstem nuclei, this finding suggests that impairment of the frontoparietal network may play a role in the development of FOG in PD. Furthermore, we suggested that the occurrence of FOG in patients with PD may be related to cognitive frontal dysfunction. This is based not only on the commonality of frontal lobe pathology between the 2 clinical manifestations but also on the evidence that patients with PD with FOG have frontal executive deficits compared with patients with PD without FOG. In addition, FOG severity correlated with the degree of frontal executive dysfunction. Gait is a complex movement with multiple contributions from many brain regions. Although the mechanisms responsible for FOG are unclear,3 our findings suggest a role for frontoparietal damage and executive dysfunction, yet still unobserved pathologies may be directly responsible for FOG.
Author Response:
The response of Filippi et al. to my Comment accompanying their article2 reiterates the original arguments. Their inferences are appropriate as a hypothesis and may be proven correct, as I previously stated.1 However, their hypothesis has no greater epistemic standing than any number of alternatives which they fail to consider. Failure to genuinely discuss alternatives may further a false sense of validity which is not offset by use of qualifiers such as “may” or “suggests” in their own inferences. They fail to differentiate correlation from cause and effect. Their reasoning is insufficient validation as it relies on the logical fallacy of pseudotransitivity which is of the form: if a implies c and b implies c, then a implies b. This fallacy is repeated throughout their attempted causal explanation from executive dysfunction (a) implying attention or perceptual problems (c) and PD (b) being associated with attention or perceptual problems (c). The fallacy is very seductive because it is such a powerful—and some would argue—necessary route to hypothesis generation but it is not a method of validation. Great confusions are created when the fallacy is taken as validation, as they seemed to have done.
Footnotes
-
Author disclosures are available upon request (journal{at}neurology.org).
References
- Copyright © 2012 by AAN Enterprises, Inc.
Letters: Rapid online correspondence
REQUIREMENTS
If you are uploading a letter concerning an article:
You must have updated your disclosures within six months: http://submit.neurology.org
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.
You May Also be Interested in
Alert Me
Recommended articles
Pattern of brain tissue loss associated with freezing of gait in Parkinson disease
CSF β-amyloid42 and risk of freezing of gait in early Parkinson disease
Increased REM sleep without atonia in Parkinson disease with freezing of gait
Effects of subthalamic nucleus stimulation and levodopa on freezing of gait in Parkinson disease