Effort‐Related Behaviors in Charcot's Lectures on Hysteria

We thank Drs. Ganos, Pareés, and Bhatia for the timely historical perspective offered apropos our article on effort‐related behaviors, which help increase by 13‐fold the certainty for a diagnosis of functional (psychogenic) movement disorder (FMD).1, 2 Their overview of Charcot's interest in spontaneous and contraption‐elicited “huffing and puffing” behaviors nicely illustrates two important points that were not, or at best tangentially, discussed in our article: (1) Effort‐related behaviors have to be interpreted within the context of other neurological features (mild, but nevertheless deliberate, effort can also be observed in organic disorders); and (2) certain functional phenotypes, such as upper‐limb functional dystonia, may not yield excessive huffing and puffing (partly explaining the low sensitivity of this sign). Furthermore, effort‐related behaviors may be present differentially among the various FMDs, although this will require further studies.

We fully agree with the spirit of the letter, namely, that effort‐related behaviors, though helpful, should not be relied upon in isolation to guide a diagnosis of FMD. They can only be added to a list of other incongruent and inconsistent signs before one can properly reach a clinically definite category of diagnostic certainty.

Author Roles

(A): Drafting/revising the manuscript for content, including medical writing for content. (B): Acquisition of data. (C): Study supervision or coordination.

H.N.L., A.J.E.: A, B, C

Disclosures

Funding Sources and Conflicts of Interest: The authors report no sources of funding and no conflicts of interest.