Reply to: “What Is in a Name”

We are grateful for the opportunity to respond to the letter entitled “What is in a name” from Daniel Ciampi de Andrade, Veit Mylius, and Santiago Perez Lloret regarding our recent article.¹ We thank these authors for providing the three steps necessary to identify pain in Parkinson's disease (PD). They are an essential prerequisite for proposing appropriate treatment of pain in PD. As the authors note, our study focused on chronic pain in PD, therefore, fulfilling the first step. The second step was also respected, because we eliminated patients suffering from pain unrelated to PD (called concomitant pain) as defined by the Marques's algorithm.² Finally, in our case, the third step was to classify and diagnose parkinsonian central pain (PCP). We applied our classification² that is very close to that of Mylius et al,³ which was published later. Based on this proposed classification, we used an algorithm aimed at disentangling PCP from other subtypes of chronic pain in PD by specifically and sequentially eliminating what is not PCP. Therefore, by respecting these different steps, we believe we have included mainly PCP patients and not patients suffering from other pain mechanisms.

Before the definition of nociplastic pain, older classifications of pain in PD defined and classified PCP as “central neuropathic pain” and described as boring, constant, ineffable, and diffuse, not limited to a dermatome or specific neural distribution.^{4, 5} We agree with the authors that the term “central neuropathic pain,” which corresponds to a lesion of the central somatosensory system, should no longer be used in PD and must be clearly distinguished from PCP. We confirm that our patients suffered from “central parkinsonian pain,” which fits the definition of nociplastic pain, as previously suggested in our classification.²

Finally, we would like to add a further step in pain identification, which is to determine and validate diagnostic criteria for each type of pain in PD, particularly for PCP, which is often misdiagnosed and probably underestimated because diagnostic criteria are not well defined. Indeed, PCP is diagnosed mainly on the basis of exclusion criteria, whereas we need to identify positive criteria. We would like to emphasize the need to better characterize the different pains in PD, which is a challenge to enable better evaluation of analgesic strategies in PD patients.

C.B.C. has received consultancy fees from Merz, BIAL, NHC, Orkyn; grants from the French Ministry of Health: projet hospitalier de recherche clinique grants; French Ministry of Research: ANR; France Parkinson, Fondation AXA, Everpharma, Elivie, NHC, and Orkyn; honoraria for speeches from Orkyn, Novartis, and AJR; and support for attending meetings and/or travel from Orkyn, AJR, AbbVie, NHC, and Adelia. A.M. has received consultancy fees from AbbVie; grants from the French Ministry of Health: projet hospitalier de recherche clinique grants; honoraria for speeches from AbbVie, Aguettant, and Orkyn; support for attending meetings and/or travel from Merz, Allergan, and Orkyn; and consultancy fees for a scientific advisory board from Aguettant and AbbVie. O.R. has received consultancy fees from Alkahest, Alzprotect, Apopharma, Astrazeneca, BIAL, Biogen, Britannia, Buckwang, Cerevel, Contera, GE Healthcare, Handltherapeutic, Ionis, Jazz, Kyowa, LGD/nuvamid, Lundbeck, Merz, Neuralight, Neuratrix, Neuroderm, ONO pharma, Orion Pharma, Parexel, PD neurotechnology, Polycaps, Roche therapeutics, Sanofi, Scienture, Servier, Sunovion, Supernus, Synagile, Thelonius, Takeda, Teva, Tolls4patients, UCB, and Zambon; honoraria for speeches Bila, Lundbeck, and Merz; support for attending meetings and/or travel from Merz, BIAL, Lundbeck, Neuralight, and Sunovion; and consultancy fees for a scientific advisory board from Alzprotect.

(1) Research project: A. Conception, B. Organization, C. Execution; (2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; (3) Manuscript: A. Writing of the First Draft, B. Review and Critique.

C.B.C.: 3A, 3B

A.M.: 3A, 3B

O.R.: 3A, 3B