Multicenter Study

. 2021 Dec;268(12):4737-4743.

doi: 10.1007/s00415-021-10583-w. Epub 2021 May 7.

Functional motor phenotypes: to lump or to split?

Michele Tinazzi^#¹, Christian Geroin^#², Enrico Marcuzzo³, Sofia Cuoco⁴, Roberto Ceravolo⁵, Sonia Mazzucchi⁵, Andrea Pilotto^{6

7}, Alessandro Padovani⁶, Luigi Michele Romito⁸, Roberto Eleopra⁸, Mario Zappia⁹, Alessandra Nicoletti⁹, Carlo Dallocchio¹⁰, Carla Arbasino¹⁰, Francesco Bono¹¹, Giuseppe Magro¹¹, Benedetta Demartini¹², Orsola Gambini¹², Nicola Modugno¹³, Enrica Olivola¹³, Laura Bonanni¹⁴, Elisabetta Zanolin¹⁵, Alberto Albanese¹⁶, Gina Ferrazzano¹⁷, Rosa De Micco¹⁸, Leonardo Lopiano¹⁹, Giovanna Calandra-Buonaura^{20

21}, Martina Petracca²², Marcello Esposito²³, Antonio Pisani^{24

25}, Paolo Manganotti²⁶, Lucia Tesolin²⁷, Francesco Teatini²⁷, Tommaso Ercoli²⁸, Francesca Morgante^{29

30}, Roberto Erro⁴

Affiliations

¹ Neurology Unit, Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, P.le Scuro 10, 37134, Verona, Italy. michele.tinazzi@univr.it.
² Neurology Unit, Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, P.le Scuro 10, 37134, Verona, Italy. christian.geroin@univr.it.
³ Neurology Unit, Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, P.le Scuro 10, 37134, Verona, Italy.
⁴ Center for Neurodegenerative Diseases (CEMAND), Department of Medicine, Surgery and Dentistry-Scuola Medica Salernitana, University of Salerno, Baronissi, SA, Italy.
⁵ Neurology Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
⁶ Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
⁷ FERB Onlus, Ospedale S. Isidoro, Trescore Balneario, Bergamo, Italy.
⁸ Parkinson and Movement Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
⁹ Department G.F. Ingrassia, Section of Neurosciences, University of Catania, Catania, Italy.
¹⁰ Department of Medical Area, Neurology Unit, ASST Pavia, Pavia, Italy.
¹¹ Botulinum Toxin Center, Neurology Unit A.O.U. Mater Domini, Catanzaro, Italy.
¹² Aldo Ravelli Research Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Milan, Italy.
¹³ IRCCS Neuromed, Pozzilli, Italy.
¹⁴ Department of Neuroscience, Imaging and Clinical Sciences, University G. D'Annunzio, Chieti-Pescara, Italy.
¹⁵ Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
¹⁶ Department of Neurology, IRCCS Humanitas Research Hospital, Rozzano Milan, Italy.
¹⁷ Department of Human Neurosciences, Università La Sapienza, Rome, Italy.
¹⁸ Department of Advanced Medical and Surgery Sciences, University of Campania-Luigi Vanvitelli, Naples, Italy.
¹⁹ Department of Neuroscience-Rita Levi Montalcini, University of Turin, Turin, Italy.
²⁰ Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
²¹ IRCCS, Institute of Neurological Sciences of Bologna, Bologna, Italy.
²² Movement Disorder Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
²³ Clinical Neurophysiology Unit, Cardarelli Hospital, Naples, Italy.
²⁴ IRCCS Mondino Foundation, Pavia, Italy.
²⁵ Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.
²⁶ Clinical Neurology Unit, Department of Medical, Surgical and Health Services, University of Trieste, Trieste, Italy.
²⁷ Functional Movement Disorders Outpt. Clinic, Clinical Neurology and Stroke Unit Department, Central Country Hospital, Bolzano, Italy.
²⁸ Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy.
²⁹ Neurosciences Research Centre, Molecular and Clinical Sciences Neurosciences Research Centre, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK.
³⁰ Department of Experimental and Clinical Medicine, University of Messina, Messina, Italy.

^# Contributed equally.

PMID: 33961091
PMCID: PMC8563631
DOI: 10.1007/s00415-021-10583-w

Multicenter Study

Functional motor phenotypes: to lump or to split?

Michele Tinazzi et al. J Neurol. 2021 Dec.

. 2021 Dec;268(12):4737-4743.

doi: 10.1007/s00415-021-10583-w. Epub 2021 May 7.

Authors

Affiliations

¹ Neurology Unit, Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, P.le Scuro 10, 37134, Verona, Italy. michele.tinazzi@univr.it.
² Neurology Unit, Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, P.le Scuro 10, 37134, Verona, Italy. christian.geroin@univr.it.
³ Neurology Unit, Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, P.le Scuro 10, 37134, Verona, Italy.
⁴ Center for Neurodegenerative Diseases (CEMAND), Department of Medicine, Surgery and Dentistry-Scuola Medica Salernitana, University of Salerno, Baronissi, SA, Italy.
⁵ Neurology Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
⁶ Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
⁷ FERB Onlus, Ospedale S. Isidoro, Trescore Balneario, Bergamo, Italy.
⁸ Parkinson and Movement Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
⁹ Department G.F. Ingrassia, Section of Neurosciences, University of Catania, Catania, Italy.
¹⁰ Department of Medical Area, Neurology Unit, ASST Pavia, Pavia, Italy.
¹¹ Botulinum Toxin Center, Neurology Unit A.O.U. Mater Domini, Catanzaro, Italy.
¹² Aldo Ravelli Research Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Milan, Italy.
¹³ IRCCS Neuromed, Pozzilli, Italy.
¹⁴ Department of Neuroscience, Imaging and Clinical Sciences, University G. D'Annunzio, Chieti-Pescara, Italy.
¹⁵ Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
¹⁶ Department of Neurology, IRCCS Humanitas Research Hospital, Rozzano Milan, Italy.
¹⁷ Department of Human Neurosciences, Università La Sapienza, Rome, Italy.
¹⁸ Department of Advanced Medical and Surgery Sciences, University of Campania-Luigi Vanvitelli, Naples, Italy.
¹⁹ Department of Neuroscience-Rita Levi Montalcini, University of Turin, Turin, Italy.
²⁰ Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
²¹ IRCCS, Institute of Neurological Sciences of Bologna, Bologna, Italy.
²² Movement Disorder Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
²³ Clinical Neurophysiology Unit, Cardarelli Hospital, Naples, Italy.
²⁴ IRCCS Mondino Foundation, Pavia, Italy.
²⁵ Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.
²⁶ Clinical Neurology Unit, Department of Medical, Surgical and Health Services, University of Trieste, Trieste, Italy.
²⁷ Functional Movement Disorders Outpt. Clinic, Clinical Neurology and Stroke Unit Department, Central Country Hospital, Bolzano, Italy.
²⁸ Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy.
²⁹ Neurosciences Research Centre, Molecular and Clinical Sciences Neurosciences Research Centre, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK.
³⁰ Department of Experimental and Clinical Medicine, University of Messina, Messina, Italy.

^# Contributed equally.

PMID: 33961091
PMCID: PMC8563631
DOI: 10.1007/s00415-021-10583-w

Abstract

Introduction: Functional motor disorders (FMDs) are usually categorized according to the predominant phenomenology; however, it is unclear whether this phenotypic classification mirrors the underlying pathophysiologic mechanisms.

Objective: To compare the characteristics of patients with different FMDs phenotypes and without co-morbid neurological disorders, aiming to answer the question of whether they represent different expressions of the same disorder or reflect distinct entities.

Methods: Consecutive outpatients with a clinically definite diagnosis of FMDs were included in the Italian registry of functional motor disorders (IRFMD), a multicenter data collection platform gathering several clinical and demographic variables. To the aim of the current work, data of patients with isolated FMDs were extracted.

Results: A total of 176 patients were included: 58 with weakness, 40 with tremor, 38 with dystonia, 23 with jerks/facial FMDs, and 17 with gait disorders. Patients with tremor and gait disorders were older than the others. Patients with functional weakness had more commonly an acute onset (87.9%) than patients with tremor and gait disorders, a shorter time lag from symptoms onset and FMDs diagnosis (2.9 ± 3.5 years) than patients with dystonia, and had more frequently associated functional sensory symptoms (51.7%) than patients with tremor, dystonia and gait disorders. Patients with dystonia complained more often of associated pain (47.4%) than patients with tremor. No other differences were noted between groups in terms of other variables including associated functional neurological symptoms, psychiatric comorbidities, and predisposing or precipitating factors.

Conclusions: Our data support the evidence of a large overlap between FMD phenotypes.

Keywords: Functional dystonia; Functional neurological disorders; Functional tremor; Functional weakness; Non-motor features; Psychogenic movement disorders.

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Conflict of interest statement

The authors declare that they have no conflict of interest.

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Functional motor phenotypes: to lump or to split?

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Functional motor phenotypes: to lump or to split?

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