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Clinical features and outcomes of the flail arm and flail leg and pure lower motor neuron MND variants: a multicentre Italian study
  1. Paride Schito1,
  2. Giulia Ceccardi1,
  3. Andrea Calvo2,
  4. Yuri Matteo Falzone1,3,
  5. Cristina Moglia2,
  6. Christian Lunetta4,
  7. Kalliopi Marinou5,
  8. Nicola Ticozzi6,7,
  9. Carlo Scialo8,
  10. Gianni Sorarù9,
  11. Francesca Trojsi10,
  12. Amelia Conte11,
  13. Rosanna Tortelli12,
  14. Massimo Russo13,
  15. Elisabetta Zucchi14,
  16. Laura Pozzi3,
  17. Teuta Domi3,
  18. Paola Carrera15,
  19. Federica Agosta16,17,
  20. Angelo Quattrini3,
  21. Raffaella Fazio1,
  22. Adriano Chiò2,
  23. Valeria Ada Sansone4,18,
  24. Gabriele Mora5,
  25. Vincenzo Silani6,7,
  26. Paolo Volanti19,
  27. Claudia Caponnetto8,
  28. Giorgia Querin9,
  29. Gioacchino Tedeschi10,
  30. Mario Sabatelli11,20,
  31. Giancarlo Logroscino12,
  32. Sonia Messina21,
  33. Jessica Mandrioli14,22,
  34. Nilo Riva1,3,
  35. Massimo Filippi1,16,17,23
  1. 1Neurology Unit, IRCCS Ospedale San Raffaele, Milano, Italy
  2. 2'Rita Levi Montalcini' Department of Neuroscience, ALS Turin Center, University of Turin, Torino, Italy
  3. 3Experimental Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, IRCCS Ospedale San Raffaele, Milano, Italy
  4. 4NEuroMuscular Omnicentre (NEMO), Serena Onlus Foundation, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
  5. 5Department of Neurological Rehabilitation, ALS Center, Maugeri Clinical Research Institutes IRCCS Milano, Milano, Italy
  6. 6Department of Neurology and Laboratory of Neuroscience, Istituto Auxologico Italiano Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy
  7. 7Department of Pathophysiology and Transplantation 'Dino Ferrari' Center, University of Milan, Milano, Italy
  8. 8AOU San Martino-IST, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genova, Italy
  9. 9Department of Neurosciences, Neuromuscolar Center, Universita degli Studi di Padova, Padova, Italy
  10. 10Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences; MRI Research Center SUN-FISM, University of Campania Luigi Vanvitelli School of Medicine and Surgery, Napoli, Italy
  11. 11NEuroMuscular Omnicentre (NEMO), Serena Onlus Foundation-Pol. A. Gemelli Foundation, University Hospital Agostino Gemelli Department of Geriatrics Neurosciences and Orthopedics, Roma, Italy
  12. 12Department of Clinical Research in Neurology, Università degli Studi di Bari Aldo Moro, Bari, Italy
  13. 13Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
  14. 14Department of Neuroscience, S. Agostino-Estense Hospital, University of Modena and Reggio Emilia, Modena, Italy
  15. 15Division of Genetics and Cell Biology, Unit of Genomics for human disease diagnosis, Laboratory of Clinical Molecular Biology, IRCCS Ospedale San Raffaele, Milano, Italy
  16. 16Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, IRCCS Ospedale San Raffaele, Milano, Italy
  17. 17Vita-Salute San Raffaele University, Milano, Italy
  18. 18Department of Biomedical Sciences for Health, University of Milan, Milano, Italy
  19. 19Neurorehabilitation Unit/ALS Center, Fondazione Salvatore Maugeri, Mistretta, Italy
  20. 20Department of Geriatrics, Neurosciences and Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart Rome Campus, Roma, Italy
  21. 21Department of Clinical and Experimental Medicine, University of Messina Faculty of Medicine and Surgery, Messina, Italy
  22. 22Department of Neuroscience, S. Agostino-Estense Hospital, Azienda Ospedaliero-Universitaria di Modena, Modena, Italy
  23. 23Neurophysiology Unit, IRCCS Ospedale San Raffaele, Milano, Italy
  1. Correspondence to Professor Massimo Filippi, Neuroimaging Research Unit, Institute of Experimental Neurology; Neurology Unit; and Neurophysiology Unit, IRCCS Ospedale San Raffaele, Milano 20132, Lombardia, Italy; filippi.massimo{at}; Dr Nilo Riva, Experimental Neuropathology Unit, Institute of Experimental Neurology; Neurology Unit, IRCCS Ospedale San Raffaele, Milano 20132, Italy; riva.nilo{at}

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Motor neuron disease (MND) is a heterogeneous group of neurodegenerative disorders defined by a progressive upper motor neuron (UMN) and lower motor neuron (LMN) loss in a varying combination, encompassing a heterogeneous clinical spectrum depending on a different body region involvement at onset, extent and rate of motor neuron (MN) loss and disease spread. Amyotrophic lateral sclerosis (ALS) is the most common and severe form of MND, leading to death in approximately 4 years from symptoms onset. To date, the mainstay neuroprotective therapy is riluzole, despite its limited efficacy, while the role of edaravon is still debated. Phenotypic heterogeneity is increasingly recognised within the MND spectrum, ranging from selective UMN or LMN involvement, to classic ALS, when widespread combination of UMN and LMN dysfunction occurs.1 The clinical spectrum of MND has been further detailed with the recognition of flail arm (FA), flail leg (FL) and pure lower motor neuron (PLMN) phenotypes, considered to be restricted MND phenotypes characterised by a predominant or selective LMN disease (LMND), when UMN dysfunction is absent or marginal.1 2 Furthermore, patients with MND can show an extra-motor involvement such as cognitive impairment with the development, in approximately 10%–15% of cases, of frontotemporal dementia.

Few studies have previously focused on these LMN-restricted phenotypes, therefore, the aim of the present study is to retrospectively investigate the differentiating features of FA, FL and PLMN phenotypes in a large Italian MND cohort.

Materials and methods

2648 patients with MND were recruited in 13 Italian ALS referral centres from January 2009 to December 2013 and data collected in a common database, which was cleaned before data analysis. To highlight the distinguishing features of patients with FA, FL and PLMN, the classic and bulbar phenotypes were used as controls. The final dataset consisted of 1944 patients. ALS diagnosis was established in accordance with …

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  • NR and MF are joint senior authors.

  • Twitter @RosannaTortelli

  • Contributors PS and GC: contributed to the design, conceptualisation, review of data collection and interpretation, statistical analysis and writing the first draft. AQ, NR and MF: contributed to the design, conceptualisation, statistical analysis and critical revision of the manuscript. ACalvo, YMF, CM, CL, KM, NT, CS, GS, FT, AConte, RT, MR, EZ, LP, TD, PC, FA, RF, AChio, VAS, GM, VS, PV, CC, GQ, GT, MS, GL, SM, JM contributed to the data collection and interpretation. All authors actively contributed to the writing and reviewing of the article and approved the final version.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The study was performed in accordance with the ethical standards statement. The study was approved by the Ethical Committees of the participating ALS centres.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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