title: Electromyographic assessment of paratonia.
abstract: Many years after its initial description, paratonia remains a poorly understood concept. It is described as the inability to relax muscles during muscle tone assessment with the subject involuntary facilitating or opposing the examiner. Although related to cognitive impairment and frontal lobe function, the underlying mechanisms have not been clarified. Moreover, criteria to distinguish oppositional paratonia from parkinsonian rigidity or spasticity are not yet available. Paratonia is very frequently encountered in clinical practice and only semi-quantitative rating scales are available. The purpose of this study is to assess the feasibility of a quantitative measure of paratonia using surface electromyography. Paratonia was elicited by performing consecutive metronome-synchronized continuous and discontinuous elbow movements in a group of paratonic patients with cognitive impairment. Goniometric and electromyographic recordings were performed on biceps and triceps brachii muscles. Facilitatory (mitgehen) and oppositional (gegenhalten) paratonia could be recorded on both muscles. After normalization with voluntary maximal contraction, biceps showed higher paratonia than triceps. Facilitatory paratonia was higher than oppositional on the biceps. Movement repetition induced increased paratonic burst amplitude only when flexion and extension movements were performed continuously. Both facilitatory and oppositional paratonia increased with movement repetition. Only oppositional paratonia increased following faster movements. This is the first study providing a quantitative and objective characterization of paratonia using electromyography. Unlike parkinsonian rigidity, oppositional paratonia increases with velocity and with consecutive movement repetition. Like spasticity, oppositional paratonia is velocity-dependent, but different from spasticity, it increases during movement repetition instead of decreasing. A quantitative measure of paratonia could help better understanding its pathophysiology and could be used for research purposes on cognitive impairment.
authors.affiliation: Institute of Neurology, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132, Genoa, Italy. lucio.marinelli@unige.it.
authors.forename: Lucio
authors.identifier: 0000-0003-0620-7654
authors.initials: L
authors.lastname: Marinelli
authors.affiliation: Institute of Neurology, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132, Genoa, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Mori
authors.affiliation: Institute of Neurology, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132, Genoa, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Pardini
authors.affiliation: Department of Radiology, University of Missouri, Columbia, MO, USA.|Department of Neurology, University of Missouri, Columbia, MO, USA.|Department of Psychological Sciences, University of Missouri, Columbia, MO, USA.|The Thompson Center for Neurodevelopmental Disorders, University of Missouri, Columbia, MO, USA.
authors.forename: David
authors.initials: D
authors.lastname: Beversdorf
authors.affiliation: Institute of Neurology, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132, Genoa, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Cocito
authors.affiliation: Academic Neurology Unit, A. Fiorini Hospital, Terracina (LT), Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Polo Pontino, Latina, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Currà
authors.affiliation: Neurology Unit, Policlinico Umberto I, Department of Neurology and Psichiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Fattapposta
authors.affiliation: Department of Physiology, Pharmacology and Neuroscience, City University of New York Medical School, New York, NY, USA.
authors.forename: Maria Felice
authors.initials: MF
authors.lastname: Ghilardi
authors.affiliation: Institute of Neurology, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132, Genoa, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Abbruzzese
authors.affiliation: Institute of Neurology, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132, Genoa, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Trompetto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009483:Neuropsychological Tests
keywords: Cognitive impairment; Electromyography; Frontal lobe; Movements; Paratonia; Spasticity