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Exp Brain Res. 2017 Mar;235(3):949-956. doi: 10.1007/s00221-016-4854-7. Epub 2016 Dec 20.

Electromyographic assessment of paratonia.

Author information

1
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.
2
Institute of Neurology, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132, Genoa, Italy.
3
Department of Radiology, University of Missouri, Columbia, MO, USA.
4
Department of Neurology, University of Missouri, Columbia, MO, USA.
5
Department of Psychological Sciences, University of Missouri, Columbia, MO, USA.
6
The Thompson Center for Neurodevelopmental Disorders, University of Missouri, Columbia, MO, USA.
7
Academic Neurology Unit, A. Fiorini Hospital, Terracina (LT), Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Polo Pontino, Latina, Italy.
8
Neurology Unit, Policlinico Umberto I, Department of Neurology and Psichiatry, Sapienza University of Rome, Rome, Italy.
9
Department of Physiology, Pharmacology and Neuroscience, City University of New York Medical School, New York, NY, USA.

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.

KEYWORDS:

Cognitive impairment; Electromyography; Frontal lobe; Movements; Paratonia; Spasticity

PMID:
27999892
DOI:
10.1007/s00221-016-4854-7
[Indexed for MEDLINE]

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