Changes in cerebral activity after decreased upper-limb hypertonus: an EMG-fMRI study

Manganotti, Paolo; Acler, Michele; Formaggio, Emanuela; Avesani, Mirko; Milanese, Franco; Baraldo, Andrea; Storti, Silvia Francesca; Gasparini, Anna; Cerini, Roberto; Mucelli, Roberto Pozzi; Fiaschi, Antonio

doi:10.1016/j.mri.2009.12.023

« Previous Next »Magnetic Resonance Imaging
Volume 28, Issue 5 , Pages 646-652, June 2010

Changes in cerebral activity after decreased upper-limb hypertonus: an EMG-fMRI study

Paolo Manganotti
- Department of Neurological and Visual Sciences, Section of Rehabilitative Neurology, University of Verona, Clinic Hospital “Gianbattista Rossi”, P.zz.le LA Scuro, 37100 Verona, Italy
- IRCCS, Instituto di Ricovero e Cura a carattere Scientifico, S. Camillo Hospital, Venice, Italy
- Corresponding author. Sezione Neurologia Riabilitativa, Dipartimento di Scienze Neurologiche e della Visione, Universita' di Verona Policlinico “Gianbattista Rossi”, P.zz.le LA Scuro, 37100 Verona, Italy. Tel.: +39 045 8124768; fax: +39 045 8104472.
Michele Acler
- Department of Neurological and Visual Sciences, Section of Rehabilitative Neurology, University of Verona, Clinic Hospital “Gianbattista Rossi”, P.zz.le LA Scuro, 37100 Verona, Italy
Emanuela Formaggio
- Department of Neurological and Visual Sciences, Section of Rehabilitative Neurology, University of Verona, Clinic Hospital “Gianbattista Rossi”, P.zz.le LA Scuro, 37100 Verona, Italy
Mirko Avesani
- Department of Neurological and Visual Sciences, Section of Rehabilitative Neurology, University of Verona, Clinic Hospital “Gianbattista Rossi”, P.zz.le LA Scuro, 37100 Verona, Italy
Franco Milanese
- Department of Neurological and Visual Sciences, Section of Rehabilitative Neurology, University of Verona, Clinic Hospital “Gianbattista Rossi”, P.zz.le LA Scuro, 37100 Verona, Italy
Andrea Baraldo
- Department of Morphological and Biomedical Sciences, Institute of Radiology, University of Verona, 37100 Verona, Italy
Silvia Francesca Storti
- Department of Neurological and Visual Sciences, Section of Rehabilitative Neurology, University of Verona, Clinic Hospital “Gianbattista Rossi”, P.zz.le LA Scuro, 37100 Verona, Italy
Anna Gasparini
- Department of Morphological and Biomedical Sciences, Institute of Radiology, University of Verona, 37100 Verona, Italy
Roberto Cerini
- Department of Morphological and Biomedical Sciences, Institute of Radiology, University of Verona, 37100 Verona, Italy
Roberto Pozzi Mucelli
- Department of Morphological and Biomedical Sciences, Institute of Radiology, University of Verona, 37100 Verona, Italy
Antonio Fiaschi
- Department of Neurological and Visual Sciences, Section of Rehabilitative Neurology, University of Verona, Clinic Hospital “Gianbattista Rossi”, P.zz.le LA Scuro, 37100 Verona, Italy

Received 23 September 2009; accepted 9 December 2009. published online 01 February 2010.

Abstract

Objective

Whereas several studies have used functional magnetic resonance imaging (fMRI) to investigate motor recovery, whether therapy to decrease post-stroke hypertonus alters central motor patterns remains unclear. In this study, we used continuous electromyography (EMG)-fMRI to investigate possible changes in movement-related brain activation in patients receiving Botulinum toxin (BoNT-A) for hand-muscle hypertonus after chronic stroke.

Methods

We studied eight stroke patients all of whom had hemiparesis and associated upper-limb hypertonus. All patients underwent an fMRI-EMG recording and clinical-neurological assessment before BoNT-A and 5 weeks thereafter. The handgrip motor task during imaging was fixed across both patients and controls. The movements were metronome paced, movement amplitude and force were controlled with a plastic orthosis, dynamometer and EMG recording. An age-matched control group was recruited from among healthy volunteers underwent the same fMRI-EMG recording.

Results

Before BoNT-A, while patients moved the paretic hand, fMRI detected wide bilateral activation in the sensorymotor areas (SM1), in the supplementary motor area (SMA) and cerebellum. After BoNT-A blood oxygenation level-dependent (BOLD) activation decreased in ipsilateral and contralateral motor areas and became more lateralized. BOLD activation decreased also in ipsilateral cerebellar regions and in the SMA.

Conclusion

Changes in peripheral upper-limb hypertonus after BoNT-A were associated to an improvement in active movements and more lateralized and focalized activation of motor areas. The clinical and EMG-fMRI coregistration technique we used to study hand-muscle hypertonus in patients receiving BoNT-A after chronic stroke should be useful in future studies seeking improved strategies for post-stroke neurorehabilitation.

Keywords: Stroke, Spasticity, fMRI, EMG, Botulinum toxin