Florian Brugger1, Regina Wegener2, Julia Walch3, Marian Galovic4, Stefan Hägele-Link3, Stephan Bohlhalter5, Georg Kägi3. 1. Department of Neurology, Rorschacherstrasse 95, Kantonsspital St. Gallen, 9007 St. Gallen, Switzerland; UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom. Electronic address: florian.brugger@kssg.ch. 2. Laboratory for Motion Analysis, Department of Paediatric Orthopaedics, Children's Hospital of Eastern Switzerland, Claudiusstrasse 6, 9007 St. Gallen, Switzerland; Department of Orthopaedics and Traumatology, Rorschacherstrasse 95, Kantonsspital St. Gallen, 9007 St. Gallen, Switzerland. 3. Department of Neurology, Rorschacherstrasse 95, Kantonsspital St. Gallen, 9007 St. Gallen, Switzerland. 4. Department of Neurology, Rorschacherstrasse 95, Kantonsspital St. Gallen, 9007 St. Gallen, Switzerland; UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom; Department of Neurology, Rämistrasse 100, University Hospital Zurich, 8091 Zurich, Switzerland. 5. Neurocenter, Luzerner Kantonsspital, Spitalsstrasse 9000 Luzern, Switzerland.
Abstract
OBJECTIVE: Motor initiation failure is a key feature of freezing of gait (FOG) due to Parkinson's disease (PD). The supplementary motor cortex (SMC) plays a central role in its pathophysiology. We aimed at investigating SMC activation, connectivity and plasticity with regard to motor initiation in FOG. METHODS: Twelve patients with FOG and eleven without FOG underwent a multimodal electrophysiological evaluation of SMC functioning including the Bereitschaftspotential and movement-related desynchronisation of cortical beta oscillations. SMC plasticity was modulated by intermittent theta burst stimulation (iTBS) and its impact on gait initiation was assessed by a three-dimensional gait analysis. RESULTS: Prior to volitional movements the Bereitschaftspotential was smaller and beta power was less strongly attenuated over the SMC in patients with FOG compared to those without. Pre-motor coherence between the SMC and the primary motor cortex in the beta frequency range was also stronger in patients with FOG. iTBS resulted in a relative deterioration of gait initiation. CONCLUSIONS: Reduced activation of the SMC along with increased SMC connectivity in the beta frequency range hinder a flexible shift of the motor set as it is required for gait initiation. SIGNIFICANCE: Altered SMC functioning plays an important role for motor initiation failure in PD-related FOG.
OBJECTIVE:Motor initiation failure is a key feature of freezing of gait (FOG) due to Parkinson's disease (PD). The supplementary motor cortex (SMC) plays a central role in its pathophysiology. We aimed at investigating SMC activation, connectivity and plasticity with regard to motor initiation in FOG. METHODS: Twelve patients with FOG and eleven without FOG underwent a multimodal electrophysiological evaluation of SMC functioning including the Bereitschaftspotential and movement-related desynchronisation of cortical beta oscillations. SMC plasticity was modulated by intermittent theta burst stimulation (iTBS) and its impact on gait initiation was assessed by a three-dimensional gait analysis. RESULTS: Prior to volitional movements the Bereitschaftspotential was smaller and beta power was less strongly attenuated over the SMC in patients with FOG compared to those without. Pre-motor coherence between the SMC and the primary motor cortex in the beta frequency range was also stronger in patients with FOG. iTBS resulted in a relative deterioration of gait initiation. CONCLUSIONS: Reduced activation of the SMC along with increased SMC connectivity in the beta frequency range hinder a flexible shift of the motor set as it is required for gait initiation. SIGNIFICANCE: Altered SMC functioning plays an important role for motor initiation failure in PD-related FOG.
Authors: Simon J G Lewis; Stewart A Factor; Nir Giladi; Mark Hallett; Alice Nieuwboer; John G Nutt; Serge Przedborski; Stella M Papa Journal: Mov Disord Date: 2021-12-22 Impact factor: 10.338
Authors: Simon Lewis; Stewart Factor; Nir Giladi; Alice Nieuwboer; John Nutt; Mark Hallett Journal: Transl Neurodegener Date: 2022-05-01 Impact factor: 9.883
Authors: Florian Brugger; Regina Wegener; Florent Baty; Julia Walch; Marie T Krüger; Stefan Hägele-Link; Stephan Bohlhalter; Georg Kägi Journal: Brain Sci Date: 2021-03-03