Transitions between repetitive tapping and upper limb freezing show impaired movement-related beta band modulation

People With Parkinson’s Disease and Freezing of Gait Show Abnormal Low Frequency Activity of Antagonistic Leg Muscles

“…From these data and the present study it is plausible to reason that these activation abnormalities relate to freezing, since freezers show premonitory activation abnormalities already outside or immediately preceding a freeze in contrast to non-freezers ( Singh et al, 2013 ; Toledo et al, 2014 ; Storzer et al, 2017 ). Instability of the motor system may be a pre-requisite to freezing there mirroring the susceptibility of a PD patient to loose effective spinal motor output ( Scholten et al, 2016b , 2020 ). During a freeze itself, the pathological rhythm can either stay unchanged or even increase ( Scholten et al, 2016a ; Anidi et al, 2018 ; Chen et al, 2019 ; Pozzi et al, 2019 ).…”

“…Briefly, upper limb freezing (ULF) showed enhanced activity around and below 10 Hz during a freeze in the alpha band ( Scholten et al, 2016a ). Moreover, cortical abnormalities of both cortico-cortical synchronization ( Scholten et al, 2016b ) and beta band decoupling abnormalities prior to a freeze indicated premonitory cortical susceptibility to freezing ( Scholten et al, 2020 ). There were similar findings in FoG, when cortico-subthalamic decoupling in the low frequency band (4–13 Hz) became evident not only during freezing episodes, but also preceded a freeze ( Pozzi et al, 2019 ).…”

Discussion of Research Priorities for Gait Disorders in Parkinson's Disease

“…62,63 Clinical data supporting cortical involvement in FOG also derive from studies using transcranial magnetic stimulation (TMS) and electrophysiology. 64,65 The TMS studies particularly implicate the SMA 66 and the prefrontal cortex 67 as relevant for understanding and treating FOG. 68 Postural instability, a cardinal symptom of PD that may also develop as part of the brain aging process, may evolve to significant balance dysfunction as disease progresses.…”

“…Neuroimaging studies have shown changes in limbic areas in patients with PD and FOG 62,63 . Clinical data supporting cortical involvement in FOG also derive from studies using transcranial magnetic stimulation (TMS) and electrophysiology 64,65 . The TMS studies particularly implicate the SMA 66 and the prefrontal cortex 67 as relevant for understanding and treating FOG 68 …”

Can Motor Arrests in Other Effectors Be Used as Valid Markers of Freezing of Gait?

“…In line, the SMA proved to be less involved when people with FOG were undergoing a FOG-provoking gait-protocol compared to those without FOG, assessed with PET (Tard et al, 2015 ). A second EEG study showed that an increase of left prefrontal beta band synchronization was predictive of upper limb freezing, pointing to the relevance of prefrontal executive dysfunction in analogy to FOG (Scholten et al, 2020 ). Taken together, it seems that non-gait freezing paradigms are able to capture components of the supraspinal locomotor networks and how it is disrupted during freezing.…”