Passive ankle dorsiflexion by an automated device and the reactivity of the motor cortical network

Abstract

Gait impairment is an important consequence of neurological disease. Passive mobilization of the affected lower limbs is often prescribed in order to safeguard tissue properties and prevent circulatory sequelae during paresis. However, passive movement could play a role also in stimulating cortical areas of the brain devoted to the control of the lower limb, so that deafferentation and learned non-use can be contrasted. The purpose of the present work is to investigate cortical involvement during active and passive movements of the ankle joint, in an attempt to gain deeper insight in the similarities between these two conditions. A wearable device to mobilize the ankle joint was implemented utilizing rotary shape memory alloy actuators. The technical characteristics of this actuator make it very compatible with the tight limitations on electromagnetic noise imposed by diagnostic instrumentation. Eleven healthy volunteers took part in the pre-clinical phase of the study. According to the protocol, brain activity was recorded by 165-channel magnetoencephalography (MEG) under three different conditions: rest, active dorsiflexion of the ankle and passive mobilization of the same joint. The acquired data were processed to obtain cortical ERD/ERS (Event Related Desynchronization/ Synchronization) maps, which were then compared. The results of this analysis show that there are similar patterns of activity between active and passive movement, particularly in β band, in the contralateral primary sensorimotor, dorsal premotor and supplementary motor areas. This result, albeit obtained from healthy subjects, might suggest that passive motion provides somatosensory afferences that, to some extent, are processed in a similar manner as for voluntary control. Should this evidence be confirmed by further experiments on neurological patients, it could support the prescription of passive exercise as a surrogate of active workout, at least, so long as patients are paretic.

Magnetoencephalographic study of hand and foot sensorimotor organization in 325 consecutive patients evaluated for tumor or epilepsy surgery

“…We found an increased occurrence of ipsilateral responses after foot movements. This could not be explained by previous M/EEG studies on lower limb movements which indicated bilateral activity over the sensorimotor areas after voluntary movements ( Müller-Putz et al, 2007 , Pfurtscheller et al, 1997 , Pittaccio et al, 2011 ) or the contribution of the PMC and supplementary motor area (SMA) ( Pittaccio et al, 2013 ).…”

Do post-stroke patients benefit from robotic verticalization? A pilot-study focusing on a novel neurophysiological approach

“…Interestingly, it has been suggested that VT may play a role in stimulating cortical areas involved in trunk and lower limb control, so that deafferentation and learned non-use can be contrasted ( Pittaccio et al, 2013 ). VT may actively contribute to enhance cognitive performances through an increase in cerebral blood flow with a consequent induction of cortical plasticity, especially in frontal lobes ( Reinstrup et al, 1994 ).…”

Applications of Shape Memory Alloys for Neurology and Neuromuscular Rehabilitation

“…This principle was implemented in different ways obtaining linear actuators as explained in [ 10 ] and rotary ones as shown in [ 29 ]. Both designs enabled successful neuroscience studies on brain reactivity to passive ankle mobilization in healthy subjects, respectively [ 20 , 30 ] and [ 20 , 31 ].…”