Cortex mapping of ipsilateral somatosensory area following anatomical hemispherectomy: A MEG study

Yao, Ning; Qiao, Hui; Shu, Ning; Wang, Zide; Chen, Daxing; Wu, Liang; Deng, Xiaofeng; Xu, Yulun

doi:10.1016/j.braindev.2012.06.004

Cited by 4 publications

(5 citation statements)

References 26 publications

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“…The localization of the focal rCBF increases is further reminiscent of activation tasks in fMRI and neurophysiological studies after hemispherotomy, pointing to residual function originated from the remaining healthy hemisphere in expected networks. As such, magnetoencephalographic somatosensory evoked potentials elicited ipsilateral responses in the primary somatosensory cortex in three patients with residual sensory function after hemispherectomy 66 . Combined neurophysiological and fMRI data showed ipsilateral activation of the sensorimotor region during passive movement of the hand in a location similar to the movements of the other hand, yet with a greater spatial extent 8 .…”

Section: Discussionmentioning

confidence: 82%

“…As such, magnetoencephalographic somatosensory evoked potentials elicited ipsilateral responses in the primary somatosensory cortex in three patients with residual sensory function after hemispherectomy. 66 Combined neurophysiological and fMRI data showed ipsilateral activation of the sensorimotor region during passive movement of the hand in a location similar to the movements of the other hand, yet with a greater spatial extent 8. Taken together, the preserved left hemispheric increased perfusion might reflect a mechanism of disinhibited neural activity after the surgery.…”

Section: Neurological Mechanismsmentioning

confidence: 96%

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Complete hemispherotomy leads to lateralized functional organization and lower level of consciousness in the isolated hemisphere

et al. 2020

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Section: Discussionmentioning

confidence: 82%

Section: Neurological Mechanismsmentioning

confidence: 96%

Complete hemispherotomy leads to lateralized functional organization and lower level of consciousness in the isolated hemisphere

et al. 2020

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“…In general, increased ipsilateral activation could be the result of reduced interhemispheric inhibition, potentially allowing information from the periphery to reach the ipsilateral somatosensory cortices. Interhemispheric inhibition is drastically altered in individuals who underwent a hemispherectomy; in these individuals ipsilateral activation of somatosensory cortices is sometimes observed in response to sensory stimulation [ 50 , 51 ]. However, the hemispherectomy was often performed at a young age and these individuals were studied many years after surgery, resulting in a long time span during which brain plasticity can occur.…”

Section: Discussionmentioning

confidence: 99%

Quantification of task-dependent cortical activation evoked by robotic continuous wrist joint manipulation in chronic hemiparetic stroke

Vlaar

Solis‐Escalante

Dewald

et al. 2017

J NeuroEngineering Rehabil

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BackgroundCortical damage after stroke can drastically impair sensory and motor function of the upper limb, affecting the execution of activities of daily living and quality of life. Motor impairment after stroke has been thoroughly studied, however sensory impairment and its relation to movement control has received less attention. Integrity of the somatosensory system is essential for feedback control of human movement, and compromised integrity due to stroke has been linked to sensory impairment.MethodsThe goal of this study is to assess the integrity of the somatosensory system in individuals with chronic hemiparetic stroke with different levels of sensory impairment, through a combination of robotic joint manipulation and high-density electroencephalogram (EEG). A robotic wrist manipulator applied continuous periodic disturbances to the affected limb, providing somatosensory (proprioceptive and tactile) stimulation while challenging task execution. The integrity of the somatosensory system was evaluated during passive and active tasks, defined as ‘relaxed wrist’ and ‘maintaining 20% maximum wrist flexion’, respectively. The evoked cortical responses in the EEG were quantified using the power in the averaged responses and their signal-to-noise ratio.ResultsThirty individuals with chronic hemiparetic stroke and ten unimpaired individuals without stroke participated in this study. Participants with stroke were classified as having severe, mild, or no sensory impairment, based on the Erasmus modification of the Nottingham Sensory Assessment. Under passive conditions, wrist manipulation resulted in contralateral cortical responses in unimpaired and chronic stroke participants with mild and no sensory impairment. In participants with severe sensory impairment the cortical responses were strongly reduced in amplitude, which related to anatomical damage. Under active conditions, participants with mild sensory impairment showed reduced responses compared to the passive condition, whereas unimpaired and chronic stroke participants without sensory impairment did not show this reduction.ConclusionsRobotic continuous joint manipulation allows studying somatosensory cortical evoked responses during the execution of meaningful upper limb control tasks. Using such an approach it is possible to quantitatively assess the integrity of sensory pathways; in the context of movement control this provides additional information required to develop more effective neurorehabilitation therapies.

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“…Seizures disappeared completely after surgery, with no signs of delayed complications, such as hydrocephalus or superficial cerebral hemosiderosis. None of the patients had taken any antiepileptic drugs since hemispherectomy [14]. The pure-tone threshold in these patients was essentially normal (≤25 dB) or very mildly impaired (≤30 dB) [15].…”

Section: Methodsmentioning

confidence: 99%

Ipsilateral and Contralateral Auditory Brainstem Response Reorganization in Hemispherectomized Patients

Yao

Qiao

et al. 2013

Neural Plasticity

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Background. Cortical hemispherectomy leads to degeneration of ipsilateral subcortical structures, which can be observed long term after the operation. Therefore, reorganization of the brainstem auditory pathway might occur. The aim of this study was to assess reorganization of brainstem auditory pathways by measuring the auditory brainstem response (ABR) in long-term hemispherectomized patients. Methods. We performed bilateral monaural stimulation and measured bilateral ABR in 8 patients ~20 years after hemispherectomy and 10 control subjects. Magnetic resonance imaging (MRI) was performed in patients to assess structural degeneration. Results. All patients showed degenerated ipsilateral brainstem structures by MRI but no significant differences in bilateral recording ABR wave latencies. However, nonsurgical-side stimulation elicited significantly longer wave V latencies compared to surgical-side stimulation. Differences in bilateral ABR were observed between hemispherectomized patients and control subjects. Waves III and V latencies elicited by nonsurgical-side stimulation were significantly longer than those in control subjects; surgical-side stimulation showed no significant differences. Conclusions. (1) Differences in ABR latency elicited by unilateral stimulation are predominantly due to bilateral brainstem auditory pathway activity rather than to changes in brainstem volume; (2) ABR Waves III and V originate predominantly in the contralateral brainstem; and (3) subcortical auditory pathways appear to reorganize after long term hemispherectomy.

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Cortex mapping of ipsilateral somatosensory area following anatomical hemispherectomy: A MEG study

Cited by 4 publications

References 26 publications

Complete hemispherotomy leads to lateralized functional organization and lower level of consciousness in the isolated hemisphere

Complete hemispherotomy leads to lateralized functional organization and lower level of consciousness in the isolated hemisphere

Quantification of task-dependent cortical activation evoked by robotic continuous wrist joint manipulation in chronic hemiparetic stroke

Ipsilateral and Contralateral Auditory Brainstem Response Reorganization in Hemispherectomized Patients

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