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

Blauwblomme, Thomas; Demertzi, Athena; Tacchela, Jean-Marc; Fillon, Ludovic; Bourgeois, Marie; Losito, Emma; Eisermann, Monika; Marinazzo, Daniele; Raimondo, Federico; Alcauter, Sarael; Steen, Frederik Van de; Colenbier, Nigel; Laureys, Steven; Dangouloff-Ros, Volodia; Naccache, Lionel; Boddaert, Nathalie; Nabbout, Rima

doi:10.1002/epi4.12433

Cited by 5 publications

(5 citation statements)

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“…RSFC analysis in this patient with remarkable clinical recovery 6 years after near-complete loss of the right hemisphere indicates increased between-network connectivity for all seven networks examined in the preserved (dominant) hemisphere. This is numerically consistent with two recent reports of eight patients who had surgical hemispherectomy in childhood (2,3). This suggests that a shift toward increased between-network connectivity can be observed not only following childhood surgical hemispherectomy due to epilepsy, but also in an adult patient within a few years after functional hemispherectomy due to ischemic stroke.…”

Section: Discussionsupporting

confidence: 91%

“…A recent study in six adults who underwent surgical hemispherectomy during childhood for intractable epilepsy reported that RSFC within seven brain networks was generally intact in the preserved hemisphere, but RSFC between networks was substantively increased compared to healthy controls (2). Moreover, increased contralateral and inter-hemispheric connectivity have been reported in a previous study employing rs-fMRI in complete surgical hemispherotomy, including total callosotomy with a perithalamic section, in two children (3). This suggests that hemispherectomy results in a strengthening of preserved inter-network connectivity, despite major structural disruptions, and shows that rs-fMRI can inform alterations in brain function in patients after hemispherectomy in childhood.…”

Section: Introductionmentioning

confidence: 90%

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Case Report: Resting-State Brain-Networks After Near-Complete Hemispherectomy in Adulthood

et al. 2022

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ObjectivesUnderstanding the dynamics of reorganized network-level brain functions after hemispherectomy is important for treatment, prognostication, and rehabilitation of brain injury, but also for investigating questions of fundamental neurobehavioral interest: How does the brain promote consciousness despite loss of one hemisphere?MethodsWe studied resting-state functional connectivity (RSFC) in a high-functioning middle-aged man 6 years after functional hemispherectomy following malignant middle cerebral artery infarction, and we compared results to RSFC in 20 healthy controls.ResultsOur analysis indicates increased between-network connectivity for all seven networks examined in the patient's preserved hemisphere, compared to healthy controls, suggesting a shift toward increased between-network connectivity following near-complete loss of one hemisphere during adulthood.ConclusionsThese data corroborate and extend recent findings of increased between-network connectivity in the remaining hemisphere after surgical hemispherectomy for intractable epilepsy during childhood. Our results support a neuroplasticity model with reorganization of distributed brain connectivity within the preserved hemisphere as part of the road to recovery after brain injury, as well as recovery of consciousness and cognitive functions, after hemispherectomy.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 90%

Case Report: Resting-State Brain-Networks After Near-Complete Hemispherectomy in Adulthood

et al. 2022

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“…All patients had preoperative MRI and postoperative MRI at day 1, day 10 (detection of hydrocephalus), and after 3 months, with a protocol including at least 3DT1, 3DT2, and diffusion-weighted MRI sequences, along perfusion imaging with arterial spin labeling and bold fMRI as previously reported. 10…”

Section: Methodsmentioning

confidence: 99%

“…8,9 We followed this technique during the past decade in our institution and reported preliminary results of both the seizure outcome and the functional postoperative reorganization of the healthy hemisphere. 10 The aim of the study is to describe in a large cohort from two centers the surgical steps with video support, to analyze the seizures' outcome and complications of the procedure, and to report failures and limitations of this approach considering systematic postoperative MRI imaging.…”

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confidence: 99%

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Interhemispheric Vertical Hemispherotomy: Technique, Outcome, and Pitfalls—A Bicentric Retrospective Case Series of 39 Cases

Pilioneta,

Chen,

Losito

et al. 2023

Operative Neurosurgery

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BACKGROUND AND OBJECTIVES: When seizure onset affects a whole hemisphere, hemispheric disconnections are efficient and safe procedures. However, both lateral peri-insular hemispherotomy and vertical paramedian hemispherotomy approaches report a failure rate around 20%, which can be explained by residual connections giving rise to persistent seizures. In this study, we present the interhemispheric vertical hemispherotomy (IVH), a technical variation of the vertical paramedian hemispherotomy approach, that aims to increase seizure control avoiding residual connections while exposing the corpus callosum. METHODS: This is a retrospective study of IVH in two centers, with analysis of clinical and MRI data and outcomes. A detailed description of the technique is provided with a video. RESULTS: IVH was performed in 39 children. The mean age at surgery was 7.2 years, and etiologies were as follows: malformations of cortical development (n = 14), Rasmussen's encephalitis (n = 10), stroke (n = 10), post-traumatic (3), and Sturge-Weber Syndrome (2). Hemispheric disconnection was complete on postoperative MRI in 34 cases. There was no mortality, hydrocephalus occurred in one case, and subdural collection occurred in four cases. A second surgery was performed in four cases because of seizure relapse (n = 3) and/or incomplete disconnection on MRI (n = 4). With a mean follow-up of 3.2 years, International League Against Epilepsy class I epilepsy outcome was obtained for 37/39 patients. CONCLUSION: IVH is a safe and effective variation of the vertical approaches for hemispheric disconnection. It allows a good exposure and anatomic control of the corpus callosum, which is a frequent site of incomplete disconnection. IVH may be limited by the thalamic volume and the ventricular size, notably in hemimegalencephaly cases.

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Hard but so valuable to define hard criteria for empirical theories of consciousness

Naccache

2020

Cognitive Neuroscience

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

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 5 publications

References 73 publications

Case Report: Resting-State Brain-Networks After Near-Complete Hemispherectomy in Adulthood

Case Report: Resting-State Brain-Networks After Near-Complete Hemispherectomy in Adulthood

Interhemispheric Vertical Hemispherotomy: Technique, Outcome, and Pitfalls—A Bicentric Retrospective Case Series of 39 Cases

Hard but so valuable to define hard criteria for empirical theories of consciousness

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