Functional connectivity after hemispherectomy

Quant Imaging Med Surg, 2020 · DOI: 10.21037/qims.2020.03.17 · Published: May 1, 2020

Simple Explanation

This editorial discusses a recent fMRI study that examined individuals who had undergone hemispherectomies early in life. The study found that despite having only one hemisphere, the interhemispheric connectivity in their brains was strikingly similar to that of individuals with two hemispheres. The researchers also noted that the interaction between the attention network and the default mode network was comparable between the hemispherectomy group and a healthy control group. This suggests that the brain has an intrinsic plan for these networks that evolves regardless of the presence of one or two hemispheres. The editorial further explores the use of various neuroimaging techniques like EEG, MEG, FDG-PET, and DTI to study brain networks and functional connectivity in patients with hemispherectomy or other brain injuries, highlighting the importance of multimodal approaches to understand brain reorganization and recovery.

Study Duration

Not specified

Participants

Six high functioning individuals who underwent anatomical hemispherectomy between birth and the age of 10

Evidence Level

Editorial Commentary

Key Findings

1
Interhemispheric connectivity in brains with only one hemisphere is strikingly similar to the functional network organization in brains with two hemispheres.
2
Global efficiency of networks in patients was increased compared to controls whereas modularity was not altered.
3
More typical connectivity is likely a marker for more successful compensation and intact cognitive abilities.

Research Summary

This editorial comments on a study by Kliemann et al. that investigated functional connectivity in individuals who had undergone hemispherectomy. The key finding was that despite having only one hemisphere, their brain networks showed remarkable similarity to those of individuals with two hemispheres. The editorial also discusses the use of various neuroimaging techniques, including fMRI, EEG, MEG, FDG-PET, and DTI, to study brain networks and functional connectivity in patients with hemispherectomy or other brain injuries. Finally, the editorial emphasizes the clinical implications of understanding brain reorganization after hemispherectomy, suggesting that post-lesional examination of functional and structural networks could inform rehabilitation strategies and predict functional outcome.

Practical Implications

Rehabilitation Strategies

Post-lesional examination of functional and structural networks could inform rehabilitation strategies aiming to improve functional recovery following unilateral hemispheric lesions.

Predicting Functional Outcome

Functional and structural networks examination can predict functional outcome after hemispherectomy.

Multimodal Approach

Functional examination of brain networks after hemispherectomy is not limited to fMRI; quantitative EEG methods should be further developed.

Study Limitations

1
Deformation of the brain in patients with severe injuries makes group-level analyses and comparisons with healthy controls challenging.
2
Functional connectivity can be confounded by the presence of a third region physically connected to two regions of interest, mimicking a direct functional link.
3
Functional rearrangement in human patients is more complex than what can be observed in animal models.

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