Clinical implications of brain asymmetries

Nat Rev Neurol 20, 383–394 (2024)

https://doi.org/10.1038/s41582-024-00974-8

[작성자: 전한울]

No two human brains are alike, and with the rise of precision medicine in neurology, we are seeing an increased emphasis on understanding the individual variability in brain structure and function that renders every brain unique. Functional and structural brain asymmetries are a fundamental principle of brain organization, and recent research suggests substantial individual variability in these asymmetries that needs to be considered in clinical practice. In this Review, we provide an overview of brain asymmetries, variations in such asymmetries and their relevance in the clinical context. We review recent findings on brain asymmetries in neuropsychiatric and neurodevelopmental disorders, as well as in specific learning disabilities, with an emphasis on large-scale database studies and meta-analyses. We also highlight the relevance of asymmetries for disease symptom onset in neurodegenerative diseases and their implications for lateralized treatments, including brain stimulation. We conclude that alterations in brain asymmetry are not sufficiently specific to act as diagnostic biomarkers but can serve as meaningful symptom or treatment response biomarkers in certain contexts. On the basis of these insights, we provide several recommendations for neurological clinical practice.

The left and right hemispheres show structural and functional differences in cortical and subcortical regions. These left–right differences manifest at the functional level, with handedness and language being lateralized to the left hemisphere and face processing and visuospatial attention being lateralized to the right hemisphere in most people. Asymmetries at the structural level include macrostructural and microstructural differences, as well as asymmetries in gene expression and protein distribution. In addition, the two hemispheres differ with regard to functional and structural connectivity.