Predicting Language Outcome After Left Hemispherotomy: A Systematic Literature Review.

Objective: Hemidecortication is a therapeutic option in patients with drug-resistant structural epilepsy. If surgery is performed early enough in left-hemispheric pathology, the plasticity of the developing brain may enable the right hemisphere to take over language-if this has not occurred before surgery. A systematic overview of potential predictors of language outcome after left hemidecortication in children is warranted.

Methods: In a systematic literature review, we analyzed 58 studies on language lateralization after congenital or postneonatally acquired left-hemispheric pathology, and on language outcome after left-sided hemidisconnection, such as hemispherotomy. Single-subject data were pooled to determine the distribution of lateralization across etiologies in congenital lesions and across age groups in acute postneonatal lesions. A hierarchical linear regression assessed the influence of age at surgery, lesion type, age at seizure onset, and presurgery language function on language outcome after left hemidecortication.

Results: In acute postneonatal lesions, younger age at injury was significantly associated with right-sided language lateralization (Cramér = 0.458; = 0.039). In patients with hemidecortication, age at surgery was not significantly associated with language outcome (Cramér = -0.056; = 0.584). Presurgical language function was the most powerful predictor for postsurgical language outcome ( = 7.35, < 0.0001), with good presurgical language bearing the risk of postsurgical deterioration. In congenital pathology, right-sided language lateralization was most frequent in pre-/perinatal stroke (Cramér = 0.357; < 0.0001).

Conclusions: We propose a presurgical decision algorithm with age, presurgical language function, language lateralization, and left-hemispheric structural pathology as decision points regarding surgery.