Functional recovery and neuroplasticity post-hemispherectomy in humans.

Hemispherectomy, introduced in the early 20th century for cerebral gliomas and intractable epilepsy, has evolved from a high-risk procedure into a valuable tool in neuroscience. Initially abandoned because of complications and high mortality, surgical refinements have markedly improved outcomes, with perioperative mortality now reported at 0-1%. This renaissance has provided a unique human model for studying neuroplasticity. We synthesize current evidence on post-hemispherectomy functional recovery across sensorimotor, linguistic, visual, visuospatial, auditory, cognitive, and social domains. Motor recovery commonly relies on alternative descending pathways and ipsilateral cortical recruitment. Language outcomes show substantial adaptability, particularly with early-life surgery, challenging rigid models of hemispheric specialization. Visual field loss remains largely persistent, yet compensatory behaviors can expand the effective field of view. Across domains, degeneracy-the capacity of structurally distinct circuits to support the same function-emerges as a core principle of reorganization and a potential framework for understanding inter-individual variability. Taken together, hemispherectomy provides a rare window into the brain's capacity for functional redistribution and offers clinically relevant lessons for individualized neurorehabilitation.