Re-organization of motor functions after early brain damage: Direct evidence from intraoperative neuromonitoring in four cases

Background

The re-organization of motor functions is a sign of adaptive brain plasticity to early brain damage and understanding its mechanisms may play a key role in the future treatment modalities. This study provides direct evidence of neural plasticity in four patients with early brain damage, who underwent epilepsy surgery due to drug-resistant epilepsy.

Methods

In this retrospective analysis, four patients with early brain damage who underwent resective or disconnective epilepsy surgery were examined. Intraoperative neuromonitoring was employed to preserve motor function during surgery, while functional MRI and diffusion tensor imaging were used to assess it before and after surgery.

Results

Preoperative functional imaging revealed that some motor representations of the limbs were located in unexpected cortical areas due to early brain damage. In the first and second patients, right-hand representations had shifted to the right hemisphere and to both hemispheres, respectively. In the remaining two patients, all motor functions of the affected hemisphere were completely relocated to the contralateral, unaffected hemisphere. Intraoperative neuromonitoring findings were in line with pre-operative functional imaging.

Conclusion

Our intraoperative neuromonitoring data provided direct evidence of motor function reorganization following early brain damage. Furthermore, the results indicated that these functional adjustments of motor circuits are progressive and long-lasting.