gms | German Medical Science

Objective: Spreading depression (SD) is a pathophysiological condition of the brain. The ECoG correlate of SD is a large slow negative potential change propagating at a rate of ~3 mm/min.The occurrence of SD has been demonstrated in the comatose patients suffering from cerebrovascular diseases. However, SD has been never recorded in the brain of an awake human. This is of great importance to study of SD effects on neuronal tissues by investigation of the symptoms induced by the propagation of SD in the brain of an awake human. The aim of our study is to clarify whether mechanical manipulations and/or electrical stimulation performed during awake brain surgery produces any negative DC deflections in normoxic human brain.

Method: DC potentials of the brain activities were recorded using ECoG during awake brain surgery. Stimulating the exposed cortex during craniotomies were performed on patients while awake, and the resulting effects, which variously involved sensory, motor, language, or memory phenomena were recorded. Furthermore, the symptoms of the patient parallelly were observed during and after SD propagation in the brain of these patients.

Results: Our preliminary results in 6 patients point to the occurrence of SD in human brain during awake neurosurgery. Occurrence of DC negative shifts was accompanied with reduction of evoked field potentials in the area that SD propagates in some patients. In addition, some patients suffering from motoric or sensory deficits relevant to the brain area affected by SD.

Conclusions: The data indicate the occurrence of SD during surgical manipulation of the brain. Further studies are needed to evaluate the clinical importance of SD occurrence during brain surgery.