Cerebral microdialysis combined with single-neuron and electroencephalographic recording in neurosurgical patients - Technical note

Monitoring physiological changes in the brain parenchyma has important appl ications in the care of neurosurgical patients. A technique is described fo r measuring extracellular neurochemicals by cerebral microdialysis with sim ultaneous recording of electroencephalographic (EEG) and single-unit (neuro n) activity in selected targets in the human brain. Forty-two patients with medically intractable epilepsy underwent stereotactically guided implantat ion of a total of 423 intracranial depth electrodes to delineate potentiall y resectable seizure foci. The electrodes had platinum alloy contacts for E EG recordings and four to nine 40-mu m microwires for recording single-unit neuron activity. Eighty-six electrodes also included microdialysis probes introduced via the electrode lumens. During monitoring on the neurosurgical ward, electrophysiological recording and cerebral microdialysis sampling w ere performed during seizures, cognitive tasks, and sleep-waking cycles. Th e technique described here could be used in developing novel approaches for evaluation and treatment in a variety of neurological conditions such as h ead injury, subarachnoid hemorrhage, epilepsy, and movement disorders.