β-band peak in local field potentials as a marker of clinical improvement in Parkinson's Disease after Deep Brain Stimulation
Frangou PD., Michmizos KP., Stathis P., Sakas D., Nikita KS.
Although locating the stimulation contact in Deep Brain Stimulation (DBS) requires a sub-mm-precision, it remains a trial-and-error, patient-specific procedure that is usually the main cause of post-operational side-effects. In this work, we used microelectrode recordings from Parkinson's disease (PD) patients, acquired at the Neurosurgery Clinic, Evangelismos Hospital, Athens, Greece, to relate the β-band peak, a known neurophysiological signature of the sensorimotor pathways with the clinical outcome of DBS, as assessed by an expert neurologist after a follow-up of at least 1 year. By combining recordings from 5 microelectrodes, we estimated a summed β-band amplitude peak, per recording depth. We suggest that the maximum aggregate β-band peak is related to the stimulation target. We verified our method in 6 patients that responded well in a bilateral DBS treatment (average increase of Unified Parkinson's Disease Rating scale by 32.6 ± 5.4). In 7 out of 12 hemispheres, the distance between the stimulation depth and that of the maximum β-band peak was 0 and for the rest cases that distance was smaller than 2 mm which is a typical effective radius of a stimulation point. Our method needs to be further supported by data acquired from patients with good and poor clinical responses after DBS. © Springer International Publishing Switzerland 2014.