Automatic noise-level detection for extra-cellular micro-electrode recordings

• Published in: Medical & biological engineering & computing Vol. 47; no. 7; pp. 791 - 800
• Main Authors: Dolan, Kevin, Martens, H. C. F, Schuurman, P. R, Bour, L. J
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.07.2009; Springer-Verlag; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Brain Mapping - methods; Computer Applications; Deep brain stimulation; Deep Brain Stimulation - methods; Electric noise; Electrodes; Human Physiology; Humans; Imaging; Intraoperative Care - methods; Localization; Microelectrodes; Noise; Normal distribution; Original Article; Parkinson Disease - physiopathology; Parkinson Disease - surgery; Parkinson's disease; Radiology; Random variables; Sensors; Signal Processing, Computer-Assisted; Standard deviation; Studies; Surgery; Electrophysiology; Noise estimation; Spike detection; Deep brain stimulation; Micro-electrode recordings
• ISSN: 0140-0118; 1741-0444
• DOI: 10.1007/s11517-009-0494-4

Extra-cellular neuro-recording signals used for functional mapping in deep brain stimulation (DBS) surgery and invasive brain computer interfaces, may suffer from poor signal to noise ratio. Therefore, a reliable automatic noise estimate is essential to extract spikes from recordings. We show that current methods are biased toward overestimation of noise-levels with increasing neuronal activity or artifacts. An improved and novel method is proposed that is based on an estimate of the mode of the distribution of the signal envelope. Our method makes use of the inherent characteristics of the noise distribution. For band-limited Gaussian noise the envelope of the signal is known to follow the Rayleigh distribution. The location of the peak of this distribution provides a reliable noise-level estimate. It is demonstrated that this new 'envelope' method gives superior performance both on simulated data, and on actual micro-electrode recordings made during the implantation surgery of DBS electrodes for the treatment of Parkinson's disease.