A Novel, Needle-Array Dry-Electrode With Stainless Steel Micro-Tips, for Electroencephalography Monitoring

A novel, needle array dry electrode consisting of 10  × 10 array of stainless steel (SS) Microtips was developed for electroencephalography (EEG) monitoring. The developed dry electrode uses commercially available, inexpensive, SS acupuncture needles certified for invasive use, to collect the EEG signal. The microtips of the acupuncture needles p roject out of a flat Teflon base by approximately 150μm. Mechanical failure analysis was carried out, with theoretical calculations for individual needles and experimental measurements with a universal testing machine (UTM). The theoretically calculated critical load for failure for individual needle was 0.88 N, while the UTM measurements show the failure occurring at 0.95 N; this difference is probably due to the simplified assumptions used in calculations. The UTM measurements of the individual needle applied against a Silicone elastomer reveal that the force required for the penetration of the needle of the electrode into skin maybe as low as 0.01 N. Needle array insertion into silicone elastomer sheet and its optical inspection was carried out to assess the ability of the microneedles to penetrate the skin. The impedance of the electrode, measured in three electrode configuration in 0.9% NaCl solution, was approximately 6.8K Ω at 20 Hz, which is sufficiently low to fulfill the requirements of biopotential measurement. The construction and characteristics of the developed needle array dry electrode show that they are sui...
Source: Journal of Medical Devices, Transactions of the ASME - Category: Medical Devices Source Type: research