PDMS- and silver-ball-based flexible multichannel surface electrode: Fabrication and application in nerve conduction study on patients with diabetic polyneuropathy

In this paper, we describe a multichannel surface electrode for measuring nerve conduction in patients with neuromuscular disorders. The electrode was constructed using a nontoxic, nonflammable poly(dimethylsiloxane) substrate and a contacting silver-ball electrode using a simple, cost-effective fabrication process. The fabricated electrode is sufficiently flexible and embossed to maintain excellent skin contact, while preventing interference from neighboring electrodes under the wet environment. It is also biocompatible, as demonstrated by the absence of skin problems after a one-week test. The electrical and mechanical properties and durability of the electrode were tested. The multichannel surface electrode was strong and durable, enduring repeated bending through 120° and resisting damage after four million repetitions in a bending test. The electrode surface was easily coated with conducting gel and recordings could be made under wet conditions without causing interference to neighboring electrodes. The enhanced impedance was comparable to that of a large commercial electrode and signals measured from the abductor pollicis brevis were noiseless. A quantitative investigation of the latencies of compound muscle action potentials in normal subjects and patients with diabetes mellitus was carried out to evaluate clinical applicability.