Adhesive electrode for EEG, evoked potentials and EMG

An adhesive surface electrode does three jobs depending on where you put it: recording electrode in surface EMG, pickup electrode in evoked potentials, and reference or ground electrode almost everywhere.

Surface size is not a comfort detail. A 20 x 25 mm electrode covers a wider area, so it picks up the activity of more fibres, which is wanted in global surface EMG and parasitic when you are after a specific muscle. The 15 x 20 mm format serves in narrow regions, in children, and anywhere two electrodes have to sit side by side without touching.

Termination is what blocks in practice. The integrated 8 cm lead with a 0.7 mm pin fits headboxes expecting that pin; the touchproof DIN 42802 versions run from a short 15 cm lead, to place the electrode next to its input, up to 250 cm to cross a room. The snap version has no cable at all: the reusable lead brings it, and that is the most economical option in use.

The bipolar 15 cm version carries two surfaces on one backing, at a fixed spacing. That is a real time saving in nerve conduction, where the distance between active electrode and reference has to be constant between patients for latencies to stay comparable.

All are single use. They are packed in sachets of several electrodes, grouped in twenties in a box.