A chronic subdermal silver-silver/chloride (Ag--Ag/Cl) electrode for the
recording of biopotentials is disclosed. The electrode is comprised of an
Ag--Ag/Cl distal end that is placed subdermally by various methods. The
recording electrode is made of solid, multi-stranded or a ball of pure
silver and the whole length of the electrode is insulated except for the
distal end which is used for voltage recordation. The electrode can be
placed subdermally by an introducer apparatus such as hypodermic or
sewing needle, a split-cannula, a staple, or a suture. Once placed, the
introducer apparatus can be removed leaving the recording wire/element in
place. The recording electrode can be placed at any location on the body
to record the local biopotential (EEG, EOG, EMG, EKG, etc). It can be
left in place for hours, days, or weeks, as it will record without any
further adjustment.