Electrode failure modes

Electrode failure modes are the catalog of mechanisms that end a channel's useful life, split into abiotic and biotic categories. Abiotic failures are pure materials and mechanical faults: insulation cracking and delamination, thin-film water ingress, corrosion and dissolution of metal traces and tips, loss of a site coating, connector and lead-wire fatigue, wire-bond fracture, and hermetic breach. Biotic failures are the tissue mechanisms: glial encapsulation, perielectrode neuronal loss, and micromotion-driven re-injury.

Explant and longitudinal analyses of chronic arrays, including human Utah arrays, repeatedly show that mechanical and material failures account for a large fraction of dead channels — insulation and wire-bond faults, connector problems, and metal tip degradation — not tissue reaction alone. This reframes chronic reliability as a whole-system property: a flawless tissue interface still fails if the feedthrough leaks, a bond wire fractures, or the percutaneous connector corrodes.