To date, CSD or PID have been reported in only ten human subjects in two papers (Mayevsky, A. et al. 1996; Strong, A. J. et al. 2002). Strong et al. reported that transient ECoG suppressions suggestive of depolarisations are common - but by no means universal - after brain injury in humans. Sub-dural ECoG electrode strips were placed in 14 patients who had undergone craniotomy for trauma or intracranial hemorrhage; monitoring was for up to 60 h following the injury. Five of these patients (36%) showed patterns of ECoG depression consistent with PID/CSD in brain regions adjacent to the primary injury.