Figure 7.

Repetitive cycles of cortical spreading depression (CSD) during sustained elevated ICP in an elderly patient with delayed deterioration associated with a severe right temporo-parietal traumatic contusion. Top and middle traces show the low-frequency (LF-electrocorticogram (ECoG); low-pass filtered at 0.05 Hz) and high-frequency (HF-ECoG; high-pass filtered at 0.5 Hz) components of recordings from three bipolar channels of a linear subdural electrode strip. Arrows highlight individual CSDs, evidenced as propagating, large amplitude slow potential changes causing the suppression of HF-ECoG. Fourteen CSDs occurred in the 8-hour epoch shown; overall, a total of 105 CSDs were recorded in this patient during 70 hours of ECoG monitoring. Throughout this period, ICP remained elevated >20 mm Hg and often persisted at 30 to 40 mm Hg. The patient died 5 days after injury on withdrawal of ventilator support, in compliance with her living will.