The decline in cognitive outcomes we observed with higher grade IVHcouldbeexplainedbyacumulativeeffectofHborbyaccumulation of one or more of its metabolites that would be more likely to occur with a larger amount of bleeding. Tariq et al. [20] found that SAH disrupts long-term potentiation in the hippocampus with little to no neuronal damage, suggesting that the disruption is not due to cell death. The disruption of long-term potentiation may explain the memory deficits in SAH survivors。