Co-occurrence of executive impairment and amnesic syndrome following sub arachnoid haemorrhage: a case study

Hematoma Locations Predicting Delirium Symptoms After Intracerebral Hemorrhage

BACKGROUND

Delirium symptoms are associated with later worse functional outcomes and long-term cognitive impairments, but the neuroanatomical basis for delirium symptoms in patients with acute brain injury is currently uncertain. We tested the hypothesis that hematoma location is predictive of delirium symptoms in patients with intracerebral hemorrhage, a model disease where patients are typically not sedated or bacteremic.

METHODS

We prospectively identified 90 patients with intracerebral hemorrhage who underwent routine twice-daily screening for delirium symptoms with a validated examination. Voxel-based lesion-symptom mapping with acute computed tomography was used to identify hematoma locations associated with delirium symptoms (N = 89).

RESULTS

Acute delirium symptoms were predicted by hematoma of right-hemisphere subcortical white matter (superior longitudinal fasciculus) and parahippocampal gyrus. Hematoma including these locations had an odds ratio for delirium of 13 (95 % CI 3.9-43.3, P < 0.001). Disruption of large-scale brain networks that normally support attention and conscious awareness was thus associated with acute delirium symptoms.

CONCLUSIONS

Higher odds ratio for delirium was increased due to hematoma location. The location of neurological injury could be of high prognostic value for predicting delirium symptoms.

Consolidation theory and retrograde amnesia in humans

Recent research on the cognitive dysfunctions experienced by human anmesic patients indicates that very long term (multidecade) changes may occur in memory. Flat retrograde amnesia (RA), consisting of a uniform memory deficit for information from all preamnesia time periods, indicates a simple, monolithic retrieval problem, whereas graded RA, with greater memory deficits for information from recent as opposed to remote time periods, suggests the presence of a gradual long-term encoding, or consolidation, process. An evaluation of 247 outcomes from 61 articles provides strong evidence of graded RA across different cerebral injuries, materials, and test procedures, as well as in measures of both absolute and relative (patient vs. control) performance. Future conceptualizations of human memory should address the possibility that memories increase in resistance to forgetting, or reduction in trace fragility, across many decades.