Chronicity of memory impairment in long-term out-of-hospital cardiac arrest survivors

As a result of out-of-hospital defibrillation initiatives, many cities have an increasing population of out-of-hospital cardiac arrest survivors. We p reviously identified that one third of these patients suffer memory problem s in the months after resuscitation. The pattern of memory impairment (impa ired recall memory and intact recognition memory) is suggestive of hippocam pal damage. In this study we followed up ten subjects who had previously be en found to have memory impairment after their cardiac arrest. To assess th e chronicity of this memory impairment, we re-tested memory function approx imately 3 years after the index events. These subjects were compared with a ge and sex matched control subjects with previous myocardial infarction and no cardiac arrest. Memory was assessed using the Rivermead Behavioural Mem ory test (RBMT). To further assess recall and recognition memory we used th e Doors and People test (DPT), which is specifically designed to identify d eficits in these functions. RBMT scores declined significantly in both grou ps compared with the original assessment 8 months after cardiac arrest, pos sibly an effect of ageing-control group: mean (S.D.) 22.2 (1.4)-18.4 (2.9); cardiac arrest group: 16.1 (2.7)-14.6 (4.4). The inter-group difference in RBMT score remained significant (P = 0.001). DPT scores were poor in the c ardiac arrest group (mean (S.D.) total 5.8 (2.8)), compared with the contro l group (10.8 (3.4)) who scored normally. Both recall and recognition memor y were poor in the cardiac arrest group. We conclude that the memory defici ts that we previously observed in cardiac arrest victims are persistent. Bo th recall and recognition memory are affected, implying that non-selective brain injury may be the mechanism. (C) 2000 Elsevier Science Ireland Ltd. A ll rights reserved.