Dissociation between recall and recognition memory in amnesia: The case of a patient with hippocampal damage following carbon monoxide poisoning

in Proceedings of the Joint Mid-year meeting of the International Neuropsychological Society, the Division of Neuropsychology of the British Psychological Society and the British Neuropsychological Society (2005)

There is currently a debate regarding the status of recall and recognition memory in amnesic patients with focal hippocampal damage. Proportionate deficits of recall and recognition memory have been ... [more ▼]

There is currently a debate regarding the status of recall and recognition memory in amnesic patients with focal hippocampal damage. Proportionate deficits of recall and recognition memory have been observed in some patients with selective hippocampal damage. In addition, these patients showed an impairment of both the recollection and familiarity aspects of recognition memory. In contrast, other amnesic patients with selective hippocampal lesions demonstrated relatively preserved recognition memory, despite severely impaired recall abilities. In some of them, familiarity processes were found to be intact. The resolution of this controversy has important implications for theories of episodic memory. In the present study, we examined the recall and recognition performance of an amnesic patient, MR, who suffered from bilateral hippocampal damage and temporoparietal cortical atrophy following carbon monoxide poisoning. Verbal and nonverbal recall and recognition memory were measured by tasks matched for difficulty. On these tasks, MR’s recall performance was more severely impaired than his recognition memory. In addition, MR’s recognition performance was normal on most of the tasks. In order to determine on which processes MR based his recognition decisions, we administered to the patient and to matched controls the process dissociation procedure. This evaluates the contribution of recollection and familiarity within a recognition task. The results indicated that, in this patient, familiarity was preserved, but recollection was impaired. This study thus supports the idea that amnesic patients with hippocampal damage can show preserved familiarity-based recognition memory, despite poor recall and recollection. [less ▲]

Preserved familiarity-based recognition memory in a case of global amnesia

in Journal of Cognitive Neuroscience (2002), 14(Supplemental), 32

Whether recognition memory can be preserved relative to recall in global amnesia is a matter of debate. Some studies suggest that amnesic patients with selective lesion to the hippocampal circuit show a ... [more ▼]

Whether recognition memory can be preserved relative to recall in global amnesia is a matter of debate. Some studies suggest that amnesic patients with selective lesion to the hippocampal circuit show a relatively normal recognition memory in the presence of impaired recall. However, other findings did not support this assumption. We investigated the recognition memory performance of a patient (ER) who became amnesic following a carbon monoxide poisoning. The MR scan revealed bilateral lesions to the pallidum. Based on the aetiology, a hippocampal lesion is suspected, but needs to be confirmed by a volumetric analysis. The recall and recognition performance of the patient was tested by means of the nonverbal subtests of the Doors and People Test Battery, which were matched on difficulty. On these subtests, ER’s recall performance was much more impaired than his recognition memory. ER’s recognition memory performance was further examined on a yes-no and a forced-choice recognition memory task, using faces as material. On the yes-no task, ER’s hit rate was normal, but he made a lot of false alarms compared to control subjects. By contrast, his forced-choice recognition memory was completely normal. This suggests that ER is able to use the familiarity process to make recognition decisions. Familiarity and recollection were finally investigated with a recognition task using the Process Dissociation Procedure (Jacoby, 1991). On this task, ER’s familiarity score was normal, whereas his recollection score was lower. These results support the assumption that familiarity-based recognition memory can be preserved in amnesia. [less ▲]