Sandra Black

K.C. has been investigated extensively over some 20 years since a motorcycle accident left him with widespread brain damage that includes large bilateral hippocampal lesions, which caused a remarkable case of memory impairment. On standard testing, K.C.'s anterograde amnesia is as severe as that of any other case reported in the literature, including H.M. However, his ability to make use of knowledge and experiences from the time before his accident shows a sharp dissociation between semantic and episodic memory. A good deal of his general knowledge of the world, including knowledge about himself, is preserved, but he is incapable of recollecting any personally experienced events. In displaying such “episodic amnesia,” which encompasses an entire lifetime of personal experiences, K.C. differs from many other amnesic cases. Here, we document for the first time the full extent of K.C.'s brain damage using MRI-based quantitative measurements. We then review the many investigations with K.C. that have contributed to our understanding not only of episodic and semantic memory but also to the development of other aspects of memory theory. These include the distinction between implicit and explicit memory, the prospect of new learning in amnesia, and the fate of recent and remote memory for autobiographical and public events, people, and spatial locations

By combining a flanker task and a cuing task into a single paradigm, the authors assessed the effects of orienting and alerting on conflict resolution and explored how normal aging and Alzheimer’s disease (AD) modulate these attentional functions. Orienting failed to enhance conflict resolution; alerting was most beneficial for trials without conflict, as if acting on response criterion rather than on information processing. Alerting cues were most effective in the older groups— healthy aging and AD. Conflict resolution was impaired only in AD. Orienting remained unchanged across groups. These findings provide evidence of different life span developmental and clinical trajectories for each attentional network.

Patients with behavioral variant of frontotemporal dementia (FTD) have difficulties recognizing facial emotions, a deficit that may contribute to their impaired social skills. In three experiments, we investigated the FTD deficit in recognition of facial emotions, by comparing six patients with impaired social conduct, nine Alzheimer’s patients, and 10 age-matched healthy adults. Experiment 1 revealed that FTD patients were impaired in the recognition of negative facial emotions. Experiment 2 replicated these findings when participants had to determine whether two faces were expressing the same or different emotions. Experiment 3 was a control study in which participants had to discriminate whether two faces were of the same sex. In this non-emotional processing task, both patient groups performed worse than normal participants, but FTD patients performed as well as Alzheimer’s patients. We conclude that FTD patients are impaired in the recognition of negative facial emotions. © 2005 Elsevier Ltd. All rights reserved.

This study explored possible deficits in selective attention brought about by Dementia of Alzheimer Type (DAT). In three experiments, we tested patients with early DAT, healthy elderly, and young adults under low memory demands to assess perceptual filtering, conflict resolution, and set switching abilities. We found no evidence of impaired perceptual filtering nor evidence of impaired conflict resolution in early DAT. In contrast, early DAT patients did exhibit a global cost in set switching consistent with an inability to maintain the goals of the task (mental set). We discuss these findings in relation to the DAT literature on executive attention, dual-tasking, and working memory. Ó 2007 Elsevier Inc. All rights reserved.

Patients suffering from the behavioral variant of Frontotemporal Dementia (FTD-b) often exaggerate their abilities. Are those errors in judgment limited to domains in which patients under-perform, or do FTD-b patients overestimate their abilities in other domains? Is overconfidence in FTD-b patients domain-specific or domain-general? To address this question, we asked patients at early stages of FTD-b to judge their performance in two domains (attention, perception) in which they exhibit relatively spared abilities. In both domains, FTD-b patients overestimated their performance relative to patients with Dementia of Alzheimer Type (DAT) and healthy elderly subjects. Results are consistent with a domaingeneral deficit in metacognitive judgment. We discuss these findings in relation to “regression to the mean” accounts of overconfidence and the role of emotions in metacognitive judgments.