Does impaired primacy recall equal impaired long‐term storage?: Serial position effects in Huntington's disease and Alzheimer's disease

Immediate recall, delayed recall, and delayed recognition of items from the primacy (beginning) and recency (terminal) regions of a word list were examined in Huntington's disease (HD) patients, Alzheimer's disease (AD) patients, and age‐matched normal controls. The HD patients, relative to middle‐aged controls, exhibited poor immediate recall of primacy words, but intact retention over time of the words they had recalled initially, and intact recognition of all primacy words. These results suggest that poor primacy recall may not always signify impairment in long‐term storage (LTS), as is often presumed. Relative to elderly controls, AD patients also showed severely impaired immediate recall of primacy words but, unlike HD patients, exhibited markedly deficient retention and recognition of these words. Thus, in AD patients, it is likely that impaired LTS is a major factor contributing to poor primacy recall. Diverging patterns of results were also found for HD and AD patients' recency item recall and recognition. These findings highlight the necessity of assessing immediate free recall, delayed recall, and recognition when evaluating the memory abilities of demented patients.