Phonological false recognition, recollection, and familiarity in healthy aging and Alzheimer's disease.

BACKGROUND Thirty healthy older people, 20 Alzheimer's disease patients (matched on age and education level) and 33 young people, participated in an experiment to implicitly induce phonological false memories, allowing us to obtain estimates of their recollection, familiarity, and false recognition. METHOD In the study task, words were selected which used half of the letters in the alphabet. In the recognition test, there were three types of non-studied new words: critical lures using letters from the same half of the alphabet as the study task words; distractors formed using the unused half of the alphabet, and distractors formed using all the letters in the alphabet. RESULTS Results showed that: (a) in all the samples, critical lures produced more false recognitions than distractors composed of all the letters in the alphabet or distractors composed of the letters not used in the study, showing a significant phonological false recognition effect; (b) both recollection and familiarity declined with age and dementia; (c) phonological false recognition increased with age and Alzheimer's disease. CONCLUSIONS These results seem to support the idea that estimates of recollection, familiarity, and phonological false recognition can be used as early markers of cognitive impairment.