Alzheimer Disease: Fleischman DA

Fleischman DA. · Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA. · Cortex. · Pubmed #17941347 No free full text.

Abstract: Two decades of research examining repetition priming in aging and Alzheimer's disease (AD) has yielded a large body of contradictory findings due to differences between studies in participant and task characteristics. Recent research that has employed methodological advances indicates that this form of implicit memory is preserved in healthy aging. When a priming deficit does occur in studies of aging, it is likely a very early signal of neurological disease. Future directions for research in this area include linking priming ability to known risk factors for development of AD, integrating priming measures into clinical neuropsychological assessment batteries, and implementing programs of cognitive retraining that enhance memory using stimulus repetition techniques.

Fleischman DA, Gabrieli J. · Department of Neurological Sciences, Section of Cognitive Neuroscience, Rush Medical College, Rush Alzheimer's Disease Center, Rush-Presbyterian-Saint Luke's Medical Center, 1645 West Jackson, Suite 450, Chicago, Illinois 60612, USA. · Curr Opin Neurobiol. · Pubmed #10322182 No free full text.

Abstract: Recent findings have further characterized the neural and psychological bases of long-term memory failure in Alzheimer's disease. Convergent volumetric neuroimaging studies indicate that loss of episodic memory is specifically related to early-stage limbic-diencephalic pathology, and that non-mnemonic impairment is specifically related to later-stage temporal-neocortical pathology. Recent studies of Alzheimer's disease have also reported informative cognitive dissociations in semantic memory and implicit memory.

Fleischman DA, Wilson RS, Gabrieli JD, Schneider JA, Bienias JL, Bennett DA. · Rush Alzheimer's Disease Center, Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA. · Brain. · Pubmed #15975947 links to  free full text

Abstract: Explicit memory failure is the defining cognitive feature of Alzheimer's disease and relates to the hallmark neuropathological features (plaques and tangles) of this illness. However, a pattern of preserved and impaired implicit memory has been found in Alzheimer's disease patients that may be explained by the association between the processing demands of certain implicit tests and the level of regional Alzheimer's disease neuropathology. In this study, we tested the hypothesis that these neuropathological features are related to implicit memory--measured by repetition priming--in a test that emphasized conceptual (or meaning-based) cognitive processing, and that the pathological changes are not related to implicit memory in a repetition priming test that emphasized perceptual (or sensory-based) cognitive processing. Subjects were older nuns, priests and brothers participating in the Religious Orders Study who agreed to annual neurological and neuropsychological evaluation for Alzheimer's disease and common neurological conditions of ageing, and brain autopsy at time of death. Explicit memory was measured by seven tests of episodic recall and recognition and converted to a previously established summary measure. Implicit memory was measured by four repetition priming tests. One test, category exemplar priming, emphasized conceptual, or meaning-based cognitive processing. A second test, word-identification priming, emphasized perceptual, or sensory-based cognitive processing. Two additional priming tests, picture-naming and word-stem completion, invoke both conceptual and perceptual processes. Neuritic and diffuse plaques, and neurofibrillary tangles identified by Bielschowsky silver stain, were quantified from five regions separately (frontal, parietal, temporal, entorhinal cortex and the hippocampus) and converted to a previously established summary measure. In linear regression analyses--controlling for age, sex and education--higher levels of Alzheimer's disease neuropathology were related to lower levels of explicit memory proximate to death. Higher levels of neuropathology were also related to lower levels of priming on the category-exemplar test, but were not related to levels of priming on the word-identification, picture-naming, or word-stem completion tests. The results suggest that hallmark indices of Alzheimer's disease neuropathology are associated with performance on priming tests to the extent that conceptual, but not perceptual, processing resources are required.

Fleischman DA, Wilson RS, Gabrieli JD, Bienias JL, Bennett DA. · Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA. · Psychol Aging. · Pubmed #15584787 No free full text.

Abstract: Decline in explicit memory with advancing age is a common finding, but it is unclear whether implicit memory (repetition priming) declines or remains stable. Meta-analyses of studies that examined differences between extreme groups (young-old), typically at a single point in time and on a single test, suggest that a mild reduction in priming occurs with advancing age. The authors examined explicit memory and priming, on multiple tests over 4 annual data-collection waves, in a large group of older persons without dementia at baseline. Explicit memory declined significantly, but priming remained stable. Findings indicate that explicit memory and priming are dissociable on the basis of age-related change and that mildly reduced priming is not an inevitable consequence of growing older.

Wilson RS, Fleischman DA, Myers RA, Bennett DA, Bienias JL, Gilley DW, Evans DA. · Rush Alzheimer's Disease Center and Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois 60612, USA. · J Neurol Neurosurg Psychiatry. · Pubmed #14742585 links to  free full text

Abstract: BACKGROUND: Chronic stress has been associated with impaired episodic memory, but the association of premorbidly experienced distress with memory function in Alzheimer's disease is unknown. OBJECTIVE: To investigate the link between proneness to distress and Alzheimer's disease. METHODS: Participants were 363 persons with clinically diagnosed Alzheimer's disease. At baseline, a knowledgeable informant rated each person's premorbid personality (that is, before dementia onset) along five dimensions, one of which was the tendency to experience psychological distress. Participants underwent structured clinical evaluations at baseline and then annually for up to four years. Each evaluation included 17 cognitive tests from which previously established measures of episodic memory, visuoconstruction, repetition, and naming were derived. RESULTS: In a series of random effects models adjusted for age, sex, and education, premorbid distress proneness was associated with baseline impairment in episodic memory but not with impairment in other cognitive domains, or with change in any cognitive domain. No other trait was related to baseline function or rate of decline in any cognitive domain. CONCLUSIONS: The results suggest that premorbid proneness to experience psychological distress is related to level of impairment in episodic memory in persons with Alzheimer's disease, but neither distress proneness nor other personality traits are related to disease progression.

Fleischman DA, Monti LA, Dwornik LM, Moro TT, Bennett DA, Gabrieli JD. · Rush-Presbyterian-St Luke's Medical Center, Department of Neurological Sciences, Chicago, Illinois, USA. · J Int Neuropsychol Soc. · Pubmed #11771621 No free full text.

Abstract: This study examined the distinction between identification and production processes in repetition priming for 16 patients with Alzheimer's disease (AD) and 16 healthy old control participants (NC). Words were read in three study phases. In three test phases, participants (1) reread studied words, along with unstudied words, in a word-naming task (identification priming); (2) completed 3-letter stems of studied and unstudied words into words in a word-stem completion task (production priming); and (3) answered yes or no to having read studied and unstudied words in a recognition task (explicit memory). Explicit memory and word-stem completion priming were impaired in the AD group compared to the NC group. After correcting for baseline slowing, word-naming priming magnitude did not differ between the groups. The results suggest that the distinction between production and identification processes has promise for explaining the pattern of preservation and failure of repetition priming in AD.

Gabrieli JD, Vaidya CJ, Stone M, Francis WS, Thompson-Schill SL, Fleischman DA, Tinklenberg JR, Yesavage JA, Wilson RS. · Department of Psychology, Stanford University, California 94305, USA. · J Exp Psychol Gen. · Pubmed #10650584 No free full text.

Abstract: Four experiments examined a distinction between kinds of repetition priming which involve either the identification of the form or meaning of a stimulus or the production of a response on the basis of a cue. Patients with Alzheimer's disease had intact priming on picture-naming and category-exemplar identification tasks and impaired priming on word-stem completion and category-exemplar production tasks. Division of study-phase attention in healthy participants reduced priming on word-stem completion and category-exemplar production tasks but not on picture-naming and category-exemplar identification tasks. The parallel dissociations in normal and abnormal memory cannot be explained by implicit-explicit or perceptual-conceptual distinctions but are explained by an identification-production distinction. There may be separable cognitive and neural bases for implicit modulation of identification and production forms of knowledge.

Thompson-Schill SL, Gabrieli JD, Fleischman DA. · Department of Psychology, University of Pennsylvania, Philadelphia 19104-6196, USA. · J Int Neuropsychol Soc. · Pubmed #10645707 No free full text.

Abstract: Impairments to either perceptual or word-retrieval processes have been hypothesized to explain confrontation naming impairments in patients with Alzheimer's disease (AD). This study measured the effects of structural similarity, which affects perceptual processing, and name frequency, which affects word retrieval, on naming latency and accuracy in 16 AD patients and 16 age-matched controls. AD patients named pictures more slowly and made more errors than control participants. Their naming accuracy was disproportionately affected by name frequency, but not by structural similarity. The findings indicate that the processing of structural properties of objects is unaffected in early-stage AD, and suggest that word-retrieval impairments underlie the naming deficit in AD.

Fleischman DA, Gabrieli JD, Gilley DW, Hauser JD, Lange KL, Dwornik LM, Bennett DA, Wilson RS. · Department of Neurological Sciences, Rush Medical College, Rush Alzheimer's Disease Center, and the Rush Institute for Healthy Aging, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA. · Neuropsychology. · Pubmed #10067772 No free full text.

Abstract: There are many conflicting results concerning the effects of age and Alzheimer's disease (AD) on word-stem completion priming. To examine potential sources of this variability, the authors examined the influences on such priming of age, cognitive status, and encoding in a large sample of young, old, and AD individuals. At study, words were processed aloud by reading, reading and rating likeability, or generating from definition. Old participants had less priming than young participants and more priming than AD patients. For the healthy old participants, priming decreased with advancing age and with cognitive loss following generation only. For AD patients, priming decreased as dementia severity increased; patients with the mildest dementia did not differ from healthy old participants. Thus, age, cognitive status, and encoding differentially influenced the magnitude of priming in healthy aging and AD.