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P4–411: Long–term effects of cholinesterase inhibitors on strategic processing using verbal fluency tests in Alzheimer's disease
Author(s) -
Behl Pearl,
Stuss Donald T.,
Lanctot Krista,
Streiner David L.,
Black Sandra E.
Publication year - 2006
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2006.05.2153
Subject(s) - verbal fluency test , fluency , psychology , executive dysfunction , audiology , demographics , executive functions , cholinesterase , perseveration , cognitive psychology , disease , clinical psychology , cognition , medicine , developmental psychology , neuropsychology , psychiatry , demography , mathematics education , sociology
Background: Although executive dysfunction occurs early on in Alzheimer’s disease (AD), routine standardized tests have not been sensitive to these deficits. A few studies have assessed executive functioning and shown improvements in working memory in patients treated with cholinesterase inhibitors compared to untreated patients. Objective(s): To further assess executive dysfunction and treatment effects in AD, analyses were performed in tests of verbal fluency (phonemic and semantic). The active search and retrieval of information is primarily mediated by the frontal lobes and these tests can provide indices of strategic component processes such as speed of initiation and sustained production. A central hypothesis underlying our approach is that frontally mediated, strategic processes (phonemic fluency) may be particularly responsive to treatment and semantic fluency, considered less strategic in nature and dependent more on semantic memory (temporal lobes), may show less benefit. Methods: 130 patients meeting NINCDS-ADRDA criteria for probable AD underwent standardized assessments including verbal fluency at baseline, one and two years. Baseline assessment was within one month of treatment with CHEIs (N 65). Untreated patients were followed for one year or more prior to treatment (N 65). Results: Groups did not differ on detailed medical evaluations and demographics. Repeated measures MANOVA on phonemic fluency showed that treated patients produced more correct words at one year (p 0.031) and fewer errors at one (p 0.021) and two years (p 0.009) compared to untreated patients. Broken down by error types, treated patients produced fewer rule-breaks at one year (p 0.018) and a trend to fewer rule-breaks (p 0.089) and intrusions (p 0.054) at two years. There was no difference in speed of initiation and sustained production over one and two years. The overall GLM was not significant for semantic fluency at one and two years. Conclusions: As predicted, treated patients were more accurate on FAS fluency and made fewer errors on rule-breaks suggesting that they were able to remember and hold instructions in working memory. Executively loaded functions, rather than memory, may show the best response pragmatically to cholinesterase inhibitors since mnemonic functions may have been too severely compromised to benefit, whereas frontally mediated executive functions may allow for stabilization.