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Predicting the neural effect of switching from donepezil to galantamine based on single‐photon emission computed tomography findings in patients with A lzheimer's disease
Author(s) -
Oka Mizuki,
Nakaaki Shutaro,
Negi Atsushi,
Miyata Jun,
Nakagawa Atsuo,
Hirono Nobutsugu,
Mimura Masaru
Publication year - 2016
Publication title -
psychogeriatrics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.647
H-Index - 32
eISSN - 1479-8301
pISSN - 1346-3500
DOI - 10.1111/psyg.12132
Subject(s) - donepezil , apathy , galantamine , frontal lobe , psychology , single photon emission computed tomography , neuropsychiatry , psychiatry , cerebral blood flow , medicine , neuroscience , dementia , cognition , disease
Background A number of neuroimaging studies have addressed the specific effect of treatment with cholinesterase inhibitors on the frontal lobe in patients with A lzheimer's disease ( AD ). However, the neural effects of cholinesterase inhibitors on both apathy and executive dysfunction remain unclear. We examined whether baseline regional cerebral blood flow, as determined by using single‐photon emission computed tomography, is capable of predicting changes in apathy and executive dysfunction in response to AD patients switching from donepezil to galantamine therapy. Methods We conducted a 24‐week, prospective, open‐label study of AD patients treated with galantamine who did not respond to previous treatment with donepezil. Single‐photon emission computed tomography was performed at baseline, and behaviour and cognitive assessments including the M ini‐ M ental S tate E xamination, the J apanese version of the A lzheimer's D isease A ssessment S cale‐cognitive subscale, the F rontal A ssessment B attery, the N europsychiatry I nventory B rief Q uestionnaire F orm, and the D ysexecutive Q uestionnaire were conducted at three time points (baseline and after 12 and 24 weeks of galantamine therapy). Results After galantamine therapy, the N europsychiatry I nventory B rief Q uestionnaire F orm scores (apathy, irritability, and aberrant motor symptoms) and the D ysexecutive Q uestionnaire score improved significantly. The single‐photon emission computed tomography findings showed that lower baseline regional cerebral blood flow values in several frontal areas, including the dorsolateral and ventrolateral prefrontal cortex, the anterior cingulate, and the orbitofrontal cortex, predicted greater reductions in the score for apathy (distress) on the N europsychiatry I nventory B rief Q uestionnaire F orm and the D ysexecutive Q uestionnaire score after patients switched from donepezil to galantamine therapy. Conclusions Our study suggests that galantamine therapy, unlike donepezil, is characterized by a dual mechanism of action that may increase acetylcholine and the nicotinic receptor‐modulation effect within the frontal lobe, both of which are associated with apathy and executive dysfunction in AD patients.