Analyzing the impact of 23 mg/day donepezil on language dysfunction in moderate to severe Alzheimer's disease

Steven H. Ferris, Frederick A. Schmitt, Judith Saxton, Sharon Richardson, Joan MacKell, Yijun Sun

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Introduction. Progressive language impairment is among the primary components of cognitive decline in Alzheimer's disease (AD). Because expressive and receptive language help to maintain emotional connections to caregivers and support the management of AD patients' functional needs, language plays a critical role in patients' emotional and physical health. Using data from a large prospective clinical trial comparing two doses of donepezil in patients with moderate to severe AD, we performed a post hoc analysis to determine whether a higher dose of donepezil was associated with greater benefits in language function. Methods. In the original randomized, double-blind clinical trial, 1,467 patients with moderate to severe AD (baseline Mini-Mental State Examination (MMSE) score 0 to 20) were randomized 2:1 to receive donepezil 23 mg/day or to continue on donepezil 10 mg/day for 24 weeks. In this post hoc analysis, the Severe Impairment Battery-Language scale (SIB-L) and a new 21-item SIB-derived language scale (SIB[lang]) were used to explore differences in language function between the treatment groups. Correlations between SIB-L and SIB[lang] scores and scores on the severe version of the Alzheimer's Disease Cooperative Study-Activities of Daily Living inventory (ADCS-ADL-sev), the Clinician's Interview-Based Impression of Severity-plus caregiver input/Clinician's Interview-Based Impression of Change-plus caregiver input (CIBIS-plus/CIBIC-plus) and the MMSE were also investigated. Results: At week 24, treatment with donepezil 23 mg/day was associated with an improvement in language in the full intention-to-treat population, whereas language function declined in the group treated with donepezil 10 mg/day (SIB-L treatment difference 0.8, P = 0.0013; SIB[lang] treatment difference 0.8, P = 0.0009). Similar results were observed in a cohort of patients with more severe baseline disease (MMSE score 0 to 16). At baseline and week 24, correlations between the SIB-derived language scales and the ADCS-ADL-sev and CIBIC-plus were moderate, but the correlations were stronger between the language scales and the MMSE scores. Conclusions: Patients with moderate to severe AD receiving donepezil 23 mg/day showed greater language benefits than those receiving donepezil 10 mg/day as measured by SIB-derived language assessments. Increasing the dose of donepezil to 23 mg/day may provide language benefits in patients with moderate to severe AD, for whom preservation of language abilities is especially critical. identifier: NCT00478205.

Original languageEnglish
Article number22
JournalAlzheimer's Research and Therapy
Issue number3
StatePublished - May 6 2011

Bibliographical note

Funding Information:
The analyses described in this article derive from a phase III clinical study ( identifier: NCT00478205) that was sponsored by Eisai Inc. Editorial assistance was provided by PAREXEL Inc. and was funded by Eisai Inc. and Pfizer Inc. The article-processing charge was financed by Eisai Inc. and Pfizer Inc. SHF has served as a paid scientific consultant to Pfizer Inc related to donepezil and several investigational compounds (≤$10,000/year; there was no payment for participation in this article). His institution has

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Cognitive Neuroscience


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