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The objective of this 10-week, randomized, double-blind, placebo-controlled multicenter study was to assess the efficacy and safety of donepezil for the treatment of cognitive dysfunction exhibited by children with Down syndrome (DS). Intervention comprised donepezil (2.5–10 mg/day) in children (aged 10–17 years) with DS of mild-to-moderate severity. The primary measures were the Vineland-II Adaptive Behavior Scales (VABS-II) Parent/Caregiver Rating Form (PCRF) the sum of nine subdomain standardized scores and standard safety measures. Secondary measures included the VABS-II/PCRF scores on the following domains and their respective individual subdomains: Communication (receptive, expressive, and written); Daily Living Skills (personal, domestic, and community); Socialization (interpersonal relationships, play and leisure time, and coping skills), and scores on the Test of Verbal Expression and Reasoning, a subject-performance-based measure of expressive language. At baseline, 129 participants were assigned treatment with donepezil or placebo. During the double-blind phase, VABS II/PCRF sum of the nine subdomain standardized scores, called v-scores, improved significantly from baseline in both groups (P

There is growing evidence to support the use of early central cholinergic enhancement to improve cognitive functioning in individuals with Down syndrome (DS). This report summarizes preliminary safety and cognitive efficacy data for seven children (8-13 years) with DS who participated in a 22-week, open-label trial of donepezil hydrochloride. Donepezil was dosed once daily at 2.5 mg and, based on tolerability, increased to 5 mg/day. Safety assessments were conducted at Week 1 (baseline), Week 8 (2.5 mg donepezil), Week 16 (5 mg) and Week 22 (after the donepezil had been discontinued). Measures of cognitive function were administered at each visit, encompassing the following domains: memory; attention; mood; and adaptive functioning. Donepezil was well tolerated at the 2.5 and 5 mg doses. The side effects were mild, transient, and consistent with the adverse events noted with cholinesterase inhibitors. Some children showed improvement on measures of memory (NEPSY Memory for Names and Narrative Memory) and sustained attention to tasks (Conners' Parent Rating Scales), although increased irritability and/or assertiveness were noted in some patients. Overall, this clinical report series adds to our initial findings of language gains in children with DS treated with donepezil. It also supports the need for larger, double-blind studies of the safety and efficacy of donepezil and other cholinesterase inhibitors for children with DS.

At present, there is no proven pharmacologic treatment for cognitive or language impairments in Down syndrome (DS). Cholinergic deficits have been documented in DS and linked to cognitive deficits. This study is a 24-week open-label clinical trial of donepezil hydrochloride for the treatment of language deficits in adults with DS. To our knowledge, this is the first prospective study to evaluate systematically the effects of donepezil, a cholinesterase inhibitor, on specific language domains in DS. The main finding that emerged was an improvement in expressive language performance following donepezil therapy. Despite the multiple methodological limitations, the results raise important questions regarding the role of the cholinergic system in language function and the specific effect of cholinergic therapy in the treatment of language impairment in DS. The results support the need for large-scale controlled studies of the effects of donepezil treatment on language and on other cognitive domains in DS.

To the Editor: In earlier pilot studies, we reported improvements in global function [Kishnani et al., 1999] and expressive language function [Heller et al., 2003] in adults with Down syndrome (DS) following cholinergic therapy (donepezil hydrochloride). In this study, we report results of a small open-label clinical trial of donepezil in children with DS. To our knowledge, this is the first study evaluating the effects of donepezil on language in children with DS. After obtaining IRB approval and written informed consent, we enrolled seven children (2M:5F) between the ages of 8 and 13 years (mean age = 10.5 years) with DS (trisomy 21 by blood chromosome analysis) and their primary caregivers in a prospective open trial of donepezil. All subjects were verbal, able to hear speech at a conversational level, and able to ingest oral medication. None of the subjects had active thyroid disease, vitamin B12 deficiency, clinically-confirmed pregnancy, or clinically-significant systemic disorders, (e.g., bradycardia (HR < 50), insulin-dependent diabetes mellitus, active peptic ulcer, celiac disease, significant reactive airways, or seizure disorder) at the time of entry into the trial. They had not previously ingested cholinesterase inhibitors or any other investigational or alternative therapies used to treat the symptoms of DS in the 30 days prior to or during the trial. IQs of six subjects (obtained from school reports) ranged from 46 to 66 (mean IQ = 50). The IQ of one subject could not be determined from records. This 22-week trial (16 week open treatment study followed by a 6-week washout) was completed at the General Clinical Outpatient Research Unit at Duke University Medical Center. Subjects attended four sessions, week 0 (baseline), week 8 (low dose), week 16 (high dose), and week 22 (washout). At the completion of the baseline visit, donepezil was dosed orally at 2.5 mg once daily for 8 weeks. Based on tolerability, the dose was increased to 5 mg daily for the remaining 8 weeks. Subjects were monitored closely for safety by regular phone calls in between scheduled visits. Two language measures were used, the Test of Problem Solving [TOPS, Zachman et al., 1984] and the Clinical Evaluation of Language Fundamentals-3 [CELF-3, Semel et al., 1995]. The CELF-3 was administered at baseline, week 16, and week 22. The TOPS was completed at all four visits. Because the CELF-3 and TOPS have not been standardized for individuals with DS and the subjects’ language performance was significantly below standard age norms, performance-based comparisons were made with raw scores and age equivalencies. The effect of the medication on language performance was measured by change from baseline performance at the week 8 and week 16 assessments. One subject was excluded from all analyses because of a protocol deviation in administered dosage. No patient experienced serious adverse effects or withdrew from the study. Performance comparisons (completed by repeated measure t-tests) were based on a total n of 6 (five subjects for the baseline vs. week 8 TOPS comparison). Due to the preliminary and exploratory nature of the study, we did not correct for multiple comparisons. P values at or below 0.05 (two-tailed) were viewed as significant. Overall, language performance levels were low. The average TOPS age score was below the 3 years 5 months test basal for all sessions, and the average CELF-3 age score was 4 years 3 months at baseline, and 4 years 7 months at week 16. Essentially no change in language performance with treatment was noted on the TOPS at week 8 (the difference between mean baseline and week 8 scores was