No financial support

AIMS: To establish: 1) whether motor deficits in acute stroke improve more in patients taking donepezil, relative to placebo, for 12 weeks; 2) whether brain functional MRI changes as a result of donepezil after 12 weeks.

Stroke is a major personal and social burden, being the commonest cause of severe adult disability. Recovery has been shown in animal models to be dependent upon adequate levels of acetylcholine within the brain - which in stroke is likely to be deficient. This is because acetylcholine-producing nerve cells in the brain are often damaged by strokes.

Consequently, the investigators hypothesise that recovery may be improved by boosting acetylcholine levels in the brain - that can be readily achieved by treating with donepezil.

Inclusion Criteria:

1. Patients diagnosed with acute stroke diagnosed on clinical and neuroimaging grounds who can enter the trial within the 1st week of stroke onset, and who have new motor dysfunction of an upper limb. Motor impairment should be moderate - severe (UE-FM Score ≤50 out of a total of 66).
2. Age: above 18 years old.
3. Patients able and willing to partake in motor tests, and to return for follow-up visit at 12 weeks.
4. Able to understand English.

Exclusion Criteria:

1. Contraindications for donepezil: pregnancy (* Female patients <50 years old will be asked if there is any possibility that they might be pregnant. If there is any uncertainty, or a likelihood that they are pregnant, this will qualify as an exclusion criterion)*; moderate - severe asthma (i.e. regular treatment prescribed for this); bradycardia, syncope, 2nd or 3rd degree heart block, acute or decompensated heart failure; peptic ulcer diagnosed endoscopically and on treatment for this; epilepsy; Parkinson's disease; end-stage renal failure or creatinine > 300 micromol/l; genitourinary tract or gastrointestinal tract obstruction; gastrointestinal tract hemorrhage; myasthenia gravis
2. Other: functionally-significant cognitive impairment (i.e. dementia); significant receptive aphasia (i.e. such that cannot understand purpose or details of trial, and will be unable to cooperate with task instructions); significant physical infirmity as judged by treating physician (e.g. severe organ failure; terminal cancer).
3. Contraindications for MRI (this only pertains for the subset of patients entering the MRI substudy, but is not a contra-indication to the main study providing a diagnosis of stroke is clear from CT): phobia, metal implants including pacemaker.