Motor cortex disinhibition in Alzheimer's disease

Objectives: To explore subclinical disturbances in the motor cortex of pati ents with Alzheimer's disease (AD). Methods: We used transcranial magnetic stimulation in a paired pulse techni que to test intracortical inhibition (ICI) and intracortical facilitation i n mildly to moderately demented AD patients with a normal neurological exam ination. Patients were studied before and during treatment with the choline sterase inhibitor donepezil. Results: AD patients had a reduced ICI compared to an age-matched control g roup. The amount of disinhibition correlated with the severity of dementia. Treatment with 10 mg donepezil daily was associated with an increase of IC L Conclusions: The subclinical motor cortex disinhibition in AD patients indi cates a functional disturbance, and is probably associated with a cholinerg ic deficit. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.