Cholinesterase inhibitors are licensed for treatment of dementia in Alzheimer's disease. However, the effects of these drugs on the cognitive symptoms of dementia are very small. We suggest that symptoms like impairment of attention and concentration, anxiety, restlessness and hallucinations, delineate a specific central cholinergic deficiency syndrome (CDS), that may be a much better target for such treatment. Changes in the quantitative electroencephalogram, muscarinic subtype radioimaging and serum anticholinergic activity may potentially help to diagnose the CDS. CDS is suggested to occur in various neurodegenerative diseases like Alzheimer's disease, Lewy body dementia and Parkinson's disease and to respond well to cholinesterase inhibitor therapy.