The A-K-T is a newly developed concentration test for geriatric patients. First results in demented patients show the test to be a good indicator of severity of dementia. Since the method is non-verbal, it can be applied to aphatic patients too. But, comparing results of patients suffering either from dementia of Alzheimer's type, multi-infarct dementia or Parkinson's disease with dementia, we are not able to objectify specific deficits of a certain dementing disease.