In the last two decades the distinction between cortical and subcortical dementia and dementia with both characteristics has received considerable attention. Within these superordinate categories further differentiation is possible. The starting-point consists of being able to distinguish distinctive complexes of symptoms, especially impairment of behaviour (cognition, affect and observable behaviour) and motor functions. Neuropsychological assessment plays an important part in making this distinction. The clinical relevance in being able to distinguish between the various characteristics of dementia syndromes depends on the phase of the diagnostic proces. The scientific relevance of the concepts of cortical and subcortical dementia primarily concerns an increase of the knowledge about the relationship between brain and behaviour in dementia. The cognitive neuropsychological model of Norman and Schallice offers an explanation for the differences between various dementia syndromes.