After giving a brief overview of the cognitive core deficit in multiple sclerosis (MS), pros and cons of considering the clinical characteristics as a form of 'subcortical dementia' are discussed. By comparing the neuropsychological descriptions of MS patients as given in the literature to other neurological diseases which are also associated with neuropsychological deficiencies, we propose the term 'multiple disconnection syndrome' to describe the variety of neuropsychological deficits encountered in MS.