The article by Berger et al. discusses whether a cognitive assessment could contribute to the clinical diagnosis of Parkinson's disease. This is a difficult topic because the only conventional method to diagnose Parkinson's disease is the presence of clinical motor symptoms. The discussion whether a parkinsonian patient is demented or not, is dependent on the way he is tested. Many tests need high motor performance and are, therefore, not suitable. The definition of dementia must be borne in mind and it is questionable to make the assumption that even without dementia the patients exhibit cognitive impairments. The presence of cognitive impairments, whether irreversible or progressive, is as such, dementia.
The article highlights some of the most frequently described problems in patients with Parkinson's disease. The concept shifting and planning is certainly disturbed and seems to be related to rigidity. However, the expected response to dopaminergic therapy, is lacking. The conclusion is obvious, no tests are available for diagnosing Parkinson's disease. Research in this field is valuable, because it gives information about the function and dysfunction of the brain.
The second article, by Guttman et al. describes the suggested role of COMT-inhibitor many years ago, in the treatment of Parkinson's disease. Theoretically, the beneficial effect is to be expected outside (Entacapone and Tolcapone) and inside (Tolcapone) the central nervous system. Tolcapone seems to be of clinical use in patients with response fluctuations. Nevertheless, much more clinical evidence is needed to make an absolute judgement about the patient's place in the treatment of Parkinson's disease.