Failure of dopamine metabolism: borderlines of parkinsonism and dementia.

Abstract

Dementia in parkinsonian patients is estimated to 10-40%. Several factors may take part in the development of cognitive impairment: i/ defective function of subcortico-cortical pathways including the mesocorticolimbic dopamine deficiency with cell loss in medial substantia nigra, the degeneration of noradrenergic, serotonergic and cholinergic systems ii/ cortical and limbic Alzheimer pathology iii/ cortical Lewy bodies iv/ vascular alterations. Using HMPAO SPECT we distinguished three main types of hypoperfusion in Parkinson patients with dementia: i/ predominantly frontal lobe type ii/ posterior ("Alzheimer-like") type iii/ multiple small vascular defects. Neuropsychological investigation was based on the use of MMSE, word pair, digit span, verbal fluency, Lurija's tapping tests. In addition CURS and Hachinski's score were also applied. Selegiline (JumexR) therapy was introduced and the patients were followed for at least 60 days. Selegiline improved significantly the MMSE values and verbal fluency in the "frontal lobe" type further the memory functions in "Alzheimer-like" patients. The mechanism is still not clarified, the increased dopaminergic tone should be taken into account.