[Frontal dysfunction in idiopathic Parkinson's disease].

INTRODUCTION

In his description of the disease in his original work, James Parkinson claimed that the 'senses remained intact', but later reports began to identify cognitive impairment that ranged from dementia to barely identifiable subclinical deteriorations. Research carried out in recent decades has revealed that cognitive disorders form part of the clinical symptoms of Parkinson's disease (PD) and point to the frontal lobes as being the most affected areas; a great deal of controversy, however, still surrounds their definition, epidemiology and pathology.

AIM

To determine and classify the frontal deficits associated to this disease and to relate this cognitive performance with certain characteristics of the disease.

SUBJECTS AND METHODS

The sample utilised in the study was made up of 222 subjects divided into two groups according to their diagnosis: 111 subjects with idiopathic PD and 111 control subjects. The neuropsychological examination was performed using the Frontal Assessment Battery, the copy of the Rey-Osterrieth complex figure and the digit test for determining frontal functioning.

RESULTS AND CONCLUSIONS

We prove the existence of a frontal dysfunction that is characterised by impaired working memory, with visuospatial and executive dysfunction, which suggests greater involvement of the dorsolateral prefrontal cortex and cingulate. According to our findings, because working memory and visuospatial functioning are correlated to the motor status and the time elapsed since the onset of the disease, they could share the same underlying neuroanatomical foundations--the nigrostriatal denervation. This is not the case of executive function, which was not found to be related to the characteristics of the disease under study.