The effect on deep brain stimulation of subthalamic nucleus and dopaminergic treatment in Parkinson disease

Impulsivity is a frequent non-motor symptom in Parkinson disease (PD). It comprises psycho-behavioral alterations that negatively impact quality of life. Dopaminergic treatments underpin many impulsive controls disorders however, side effects, such as increased impulsivity, are described also after neurosurgical procedure of deep brain stimulation (DBS). We investigated the effect of deep brain stimulation on psycho-behavioral alterations and quality of life (QoL) in PD patients, analyzing, also, the role of dopaminergic therapies.

Twenty idiopathic PD patients with and 20 idiopathic PD patients without DBS were included in the study. All patient underwent to neuropsychological assessment for a screening of executive functions, impulsivity, anxiety and depressive symptoms and QoL.

Differences were found between DBS and no DBS groups and in term of dopaminergic therapies. The comparison between 2 groups showed a greater motor and attentional impulsivity in DBS patients. Moreover, this impulsivity worse QoL and interpersonal relationships. The combination of Levodopa and dopamine agonists exerted a great impact on impulsivity behavior.

The emergence of postoperative impulsivity seems to be a neurostimulator phenomenon related to the computational role of the subthalamic nucleus in modulation of behavior.