Impulse control disorder and response-inhibition alterations in Parkinson's disease. A rare case of totally absent functionality of the medial-prefrontal cortex and review of literature

This report illustrates a Parkinson's disease (PD) patient with impulse-control disorder (ICD) and selective impairment in response-inhibition abilities as revealed by the performance in a functional magnetic resonance imaging (fMRI) anterior cingulate cortex - sensitive GO-NOGO task. In line with hypothesis on the role of response-inhibition disabilities in the arising of impulsivity in PD, the patient completely failed the GO-NOGO task. Moreover, fMRI acquisition revealed absent task-sensitive activity in the anterior cingulate cortex, medial prefrontal, and orbitofrontal cortices for the contrast NOGO versus Go, which signifying that a hypo-function of this network could be associated with ICD. A fronto-striatal and cingulo-frontal dysfunction may reflect impairment in metacognitive-executive abilities (such as response-inhibition, action monitoring, and error awareness) and promote compulsive repetition of behavior. Response inhibition tasks may be useful in PD post-diagnostic phase, to better identify individuals at risk of developing ICD with dopaminergic medication. (C) 2017 Production and hosting by Elsevier B.V. on behalf of Cairo University. This is an open access article under the CC BY-NC-ND license