Cortical volume and folding abnormalities in Parkinson's disease patients with pathological gambling

Pathological gambling (PG) is one of the most devastating non-motor complications of Parkinson's disease (PD). Neuroanatomical abnormalities in PD patients with PG are poorly understood.

In the current study we investigated PD patients with and without PG using Voxel Based Morphometry (VBM) and local Gyrification Index (lGI), two neuroimaging techniques useful for detecting complementary morphological metrics in the brain. Twelve PD patients with PG were compared to 12 clinically-matched PD patients without PG and 24 healthy controls.

PD patients with PG showed grey matter volume loss specifically in the orbitofrontal cortex (OFC) when compared to patients without PG, with the atrophy of this region correlating with the increase of gambling symptoms (G-SAS). Surface-based analysis complemented this evidence revealing that the OFC in the PD patients with PG was also characterized by a reduced lGI. Moreover, when compared to controls, PD patients with PG showed a more widespread anatomical neurodegeneration involving several limbic regions such as: the OFC, cingulate cortex, inferior frontal cortex and insular cortex. Otherwise, demographically-/clinically-matched PD patients without PG did not display significant anatomical changes.

Our study demonstrates that combined grey matter atrophy and reduced lGI in the OFC differentiates PD patients with PG from those without PG, suggesting that this cortical area may play a critical role in the development of this drug-induced behavioral disorder.