Thirty PD-FoG and 11 PD-FoG-converters patients were recruited. Patients underwent 3D T1-weighted magnetic resonance imaging. Whole brain cortical thickness and volumes of basal ganglia, thalamus, nucleus accumbens, amygdala and hippocampus were assessed. Paired t test corrected for multiple comparisons using the Bonferroni procedure at p<0.05 were used to assess GM changes over one and two years of follow-up in PD-FoG and PD-FoG-converters patients.

Both PD-FoG and PD-FoG-converters patients showed no cortical thickness changes over time. The analysis of GM volumes showed that PD-FoG patients presented decreased volume of the right putamen between baseline and one year and reduced volume of left pallidum, right thalamus and hippocampus between one and two years of follow-up. Moreover, PD-FoG-converters showed GM atrophy accumulation in the right putamen and hippocampus between baseline and two years and of the right putamen between one and two years of follow-up.

PD-FoG and PD-FoG-converters are characterized by a progressive accumulation of GM atrophy in areas involved both in motor and cognitive functions such as basal ganglia and hippocampus. These findings support the hypothesis concerning the problematic interplay between motor and cognitive circuits in the underlying mechanisms of FoG in PD.