LRRK2 and Mental deterioration: As anticipated, there was a worse rate of cognitive decline in participants with GBA PD compared with participants with idiopathic PD (B [SE], −0.23 [0.08] points/y; P = .005) and LRRK2 PD (B [SE], −0.33 [0.09] points/y; P < .001), as well as those with LRRK2/GBA PD (B [SE], −0.31 [0.09] points/y; P < .001).