Table 2.

Group differences in Stop-signal performance

	HC (n=12)	PD-Control (n=12)		PD-ICD (n=12)
		ON	OFF	ON	OFF
Choice RT	520 (113)	535 (98)	515 (133)	569 (141)	526 (118)
Choice Error	1.8 (2.1)	1.7 (1.3)	2.3 (2.1)	1.5 (1.2)	1.4 (1.0)
Stop Probability	49.2 (5.4)	50.8 (3.8)	49.2 (3.3)	50.5 (7.8)	48.9 (3.5)
Signal Respond RT	450 (93)	439 (42)	447 (89)	482 (109)	455 (95)
Stop Signal RT	237 (29)	241 (26)	227 (35)	200 (52)	194 (33)

OHC= Older Healthy Controls; PD= Parkinson Disease; ICD= Impulse Control Disorder; RT= Reaction Time; ON= Testing 1 hour after Dopamine Agonist; OFF= Testing after 24 hour washout of Dopamine Agonist