Table 2.

Levodopa responsiveness of the study sample, overall and stratified on FOG status.

Characteristic	All N = 45	NO-FOG N = 15	OFF-FOG N = 11	ONOFF-FOG N = 19
Levodopa challenge dose
Levodopa equivalent (mg)	391 ± 260	282 ± 133	438 ± 349	451 ± 263
Proportion of morning dose (%)*	138 ± 59	119 ± 31	181 ± 92a	128 ± 38a
Serum levodopab,c,d
OFF (ng/mg)	0.3 ± 0.4	0.1 ± 0.1	0.4 ± 0.3	0.5 ± 0.5
ON (ng/mg)	27.9 ± 16.8	19.9 ± 11.3a	28.0 ± 11.9	34.8 ± 20.8a
MDS-UPDRS-III (item 11 excluded)c
OFF (/128)	30.8 ± 10.7	27.9 ± 10.9	29.4 ± 9.7	34.1 ± 10.8
ON (/128)	16.6 ± 8.1	13.9 ± 7.2	16.5 ± 8	18.7 ± 8.5
MDS-UPDRS-III item 11**,c,d
OFF (/4)	1.6 ± 1.4	0 ± 0a,e	1.6 ± 0.7a,c	2.9 ± 0.9c,e
ON (/4)	0.7 ± 0.9	0 ± 0a,e	0 ± 0a	1.6 ± 0.6e

NO-FOG no Freezing of Gait, OFF-FOG Freezing of Gait in the OFF state only, ONOFF-FOG Freezing of Gait in the ON and OFF state

*^,**Significant effect of group, *P < 0.05; **P < 0.01

^a,eSignificant difference between listed groups in post-hoc tests, P < 0.05. P values are adjusted for PD duration; summary statistics are unadjusted

^bN = 43

^cSignificant effect of medication state (OFF vs. ON), P < 0.01

^dSignificant group × state interaction, P < 0.05