Table 1.

Patient information

Sub	Age	Hand	Post-op	LED	Left hemibody		Right hemibody		Total
					Off	On	Off	On	Off	On
1	60	Right	24	598.75	11	5	12	10	38	21
2	64	Right	22	632.00	22	7	18	10	61	29
3	34	Right	24	1190.00	29	12	24	11	69	30
4	43	Right	5	825.00	11	7	5	1	26	12
5	50	Right	28	72.00	21	11	18	8	55	28
6	43	Right	7	600.00	21	13	16	11	52	31
7	49	Right	37	882.00	26	14	24	15	75	45
8	52	Left	25	460.00	17	2	17	7	45	12
9	58	Right	12	370.00	23	8	19	7	54	22
10	61	Right	9	1731.75	17	12	14	7	43	25
11	65	Right	3	948.00	10	3	10	2	32	8
Mean	53		18	755.41	19	9	16	8	50	24
SD	9.7		11.2	443.50	6.3	4.1	5.7	4.0	15.1	10.6

Patients had received chronic bilateral STN DBS for at least 3 months. Electrode implantation was performed using stereotactic T₂-weighted MRI, for both preoperative targeting and immediate postoperative verification (Foltynie et al., 2011; Zrinzo et al., 2011), ensuring electrode contacts were well-sited within the STN. All patients received bilateral electrodes (Model 3389, Medtronic) and a dual channel pacemaker (‘implanted pulse generator’, IPG, ActivaPC^TM, Medtronic) implanted in the left pectoral region. Scanning proceeded with no adverse effects; DBS system impedances were unaffected by scanning, and following administration of medication, patients returned to their pre-scan clinical baseline. All UPDRS-III scores were conducted OFF medication. Right and left hemibody scores do not equal total score because there are additional points for axial signs that are not detailed in this table.

LED = daily levodopa equivalent dose; Post-op = months since DBS implantation; SD = standard deviation.