Improvement of Isolated Myoclonus Phenotype in Myoclonus Dystonia after Pallidal Deep Brain Stimulation

Ritesh A. Ramdhani; Steven J. Frucht; Anousheh Behnegar; Brian H. Kopell

doi:10.5334/tohm.290

Figures & Tables

Video 1.

Pre- and Postoperative Examinations for Patient 1. In the pre-surgical state, the patient has persistent truncal and left arm myoclonus while sitting, during rest, and walking. Three years with bilateral globus pallidus internus deep brain stimulation there is no visible myoclonus.

Video 2.

Pre- and Postoperative Examinations for Patient 2. In the pre-surgical state, the patient has myoclonic jerks of the right arm at rest and when writing. Right leg myoclonus emerges when she walks. At 1 and 3 months with bilateral globus pallidus internus deep brain stimulation, there is no rest or action myoclonus.

Postoperative T2-weighted Magnetic Images of Globus Pallidus Internus (GPi) Electrode Positioning with Coordinates in Anterior Commissure - Posterior Commissure Line Space. Patient 1: (A) coronal image of GPi electrodes; (B) axial image showing most ventral tip of electrodes (arrows) in GPi (Left: X = −19.1, Y = +2.2, Z = −4.1; Right: X = 19.1, Y = 2.2, Z = −4.4). Patient 2: (C) coronal image of GPi electrodes; (D) axial image showing most ventral tip of electrodes (arrows) in GPi (Left: X = −20.1, Y = 1.5, Z = −3.2; Right: X = 19.3, Y = 2.0, Z = −3.5).

Table 1

Pre- and Postoperative Unified Myoclonus Rating Scale Scores

	Rest	Action	Stimulus	% Change
Patient 1
Preoperative	21	38	2
Postoperative
6 weeks	0	0	0	−100/−100/−100
7 month	2	4	0	−90/−89/−100
2 years	0	0	0	−100/−100/−100
3 years	0	0	0	−100/−100/−100
Patient 2
Postoperative
Preoperative	8	15	0	–
Postoperative
1 week	1	5	0	−88/−67
1 month	0	2	0	−100/−87
2 month	0	0	0	−100/−100
3 month	0	0	0	−100/−100
4 month	0	2	0	−100/−87
5 month	0	1	0	−100/−93
6 month	0	2	0	−100/−87

Table 2

Summary of Published Cases of Pallidal Deep Brain Stimulation and SGCE-positive Myoclonus–Dystonia

Study	N	Age (Years) (Range)	Disease Duration (Range)	UMRS Preop/Postop/% Change				BFM Preop/Postop/% Change				Contact	Volts	PW	Freq	Mean Follow-up (Months)	Target
Papuc et al.6	1	31	27 years		NA	NA	NA	37	14	−62		NA	NA	NA	NA	6	GPi (B)
Uruha et al.⁷	1	42	37 years		Rest: 29	Rest: 9	−70	14	4	−70		NA	NA	NA	NA	36	GPi (B)
					Action: 55	Action: 16
					Stimulus: 15	Stimulus: 5
					Functional: 13	Functional: 3
Kurtis et al.⁸	1	63	61 years		2	NA	NA	40.5	22.5	−43		1	2.0	180	135	14	GPi (B)
Kuhn et al.⁹	1	17	10 years		101	11	−89	26	4.5	−83		1	3.4	90	130	9	GPi (B)
Gruber et al.¹⁰	10	24–69	13–63		108.4 (mean)	36 (mean)	−66 (mean)	16.8 (mean)	13.9 (mean)	−48 (mean)		NA	NA	NA	NA	62	GPi/VIM (B)
Cif et al.¹¹	1	8	7 years		69	13	−81	18.5	2.5	−86		NA	NA	NA	NA	20	GPi (B)
Azoulay-Zyss et al.¹²	5	30–71	18–65 years	1	116	36	-73	16	16.5	−70	R	C+:1−	4.7	60	130	18	GPi (B)
											L	C+:1−	3.7	60	130
				2	76	20	-83	5.5	6.0	−70	R	C+:1−	3.3	60	130
											L	C+:1−	3.2	60	130
				3	38	8	-74	4.5	5.0	−85	R	C+:2−	2.0	60	130
											L	C+:2−	1.6	60	130
				4	70	6	-89	3.5	2.5	−86	R	C+:1−	3.3	60	130
											L	C+:1−	2.9	60	130
				5	86	8	-93	3.5	2.5	−91	R	C+:1−	3.4	60	130
											L	C+:1−	3.5	60	130
Contarino et al.¹³	5	18–50	NA		NA	NA	−23–89 (−72)	NA	NA	−17–76 (−56)		NA	(2.9)	(72)	(130)	12	GPi (B)
Beukers et al.¹⁴	3	29–48	NA	1	46	8	−83	18	4	−78	R	NA	2.8	90	130	27	GPi (B)
											L	NA	3.5	120	130
				2	70	58	−17	26	20	−23	R	NA	3.0	60	130	12	GPi (B)
											L	NA	3.2	60	130
				3	100	0	−100	20	7	−65	R	NA	NA	NA	NA	19	GPi (B)
											L	NA	3	60	130
Roze et al.¹⁵	2	52–54	33–35	1	70	0	−100	25.5	1	−96	L	C+:1	2.4	60	130	120	GPi (B)
											R	C+:1−	2.5	60	130
				2	86	1	-99	30.5	1	−97	L	C+:1−	2.5	60	130	120	GPi (B)
											R	C+:1−	3.1	60	130
Current study	1	32	-	1	Rest: 21	Rest: 0	Rest: −100	NA	NA	NA	L	C+:1−	2.4	60	130	36	GPi (B)
					Action: 38	Action: 0	Action: −100				R	C+:1−	2.5	60	130
					Stimulus: 2	Stimulus: 0	Stimulus: −100

[i] Abbreviations: # -, Active Contact(s); (B), Bilateral; BFM, xxx; C+, Case Positive; GPi, Globus Pallidus Internus; L, Left; NA, Not Available; PW, Pulse Width; R, Right; SGCE, Epsilon Sarcoglycan Gene; UMRS, Unified Myoclonus Rating Scale; VIM, Ventral Intermediate Nucleus.

Table 3

Summary of Published Cases of Pallidal Deep Brain Stimulation and SGCE-negative Myoclonus–Dystonia

Study	N	Age (Range)	Disease Duration (Range)	UMRS Preop/Postop/% Change					BFM Preop/Postop/% Change				Contact	V	PW	Freq	Mean Follow-up (Months)	Target
Sidiropoulos et al.16	2											R	C+:2−	3	60	130
		14	12 years	112/325		77/325		31.3%	10.5/120	4.5/120	57.1%	L	C+:10−	3	60	130	4	GPi(B)
												R	C+:2,3−	2.7	90	125
												L	11+10−	2	90	125
		49	34 years	29/325		9/325		69%	NA	NA	NA		11+9−	2.7	60	125	4.5	GPi (B)
Kim et al.17	1	37	29 years	93	2 wks		82	11.8%		38.5	14.4%	R	C+:0,1−	1.6	120	70	46	GPi (B)
					2 wks		82	11.8%		38.5	14.4%	L	C+:0−1−	1.6	120	70
					6 mos.		45	51.6%	45	15.5	65.6%	R	C+:1,2,3−	2.3	150	120
					6 mos.		45	51.6%	45	15.5	65.6%	L	C+:0,1,2−	2.2	120	120
					3 yrs		39	58.1%		9	80%	R	C+:1,2,3−	2.4	150	120
					3 yrs		39	58.1%		9	80%	L	C+:0,1,2−	2.0	120	135
Gruber et al.10	1	42	–	NA		NA	NA	NA	NA	NA			NA	NA	NA	NA	48	GPi VIM
Current study	1	16	6 years	Rest: 8	Rest: 0	Rest: −100						R	C+:2−	2.6	140	130
				Action: 15	Action: 1	Action: −93	NA	NA	NA			L	C+:2−	3.4	90	130	6	GPi (B)
				Stimulus: 0	Stimulus: 0	Stimulus: 0

[i] Abbreviations: (B), Bilateral; BFM, xxx; GPi, Globus Pallidus Internus; NA, Not Available; PW, Pulse Width; SGCE, Epsilon Sarcoglycan Gene; UMRS, Unified Myoclonus Rating Scale; VIM, Ventral Intermediate Nucleus.