Table 2.
Deep brain stimulation with diffusion tensor imaging for tremor.
| First author (ref) | Response | Scale | Mean preop, score (range) | Mean postop, score (range) | Mean improvement (%) | Target |
|---|---|---|---|---|---|---|
| Prospective direct tract targeting | ||||||
| Fenoy (16) | 20 responders | TETRAS (head) | 2.3 ± 0.5 (2–3) | 0.8 ± 0.4 (0–1) | 63.9 ± 19.5 | VIM |
| TETRAS (right arm) | 2.6 ± 0.5 (2–3.5) | 0.8 ± 0.5 (0–1.5) | 71.7 ± 18.4 | |||
| TETRAS (left arm) | 2.7 ± 0.5 (2–4) | 0.8 ± 0.6 (0–1.5) | 71.9 ± 20.6 | |||
| Coenen (17) | 1 responder | ETRS | 51 | 20 | 61 | VIM |
| O’Halloran (18) | 2 responders | UPDRS–III global | 41.0 ± 46.7 (8–74) | 8.5 ± 5.0 (5–12) | 60.6 ± 32.5 | cZIa |
| Coenen (19) | 2 responders | UPDRS–III global | 59.5 ± 5.0 (56–63) | Both 11 | 81.4 ± 1.5 | STN |
| UPDRS–III tremor | 13.5 ± 3.5 (11–16) | 2.5 ± 0.7 (2–3) | 81.5 ± 0.4 | |||
| Coenen (20) | 1 responder | ETRS | 63 | 22 | 65 | VIM |
| Coenen (21) | 1 responderb | ETRS | 11 | 9 | 18 | VIM |
| Head tremor | 90 | |||||
| Retrospective tract proximity analyses | ||||||
| King (22)/Sammartino (23) | 6 responders | CRST B | 19.2 ± 5.7 (11–28) 17.8 ± 5.4 |
7.8 ± 2.6 (5–11) | 56.9 ± 15.5 56.0 ± 11.9 (overall) 78.0 ± 17.2 (op side) |
VIM |
| TETRAS | ||||||
| Coenen (24) | 8 responders | CRST | 49.6 ± 12.8 (36–68) | 12.4 ± 7.4 (3–23) | 76.7 ± 10.9 | VIM |
| 1c non-responder | 35 | 21 | 40.0 | |||
| Sweet (25) | 4d responders 3 non-responders |
UPDRS–III tremor | 8.2 ± 3.1 (5.5–11.5) 7.5 ± 4.2 (3–13) |
6.3 ± 2.1 (4–8) 1.1 ± 1.4 (0–3) |
87.8 ± 17.4 21.3 ± 12.5 |
STN |
| Coenen (26) | 1 responder | ETRS UPDRS–III global UPDRS–III tremor |
33 27 7 |
9 17 1 |
72.7 37.0 (stopped meds) 85.7 (stopped meds) |
VIM |
| Retrospective tract stimulation modeling | ||||||
| Boccard (27) | 1 responder | CRST | 25 | 7 | 72.0 | VOP-ZI |
| Klein (28) | 12 responder | FTM A + B | 46.2 ± 16.5 (18–77) | 13.6 ± 8.6 (3–33) | 71.8 ± 11.8 | VIM |
| Pouratian (29) | 6 responder | FTM global FTM A FTM B |
53.7 ± 24.0 (9–73) 10.0 ± 6.3 (2–19) 5.4 ± 2.7 (2–10) |
32.8 ± 24.0 (9–66) 5.9 ± 4.5 (0–15) 2.1 ± 1.4 (0–4) |
39.0 41.0 61.0 |
VIM |
| Prospective cohort: | Retrospective cohort: | |||||
| Overall responder proportion = 27 out of 27 (100%) | Overall responder proportion = 38 out of 42 (90%) | |||||
| Overall mean improvement in responders = 71.7 ± 17.9% | Overall mean improvement in responders = 73.1 ± 11.6% | |||||
| Overall mean improvement among non-responders = nil | Overall mean improvement among non-responders = 31.0 ± 13.2% | |||||
Scales. TETRAS, The Essential Tremor Rating Assessment Scale (51); ETRS, Essential Tremor Rating Scale; UPDRS-III, Unified Parkinson’s Disease Rating Scale part III measures motor signs of PD (52); CRST, clinical rating scale for tremor (53); FTM, Fahn-Tolosa-Marin tremor rating scale (54); FTM A measures tremor severity; FTM B measures task-related tremor.
Targets. cZI, caudal zona incerta; STN, subthalamic nucleus; VIM, ventral intermediate thalamus; VOP-ZI, ventral oral posterior thalamic nucleus-zona incerta.
aOne patient had initial right-sided lead implanted within cZI, but the DRT (with an atypical anterior trajectory) was outside of field of stimulation. Patient experienced stimulation-induced dystonic symptoms and the lead was replaced with one implanted in a more anterior position within DRT, giving good tremor relief with reduced side effects.
bPatient demonstrated excellent head tremor control (>90%) which was not well expressed by 18% improvement in ETRS.
cPatient showed 42% improvement in ETRS but had complicated ET with “yes-yes”-type of head tremor which was hard to judge intraoperatively.
dExcluded two patients who did not have tremor symptoms preoperatively.