Figure 1
Preoperative MRI. A. Axial FLAIR-weighted preoperative MRI image showing diffuse cortical FLAIR signal hyperintensities as well as areas of FLAIR signal changes in the corona radiata (arrows). B. Axial FLAIR-weighted MRI image showing subtle FLAIR hyperintensities in the head of the bilateral caudate nuclei (arrows).
Video 1
Pre-DBS. Demonstration of the patient’s resting and action myoclonus which impair her ability to perform functional tasks.
Figure 2
Pallidal DBS lead placement. A. Axial T2-weighted postoperative MRI image showing DBS lead artifacts (white arrows) at the AC-PC plane. B. Coronal T1-weighted posteropative MRI image showing DBS lead artifacts (white arrows) in the region of the posterior pallidum. C and D. Axial (C) and coronal (D) inversion recovery images showing borders of the globus pallidus externa and interna. DBS lead trajectories are indicated by orange lines. Intended left DBS target: 21 mm lateral, 2 mm anterior, 1 mm superior to MC with final DBS tip location extended 3.5 mm beyond the targeting plane to reach the base of the pallidum (above the optic tract). Intended right DBS target: 21.3 mm lateral, 2.3 mm anterior, 1 mm superior to MC with final DBS tip location extended 3.5 mm beyond the targeting plane. Left DBS lead location at targeting plane: 21.2 mm lateral, 1.9 mm anterior, 1 mm superior to MC (radial error of 0.3 mm). Right DBS lead location at targeting plane: 21.3 mm lateral, 2.3 mm anterior, 1 mm superior to MC (radial error of 0). MC=mid-commissural point (half point between anterior commissure to posterior commissure).
Video 2
12 Months Post-DBS. The patient’s myoclonic movements are reduced, and ability to perform functional tasks are improved.
Table 1
Summary of published cases of post-hypoxic myoclonus treated with bilateral pallidal deep brain stimulation.
| Case | Age | Sex | Mechanism of hypoxic injury | Time from injury to DBS | Target site and method | Stimulation parameters | DBS Efficacy | ||
|---|---|---|---|---|---|---|---|---|---|
| Preop UMRS | Postop UMRS (Length of follow up) | % improve-ment | |||||||
| Current case | 33 | F | Asphyxia due to drowning leading to CPA | 5 months | Bilateral GPi Asleep, iMRI guided | L and R: Double monopolar C(+),1(–),2(–) Amp: 3.2 V Freq: 180 Hz PW: 60 µs | Action: 61 Resting: 2 | Action: 40 Resting: 0 (1 yr) | Action: 35% Resting: 100% |
| Ramdhani et al | 23 | M | Asthma attack leading to CPA | 3 years | Bilateral GPi Awake, stereotactic | R: Monopolar C(+),3(–) Amp: 2.8 V Freq: 130 Hz PW: 90 µs L: Triple monopolar C(+),1(–),2(–),3(–) Amp: 2.5 V Freq: 130 Hz PW: 60 µs | Action: 52 Resting: 75 | Action: 32 Resting: 0 (6 mo) | Action: 38% Resting: 100% |
| Asahi et al | 54 | M | Respiratory distress leading to CPA | 1 year | Bilateral GPi Awake, stereotactic | L and R: Bipolar 1(–),2(+) Amp: 2.0 V Freq: 125 Hz PW: 60 µs | Action: 25 Resting: 8 | Action: 5 Resting: 0 (6 mo) | Action: 80% Resting: 100% |
[i] UMRS: Unified Myoclonus Rating Scale; CPA: cardiopulmonary arrest; Amp: amplitude, Freq: frequency; PW: pulse width; L: left; R: right.