Functional Neural Changes after Low-Frequency Bilateral Globus Pallidus Internus Deep Brain Stimulation for Post-Hypoxic Cortical Myoclonus: Voxel-Based Subtraction Analysis of Serial Positron Emission

Abstract

Post-hypoxic myoclonus (PHM) and Lance–Adams syndrome (LAS) are rare conditions following cardiopulmonary resuscitation. The aim of this study was to identify functional activity in the cerebral cortex after a hypoxic event and to investigate alterations that could be modulated by deep brain stimulation (DBS). A voxel-based subtraction analysis of serial positron emission tomography (PET) scans was performed in a 34-year-old woman with chronic medically refractory PHM that improved with bilateral globus pallidus internus (Gpi) DBS implanted three years after the hypoxic event. The patient required low-frequency stimulation to show myoclonus improvement. Using voxel-based statistical parametric mapping, we identified a decrease in glucose metabolism in the prefrontal lobe including the dorsolateral, orbito-, and inferior prefrontal cortex, which was suspected to be the origin of the myoclonus from postoperative PET/magnetic resonance imaging (MRI) after DBS. Based on the present study results, voxel-based subtraction of PET appears to be a useful approach for monitoring patients with PHM treated with DBS. Further investigation and continuous follow-up on the use of PET analysis and DBS treatment for patients with PHM are necessary to help understanding the pathophysiology of PHM, or LAS.

Is deep brain stimulation useful in Lance–Adams syndrome?

“…Ramdhani et al 8 were the first to review DBStreated LAS, and they stimulated bilateral GPi in an LAS patient with a CPA etiology and an interval of three years between the injury and DBS. In their 5 reported a case involving low frequency (110 Hz) GPi-DBS, with an interval of three years from injury to DBS. They also published a successful clinical result, with a 35% improvement in action myoclonus at the 5-year follow-up.…”

“…In this article, we present an LAS case that did not benefit from bilateral GPi-DBS, unlike the five cases published in the literature. [4][5][6][7][8]…”

Long‐term changes of the neural network in case of improved post‐hypoxic myoclonus and gait

“…There was a large body evidence that described deep brain stimulation of PPN either alone or combined with STN for improvement in postural stability and axial symptoms in movement disorders. 9 In addition, recently published deep brain stimulation studies in the cases of intractable PHM showed that a mid-range (40 Hz) 10 or 110-Hz frequency 11 stimulation of GPi elicited long-term improvement in both rest and action myoclonus. When the authors observed brain metabolic changes in the former case study using fluorodeoxyglucose positron emission tomography, increased metabolism was found in thalamus, pontine tegmentum, and medulla, 10 that is, in line with the previous functional imaging study.…”

“…9 In addition, recently published deep brain stimulation studies in the cases of intractable PHM showed that a mid-range (40 Hz) 10 or 110-Hz frequency 11 stimulation of GPi elicited long-term improvement in both rest and action myoclonus. When the authors observed brain metabolic changes in the former case study using fluorodeoxyglucose positron emission tomography, increased metabolism was found in thalamus, pontine tegmentum, and medulla, 10 that is, in line with the previous functional imaging study. 3 In addition, the red nucleus is believed to supplement the dominant corticospinal tract in controlling trunk and limb movements.…”

Pallidal Deep Brain Stimulation for Refractory Celiac-Related Myoclonus

“…Among the myoclonic disorders, MD is the most common myoclonus disorder responsive to pallidal stimulation [ 4 ], in keeping with the observation that pallidal neuronal firing is modulated by the occurrence of myoclonus [ 4 ]. While the myoclonus in MD is subcortical, the myoclonus in CD is of cortical origin [ 5 , 7 ]. Based on the different responses to GPi DBS, pallidal stimulation could be effective mainly for subcortical myoclonus, although its effect on cortical myoclonus is still unclear.…”