Spinal cord stimulation treatment for freezing of gait in Parkinson's disease: A case report

Parkinson's disease (PD) is a common degenerative disease of the nervous system. Currently, it is predominantly treated with dopamine-like drugs. However, as the disease progresses and the dosage of drugs increases, patients with PD experience a series of motor complications, including symptom fluctuations, switching phenomena, dyskinesias, and freezing of gait (FoG). This case highlights previously unreported spinal cord stimulation treatment for FoG in PD. The patient was a 66-year-old Asian female with a history of PD for 15 years. She had taken medications such as trihexyphenidyl, amantadine, and Madopar (levodopa plus benserazide) in the past, but the symptom relief was not satisfactory. She had been slow to act in the past 6 months, with difficulty in walking, which mainly manifested as feeling like her feet were sticking to the ground while standing up, turning, or encountering obstacles and feeling unable to move. We conducted related pre-admission assessments as follows: the Hamilton Depression Rating Scale (HAMD) score was 25 points, the New Freezing of Gait Questionnaire (NFOGQ) score was 22 points, the Gait and Fall Questionnaire (GFQ) score was 38 points, the Parkinson's Disease Quality of Life Questionnaire (PDQ-39) score was 117 points, the motor function test score of the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS-Ⅲ) was 33 points (before medication) and 19 points (1 h after medication), the Berg Balance Scale score was 18 points, and her 7-m Timed Up-and-Go Test (TUG) results were 31 s, 63 steps, and 4 freezes (Supplemental Video 1). Therefore, to relieve her FoG symptoms, we implemented a trial implantation of a primary spinal cord electrical stimulation (SCS) system on June 24, 2021. During the operation, we used C-arm positioning, marked the body surface at T9-T10 for a straight incision about 4 cm long, opened the T9 and T10 parts of the laminae, and inserted the electrode (model 565 DEFINE 2 ∗ 8; Medtronic, USA) upwards into the epidural space (Fig. 1). The test resistance was normal during the operation and it was connected to an external temporary stimulator. After the patient returned to the ward safely, we performed postoperative adjustments. After repeated adjustments, the final parameters were as follows: (voltage, 1.0 V; pulse width, 210 μs; frequency, 260 Hz). The patient's bilateral lower limb rigidity and involuntary tremor were significantly reduced, and the symptoms such as slow movement and difficulty in movement were significantly relieved. Her postoperative results for the 7-m TUG was 9 s with 14 steps and 0 freezes (Supplemental Video 2). The patient was implanted with an implantable pulse generator in the second week. We conducted a follow-up 3 months after discharge with the following results: HAMD, 10 points; NFOGQ, 6 points; GFQ, 11 points; PDQ-39, 39 points; motor function test score of MDS-UPDRS-III, 12 points (before medication) and 8 points (1 h after medication), and Berg Balance Scale score, 32 points. The following are the supplementary data related to this article:https://www.brainstimjrnl.com/cms/asset/bce53df2-aefb-4849-8f8b-a862630daf29/mmc1.mp4Loading ...(mp4, 4.13 MB) Download video https://www.brainstimjrnl.com/cms/asset/e6af5c38-12e2-4e99-adc8-0f310b567186/mmc2.mp4Loading ...(mp4, 1.72 MB) Download video https://www.brainstimjrnl.com/cms/asset/bce53df2-aefb-4849-8f8b-a862630daf29/mmc1.mp4Loading ...(mp4, 4.13 MB) Download video https://www.brainstimjrnl.com/cms/asset/e6af5c38-12e2-4e99-adc8-0f310b567186/mmc2.mp4Loading ...(mp4, 1.72 MB) Download video FoG is the most common and most disabling pathological gait in the clinical manifestations of PD. It mostly occurs in the middle and late stages of the disease, which can easily lead to falls, trauma, and depression, seriously affecting the patient's quality of life and social function [[1]Rahimpour S. Gaztanaga W. Yadav A.P. et al.Freezing of gait in Parkinson's disease: invasive and noninvasive neuromodulation.Neuromodulation. 2021; 24: 829-842https://doi.org/10.1111/ner.13347Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar]. Epidemiological and clinical research data show that about 50% of patients with PD with a disease course of more than 10 years have experienced FoG. As the disease progresses, the incidence of FoG increases. In addition, 7% of patients with early-stage PD have experienced mild FoG. There are currently a variety of treatments, including drug and non-drug treatment. Non-drug treatment includes invasive and non-invasive brain and vagus nerve stimulation and physical therapy methods. Drug treatment mainly includes adjusting the dose of levodopa or changing the form of levodopa to maintain the patient in the "on" state, which is the most conventional treatment at present. FoG during the "off" stage can also be relieved by increasing the amount of dopamine receptor agonists and adding catechol-oxygen level-methyltransferase inhibitors, monoamine oxidase inhibitors, and amantadine [[2]Nonnekes J. Snijders A.H. Nutt J.G. Deuschl G. Giladi N. Bloem B.R. Freezing of gait: a practical approach to management.Lancet Neurol. 2015; 14: 768-778https://doi.org/10.1016/S1474-4422(15)00041-1Abstract Full Text Full Text PDF PubMed Scopus (179) Google Scholar]. Non-drug treatment mainly includes deep brain stimulation surgery, which has the best effect on resting tremor and muscle stiffness and the effect is immediate. Deep brain stimulation also has a significant effect on motor retardation, but the effect on gait ignition failure and freezing symptoms are relatively poor and there is no obvious effect on severe postural instability [[3]Kim R. Kim H.J. Shin C. et al.Long-term effect of subthalamic nucleus deep brain stimulation on freezing of gait in Parkinson's disease.J Neurosurg. 2019; 131: 1797-1804https://doi.org/10.3171/2018.8.JNS18350Crossref PubMed Scopus (14) Google Scholar]. However, this case highlights the use of SCS for the treatment of FoG with significant results. SCS is a neuromodulation technique used to relieve chronic pain. SCS most commonly treats failed back surgery syndrome (posterior laminectomy syndrome). Although the mechanism of SCS is still unclear [[4]Melzack R. Wall P.D. Pain mechanisms: a new theory.Science. 1965; 150: 971-979https://doi.org/10.1126/science.150.3699.971Crossref PubMed Scopus (6802) Google Scholar], the reason why SCS can alleviate FoG seems to be that it affects the cortical motor circuit, involving the supplementary motor area [[5]de Lima-Pardini A.C. Coelho D.B. Souza C.P. et al.Effects of spinal cord stimulation on postural control in Parkinson's disease patients with freezing of gait.Elife. 2018; 7 (e37727. Published 2018 Aug 2)https://doi.org/10.7554/eLife.37727Crossref PubMed Scopus (23) Google Scholar]. In the future, after clinical trials with larger sample sizes, the use of similar instrumental posture and gait assessment methods may help to better understand the impact of SCS in different gait and posture situations. This study was supported by the Liaoning Provincial Natural Science Grant (No. 20180530001 ).