Low-frequency stimulation of STN-DBS reduces aspiration and freezing of gait in patients with PD

Abstract

Objectives: To study whether 60-Hz stimulation, compared with routine 130 Hz, improves swallowing function and freezing of gait (FOG) in patients with Parkinson disease (PD) who undergo bilateral subthalamic nucleus (STN) deep brain stimulation (DBS). Methods:We studied 7 patients with PD who experienced FOG that persisted despite routine 130-Hz stimulation and dopaminergic medication. Each patient received 3 modified barium swallow (MBS) studies in a single day under 3 DBS conditions in the medication-on state: 130 Hz, 60 Hz, or DBS off, in a randomized double-blind manner. The laryngeal penetration and aspiration events were cautiously assessed, and a swallowing questionnaire was completed. The Unified Parkinson's Disease Rating Scale, Part III motor score, axial subscore, tremor subscore, and FOG by a questionnaire and stand-walk-sit test were also assessed. The best DBS condition (60 Hz here) producing the least FOG was maintained for 3 to 8 weeks, and patients were assessed again. Changes in measurements between the 60 Hz and 130 Hz were analyzed using paired t test, with swallowing function as primary and the remainder as secondary outcomes. Changes between other DBS conditions were further explored with Bonferroni correction.Results: Compared with the routine 130 Hz, 60-Hz stimulation significantly reduced aspiration frequency by 57% on MBS study and perceived swallowing difficulty by 80% on questionnaire. It also significantly reduced FOG, and axial and parkinsonian symptoms. The benefits at 60-Hz stimulation persisted over the average 6-week assessment. Conclusions:Compared with the routine 130 Hz, the 60-Hz stimulation significantly improved swallowing function, FOG, and axial and parkinsonian symptoms in patients with PD treated with bilateral STN-DBS, which persisted over the 6-week study period. 1-5 However, DBS is less effective at improving the axial symptoms of postural instability, gait disorders, and speech and swallowing dysfunction. STN-DBS might transiently improve the axial symptoms, but could make them worse over the course of 2 to 5 years. Classification of evidence:6-15 The DBS stimulation settings typically used in these studies were high frequency of 130 to 185 Hz.Recently, a stimulation frequency of 60 Hz has been found to improve the axial symptoms of freezing of gait (FOG) 16-19 and dysarthria 15,19 compared with the routinely used 130-Hz stimulation. However, whether or not the stimulation frequency could also affect another axial symptom, swallowing function, remains unknown. The answer to this question is critical, because dysphagia is frequently present in patients with mid-and late-stage PD 20,21 and is associated with

Improving outcomes of subthalamic nucleus deep brain stimulation in Parkinson’s disease

“…In particular, short pulse widths decrease the activation of surrounding fibers as a result of specific axon properties such as chronaxie. Recently, an increasing number of reports have explored the use of low-frequency stimulation (60-80 Hz) to improve axial symptoms including freezing of gait, postural control, dysarthria, swallowing function and also bradykinesia [50,[52][53][54][55]. However, these reports only addressed the short-term effects, and the initial promising results were limited either by the transient clinical benefits or worsening of appendicular symptoms [52,56].…”

Long-term effect of low frequency stimulation of STN on dysphagia, freezing of gait and other motor symptoms in PD

“…Recently, we found that 60 Hz stimulation improved swallowing dysfunction, along with FOG and overall axial and motor symptoms, in PD patients with FOG at HFS and medication on state 18. This is important, as dysphagia is commonly present in PD,19 and often refractory to pharmacological management,20 21 with high risk of morbidity and mortality.…”

“…This is important, as dysphagia is commonly present in PD,19 and often refractory to pharmacological management,20 21 with high risk of morbidity and mortality. However, it remains unknown whether there is a long-term benefit on swallowing function beyond the 6 weeks studied,18 especially considering the potential disease progression and potential carryover effect associated with the order of DBS assessment.…”

Deep brain stimulation for movement disorders: update on recent discoveries and outlook on future developments

“…Two studies found that using 60 Hz instead of 130 Hz subthalamic stimulation significantly reduced number of FOG episodes [76,77]. Furthermore, improvements in dysarthria and aerodynamic speech parameters with 60 Hz compared to 130 Hz subthalamic stimulation have been reported [78].…”

“…Furthermore, improvements in dysarthria and aerodynamic speech parameters with 60 Hz compared to 130 Hz subthalamic stimulation have been reported [78]. Importantly, the use of low-frequency stimulation is also associated with a reduced aspiration tendency, as demonstrated by barium swallow studies, along with a reduction of perceived swallowing difficulty [76]. Low-frequency stimulation might even help to overcome STN DBS-induced verbal fluency impairment [79].…”