Effects of subthalamic nucleus stimulation and medication on resting and postural tremor in Parkinson's disease

Abstract

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) and antiparkinsonian medication have proved to be effective treatments for tremor in Parkinson's disease. To date it is not known how and to what extent STN DBS alone and in combination with antiparkinsonian medication alters the pathophysiology of resting and postural tremor in idiopathic Parkinson's disease. The purpose of this study was to examine the effects of STN DBS and antiparkinsonian medication on the neurophysiological characteristics of resting and postural hand tremor in Parkinson's disease. Resting and postural hand tremor were recorded using accelerometry and surface electromyography (EMG) from 10 Parkinson's disease patients and 10 matched control subjects. The Parkinson's disease subjects were examined under four treatment conditions: (i) off treatment; (ii) STN DBS; (iii) medication; and (iv) medication plus STN DBS. The amplitude, EMG frequency, regularity, and 1-8 Hz tremor-EMG coherence were analysed. Both STN DBS and medication reduced the amplitude, regularity and tremor-EMG coherence, and increased the EMG frequency of resting and postural tremor in Parkinson's disease. STN DBS was more effective than medication in reducing the amplitude and increasing the frequency of resting and postural tremor to healthy physiological levels. These findings provide strong evidence that effective STN DBS normalizes the amplitude and frequency of tremor. The findings suggest that neural activity in the STN is an important modulator of the neural network(s) responsible for both resting and postural tremor genesis in Parkinson's disease.

Intraoperative acceleration measurements to quantify improvement in tremor during deep brain stimulation surgery

“…Accelerometers have been applied outside the operating room (OR) for a wide variety of purposes, e.g., to characterize pathological tremor [8,13], to compare it with physiological tremor [20,35,36], and to evaluate the severity and evolution of tremor [28,29,40] and the tremor-alleviating effect of drugs or DBS [22,36,47]. Pulliam et al [34] used motion sensors during postoperative DBS pulse generator programming to develop automated programming algorithms and concluded that objective assessment can improve patients' outcomes.…”

Signal features of surface electromyography in advanced Parkinson’s disease during different settings of deep brain stimulation

“…Therefore, it may be useful in quantifying treatment efficacy in PD. Previous EMG-based studies have shown that DBS may change the EMG signal characteristics by increasing the dominant tremor frequency in the EMG spectrum (Blahak et al, 2007;Sturman et al, 2004) and by reducing the EMG-acceleration coherence during a resting condition and with backward counting (Sturman et al, 2004(Sturman et al, , 2007. DBS may also increase the size of the first agonist burst and the number of agonist bursts during rapid point-to-point movements of the elbow and ankle (Vaillancourt et al, , 2006.…”

Effects of STN DBS on Rigidity in Parkinson's Disease

“…As the disease progresses, the efficacy of L-dopa decreases and the incidence and severity of the side effects increase [2]. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been shown to modify several of the neurophysiological parameters associated with tremor and bradykinesia better than medication alone [3], [4]. STN DBS has also been shown to improve clinical measures of rigidity [2], [5]- [8].…”