Managing Essential Tremor

Abstract

Essential tremor is one of the most common tremor syndromes. According to the recent tremor classification, tremor as a symptom is defined as an involuntary, rhythmic, oscillatory movement of a body part and is classified along two axes: axis 1-defining syndromes based on the clinical features such as historical features, tremor characteristics, associated signs, and laboratory tests; and axis 2-classifying the etiology (Bhatia et al., Mov Disord 33:75-87, 2018). The management of this condition has two major approaches. The first is to exclude treatable etiologies, as particularly during the onset of this condition the presentation of a variety of etiologies can be with monosymptomatic tremor. Once the few etiologies with causal treatments are excluded, all further treatment is symptomatic. Shared decision-making with enabling the patient to knowledgeably choose treatment options is needed to customize the management. Mild to moderate tremor severity can sometimes be controlled with occupational treatment, speech therapy of psychotherapy, or adaptation of coping strategy. First-line pharmacological treatments include symptomatic treatment with propranolol, primidone, and topiramate. Botulinum toxin is for selected cases. Invasive treatments for essential tremor should be considered for severe tremors. They are generally accepted as the most powerful interventions and provide not only improvement of tremor but also a significant improvement of life quality. The current standard is deep brain stimulation (DBS) of the thalamic and subthalamic region. Focused ultrasound thalamotomy is a new therapy attracting increasing interest. Radiofrequency lesioning is only rarely done if DBS or focused ultrasound is not possible. Radiosurgery is not well established. We present our treatment algorithm.

Keywords: Tremor; deep brain stimulation; essential tremor; focused ultrasound; managing of essential tremor; treatment of essential tremor.

Fig. 1

Drug interventions for essential tremor. The mean improvement of the tremor scores are shown (study selection see text). The suppression of tremor amplitude is shown for the different drugs. They are grouped according to MDS criteria of clinical usefulness [29].

Fig. 2

Surgical interventions for essential tremor. The four options are shown with the grading of usefulness of the Movement Disorder Society [29]. The bars show the mean improvement in percent for the different interventions reported in the studies mentioned in the text. The lateralized TRS is summarizing tremor severity items only on the side contralateral to the intervention. The total TRS covers tremor severity, performance tests, and activities of daily living. The dotted line is the average improvement of the lateralized score exerted by medications (see Fig. 2). The grading of clinical usefulness does not reflect the strength of the effect size of the intervention but the strength of published evidence.

Fig. 3

Decision tree for the treatment of patients with essential tremor.