The treatment of dystonic tremor: a systematic review

Abstract

Tremor is one of the clinical manifestations of dystonia; however, there are no specific therapeutic trials evaluating the efficacy of treatments for dystonic tremor (DT), tremor associated with dystonia or primary writing tremor (PWT). We systematically reviewed the literature available up to July 2013 on the treatment of these tremors and retrieved the data of 487 patients published in 43 papers detailing the effects of given interventions on tremor severity. Treatment outcome was highly variable, depending on the specific type of intervention and tremor distribution. No specifically designed studies were available for the treatment of tremor associated with dystonia. As for the other tremors, drug efficacy was generally disappointing and a moderate effect was only found with anticholinergics, tetrabenazine, clonazepam, β-blockers and primidone; levodopa was only efficacious on tremor due to dopa-responsive dystonia. The largest amount of data was available for botulinum toxin injections, which provided a marked improvement, particularly for the management of axial tremors (head or vocal cords). In refractory DTs, deep brain stimulation of several targets was attempted. Deep brain stimulation of globus pallidus internus, thalamus or subthalamic area led to a marked improvement of dystonic axial or appendicular tremors in most cases refractory to other treatments. Few other non-invasive treatments, for example, orthotic device in PWT, have been used with anecdotal success. In conclusion, considering the lack of good-quality studies, future randomised controlled trials are needed. In absence of evidence-based guidelines, we propose an algorithm for the treatment of DT based on currently available data.

Diagnosis and Treatment of Dystonia

“…Anecdotal experience suggests they may be most useful for suppressing phasic aspects of dystonia, such as blinking in blepharospasm or tremor-dominant forms of dystonia. 67,81,82 They also appear to be useful in the paroxysmal dyskinesias, where dystonia can be a prominent feature. 83 Common side effects include sedation, impaired mentation and coordination, and depression.…”

A Pilot Study of Botulinum Toxin for Jerky, Position-Specific, Upper Limb Action Tremor

“…BT injections have a fairly accepted role in managing head tremor, tremulous spasmodic dysphonia, and primary writing tremor 8,9. However, studies of the effect of BT on other upper limb tremor types have had heterogeneous results in terms of functional disability.…”

Medical and Surgical Treatment of Tremors

“…Anticholinergics (ie, trihexyphenidyl, range 3-6 mg/d) produced the best result; propranolol also produced some benefit. 79 Fasano and colleagues 80 recently presented a review of 487 patients with dystonic tremor published in 43 articles and concluded that drug efficacy is generally moderate (total improvement approximately 40%), depending on the distribution and type of tremor. Anticholinergics led to approximately 40% improvement.…”