Journal of the Neurological Sciences issue 435 now available

Review Article [FREE]

Non-invasive electrical stimulation of peripheral nerves for the management of tremor Pascual-Valdunciel et al.

Published online: February 19, 2022

Pathological tremor in patients with essential tremor and Parkinsons disease is typically treated using medication or neurosurgical interventions. There is a widely recognized need for new treatments that avoid the side effects of current medications and do not carry the risks of surgical interventions. Building on decades of research and engineering development, non-invasive electrical stimulation of peripheral nerves has emerged as a safe and effective strategy for reducing pathologic tremor in essential tremor.

This review surveys the peripheral electrical stimulation (PES) literature and summarizes effectiveness, safety, clinical translatability, and hypothesized tremor-reduction mechanisms of various PES approaches. The review also proposes guidelines for assessing tremor in the context of evaluating new therapies that combine the strengths of clinician assessments, patient evaluations, and novel motion sensing technology.

The review concludes with a summary of future directions for PES, including expanding clinical access for patients with Parkinson's disease and leveraging large, at-home datasets to learn more about tremor physiology and treatment effect that will better characterize the state of tremor management and accelerate discovery of new therapies. Growing evidence suggests that non-invasive electrical stimulation of afferent neural pathways provides a viable new option for management of pathological tremor, with one specific PES therapy cleared for prescription and home use, suggesting that PES be considered along with medication and neurosurgical interventions for treatment of tremor.

Review Article [FREE]

Tremor rating scales and laboratory tools for assessing tremor Elble et al.

Published online: February 21, 2022

The purpose of this review is to characterize and compare validated clinical rating scales and transducers that are used in the clinical assessment of tremor disorders.

Tremor is an involuntary oscillatory movement of a body part. Tremor can be characterized in terms of amplitude and frequency of oscillation, and these kinematic properties vary randomly and with activities of daily living.

Clinical rating scales are most useful when performing a comprehensive assessment of tremor severity (amplitude), anatomical distribution, activation conditions, and impact on activities of daily living and quality of life. Motion transducers are often used in conjunction with surface electromyography to discern properties of tremor that are important diagnostically. Motion transducers are needed for an accurate determination of tremor frequency and for precise quantification of changes in amplitude and frequency over time. The precision and accuracy of motion transducers exceed that of all clinical rating scales. However, these advantages of transducers are mitigated by the considerable within-subject random variability in tremor amplitude, such that the smallest detectable statistically significant change in tremor amplitude is comparable for scales and transducers.

Comprehensive anatomical and behavioral assessment of tremor with transducers is not clinically feasible. Transducers and scales are presently viewed as complementary methods of quantifying tremor amplitude. Transducer measures are logarithmically related to clinical ratings, as predicted by the Weber-Fechner law of psychophysics. This relationship must be considered when interpreting change in clinical ratings, produced by disease or treatment.

Review article [Open Access]

Deep brain stimulation for the treatment of tremor Chandra et al.

Published online: March 4, 2022

This review article provides a brief historical perspective on the use of DBS for tremor, reviews the various etiologies for tremor that can be effectively managed with DBS therapy, discusses the DBS targets that have been used for suppression of tremor, and reviews in detail important aspects of DBS surgical technique, including significant technological advances over the past several years that, when applied, can substantially improve the outcomes of DBS for tremor.

Review article [Open Access]

Medications used to treat tremors Frei et al.

Published online: February 19, 2022

Tremor is one of the most common movement disorders, though it can arise in the context of several unrelated neurological disorders whose pharmacology and anatomical origins differ greatly. Treatment of tremors can take advantage of several medications and neurosurgical treatments. Medications useful for treating tremor are discussed in this review, including those for action tremor as seen in essential tremor, the resting tremor of Parkinson's disease, orthostatic tremor, cerebellar tremor, Holmes tremor, dystonic tremor, and drug-induced tremors. A medication that is useful for most types of tremors is the beta-blocker propranolol, though even in essential tremor it can fail to be effective at tremor control.