PURPOSE OF REVIEW Tremor may be defined as an involuntary movement that is rhythmic (ie, regularly recurrent) and oscillatory (ie, rotating around a central plane) and may manifest in a variety of ways; accordingly, tremor has a rich clinical phenomenology. Consequently, the diagnosis of tremor disorders can be challenging, and misdiagnoses are common. The goal of this article is to provide the reader with straightforward approaches to the diagnosis and treatment of tremors.

RECENT FINDINGS Focused ultrasound thalamotomy of the ventral intermediate nucleus of the thalamus is an emerging and promising therapy for the treatment of essential tremor.

SUMMARY The evaluation should start with a detailed tremor history followed by a focused neurologic examination, which should attend to the many subtleties of tremor phenomenology. Among other things, the history and examination are used to establish whether the primary tremor is an action tremor (ie, postural, kinetic, or intention tremor) or a resting tremor. The clinician should then formulate two sets of diagnoses: disorders in which action tremor is the predominant tremor versus those in which resting tremor is the predominant tremor. Among the most common of the former type are essential tremor, enhanced physiologic tremor, drug-induced tremor, dystonic tremor, primary writing tremor, orthostatic tremor, and cerebellar tremor. Parkinson disease is the most common disorder of resting tremor. This article details the clinical features of each of these disorders, as well as those of additional tremor disorders.

Address correspondence to Dr Elan D. Louis, Yale School of Medicine, Department of Neurology, LCI 710, 15 York St, PO Box 20818, New Haven, CT 06520-8018, [email protected].

RELATIONSHIP DISCLOSURE: Dr Louis serves on the clinical advisory boards of CADENT Therapeutics and SAGE Therapeutics, Inc and receives publishing royalties from Elsevier for Merritt’s Neurology.

UNLABELED USE OF PRODUCTS/INVESTIGATIONAL USE DISCLOSURE: Dr Louis discusses the unlabeled/investigational use of alprazolam, benzodiazepines, carbidopa/levodopa, clonazepam, gabapentin, primidone, and topiramate for the treatment of essential tremor; trihexyphenidyl for the treatment of dystonic tremor; acetazolamide, baclofen, carbamazepine, clonazepam, ethosuximide, and phenytoin for the treatment of orthostatic tremor; pregabalin for the treatment of neuropathic tremor; benzodiazepines for the treatment of parkinsonian resting tremor; and phenobarbital to treat the side effects of acute nausea and unsteadiness that occur as a result of other treatments for tremor.