Twelve clinical pearls to help distinguish essential tremor from other tremors

Abstract

The features of the tremor in essential tremor are often not fully appreciated, and essential tremor is frequently mis-diagnosed. Close inspection indicates that the tremor is characterized by a specific and definable pattern of features. Recognizing these features will aid in the diagnosis. The features are as follows: (1) kinetic tremor is greater than postural tremor, for postural tremor, (2) wrist tremor is greater than metacarpal joint tremor and wrist flexion-extension tremor is greater than wrist rotation tremor, (3) tremor is regularly recurrent and without directionality, (4) arm tremor is generally mildly asymmetric, (5) postural tremors (right, left) are out of phase, (6) on spiral drawing, a single tremor orientation axis is often identifiable, (7) intention tremor (finger-nose-finger) occurs in 50% of cases, (8) rest tremor (in the arms but not the legs) can occur as a late feature, (9) arm tremor precedes head tremor, and head tremor occurs mainly in women, (10) head tremor, unless severe, resolves while supine, (11) patients are often unaware of head tremor, (12) tremor is progressive.

Keywords::

• clinical
• diagnosis
• dystonia
• essential tremor
• neurological examination
• Parkinson’s disease

Financial & competing interests disclosure

The author received funding from National Institutes of Health R01NS042859, R01 NS039422, R01 NS085136, and R01 NS073872. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Essential tremor (ET) is the most common tremor disorder, with patients being cared for by a broad range of practitioners, ranging from family physicians to movement disorder neurologists.

• ET is overdiagnosed, with estimates indicating that 30–50% of ET diagnoses are incorrect. As such, the ET diagnosis is used as a diagnostic waste basket for tremor.

• The misdiagnosis of ET has important consequences in terms of clinical care, the conduct and interpretation of clinical trials, and the value of epidemiological, genetic and pathomechanistic studies.

• Twelve clinical pearls were enumerated, drawing attention to specific characteristics of the tremor of ET. Attention to these clinical features should aid in attaining greater diagnostic accuracy.

• ET may be distinguished from dystonia based on several clinical features including but not limited to the regularity and lack of directionality of tremor.

• ET may be distinguished from Parkinson’s disease based on differences in the features of the postural tremor as well as the presence of other features.