DIAGNOSIS OF ESSENTIAL TREMOR: ADVANCES IN CLINICAL AND NEUROPHYSIOLOGICAL TOOLS

Abstract

Essential tremor (ET) is the most common tremor syndrome, but its diagnosis has historically been challenging, leading to high error rates and confusion, particularly with dystonic tremor and Parkinson's disease (PD). This narrative review addresses advances in diagnostic tools. The 2018 International Parkinson and Movement Disorders Society (MDS) classification refined the criteria, introducing the concept of "Essential Tremor Plus" (ET+) to categorize patients with ET who present with "neurological soft signs" of uncertain significance, recognizing the heterogeneity of the condition. Differential diagnosis remains the greatest challenge: while PD can be differentiated by clinical findings (resting tremor, bradykinesia) and imaging (DAT-SPECT), dystonic tremor requires attention to clinical clues such as irregularity and "sensory tricks." Advances in neurophysiological tests, such as the Somatosensory Temporal Discrimination Threshold and the Blink Reflex, show promise in distinguishing pure ET from ET+ and dystonia. Furthermore, advances in biomarkers (α-synuclein) and neuroimaging (DTI, PET) reinforce the understanding of ET as a disorder of the cerebello-thalamic-cortical network, although many of these tools are still in the research stage.