National Survey of Essential Tremor Plus in China

Essential tremor (ET) is one of the most common adult-onset movement disorders, affecting 0.9% of the population across all ages worldwide. ET is a chronic, progressive neurologic disease whose the most recognizable clinical feature is a 4~12 Hz kinetic tremor of the upper limbs, usually occurring during a variety of voluntary movements. The etiology and pathogenesis of ET remain elusive.

Essential tremor-plus (ET-plus) is a new term coined in 2018 MDS consensus statement on tremor. ET-plus is defined as tremor with the characteristics of essential tremor, with additional neurological signs of uncertain clinical significance, such as impaired tandem gait, questionable dystonic posturing, memory impairment, or other mild neurological signs of unknown clinical significance that do not suffice to make an additional syndrome classification or diagnosis.

ET-plus is a controversial new concept. We will use scales or questionnaires to investigate the common soft neurological signs of ET-plus in mainland China. The details are as follows: (1) The tremor's impact on activities of daily living and clinical measurement of ET severity are evaluated by The Essential Tremor Rating Assessment Scale (TETRAS). (2) Cognitive condition is assessed by Mini Mental State Examination (MMSE) and Montreal Cognitive Assessment (MOCA). (3) The non-motor symptoms are evaluated by Non-motor Symptom Scale (NMSS). (4) Clinical assessment of balance and gait in ET-plus: we will use Tandem walk, Berg balance scale (BBS) and 10 meter walk timing test. (5) The Unified Dystonia Rating Scale (UDRS) for evaluation of dystonia in ET-plus. (6) The scale for the Assessment and Rating of Ataxia (SARA) is used to evaluate ataxia in ET-plus.