Clinical characteristics of patients with essential tremor or essential tremor plus

Abstract

Background The International Parkinson and Movement Disorder Society introduced the category of essential tremor (ET)‐plus in its new ET classification scheme, but how the clinical correlates of ET‐plus differ from those of “pure” ET is unclear. By comparing the clinical characteristics of ET and ET‐plus patients, we expect to better understand the impact and invoked questions of the new classification on clinical practice. Methods We reviewed the medical records of 280 ET syndrome patients in an ongoing cross‐sectional study in a Chinese population and reclassified them according to the new criteria. Clinico‐demographic characteristics were compared between ET and ET‐plus patients. Risk factors of diagnosis of ET‐plus were explored using logistic regression. Results A total of 121 patients (50.8%) were reclassified as having ET and 117 as having ET‐plus. ET‐plus group was significantly older at tremor onset, less educated, and more likely to have cranial tremor, depression symptom, anxiety symptom, and probable REM sleep behavior disorder. ET‐plus group also showed more severe upper limb tremor and cognition impairment. Regression analysis identified four independent risk factors associated with ET‐plus: late tremor onset (OR 3.04, 95%CI 1.60‐5.79), less educated (OR 0.91, 95%CI 0.85‐0.97), severe upper limb tremor (OR 2.46, 95%CI 1.30‐4.62), and presence of cranial tremor (OR 2.30, 95%CI 1.20‐4.41). Conclusions The new classification scheme emphasized that ET syndrome is heterogeneous. ET‐plus cannot be seen as a subtype or a diagnosis of ET syndrome, but rather as a placeholder, representing an area of current scientific uncertainty.

Phenotypic Features of Isolated Essential Tremor, Essential Tremor Plus, and Essential Tremor-Parkinson’s Disease in a Movement Disorders Clinic

“…Furthermore, ET plus patients had a significantly higher prevalence of head tremor compared to those with isolated ET, which may indicate more severe tremor or a separate ET subtype. Another study similarly showed more severe upper limb tremors and a higher prevalence of head tremor in ET plus patients [28]. Our ET plus patients also required treatment with significantly more medications than isolated ET patients.…”

“ET Plus”: Instability of the Diagnosis During Prospective Longitudinal Follow-up of Essential Tremor Cases

“…The ET plus “subtype” of ET has been the source of considerable scrutiny ( 10 ). Several cross-sectional studies have reported a prevalence of more than 50% for ET plus, after reclassifying ET cohorts into those with ET vs. those with ET plus ( 5 , 6 , 8 ). In the current study, 85.6% of the cohort received at least one ET plus diagnosis during the span of four time intervals and the proportion with ET plus reached 72.1% by the fourth and final time interval.…”

“…The new term has generated interest and several publications have assessed the proportions with ET vs. ET plus in their cohorts ( 5 – 8 ). On the other hand, the new classification has also engendered criticism and controversy, with considerable concern that it represents a disease stage rather than a true disease subtype ( 9 – 13 ).…”

“…Although several investigators have quantified the prevalence of ET plus in cross-sectional samples of patients, those with ET plus have not been tracked longitudinally, so there is no understanding of how this designation behaves over time and whether it is stable ( 5 , 6 , 8 ).…”

Do We Belittle Essential Tremor by Calling It a Syndrome Rather Than a Disease? No

“…Retrospective reviews of outpatient clinical cohorts have shown that 40% or more of patients previously diagnosed as ET are reclassified as ET plus or a combined tremor syndrome when the new MDS classification scheme is applied ( 23 – 25 ). For example, 20 of the last 34 patients undergoing DBS surgery for ET at our center were reclassified as ET plus due to the following Axis 1 features: rest tremor or questionable rest tremor ( n = 9), questionable dystonic posturing ( n = 14), jerky tremor ( n = 7), asymmetry in upper limb tremor exceeding 1 point on the Essential Tremor Rating Assessment Scale ( n = 8) ( 26 ), rapid progression ( n = 6), strained voice ( n = 3), and impaired tandem gait ( n = 7).…”