Longitudinal study of clinical and neurophysiological features in essential tremor

Abstract

Background and purpose Essential tremor (ET) is a common and heterogeneous disorder characterized by postural/kinetic tremor of the upper limbs and other body segments and by non‐motor symptoms, including cognitive and psychiatric abnormalities. Only a limited number of longitudinal studies have comprehensively and simultaneously investigated motor and non‐motor symptom progression in ET. Possible soft signs that configure the ET‐plus diagnosis are also under‐investigated in follow‐up studies. We aimed to longitudinally investigate the progression of ET manifestations by means of clinical and neurophysiological evaluation. Methods Thirty‐seven ET patients underwent evaluation at baseline (T0) and at follow‐up (T1; mean interval ± SD = 39.89 ± 9.83 months). The assessment included the clinical and kinematic evaluation of tremor and voluntary movement execution, as well as the investigation of cognitive and psychiatric disorders. Results A higher percentage of patients showed tremor in multiple body segments and rest tremor at T1 as compared to T0 (all p‐values < 0.01). At T1, the kinematic analysis revealed reduced finger‐tapping movement amplitude and velocity as compared to T0 (both p‐values < 0.001). The prevalence of cognitive and psychiatric disorders did not change between T0 and T1. Female sex, absence of family history, and rest tremor at baseline were identified as predictive factors of worse disease progression. Conclusions ET progression is characterized by the spread of tremor in multiple body segments and by the emergence of soft signs. We also identified possible predictors of disease worsening. The results contribute to a better understanding of ET classification and pathophysiology.

Elevated serum neurofilament light chain protein in patients with essential tremor

“…Thus, our findings of increased sNfL in ET may suggest some common underlying neuro-axonal damage. This is also supported by a recent longitudinal study which showed clinical progression of motor symptoms in ET, namely spread of tremor in multiple body segments and emergence of soft signs, over time [27].…”

Treatment patterns in essential tremor: Real‐world evidence from a United Kingdom and France primary care database

“…It should be also acknowledged, however, that relying on diagnostic codes from GP databases to select incident ET cases might lead to an incorrect diagnosis in approximately 35% to 50% of ET cases, as reported in previous studies [7, 41–44]. This, in turn, might overestimate our results either in terms of undertreatment or in terms of proportion of true ET patients discontinuing the treatment.…”

“…First, as previously mentioned, we used a set of diagnostic codes from GP databases to select incident ET cases rather than employing a population-based design. This approach, on the one hand, might underestimate the true disease burden [7], but on the other hand, might lead to an incorrect diagnosis of ET [7,[41][42][43][44]. To avoid these biases, we applied very strict criteria to exclude tremor-related diseases, such as dystonia, ataxia, Parkinson's disease, or parkinsonism.…”

“…However, over time, tremor progression may spread to other body segments to severely impair basic daily activities such as eating, writing, personal care, and driving [1,2,6]. In this regard, a recent longitudinal study evaluated the temporal progression of ET severity and reported an annual worsening ranging between 3.1% and 12% [7].…”

Insight Into the Relationship Between Motor and Cognitive Symptoms in Essential Tremor

“…In this context, individuals with ET may exhibit a mild slowing of voluntary movement, often referred to as bradykinesia [2][3][4][5][6][7][8][9][10][11][12][13], and the impaired movement performance cannot be solely attributed to the secondary effects of tremor [3][4][5][6][7][9][10][11]. Furthermore, various studies have documented the presence of cognitive dysfunction in ET patients [2,7,8,[13][14][15][16][17][18][19]. For instance, recent ndings indicate that over 30% [8], and possibly up to 50% of ET patients [7] exhibit mild cognitive impairment (MCI) based on neurophysiological assessments [20,21].…”