Essential tremor vs idiopathic Parkinson disease

Abstract

Substantia nigra (SN) hyperechogenicity measured by transcranial sonography (TCS) is a promising biomarker for Parkinson disease (PD). The aim of this study was to explore the diagnostic accuracy of SN hyperechogenicity (SN+) for differentiating PD from essential tremor (ET). A total of 119 patients with PD, 106 ET patients and 112 healthy controls that underwent TCS from November 2016 to February 2019 were included in this single-center retrospective case–control study. Two reviewers who were blinded to clinical information independently measured the SN+ by TCS imaging. The diagnostic sensitivity, specificity, and accuracy of TCS imaging were evaluated between the PD and healthy controls and between patients with PD and ET. Interrater agreement was assessed with the Cohen κ statistic. TCS imaging of the SN+ allowed to differentiate between patients with PD and ET with a sensitivity (91.6% and 90.8%) and specificity (91.5% and 89.6%) for readers 1 and 2, respectively. Interobserver agreement was excellent (к = 0.87). In addition, measurement of the SN+ allowed to differentiate between patients with PD and healthy subjects with a sensitivity (91.6% and 90.8%) and specificity (88.4% and 89.3%) for readers 1 and 2, respectively. Interobserver agreement was excellent (к = 0.91). Measurement of SN+ on TCS images could be a useful tool to distinguishing patients with PD from those with ET.

Differentiating Parkinson’s Disease from Essential Tremor Using Transcranial Sonography: A Systematic Review and Meta-Analysis

“…Except of two [13,26], all studies were prospective and reported blinded procedure. Formal assessment of interrater variability was performed in four of the above-mentioned studies [16,17,24,25], with good interrater correlation for TCS.…”

Value of ultrasound fusion imaging in detecting vascular cerebral white matter pathology

“…Transcranial sonography of brain parenchyma is well established in diagnosing and monitoring degenerative brain disorders [ 9 , 10 ]. Particularly, transcranial ultrasound assessment of the substantia nigra in neurodegenerative disorders can help to differentiate between Parkinson disease and essential tremor with a sensitivity of > 90% and a specificity of > 89% [ 11 ]. The usage of TCS also in emergency department setting is a promising application, since it might be able to distinguish, e.g., unclear neurological movement disorders with acute onset in patients presenting at ED [ 12 ].…”

An unusual gait disorder at the Emergency Department: role of the quantitative assessment of parenchymal transcranial Doppler sonography

“…Moreover, for early diagnosis of PD and differential diagnosis between PD and atypical parkinsonian syndromes, both the sensitivity and positive predictive value of SN hyperechogenicity were higher than 90%, and both the specificity and negative predictive value were higher than 80% (5). TCS imaging of the SN also allows to differentiate between PD and essential tremor, with a high sensitivity (>90%) and specificity (>89%) (6). The diagnostic specificity further increased when combining pTCS findings of SN, lenticular nucleus (LN), and third ventricle width.…”