Gennarina Arabia1, Angela Lupo1, Lucia Ilaria Manfredini1, Basilio Vescio2, Rita Nisticò3, Gaetano Barbagallo1, Maria Salsone3, Maurizio Morelli1, Fabiana Novellino3, Giuseppe Nicoletti3, Andrea Quattrone1, Giuseppe Lucio Cascini4, Elan D Louis5, Aldo Quattrone6. 1. Institute of Neurology, Department of Medical Sciences, University "Magna Graecia" of Catanzaro, Italy. 2. Biotecnomed S.C.aR.L, Catanzaro, Italy. 3. Neuroimaging Research Unit, IBFM, National Research Council, Catanzaro, Italy. 4. Institute of Nuclear Medicine, University "Magna Graecia" of Catanzaro, Italy. 5. Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA. 6. Neuroimaging Research Unit, IBFM, National Research Council, Catanzaro, Italy; Neuroscience Center, University "Magna Graecia" of Catanzaro, Italy. Electronic address: quattrone@unicz.it.
Abstract
INTRODUCTION: Essential tremor-Parkinson's disease (ET-PD) syndrome is a clinical condition in which individuals with a long-lasting history of Essential tremor (ET) eventually develop Parkinson's disease (PD). The aim of the study was to investigate the accuracy performances of clinical, neurophysiological, and imaging biomarkers in differentiating patients affected by ET-PD syndrome from patients with ET or PD. METHODS: Nineteen patients affected by ET-PD syndrome, 48 ET patients, and 37 tremor-dominant PD (t-PD) patients were included. Electrophysiological studies, including blink-reflex recovery cycle and tremor parameters analyses, were performed in all groups. Nigro-striatal and cardiac sympathetic denervation were also investigated. Sensitivity, specificity and accuracy of clinical, electrophysiological, and radiological features in differentiating ET-PD syndrome from ET and PD were calculated. RESULTS: ET-PD patients had significantly lower rigidity (p = 0.007) and higher postural/kinetic tremor (p = 0.007) scores, in comparison to t-PD patients. ET-PD patients, differently from PD patients, had a synchronous pattern of resting tremor and, differently from ET patients, had abnormal blink-reflex recovery cycle. ET-PD patients also showed reduced nigro-striatal and cardiac sympathetic uptakes, albeit to a lesser extent than in PD patients. The highest accuracy values were found for the synchronous pattern of resting tremor (97.1%) in distinguishing ET-PD from PD, and for presence of abnormal blink-recovery cycle (100%) in distinguishing ET-PD syndrome from ET. CONCLUSION: Our study demonstrates that some electrophysiological parameters, such as a synchronous resting tremor pattern and the abnormal blink-recovery cycle were the most accurate biomarkers in distinguishing patient with ET-PD syndrome from those with ET or those with PD.
INTRODUCTION: Essential tremor-Parkinson's disease (ET-PD) syndrome is a clinical condition in which individuals with a long-lasting history of Essential tremor (ET) eventually develop Parkinson's disease (PD). The aim of the study was to investigate the accuracy performances of clinical, neurophysiological, and imaging biomarkers in differentiating patients affected by ET-PD syndrome from patients with ET or PD. METHODS: Nineteen patients affected by ET-PD syndrome, 48 ET patients, and 37 tremor-dominant PD (t-PD) patients were included. Electrophysiological studies, including blink-reflex recovery cycle and tremor parameters analyses, were performed in all groups. Nigro-striatal and cardiac sympathetic denervation were also investigated. Sensitivity, specificity and accuracy of clinical, electrophysiological, and radiological features in differentiating ET-PD syndrome from ET and PD were calculated. RESULTS: ET-PDpatients had significantly lower rigidity (p = 0.007) and higher postural/kinetic tremor (p = 0.007) scores, in comparison to t-PDpatients. ET-PDpatients, differently from PDpatients, had a synchronous pattern of resting tremor and, differently from ET patients, had abnormal blink-reflex recovery cycle. ET-PDpatients also showed reduced nigro-striatal and cardiac sympathetic uptakes, albeit to a lesser extent than in PDpatients. The highest accuracy values were found for the synchronous pattern of resting tremor (97.1%) in distinguishing ET-PD from PD, and for presence of abnormal blink-recovery cycle (100%) in distinguishing ET-PD syndrome from ET. CONCLUSION: Our study demonstrates that some electrophysiological parameters, such as a synchronous resting tremor pattern and the abnormal blink-recovery cycle were the most accurate biomarkers in distinguishing patient with ET-PD syndrome from those with ET or those with PD.