TY - BOOK AU - Lee, Sang Wook TI - The Pathophysiology of Dystonic Tremors and Comparison With Essential Tremor SN - 0270-6474 PY - 2020/// KW - *Dystonia/pp [Physiopathology] KW - *Essential Tremor/pp [Physiopathology] KW - *Tremor/pp [Physiopathology] KW - Accelerometry KW - Aged KW - Cerebellum/pp [Physiopathology] KW - Dystonic Disorders/pp [Physiopathology] KW - Electromyography KW - Female KW - Humans KW - Male KW - Middle Aged KW - Movement/ph [Physiology] KW - Transcranial Magnetic Stimulation KW - MedStar National Rehabilitation Network KW - Journal Article N1 - Available online from MWHC library: 1981 - present (after 18 months) N2 - There are two types of dystonic tremor syndromes (DTS), dystonic tremor (DT) and tremor associated with dystonia (TAWD), and neither is understood. DTS likely share some mechanisms with non-tremulous dystonia, and there may also be overlaps with essential tremor. We studied 21 ET (8 females, 13 males) and 22 DTS human patients (10 females, 12 males), including 13 human patients with DT (DT; writer's cramp with writing tremor) and 9 human patients with tremor associated with dystonia (TAWD; cervical dystonia with hand tremor). Tremors were analyzed using accelerometry and surface EMG of the antagonist pairs of arm muscles during posture, simple kinetic movement, and writing. Cerebellar inhibition (CBI) was performed to assess cerebello-thalamo-cortical (CTC) involvement. DT exhibited higher variability of peak frequency and greater instability of tremor burst intervals over time (higher tremor stability index; TSI) than ET or TAWD regardless of tasks. Intermuscular coherence magnitude between the antagonist pairs increased during the writing task in DT, but not ET or TAWD. ET and TAWD exhibited different phase relationships of the temporal fluctuations of voluntary movement and tremor in the kinetic condition. A linear discriminant classifier based on these tremor parameters was able to distinguish the three groups with a classification accuracy of 95.1%. CBI was significantly reduced in DT, but not in TAWD, compared to ET and healthy controls. Our study shows that the two DTS are distinct entities with DT closer to non-tremorous dystonia and TAWD closer to ET. SIGNIFICANCE STATEMENTThis study provides novel findings about characteristics and pathophysiology of the two different types of dystonic tremor syndromes (DTS), in comparison with essential tremor. Patients with DT are classified into DT (DT) who have dystonia and tremor in the same area, and tremor associated with dystonia (TAWD) who have dystonia and tremor elsewhere. Our results showed that DT exhibits increased tremor variability, instability, and intermuscular coherence, and decreased cerebello-thalamo-cortical inhibition compared to TAWD. Our study shows that DT and TAWD are distinct phenotypes, and that the physiological characteristics of DT are more similar to non-tremorous dystonia, and TAWD is closer to ET. Copyright (c) 2020 the authors UR - https://dx.doi.org/10.1523/JNEUROSCI.1181-20.2020 ER -