Table 2.
Studies on other neuroimaging about prodromal markers of new-onset PD in ET patients.
| Neuroimaging techniques | Subjects | Results | References | |
|---|---|---|---|---|
| Structural neuroimaging | VBM | ET vs. healthy controls | White and gray matter of many brain regions changed in ET patients | (33) |
| ET vs. PD | PD and ET caused specific patterns of brain volume alterations | (34) | ||
| DTI | ET vs. healthy controls | MD was significantly higher in the cerebellar gray matter of ET group, indicating cerebellum microstructural changes and some other networks involved | (35) | |
| VBM+DTI | ET vs. PD | Combination of two methods helps in differentiating two kinds of patients | (36) | |
| Metabolic neuroimaging | 1H-MRS | ET vs. healthy controls | Cortical NAA/Cr in the cerebellar was reduced in ET cases and the value was inversely proportional to arm tremor severity | (37) |
| ET vs. healthy controls | Glx and Glx/Cr values increased in both thalami of ET patients and the value was proportional to tremor severity, indicating thalamic glutamatergic transmission and cerebellum invloved | (38) | ||
| Iron deposition | ET vs. healthy controls | Iron accumulation increased in ET patients, suggesting a possible involvement of motor systems outside of the cerebellar pathway | (39) | |
| Functional neuroimaging | DAT-SPECT+MIBG | Mixed tremor vs. PD vs. ET vs. controls | Combined use of these two techniques can help distinguish ET patients from PD patients and parkinsonism | (40) |
| fMRI | ET VS healthy controls | Cerebellar neurodegeneration underlying essential tremor is reflected in abnormal communications between key working memory regions and that adaptive mechanisms involved in to influence cognition | (41) |
VBM, voxel-based morphometry; PD, Parkinson's disease; ET, essential tremor; DTI, Diffusion tensor imaging; MD, Mean diffusivity; 1H-MRS, Proton MR Spectroscopy; NAA, N-acetyl-aspartate + N-acetyl-aspartyl-glutamate; Cr, creatine + phosphocreatine; Glx, glutamate + glutamine; DAT-SPECT, Dopamine transporter 123I-FP-CIT-single-photon emission tomography; MIBG, myocardial scintigraphy with 123metaiodobenzylguanidine.