INTRODUCTION: Despite substantial clinical and pathophysiological differences, the characteristics of tremor in Parkinson's disease (PD) and essential tremor (ET) patients bear certain similarities. The presented study delineates tremor-related structural networks in these two disorders. METHODS: 42 non-advanced PD patients (18 tremor-dominant, 24 without substantial tremor), 17 ET, and 45 healthy controls underwent high-angular resolution diffusion-weighted imaging acquisition to reconstruct their structural motor connectomes as a proxy of the anatomical interconnections between motor network regions, implementing state-of-the-art globally optimised probabilistic tractography. RESULTS: When compared to healthy controls, ET patients exhibited higher structural connectivity in the cerebello-thalamo-cortical network. Interestingly, the comparison of tremor-dominant PD patients and PD patients without tremor yielded very similar results - higher structural connectivity in tremor-dominant PD sharing multiple nodes with the tremor network detected in ET, despite the generally lower structural connectivity between basal ganglia and frontal cortex in the whole PD group when compared to healthy controls. CONCLUSION: The higher structural connectivity of the cerebello-thalamo-cortical network seems to be the dominant tremor driver in both PD and ET. While it appears to be the only tremor-related network in ET, its combination with large scale hypoconnectivity in the frontal cortico-subcortical network in PD may explain different clinical features of tremor in these two disorders.
Transkraniální sonografie (TCS) je rychlé, levné a široce dostupné vyšetření, dobře využitelné v diagnostice Parkinsonovy nemoci (PN) a demence s Lewyho tělísky (DLB), zejména pro screening v časných a prodromálních stadiích těchto onemocnění. Pacienti s PN a DLB vykazují zvýšenou echogenitu substantia nigra (SN). Hyperechogenita SN odráží zejména nadměrné hromadění železa v tkáni a degeneraci. Cílem této přehledové práce je popsat roli a využitelnost TCS v diagnostice pacientů s PN a DLB, včetně zaměření se na jejich prodromální stadia a diferenciální diagnostiku. V bezpříznakovém období je nález hyperechogenity SN považován za jeden z rizikových faktorů pro rozvoj synukleinopatií, zejména PN. Výsledky TCS studií jsou dány do kontextu diagnostických kritérií pro PN a DLB.
Transcranial sonography (TCS) is a quick, inexpensive, widely available and well applicable examination in the diagnosis of Parkinson's disease (PD) and Lewy body dementia (LBD), especially for screening in the early and prodromal stages of these diseases. Patients with PD and DLB reveal increased echogenicity of substantia nigra (SN). The SN hyperechogenicity particularly reflects excessive iron accumulation and tissue degeneration. The aim of this review is to describe the role and utility of TCS in the diagnosis of patients with PD and LBD, including a focus on their prodromal stages and differential diagnosis. In the asymptomatic period, the finding of SN hyperechogenicity is considered to be one of the risk factors for the development of synucleinopathies, especially PD. The results of TCS studies are placed in the context of diagnostic criteria for PD and LBD.
- MeSH
- Lewy Body Disease * diagnostic imaging diagnosis MeSH
- Echoencephalography methods MeSH
- Essential Tremor diagnostic imaging diagnosis MeSH
- Humans MeSH
- Parkinson Disease * diagnostic imaging diagnosis MeSH
- Parkinsonian Disorders diagnostic imaging diagnosis MeSH
- Substantia Nigra diagnostic imaging pathology MeSH
- Synucleinopathies diagnostic imaging diagnosis MeSH
- Ultrasonography, Doppler, Transcranial methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
Differential diagnosis of the most common tremor syndromes - essential tremor (ET) and Parkinson's disease (PD) is burdened with high error rate. However, diagnostic MRI biomarkers applicable in this clinically highly relevant scenario remain an unfulfilled objective. The presented study was designed in search for possible candidate MRI protocols relevant for differential diagnostic process in tremor syndromes.10 non-advanced tremor-dominant PD patients meeting diagnostic criteria for clinically established PD, 12 isolated ET patients and 16 healthy controls were enrolled into this study. The study focused on relaxation MRI protocols - T1, T2, adiabatic T1ρ and adiabatic T2ρ due to their relatively low post-processing requirements enabling implementation into routine clinical practice. Compared to ET, PD patients had significantly longer T2 relaxation times in striata with dominant findings in the putamen contralateral to the clinically more affected body side. This difference was driven by alterations in the PD group as confirmed in the complementary comparison with healthy controls. According to the receiver operating characteristic analysis, this region provided a reasonable sensitivity of 0.91 and specificity of 0.89 in the differential diagnosis of PD and ET. In PD patients, we further found prolonged T1ρ in the substantia nigra compared to ET and healthy controls, and shorter T2 and T2ρ in the cerebellum compared to healthy controls. T2 relaxation time in the putamen contralateral to the clinically more affected body side is a plausible candidate diagnostic marker for the differentiation of PD and ET.
- MeSH
- Diagnosis, Differential MeSH
- Essential Tremor diagnostic imaging MeSH
- Middle Aged MeSH
- Humans MeSH
- Magnetic Resonance Imaging methods standards MeSH
- Neuroimaging methods standards MeSH
- Parkinson Disease diagnostic imaging MeSH
- Putamen diagnostic imaging MeSH
- Aged MeSH
- Sensitivity and Specificity MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
BACKGROUND: An evolving pathophysiological concept of essential tremor (ET) points to diffuse brain network involvement, which emphasizes the need to investigate white matter (WM) changes associated with motor symptoms of ET. OBJECTIVES: To investigate ET-related WM changes and WM correlates of tremor severity using tremor clinical rating scales and accelerometry. METHODS: Tract-based spatial statistics (TBSS) approach was utilized to compare 3 Tesla diffusion tensor imaging (DTI) data from 12 ET patients and 10 age- and gender-matched healthy individuals. Clinical scales, tremor frequency and amplitude as measured by accelerometry were correlated with DTI data. RESULTS: ET patients demonstrated mean (MD) and radial diffusivity (RD) abnormalities in tracts involved in primary and associative motor functions such as bilateral corticospinal tracts, the superior longitudinal fascicles, and the corpus callosum but also in nonmotor regions including the inferior fronto-occipital and longitudinal fascicles, cingulum bundles, anterior thalamic radiations, and uncinate fascicles. A combined tremor frequency and amplitude score correlated with RD and MD in extensive WM areas, which partially overlapped the regions that were associated with tremor frequency. No significant relationship was found between DTI measures and clinical rating scales scores. CONCLUSIONS: The results show that ET-related diffusion WM changes and their correlates with tremor severity are preferentially located in the primary and associative motor areas. In contrast, a relationship between WM was not detected with clinical rating scales. Accelerometry parameters may, therefore, serve as a potentially useful clinical measures that relate to WM deficits in ET.
- MeSH
- Accelerometry MeSH
- White Matter diagnostic imaging physiology MeSH
- Adult MeSH
- Essential Tremor diagnostic imaging physiopathology MeSH
- Middle Aged MeSH
- Humans MeSH
- Brain Mapping methods MeSH
- Young Adult MeSH
- Pilot Projects MeSH
- Aged MeSH
- Severity of Illness Index MeSH
- Diffusion Tensor Imaging methods MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Purpose: Transcranial B-mode sonography (TCS) of brain parenchyma is increasingly used as a diagnostic tool for movement disorders. Accordingly, experimental B-Mode Assist software was developed to enable digitized analysis of the echogenicity of predefined brain regions. The aim of the study was to assess the reproducibility of digitized TCS image analysis of the insula. Materials and Methods: A total of 130 patients with an indication for neurosonological examination were screened for participation in the study. The insula was imaged from the right temporal bone window using Virtual Navigator and TCS-MRI (magnetic resonance imaging) fusion imaging. All subjects were examined three times by two experienced sonographers. Corresponding images of the insula in the axial thalamic plane were encoded and digitally analyzed. Interclass correlation coefficient (ICC) and Spearman's rank correlation coefficient were used for the assessment of intra- and inter-reader as well as intra- and inter-investigator reliabilities. Results: TCS images of 114 patients were evaluated (21 patients with TIA, 53 patients with headache, 18 patients with essential tremor, 22 patients with neurodegerative disease). 16 patients were excluded from analysis due to insufficient bone window. The intra-reader, inter-reader, intra-investigator and inter-investigator ICCs/Spearman's rank correlation coefficients were 0.995/0.993, 0.937/0.921, 0.969/0.961 and 0.875/0.858, resp. Conclusion: The present study demonstrates a high reliability to reproduce echogenicity values of the insula using digitized image analysis and TCS-MRI fusion images with almost perfect intra-reader, inter-reader, intra-investigator and inter-investigator agreement.
- MeSH
- Headache diagnostic imaging MeSH
- Essential Tremor diagnostic imaging MeSH
- Image Interpretation, Computer-Assisted methods MeSH
- Contrast Media * MeSH
- Humans MeSH
- Magnetic Resonance Imaging methods MeSH
- Cerebral Cortex diagnostic imaging MeSH
- Multimodal Imaging methods MeSH
- Neurodegenerative Diseases diagnostic imaging MeSH
- Infant, Newborn MeSH
- Observer Variation MeSH
- Reproducibility of Results MeSH
- Statistics as Topic MeSH
- Pregnancy MeSH
- Thalamus diagnostic imaging MeSH
- Ischemic Attack, Transient diagnostic imaging MeSH
- Ultrasonography, Doppler, Transcranial methods MeSH
- User-Computer Interface MeSH
- Image Enhancement methods MeSH
- Check Tag
- Humans MeSH
- Infant, Newborn MeSH
- Pregnancy MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
