Transcranial B-Mode Sonography in Movement Disorders

Systematic review-based guideline "Parkinson's disease" of the German Society of Neurology: diagnostic use of transcranial sonography

BACKGROUND AND OBJECTIVE

Transcranial brain parenchyma sonography (TCS) has been recommended as a tool for the early and differential diagnosis of Parkinson's disease (PD) in German and European clinical guidelines. Still, the brain structures to be examined for the diagnostic questions and the requirements for being a qualified investigator were not specified in detail. These issues have now been addressed in the 2023 update of the clinical guideline on PD by the German Society of Neurology (DGN).

METHODS

The recommendations were based on a systematic literature review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

Three diagnostic questions were defined: (1) What is the accuracy of TCS in the differential diagnosis of PD versus atypical and secondary Parkinsonian syndromes? (2) What is the accuracy of TCS in the differential diagnosis of PD versus essential tremor? (3) What is the accuracy of TCS in the diagnosis of PD in persons with typical early symptoms, compared with the diagnosis established by clinical follow-up? The brain structures to be assessed and the level of recommendation were formulated for these questions. The training requirements for being regarded as qualified TCS investigator were stipulated by the responsible medical societies (German Society of Ultrasound in Medicine, DEGUM; German Society for Clinical Neurophysiology and Functional Imaging, DGKN). Finally, the recommendations for these diagnostic questions reached strong consensus (each ≥ 97%) of the guideline committee. Here, the details of review and recommendations are presented.

CONCLUSION

The updated guideline clarifies the diagnostic uses and limitations of TCS in PD.

Transcranial Sonography Characteristics of Cerebellar Neurodegenerative Ataxias

Cerebellar neurodegenerative ataxias are a group of disorders affecting the cerebellum and its pathways with different neurological structures. Transcranial sonography (TCS) has been used for the evaluation of brain parenchymal structures in various diseases because of its fast and safe utilization, especially in neuropsychiatric and neurodegenerative diseases. The aim of our study was to investigate TCS characteristics of patients with neurodegenerative cerebellar ataxias. In our study, we included 74 patients with cerebellar degenerative ataxia; 36.5% had autosomal dominant onset, while 33.8% had sporadic onset. Standardized ultrasonographic planes were used for the identification of brain structures of interest. The SARA, INAS, neuropsychological and psychiatric scales were used for the further clinical evaluation of our study participants. The brainstem raphe was discontinued in 33.8% of the patients. The substantia nigra (SN) hyperechogenicity was identified in 79.7%. The third and fourth ventricle enlargement had 79.7% and 45.9% of patients, respectively. A positive and statistically significant correlation was found between SN hyperechogenicity with dystonia (p < 0.01), rigidity and dyskinesia (p < 0.05). The higher SARA total score is statistically significantly correlated with the larger diameter of the III (r = 0.373; p = 0.001) and IV ventricles (r = 0.324; p = 0.005). In such patients, the echogenicity of substantia nigra has been linked to extrapyramidal signs, and raphe discontinuity to depression. Furthermore, ataxia and its clinical subtypes have positively correlated with the IV ventricle diameter, indicating brain atrophy and brain mass reduction.

Transcranial sonography in neurodegeneration with brain iron accumulation disorders

BACKGROUND

Transcranial Sonography is a non-invasive technique that has been used as a diagnostic tool for a variety of neurodegenerative disorders. However, the utility and potential application of this technique in NBIA disorders is scarce and inconclusive.

METHODS

In this cross-sectional retrospective case-control study, the echogenicity of Substantia Nigra (SN), Lentiform Nucleus (LN), and Diameter of the Third Ventricle (DTV) were assessed by TCS in genetically confirmed NBIA patients referring to the movement disorder clinic. The normal echogenicity area of SN was defined based on the 90th percentile of an age-and-gender-matched control group. NBIA patients underwent neurologic examination at each visit, but their brain magnetic resonance imaging and demographics were extracted from electronic records.

RESULTS

Thirty-five NBIA patients of four subtypes with a mean disease duration of 10.54 years and 35 controls were enrolled. The normally defined SN echogenicity in controls was 0.23 cm2. DTV and SN echogenicity areas were significantly higher in patients compared to the controls (P = 0.002 and < 0.001, respectively). Around 85% and 63% of the patients showed LN and SN hyperechogenicity at least on one side, respectively. Disease duration was positively correlated with DTV (r = 0.422, p = 0.015). Cases with Pantothenate Kinase Associated Neurodegeneration (n = 23) also had significantly higher DTV and SN echogenicity area compared to the controls.

CONCLUSION

Despite most NBIA patients displayed increased DVT and higher SN and LN hyperechogenicity than healthy controls, the discriminatory role of TCS on different NBIA subtypes remains to be determined.

Can Plasma α-Synuclein Help Us to Differentiate Parkinson's Disease from Essential Tremor?

Background

Studies have revealed controversial results regarding the diagnostic accuracy of plasma α-synuclein levels in patients with Parkinson's disease (PD). This study was aimed to analyze the diagnostic accuracy of plasma α-synuclein in PD versus healthy controls and patients with essential tremor (ET).

Methods

In this cross-sectional study, we included de novo (n = 19) and advanced PD patients [OFF (n = 33), and On (n = 35) states], patients with ET (n = 19), and controls (n = 35). The total plasma α-synuclein levels were determined using an ELISA sandwich method. We performed adjusted multivariate regression analysis to estimate the association of α-synuclein levels with group conditions [controls, ET, and de novo, OFF and ON-PD]. We studied the diagnostic accuracy of plasma α-synuclein using the area under the curve (AUC).

Results

The plasma α-synuclein levels were higher in controls compared to PD and ET (p < 0.0001), discriminating de novo PD from controls (AUC = 0.74, 95% CI 0.60-0.89), with a trend towards in advanced PD (OFF state) from ET (AUC = 0.69, 95% CI 0.53-0.84).

Conclusions

This is the first study examining and comparing plasma α-synuclein levels in ET vs. PD and controls. Preliminary findings suggest that plasma α-synuclein levels might help to discriminate de novo and advanced PD from controls and ET.

Parkinson's Disease: Available Clinical and Promising Omics Tests for Diagnostics, Disease Risk Assessment, and Pharmacotherapy Personalization

Parkinson's disease is the second most frequent neurodegenerative disease, representing a significant medical and socio-economic problem. Modern medicine still has no answer to the question of why Parkinson's disease develops and whether it is possible to develop an effective system of prevention. Therefore, active work is currently underway to find ways to assess the risks of the disease, as well as a means to extend the life of patients and improve its quality. Modern studies aim to create a method of assessing the risk of occurrence of Parkinson's disease (PD), to search for the specific ways of correction of biochemical disorders occurring in the prodromal stage of Parkinson's disease, and to personalize approaches to antiparkinsonian pharmacotherapy. In this review, we summarized all available clinically approved tests and techniques for PD diagnostics. Then, we reviewed major improvements and recent advancements in genomics, transcriptomics, and proteomics studies and application of metabolomics in PD research, and discussed the major metabolomics findings for diagnostics and therapy of the disease.