Quantitative susceptibility mapping (QSM) and R2* relaxation rate mapping have demonstrated increased iron deposition in the substantia nigra of patients with idiopathic Parkinson's disease (PD). ...However, the findings in other subcortical deep gray matter nuclei are converse and the sensitivity of QSM and R2* for morphological changes and their relation to clinical measures of disease severity has so far been investigated only sparsely.
The local ethics committee approved this study and all subjects gave written informed consent. 66 patients with idiopathic Parkinson's disease and 58 control subjects underwent quantitative MRI at 3T. Susceptibility and R2* maps were reconstructed from a spoiled multi-echo 3D gradient echo sequence. Mean susceptibilities and R2* rates were measured in subcortical deep gray matter nuclei and compared between patients with PD and controls as well as related to clinical variables.
Compared to control subjects, patients with PD had increased R2* values in the substantia nigra. QSM also showed higher susceptibilities in patients with PD in substantia nigra, in the nucleus ruber, thalamus, and globus pallidus. Magnetic susceptibility of several of these structures was correlated with the levodopa-equivalent daily dose (LEDD) and clinical markers of motor and non-motor disease severity (total MDS-UPDRS, MDS-UPDRS-I and II). Disease severity as assessed by the Hoehn & Yahr scale was correlated with magnetic susceptibility in the substantia nigra.
The established finding of higher R2* rates in the substantia nigra was extended by QSM showing superior sensitivity for PD-related tissue changes in nigrostriatal dopaminergic pathways. QSM additionally reflected the levodopa-dosage and disease severity. These results suggest a more widespread pathologic involvement and QSM as a novel means for its investigation, more sensitive than current MRI techniques.
An objective evaluation of tremor severity is necessary to document the course of disease, the efficacy of treatment, or interventions in clinical trials. Most available objective quantification ...devices are complex, immobile, or not validated.
We used the TREMITAS-System that comprises a pen-shaped sensor for tremor quantification. The Power of Main Peak and the Total Power were used as surrogate markers for tremor amplitude. Tremor severity was assessed by the TREMITAS-System and relevant subscores of the MDS-UPDRS and TETRAS rating scales in 14 patients with Parkinson's disease (PD) and 16 patients with Essential tremor (ET) off and on therapy. We compared tremor amplitudes assessed during wearable and hand-held constellations.
We found significant correlations between tremor amplitudes captured by TREM and tremor severity assessed by the MDS-UPDRS in PD (r = 0.638–0.779) and the TETRAS in ET (r = 0.597–0. 704) off and on therapy. The TREMITAS-System captured the L-Dopa-induced improvement of tremor in PD patients (p = 0.027). Tremor amplitudes did not differ between the handheld and wearable constellation (p > 0.05).
We confirm the results of previous studies using inertial based sensors that tremor severity and drug-induced changes of tremor severity can be quantified using inertial based sensors. The assessment of tremor amplitudes was not influenced by using a handheld or wearable constellation.
The TREMITAS-System can be used to quantify rest tremor in PD and postural tremor in ET and is capable of detecting clinically relevant changes in tremor in clinical and research settings.
Accelerometer; Essential tremor; Mobile Monitoring; Parkinson's disease; Pen-Shaped Sensor; Tremor; Biomedical engineering; Biomedical Devices; Neurology; Clinical Research; Diagnostics; Biomarkers
Background:
Cervical dystonia is the most common form of focal dystonia. The frequency and pattern of degenerative changes of the cervical spine in patients with cervical dystonia and their relation ...to clinical symptoms remain unclear as no direct comparison to healthy controls has been performed yet. Here, we used magnetic resonance imaging (MRI) to investigate (1) whether structural abnormalities of the cervical spine are more common in patients with cervical dystonia compared to age-matched healthy controls, (2) if there are clinical predictors for abnormalities on MRI, and (3) to calculate the inter-rater reliability of the respective radiological scales.
Methods:
Twenty-five consecutive patients with cervical dystonia and 20 age-matched healthy controls were included in the study. MRI scans of the cervical spine were analyzed separately by three experienced raters blinded to clinical information, applying different MRI rating scales. Structural abnormalities were compared between groups for upper, middle, and lower cervical spine segments. The associations between scores differentiating both groups and clinical parameters were assessed in dystonia patients. Additionally, inter-rater reliability of the MRI scales was calculated.
Results:
Comparing structural abnormalities, we found minor differences in the middle cervical spine, indicated by a higher MRI total score in patients but no significant correlation between clinical parameters and MRI changes. Inter-rater reliability was satisfying for most of the MRI rating scales.
Conclusion:
Our results do not provide evidence for a role of MRI of the cervical spine in the routine work-up of patients with cervical dystonia in the absence of specific clinical signs or symptoms.
Background and purpose
Quantification of neurofilament light chain protein in serum (sNfL) enables the neuro‐axonal damage in peripheral blood to be reliably assessed and monitored. There is a ...long‐standing debate whether essential tremor represents a ‘benign’ tremor syndrome or whether it is linked to neurodegeneration. This study aims to investigate sNfL concentrations in essential tremor compared to healthy controls (cross‐sectionally and longitudinally) and to assess whether sNfL is associated with motor and nonmotor markers of disease progression.
Methods
Data of patients with essential tremor from our prospective registry on movement disorders (PROMOVE) were retrospectively analysed. Age‐, sex‐ and body‐mass‐index‐matched healthy controls were recruited from an ongoing community‐dwelling aging cohort. sNfL was quantified by an ultra‐sensitive single molecule array (Simoa). All participants underwent detailed clinical examination at baseline and after approximately 5 years of follow‐up.
Results
Thirty‐seven patients with clinically diagnosed essential tremor were included and 37 controls. The essential tremor group showed significantly higher sNfL levels compared to healthy controls at baseline and follow‐up. sNfL levels increased over time in both groups, and the slope of sNfL increase was similar in the essential tremor and healthy control groups. Comparing patients with a disease duration under 5 years to those with a longer disease duration, the former group had a significantly greater increase of sNfL over time, which strongly correlated to worsening of tremor and cognition.
Conclusion
Our findings indicate that neurodegeneration, possibly happening at an early disease stage, might play a role in the pathophysiology of essential tremor.
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