Elevated serum neurofilament light chain protein in patients with essential tremor.

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.

Differences in aphasia syndromes between progressive supranuclear palsy-Richardson's syndrome, behavioral variant frontotemporal dementia and Alzheimer's dementia.

Language impairments, hallmarks of speech/language variant progressive supranuclear palsy, also occur in Richardson's syndrome (PSP-RS). Impaired communication may interfere with daily activities. Therefore, assessment of language functions is crucial. It is uncertain whether the Aachen Aphasia Test (AAT) is practicable in PSP-RS, behavioral variant frontotemporal dementia (bvFTD) and Alzheimer's dementia (AD) and language deficits differ in these disorders. 28 PSP-RS, 24 AD, and 24 bvFTD patients were investigated using the AAT and the CERAD-Plus battery. 16-25% of all patients failed in AAT subtests for various reasons. The AAT syndrome algorithm diagnosed amnestic aphasia in 5 (23%) PSP-RS, 7 (36%) bvFTD and 6 (30%) AD patients, Broca aphasia in 1 PSP-RS and 1 bvFTD patient, Wernicke aphasia in 1 bvFTD and 3 (15%) AD patients. However, aphasic symptoms resembled non-fluent primary progressive aphasia in 14 PSP-RS patients. In up to 46% of PSP-RS patients, 61% of bvFTD and 64% of AD patients significant impairments were found in the AAT subtests spontaneous speech, written language, naming, language repetition, language comprehension and the Token subtest. The CERAD-Plus subtest semantic fluency revealed significant impairment in 81% of PSP-RS, 61% of bvFTD, 44% of AD patients, the phonemic fluency subtest in 31, 40 and 31%, respectively. In contrast to bvFTD and AD, severity of language impairment did not correlate with cognitive decline in PSP-RS. In summary, the patterns of aphasia differ between the diagnoses. Local frontal language networks might be impaired in PSP-RS, whereas in AD and bvFTD, more widespread neuropathology might underly language impairment.

Caregiver strain in progressive supranuclear palsy and corticobasal syndromes.

Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) progress relentlessly and lead to a need for care. Caregiving is often burdensome. Little is known about the course of caregiver burden (CB) in PSP and CBS patients. Longitudinal analysis of CB in family members caring for PSP and CBS patients. Single-center longitudinal pilot study in 68 newly diagnosed patients with probable PSP and CBS (52 Richardson's syndrome; 1 progressive gait freezing of PSP; 15 CBS). Demographic, educational, occupational parameters, family status, motor functions (UPDRSIII, Hoehn and Yahr Score, Tinetti) and neuropsychological performance (CERAD Plus, Frontal Assessment Battery) were assessed, as well as behavioral and neuropsychiatric impairments (Frontal Behavioral Inventory, Neuropsychiatric Inventory), activities of daily living (ADL) and caregiver burden using the Caregiver Strain Index (CSI), in most patients also the Zarit Burden Interview (ZBI). Patients were followed up every 6 months for up to 2 years. Caregivers reported mild to moderate CB at baseline, which increased by 25-30% in 2 years and was significantly greater in PSP than in CBS. Risk for mental health problems increased over time, especially in female caregivers (depression). Important patient-related factors were apathy, aspontaneity, depression, irritability, disorganization, poor judgment, impairment of language, impairments in ADL, a high educational level of the patient and close family relationship. Behavioral symptoms and impaired ADL are the main patient-related factors of CB in PSP and CBS. CB can be severe and needs to be assessed repeatedly from the time of diagnosis to provide comprehensive support.

Quantification of tremor severity with a mobile tremor pen.

BACKGROUND: 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. NEW METHOD: 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. RESULTS: 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). COMPARISON WITH EXISTING METHODS: 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. CONCLUSIONS: 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.

Minor Structural Differences in the Cervical Spine Between Patients With Cervical Dystonia and Age-Matched Healthy Controls.

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.

Nigral iron deposition in common tremor disorders.

OBJECTIVE: We investigated R2* relaxation rates as a marker of iron content in the substantia nigra in patients with common tremor disorders and explored their diagnostic properties. METHODS: Mean nigral R2* rates were measured in 40 patients with tremor-dominant Parkinson's disease (PD), 15 with tremor in dystonia, 25 with essential tremor, and 25 healthy controls. RESULTS: Tremor-dominant PD patients had significantly higher nigral R2* values (34.1 ± 5.7) than those with tremor in dystonia (30.0 ± 3.9), essential tremor (30.6 ± 4.8), and controls (30.0 ± 2.8). An R2* threshold of 31.15 separated tremor-dominant PD from controls with a sensitivity and specificity of 67.5% and 72%. The sensitivity and specificity for discrimination between PD and non-PD tremor patients was 67.5% and 60%. CONCLUSION: Iron content in the substantia nigra is significantly higher in tremor-dominant PD than in tremor in dystonia, essential tremor, and controls. Because of the considerable overlap, nigral R2* cannot be suggested as a useful diagnostic tool. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.