Vitamin D3 deficiency and osteopenia in spastic paraplegia type 5 indicate impaired bone homeostasis.

Hereditary spastic paraplegia type 5 (SPG5) is an autosomal recessively inherited movement disorder characterized by progressive spastic gait disturbance and afferent ataxia. SPG5 is caused by bi-allelic loss of function mutations in CYP7B1 resulting in accumulation of the oxysterols 25-hydroxycholesterol and 27-hydroxycholesterol in serum and cerebrospinal fluid of SPG5 patients. An effect of 27- hydroxycholesterol via the estrogen and liver X receptors was previously shown on bone homeostasis. This study analyzed bone homeostasis and osteopenia in 14 SPG5 patients as a non-motor feature leading to a potential increased risk for bone fractures. T-Scores in CT bone density measurements were reduced, indicating osteopenia in SPG5 patients. Further, we analyzed various metabolites of bone homeostasis by ELISA in serum samples of these patients. We identified a lack of vitamin D3 metabolites (Calcidiol and Calcitriol), an increase in Sclerostin as a bone formation/mineralization inhibiting factor, and a decrease in cross-linked N-telopeptide of type I collagen (NTX), a marker indicating reduced bone resorption. As statin treatment has been found to lower oxysterol levels, we evaluated its effect in samples of the STOP-SPG5 trial and found atorvastatin to normalize the increased sclerostin levels. In summary, our study identified osteopenia as a non-motor feature in SPG5 and suggests the need for vitamin D3 substitution in SPG5 patients. Sclerostin may be considered a therapeutic target and biomarker in upcoming therapeutical trials in SPG5.

[Interdisciplinary networks in diseases of peripheral nerves-Exemplified by the Tübingen nerve team]. / Interdisziplinäre Netzwerke bei Erkrankungen der peripheren Nerven ­ am Beispiel des Tübinger Nerve Teams.

BACKGROUND: Nerve damage can be autoimmune inflammatory, metabolic or traumatic, among others, and can be difficult to differentiate. OBJECTIVE: What are the advantages of interdisciplinary networks and how do they work? MATERIAL AND METHOD: Field report with case presentation from the University Hospital Tübingen in cooperation with the BG Accident Clinic Tübingen. CONCLUSION: Interdisciplinary networks improve the care of our patients and also serve as regular multidisciplinary continuing education.

[Choosing the right imaging for the diagnostics and assessment of the course of peripheral nerve injuries]. / Die Wahl der richtigen Bildgebung zur Diagnostik und Verlaufsbeurteilung peripherer Nervenverletzungen.

BACKGROUND: Nerve injuries are a frequent problem in routine clinical practice and require intensive interdisciplinary care. OBJECTIVE: The current status of imaging to confirm the diagnosis of nerve injuries is described. The role of high-resolution ultrasound and magnetic resonance imaging (MRI) in the diagnostics and follow-up of peripheral nerve injuries is elaborated. MATERIAL AND METHODS: Review of the current state of imaging to confirm the diagnosis of nerve injuries. RESULTS: Depending on the suspected site of damage, the primary domain of magnetic resonance (MR) imaging (MR neurography) is injuries in the region of the spine, nerve roots, brachial plexus and lumbar plexus, pelvis and proximal thigh. In contrast, in other peripheral nerve lesions of the extremities the advantages of high-resolution nerve ultrasound in a dynamic setting predominate. The MR neurography is indicated here, especially in the frequent bottleneck syndromes and only in very isolated and selected cases. CONCLUSION: In addition to a correct anatomical assignment, the timely decision for a possible intervention and the appropriate concomitant treatment are an important basis for a favorable prognosis of nerve injuries. Imaging techniques should therefore be used early in the diagnostics and follow-up controls of peripheral nerve injuries.

Clinical-Radiological Mismatch in Multiple Sclerosis Patients during Acute Relapse: Discrepancy between Clinical Symptoms and Active, Topographically Fitting MRI Lesions.

BACKGROUND: Relapses in multiple sclerosis (MS) patients are usually defined as subacute clinical symptoms that last for at least 24 h. To validate a clinical relapse on magnetic resonance imaging (MRI), an anatomically fitting lesion with gadolinium enhancement in the central nervous system (CNS) would be mandatory. The aim of this study was to validate clinical relapses in regard to the concomitant detection of active, anatomically fitting MRI lesions. METHODS: We performed a retrospective analysis of 199 MS patients with acute relapse who had received an MRI scan before the initiation of methylprednisolone (MPS) therapy. Clinical data and MRIs were systematically reanalyzed by correlating clinical symptoms with their anatomical representation in the CNS. Patients were then categorized into subgroups with a clinical-radiological match (group 1) or clinical-radiological mismatch (group 2) between symptoms and active, topographically fitting lesions and further analyzed in regard to clinical characteristics. RESULTS: In 43% of our patients, we observed a clinical-radiological mismatch (group 2). Further analysis of patient characteristics showed that these patients were significantly older at the time of relapse. MS patients in group 2 also showed a significantly longer disease duration and significantly more previous relapses when compared to group 1. Comparing symptom clusters, the appearance of motor dysfunction during the current relapse was significantly more frequent in group 2 than in group 1. The overall dose of MPS treatment was significantly lower in group 2 than in group 1 with a similar treatment response in both groups. CONCLUSIONS: The substantial clinical-radiological mismatch during acute relapse in our study could be explained by several factors, including a psychosomatic component or disturbance of network connectivity. Alternatively, secondary progression or a diffuse neuro-inflammatory process might cause clinical symptoms, especially in older patients with a longer disease duration. As a consequence, treatment of clinical relapses and the definition of breakthrough disease should be reconsidered in regard to combined clinical and MRI criteria and/or additional biomarkers. Further studies are necessary to address the contribution of diffuse neuro-inflammation to the clinical presentation of symptoms.

Speech and Nonspeech Parameters in the Clinical Assessment of Dysarthria: A Dimensional Analysis.

Nonspeech (or paraspeech) parameters are widely used in clinical assessment of speech impairment in persons with dysarthria (PWD). Virtually every standard clinical instrument used in dysarthria diagnostics includes nonspeech parameters, often in considerable numbers. While theoretical considerations have challenged the validity of these measures as markers of speech impairment, only a few studies have directly examined their relationship to speech parameters on a broader scale. This study was designed to investigate how nonspeech parameters commonly used in clinical dysarthria assessment relate to speech characteristics of dysarthria in individuals with movement disorders. Maximum syllable repetition rates, accuracies, and rates of isolated and repetitive nonspeech oral-facial movements and maximum phonation times were compared with auditory-perceptual and acoustic speech parameters. Overall, 23 diagnostic parameters were assessed in a sample of 130 patients with movement disorders of six etiologies. Each variable was standardized for its distribution and for age and sex effects in 130 neurotypical speakers. Exploratory Graph Analysis (EGA) and Confirmatory Factor Analysis (CFA) were used to examine the factor structure underlying the diagnostic parameters. In the first analysis, we tested the hypothesis that nonspeech parameters combine with speech parameters within diagnostic dimensions representing domain-general motor control principles. In a second analysis, we tested the more specific hypotheses that diagnostic parameters split along effector (lip vs. tongue) or functional (speed vs. accuracy) rather than task boundaries. Our findings contradict the view that nonspeech parameters currently used in dysarthria diagnostics are congruent with diagnostic measures of speech characteristics in PWD.

The prodromal phase of hereditary spastic paraplegia type 4: the preSPG4 cohort study.

This cohort study aimed to characterize the prodromal phase of hereditary spastic paraplegia type 4 (SPG4) using biomarkers and clinical signs and symptoms that develop before manifest gait abnormalities. Fifty-six first-degree relatives at risk of developing SPG4 underwent blinded genotyping and standardized phenotyping, including the Spastic Paraplegia Rating Scale (SPRS), complicating symptoms, non-motor affection, Three-Minute Walk, and neurophysiological assessment. Automated MR image analysis was used to compare volumetric properties. CSF of 33 probands was analysed for neurofilament light chain (NfL), tau, and amyloid-ß (Aß). Thirty participants turned out to be SPAST mutation carriers, whereas 26 did not inherit a SPAST mutation. Increased reflexes, ankle clonus, and hip abduction weakness were more frequent in prodromal mutation carriers but were also observed in non-mutation carriers. Only Babinski's sign differentiated reliably between the two groups. Timed walk and non-motor symptoms did not differ between groups. Whereas most mutation carriers had total SPRS scores of 2 points or more, only two non-mutation carriers reached more than 1 point. Motor evoked potentials revealed no differences between mutation and non-mutation carriers. We found NfL but not tau or Aß to rise in CSF of mutation carriers when approaching the time point of predicted disease manifestation. Serum NfL did not differ between groups. Volumetric MRI analyses did not reveal group differences apart from a smaller cingulate gyrus in mutation carriers. This study depicts subtle clinical signs which develop before gait abnormalities in SPG4. Long-term follow-up is needed to study the evolution of SPG4 in the prodromal stage and conversion into manifest disease. NfL in CSF is a promising fluid biomarker that may indicate disease activity in prodromal SPG4 but needs further evaluation in longitudinal studies.

Progressive Spinal Cord Degeneration in Friedreich's Ataxia: Results from ENIGMA-Ataxia.

BACKGROUND: Spinal cord damage is a hallmark of Friedreich's ataxia (FRDA), but its progression and clinical correlates remain unclear. OBJECTIVE: The objective of this study was to perform a characterization of cervical spinal cord structural damage in a large multisite FRDA cohort. METHODS: We performed a cross-sectional analysis of cervical spinal cord (C1-C4) cross-sectional area (CSA) and eccentricity using magnetic resonance imaging data from eight sites within the ENIGMA-Ataxia initiative, including 256 individuals with FRDA and 223 age- and sex-matched control subjects. Correlations and subgroup analyses within the FRDA cohort were undertaken based on disease duration, ataxia severity, and onset age. RESULTS: Individuals with FRDA, relative to control subjects, had significantly reduced CSA at all examined levels, with large effect sizes (d > 2.1) and significant correlations with disease severity (r < -0.4). Similarly, we found significantly increased eccentricity (d > 1.2), but without significant clinical correlations. Subgroup analyses showed that CSA and eccentricity are abnormal at all disease stages. However, although CSA appears to decrease progressively, eccentricity remains stable over time. CONCLUSIONS: Previous research has shown that increased eccentricity reflects dorsal column (DC) damage, while decreased CSA reflects either DC or corticospinal tract (CST) damage, or both. Hence our data support the hypothesis that damage to the DC and damage to CST follow distinct courses in FRDA: developmental abnormalities likely define the DC, while CST alterations may be both developmental and degenerative. These results provide new insights about FRDA pathogenesis and indicate that CSA of the cervical spinal cord should be investigated further as a potential biomarker of disease progression. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Cortical reactivity to transcranial magnetic stimulation predicts risk of post-stroke delirium.

OBJECTIVE: Post-stroke delirium (PSD) is a frequent and with regard to outcome unfavorable complication in acute stroke. The neurobiological mechanisms predisposing to PSD remain poorly understood, and biomarkers predicting its risk have not been established. We tested the hypothesis that hypoexcitable or disconnected brain networks predispose to PSD by measuring brain reactivity to transcranial magnetic stimulation with electroencephalography (TMS-EEG). METHODS: We conducted a cross-sectional study in 33 acute stroke patients within 48 hours of stroke onset. Brain reactivity to single-pulse TMS of dorsolateral prefrontal cortex, primary motor cortex and superior parietal lobule of the right hemisphere was quantified by response intensity, effective connectivity, perturbational complexity index (PCIST), and natural frequency of the TMS-EEG response. PSD development was clinically tracked every 8 hours before and for 7 days following TMS-EEG. RESULTS: Fourteen patients developed PSD while 19 patients did not. The PSD group showed lower excitability, effective connectivity, PCIST and natural frequency compared to the non-PSD group. The maximum PCIST over all three TMS sites demonstrated largest classification accuracy with a ROC-AUC of 0.943. This effect was independent of lesion size, affected hemisphere and stroke severity. Maximum PCIST and maximum natural frequency correlated inversely with delirium duration. CONCLUSIONS: Brain reactivity to TMS-EEG can unravel brain network states of reduced excitability, effective connectivity, perturbational complexity and natural frequency that identify acute stroke patients at high risk for development of delirium. SIGNIFICANCE: Findings provide novel insight into the pathophysiology of pre-delirium brain states and may promote effective delirium prevention strategies in those patients at high risk.