Evaluation of the Peripheral Nerve Ultrasound as a Diagnostic Tool in CANVAS Neuropathies

Study Overview
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Brief Summary
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Cerebellar ataxia with neuropathy and bilateral areflexia syndrome (CANVAS) is a late onset neurodegenerative disorder with a slowly progressive ataxia. It's genetic causative etiology with an autosomal recessive inheritance has a recent discovery. It is clinically characterized by impaired visually enhanced vestibulo-ocular reflex, although patients commonly present with imbalance as a main concern, associated with sensory complaints. It has been demonstrated that sensory impairment in CANVAS patients is due to degeneration of dorsal root with abnormal sensory nerve conduction. Previously defined diagnostic criteria included cerebellar atrophy on brain MRI, neuronopathy on electrophysiological studies and negative genetic testing for other inherited ataxia syndromes like Friedriech ataxia and spinal cerebellar ataxia (SCA). Peripheral nerve ultrasound is a noninvasive technique, able to identify abnormal peripheral nerves with underlying injuries and specific sonographic characteristics. Pelosi et al established that patients with CANVAS have a smaller nerve cross sectional area (CSA) compared to healthy individuals and/ or axonal neuropathies. The main objective of this study was to obtaine a detailed description of peripheral nerves in consecutive patients with CANVAS syndrome followed in theneurology department of the Universitary Hospital of Nimes (France), using conventional electrophysiology and peripheral nerve ultrasound.

Official Title
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Evaluation of the Peripheral Nerve Ultrasound as a Diagnostic Tool in CANVAS (Cerebellar Ataxia With Neuropathy and Vestibular Areflexia Syndrome) Neuronopathies

Conditions
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Neuropathy, Cerebellar Ataxia, Neurodegenerative Diseases

Intervention / Treatment
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* Other: No intervention


Participation Criteria
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Eligibility Criteria
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CANVAS Patients : Inclusion Criteria: Patients followed at the University Hospital of Nîmes between 2018-2021 Age > 18 years Diagnosis of CANVAS with genetic evidence (RFC1+) Diagnosis of neuronopathy Exclusion Criteria: Age <18 years Chronic polyradiculoneuritis or other demyelinating neuropathy Control group, inclusion criteria : Patient with axonal sensory-motor or pure sensory neuropathy confirmed by electro neuromyography, and concordant with the clinic.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| CANVAS Patients<br>Patient with a CANVAS diagnosis with genetic evidence (RFC1+) | Other: No intervention<br>* Pure observational study<br>|
| control group<br>Patient with axonal sensory-motor or pure sensitive neuropathy confirmed by electroneuromyography | Other: No intervention<br>* Pure observational study<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| median ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of median nerve ultrasound | Baseline | 
| ulnar nerve at wrist ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of ulnar nerve at wrist, ultrasound | Baseline | 
| mid-arm ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of ulnar nerve, mid-arm, ultrasound | Baseline | 
| elbow ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of ulnar nerve, elbow, ultrasound | baseline | 
| ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of ulnar nerve, mid-forearm, ultrasound | Day of the evaluation | 
| radial nerve ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of radial nerve ultrasound | Baseline | 
| superficial radial branch nerve ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of superficial radial branch nerve ultrasound | Baseline | 
| C5, C6 ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of C5, C6 roots ultrasound | Baseline | 
| sural nerve ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of sural nerve ultrasound | Baseline | 
| superficial fibular nerve ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of superficial fibular nerve ultrasound | Baseline | 
| popliteus ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of popliteus tibial nerve at ankle ultrasound | Baseline | 
| tibial ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of tibial nerveat ankle ultrasound | Baseline | 
| fibular ultrasound | Comparison of axial cross-sectional area to Bilateral exploration of fibular nerve at the neck ultrasound | Baseline |