Prevalence of Orthostatic Tremor in Patients With Unsteadiness

Study Overview
=================
Brief Summary
-----------------
Clinical presentation of orthostatic tremor (OT) may be misleading and simply perceived by a postural instability such as in several peripheral neuropathies. In addition, peripheral neuropathies represent the leading cause of pathologies associated with OT. Among patients referred for an electroneuromyogram (ENMG) for peripheral neuropathy and presenting with postural unsteadiness, OT assessment will be systematically performed. Demographic, clinical and polygraphy characteristics of these patients will be analyzed and prevalence of OT in the general population of peripheral neuropathies will be assessed.

Detailed Description
-----------------
Among patients who will be referred for ENMG and exploration of a neuropathy, orthostatic tremor will be investigated systematically. Main objective and primary endpoint: To estimate the prevalence of OT with its 95% confidence interval in the population of patients defined above Presence of OT confirmed by surface EMG (polygraphy) in patients with standing instability referred for ENMG. Secondary objectives and end points Determine the demographic, clinical, electrophysiological characteristics of patients with OT; Estimate the prevalence of peripheral neuropathy in patients with OT; Duration of symptoms; Correlation with quantitative neuropathy scores (ISS, MRC, ONLS, R-ODS) Age, sex, clinical parameters: symptoms reported by the patient (instability, tremor, weakness, pain, falls), duration, current medications, ISS score, MRC score, ONLS score, R-ODS score) and electrophysiological parameters (mean frequency of OT in Hertz, MUNIX score (number of motor units in the anterior tibialis, calculated by software on the ENMG machine).

Official Title
-----------------
Prevalence of Orthostatic Tremor by Surface Electromyographic Recording in Patients Reporting Unsteadiness

Conditions
-----------------
Orthostatic Tremor, Neuropathy

Intervention / Treatment
-----------------
* Diagnostic Test: Polygraphy with surface electrodes


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age ≥ 18 years old All patients complaining of instability when standing up and referred for an ENMG Patient informed and having expressed his non-opposition to participating in the research Exclusion Criteria: Patient's refusal to participate in the study Impossibility to stand No affiliation to health insurance Patients under a legal protection measure or unable to express their will Patient under the State Medical Assistance (AME) Patient under 18 years old Pregnant women, parturients and breast-feeding mothers

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with unsteadiness<br>Patients with unsteadiness referred for an ENMG | Diagnostic Test: Polygraphy with surface electrodes<br>* Patients referred for ENMG to the Clinical Physiology Department and complaining of postural unsteadiness will undergo a polygraphy recording using surface electrodes (Natus Medical Incorporated), performed at the end of ENMG<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of orthostatic tremor (OT | Prevalence of OT (95% confidence interval) in patients complaining of postural instability and referred for ENMG | Day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inflammatory Neuropathy Cause and Treatment (INCAT) Sensory Sum Score (ISS) simplified | The ISS ranges from 0 (normal sensation) to 20 (most severe sensory deficit) and is composed of the summation of the following sensation evaluations : pinprick arm grade (range 0-4) ; vibration arm grade (range 0-4) ; pinprick leg grade (range 0-4); vibration leg grade (range 0-4): two-point discrimination grade (range 0-4) | Day 0 | 
| Medical Research Council (MRC) score | The MRC score grades muscle power on a scale of 0 (no detectable contraction) to 5 (normal force, comparable to the healthy side) | Day 0 | 
| Overall Neuropathy Limitations Scale (ONLS) score | The ONLS score is be completed by adding the total of the Arm disability scale score (0-5) and Leg disability scale score (0-7) yielding a total score of 0-12 (higher score indicates higher disability) | Day 0 | 
| Rasch-built Overall Disability Scale (R-ODS) score | R-ODS scale comprising 24 items evaluates the ability to perform daily activities. The answers are rated on a scale of 0 to 48 (with 0 being very poor and 48 being best performance) | Day 0 | 
| OT frequency | OT frequency in Hz | Day 0 | 
| Motor unit number index (MUNIX) | MUNIX is a method for assessment of number of motor units using the compound muscle action potential (CMAP) and surface electromyographic interference pattern (SIP). | Day 0 | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Electroneuromyography, Polygraphy, Unsteadiness, Tremor, Anti-MAG neuropathy, Chronic demyelinating inflammatory neuropathy