Treatment of Pendular Nystagmus in OPT

Study Overview
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Brief Summary
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Pendular nystagmus corresponds to an enduring to and fro eye oscillation without resetting quick phases. The most common causes of acquired pendular nystagmus (APN) are multiple sclerosis (MS) and focal brainstem lesions (oculopalatal tremor, OPT). Based on pathophysiological hypothesis, pharmacological treatments of acquired nystagmus have been thoroughly proposed over different publications of cases, series, reviews or expert opinions. Acquired pendular nystagmus underwent the most rigorous treatment trials, leading to the proposal of gabapentin or memantine as valuable drugs. Whether gabapentin and memantine are effective in APN associated with OPT remains unclear, since none of the previous studies has evaluated the effect of these medications in a group of OPT patients. However, this is an important issue in prospect to a clinical use of these medications. In the current study, the investigators aim is to evaluate the effect of gabapentin and memantine on the mean velocity, amplitude and frequency of pendular nystagmus, as well as on visual acuity and vision-specific health-related quality of life score, in a group of OPT patients

Official Title
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Treatment of Pendular Nystagmus With Gabapentin and Memantine in Patients With Oculopalatal Tremor: a Controled Open-label Study

Conditions
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Pendular Nystagmus, Oculopalatal Tremor

Intervention / Treatment
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* Drug: Memantine
* Drug: Gabapentin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with a diagnosis of oculopalatal tremor (OPT), following a focal brainstem lesion. All patients may present a chronic acquired pendular nystagmus due to OPT, observed over a period of 6 months. All patients will be informed about the design and purpose of the study, and all will give their informed, written consent to the protocol, which may have been approved by the local ethics committee. Age: above 18 Able to understand the instructions Having a health coverage Able to sit down for 1 hour Stable dosage of previous medications (beginning 3 weeks previously and terminating at the end of the trial duration), except gabapentin or memantine. For women: efficient contraception during the experimental time and in the two month following treatment withdrawal. Exclusion Criteria: Ophthalmological Other ophthalmological disorder that could impair corrected visual acuity (Maculopathy, Retinopathy…) Neurological Ongoing seizure Severe handicap that does not allow sitting down position for 1 hour Suicidal behavior or risk Treatment Under memantine or gabapentin medication (these medications should have been stopped for at least 1 week for gabapentin and 3 weeks for memantine) Under morphine, N-methyl-D-aspartate such as amantadine, ketamine or dextromethorphan Steroid medication for a current relapse (beginning 3 weeks previously and terminating at the end of the trial duration Known hypersensitivity to memantine or gabapentin General Unstable medical state Patient with a galactose intolerance, a lapp lactase deficiency or glucose-galactose malabsorption Moderate renal failure (creatinine clearance < 50 mL/min on bioassay dated from less than one month) Recent heart infarction (<3months) Unstable congestive heart insufficiency Unstable arterial hypertension Leucopenia (<2500/mm3) Transaminase increase (>5 time normal values) Pregnancy (on questioning) Tutelage or any legal protection measure

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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: memantine first<br>Patients will be randomly assigned to start on either memantine or gabapentin. For tolerance reasons, each treatment begins with a progressive increasing dose and stops with a progressive decreasing dose. The duration of the period of last dose (8 to 11 days) will be chosen according to the investigator's availability to organize post-tests. | Drug: Memantine<br> <br> |
| Experimental: gabapentin first<br>Patients will be randomly assigned to start on either memantine or gabapentin. For tolerance reasons, each treatment begins with a progressive increasing dose and stops with a progressive decreasing dose. The duration of the period of last dose (8 to 11 days) will be chosen according to the investigator's availability to organize post-tests. | Drug: Gabapentin<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Velocity, amplitude and frequency of nystagmus using eye movement recording |  | at Day 17-21 | 
| Velocity, amplitude and frequency of nystagmus using eye movement recording |  | at Day 34-42 | 
| Velocity, amplitude and frequency of nystagmus using eye movement recording |  | at Day 64-79 | 
| Velocity, amplitude and frequency of nystagmus using eye movement recording |  | at Day 81-100 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Functional score on questioning as measured by the 25-Item National Eye Institute Visual Function Questionnaire |  | at Day 17-21 | 
| Functional score on questioning as measured by the 25-Item National Eye Institute Visual Function Questionnaire |  | at Day 34-42 | 
| Functional score on questioning as measured by the 25-Item National Eye Institute Visual Function Questionnaire |  | at Day 64-79 | 
| Functional score on questioning as measured by the 25-Item National Eye Institute Visual Function Questionnaire |  | at Day 81-100 | 
| subjective measure of oscillopsia |  | at Day 17-21 | 
| subjective measure of oscillopsia |  | at Day 34-42 | 
| subjective measure of oscillopsia |  | at Day 64-79 | 
| subjective measure of oscillopsia |  | at Day 81-100 | 
| far visual acuity as measured by monocularly and binocularly direction and amplitude (measures in degrees) of their oscillopsia while viewing, with best correction, a stationary target at far (5 m) and near (57 cm) location. |  | at Day 17-21 | 
| far visual acuity as measured by monocularly and binocularly direction and amplitude (measures in degrees) of their oscillopsia while viewing, with best correction, a stationary target at far (5 m) and near (57 cm) location. |  | at Day 34-42 | 
| far visual acuity as measured by monocularly and binocularly direction and amplitude (measures in degrees) of their oscillopsia while viewing, with best correction, a stationary target at far (5 m) and near (57 cm) location. |  | at Day 64-79 | 
| far visual acuity as measured by monocularly and binocularly direction and amplitude (measures in degrees) of their oscillopsia while viewing, with best correction, a stationary target at far (5 m) and near (57 cm) location. |  | at Day 81-100 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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nystagmus, pharmacological trial, multiple sclerosis, oscillopsia