Trial of Alternating Current Stimulation in Optic Neuropathy

Study Overview
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Brief Summary
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Non-invasive brain stimulation can increase cortical excitability in the visual system, but it is not known if this is of clinical value. The investigators now assessed if repetitive, transcranial alternating current stimulation (rtACS) can improve visual field size in patients with optic nerve damage. The investigators hypothesized that rtACS would improve visual functions within the defective visual field sectors of the visual field (primary outcome measure).

Detailed Description
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In a prospective, double-blind, randomized, placebo-controlled clinical trial 22 patients with optic nerve damage were randomly assigned to a rtACS- (n=12) or placebo-group (n=10). Visual field measures, visual acuity and EEG-recordings were collected before and after a daily 20-40min treatment for 10-days and at a 2-months-follow-up. Primary outcome measure was detection accuracy (DA) in defective visual field sectors of computer-based high resolution perimetry (HRP). Secondary outcome parameters included DA in static and kinetic perimetry, reaction time (RT) in HRP, visual acuity (VA), contrast vision, and EEG power spectra.

Official Title
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Treatment of Patients With Optic Neuropathy Using Transorbital Alternating Current Stimulation - a Randomized Trial

Conditions
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Optic Nerve Diseases, Optic Nerve Injuries, Optic Neuropathies

Intervention / Treatment
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* Device: Repetitive transorbital alternating current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria patients with optic nerve lesion stable visual field defect with residual vision lesion age at least 6 months Exclusion Criteria heart pacemakers and any metal artefacts in head and truncus epileptic seizure within the last 3 years photosensitive epilepsy as determined by EEG mental diseases (schizophrenia etc.) unstable diabetes, diabetes causing diabetic retinopathy macular degeneration, maculopathy with decimal visual acuity below 0.4 high blood pressure instable or high level of intraocular pressure (i.e. >27 mmHg) presence of an un-operated tumor anywhere in the body total blindness primary or secondary glaucoma pathological nystagmus

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 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: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: rtACS (Verum condition)<br>Repetitive transorbital alternating current stimulation (rtACS) | Device: Repetitive transorbital alternating current stimulation<br>* Repetitive, transorbital alternating current stimulation (rtACS) was applied with a multi-channel device generating weak current pulses in predetermined firing bursts of 2 to 9 pulses. The amplitude of each current pulse was below 1000µA. Current intensity was individually adjusted according to how well patients perceived phosphenes, i.e. any sensation of flickering light in response to the rtACS stimulation.<br>* Other names: EBS Alpha Synch;|
| No Intervention: Sham stimulation (placebo condition)<br>A clicking sound was presented and the same electrode montage set-up was used during rtACS- and placebo-stimulation, except that placebo patients received no current (stimulator turned off) | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Detection Accuracy (DA) Change in Percent Over Baseline Within Defective Visual Field Sectors | Central visual fields were assessed with computer-based high-resolution perimetry (HRP). Based on such plots, areas of the visual field were characterized as intact, partially damaged or absolutely impaired (blind). Detection accuracy (DA) change in percent above baseline within defective visual field sectors was defined as the primary outcome criterion. | Outcome measures were assessed at initial diagnostics (baseline) and after 10 days stimulation at post diagnostics | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Other Visual and EEG Parameters | Secondary outcome parameters included DA in static and kinetic perimetry, reaction time (RT) in HRP, visual acuity (VA), contrast vision, and EEG power spectra. | Nov 2006 - Dec 2010 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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vision recovery, optic neuropathy, alternating current stimulation, restoration, plasticity