Paraorbital-Occipital Electric Stimulation in Patients With Optic Neuropathy (BCT_optnerve)

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 with the defective visual field sectors of the visual field (primary outcome measure).

Detailed Description
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exploratory, randomized, controlled study

Official Title
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Paraorbital-occipital Alternating Electric Current Stimulation in Patients With Optic Neuropathy

Conditions
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Visual Impairment

Intervention / Treatment
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* Device: rtACS (verum condition)
* Device: placebo stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: residual vision patients with optic nerv lesion lesion age at least 6 months stable visual field defect Exclusion Criteria: electric or electronic implants such as pace maker any metal artefacts in head and truncus epilepsia photosensitive epilepsy as determines by EEG autoimmune illnesses in acute stage mental diseases such e.g. schizophrenia etc. diabetes causing diabetic retinopathy addiction high blood pressure unstable or high level intraocular pressure (i.e. > 27 mmHg) retinitis pigmentosa pathological nystagmus presence of an un-operated tumor or tumor recidive

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: rtACS (Verum condition)<br>Repetitive transorbital alternating current stimulation (rtACS) | Device: rtACS (verum condition)<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 1000 microA. 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: Modifications of the device have been performed before the SLG test by Eurotronics Weißenfelser Straße 67, D-04229 Leipzig;|
| Placebo Comparator: Placebo stimulation<br>no intervention (Sham stimulation) | Device: placebo stimulation<br>* a clicking sound was presented and the same electrodes montage set-up was used during rtACS and placebo stimulation, except that placebo patients received no current (stimulator turned off).<br>* Other names: Modifications of the device have been performed before the SLG test by Eurotronics Weißenfelser Straße 67, D-04229 Leipzig;|

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 visus 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). | between baseline and 60 days after stimulation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual Parameters 1 | DA in static and kinetic perimetry | baseline to 60 days after stimulation | 
| Visual Parameters 2 | reaction time (RT) in HRP | baseline to 60 days after stimulation | 
| Visual Parameters 3 | visual acuity (VA) | baseline to 60 days after stimulation | 
| Visual Parameters 4 | contrast vision | baseline to 60 days after stimulation | 
| EEG parameters | EEG power spectra | baseline to 60 days after stimulation |