Optic Nerve Diseases, Optic Nerve Injuries, Optic Neuropathies
Conditions
Keywords
optic neuropathy, alternating current stimulation, vision recovery, restoration, plasticity
Brief summary
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
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.
Interventions
DEVICERepetitive transorbital alternating current stimulation
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.
Sponsors
EBS Technologies GmbH
University of Magdeburg
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Detection Accuracy (DA) Change in Percent Over Baseline Within Defective Visual Field Sectors | Outcome measures were assessed at initial diagnostics (baseline) and after 10 days stimulation at post diagnostics | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Other Visual and EEG Parameters | Nov 2006 - Dec 2010 | Secondary outcome parameters included DA in static and kinetic perimetry, reaction time (RT) in HRP, visual acuity (VA), contrast vision, and EEG power spectra. |
Countries
Germany
Participant flow
Recruitment details
* Assessed for eligibility (n=325)from local institutional database and upon response on announcements in local newspapers from Nov 2006 - Dec 2008. * Excluded (n=303): not meeting inclusion criteria (n=248), declined to participate (n=40), other reasons (n=15)
Participants by arm
| Arm | Count |
|---|---|
| rtACS (Verum Condition) Repetitive transorbital alternating current stimulation (rtACS)
Repetitive transorbital alternating current stimulation : 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. | 12 |
| Sham Stimulation (Placebo Condition) 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) | 10 |
| Total | 22 |
Baseline characteristics
| Characteristic | Sham Stimulation (Placebo Condition) | rtACS (Verum Condition) | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 2 Participants | 4 Participants | 6 Participants |
| Age, Categorical Between 18 and 65 years | 8 Participants | 8 Participants | 16 Participants |
| Age, Continuous | 51.9 years STANDARD_DEVIATION 17.3 | 52.3 years STANDARD_DEVIATION 14.3 | 52.1 years STANDARD_DEVIATION 15.4 |
| Region of Enrollment Germany | 10 participants | 12 participants | 22 participants |
| Sex: Female, Male Female | 3 Participants | 6 Participants | 9 Participants |
| Sex: Female, Male Male | 7 Participants | 6 Participants | 13 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 12 | 0 / 10 |
| other Total, other adverse events | 7 / 12 | 2 / 10 |
| serious Total, serious adverse events | 0 / 12 | 0 / 10 |
Outcome results
Primary
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.
Time frame: Outcome measures were assessed at initial diagnostics (baseline) and after 10 days stimulation at post diagnostics
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| rtACS (Verum Condition) | Detection Accuracy (DA) Change in Percent Over Baseline Within Defective Visual Field Sectors | 24.75 percent change | Standard Deviation 22.4 |
| Sham Stimulation (Placebo Condition) | Detection Accuracy (DA) Change in Percent Over Baseline Within Defective Visual Field Sectors | 39.16 percent change | Standard Deviation 25.26 |
Secondary
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.
Time frame: Nov 2006 - Dec 2010