Visual Impairment
Conditions
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 with the defective visual field sectors of the visual field (primary outcome measure).
Detailed description
exploratory, randomized, controlled study
Interventions
DEVICErtACS (verum condition)
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.
DEVICEplacebo stimulation
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).
Sponsors
EBS Technologies GmbH
University of Magdeburg
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Detection accuracy (DA) change in percent over baseline within defective visual field sectors | between baseline and 60 days after stimulation | 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). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Visual Parameters 1 | baseline to 60 days after stimulation | DA in static and kinetic perimetry |
| Visual Parameters 2 | baseline to 60 days after stimulation | reaction time (RT) in HRP |
| Visual Parameters 3 | baseline to 60 days after stimulation | visual acuity (VA) |
| Visual Parameters 4 | baseline to 60 days after stimulation | contrast vision |
| EEG parameters | baseline to 60 days after stimulation | EEG power spectra |
Countries
Germany
Outcome results
None listed