Paraorbital-Occipital Alternating Current Stimulation Therapy of Patients With Post-Chiasmatic Lesions

Sponsor

University of Magdeburg (Other)

Overall Status

Completed

CT.gov ID

NCT01418820

Collaborator

EBS Technologies GmbH (Industry)

Enrollment

Location

Arms

33.1

Actual Duration (Months)

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Visual field areas, which are not absolutely blind, are hypothesized to have some residual capacities that constitute their potential for vision restoration. Vision restoration can be achieved by varies methods including behavioral training and electrical brain stimulation such as transcranial direct current stimulation (tDCS) and repetitive transorbital alternating current stimulation (rtACS) which are able to influence the excitability and activity of cortical areas.

It is hypothesized that transorbital alternating current stimulation (tACS) can improve the residual field of vision in patients with post-chiasmatic lesions.

Condition or Disease	Intervention/Treatment	Phase
Complete Hemianopia Incomplete Hemianopia Scotoma Quadrantanopia Stroke Hemorrhage Brain Trauma	Device: Verum stimulation Device: Placebo stimulation	Phase 2

Study Design

Study Type:

Interventional

Actual Enrollment :

32 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Triple (Participant, Investigator, Outcomes Assessor)

Primary Purpose:

Treatment

Official Title:

Paraorbital-Occipital Alternating Current Stimulation Therapy of Patients With Post-Chiasmatic Lesions

Actual Study Start Date :

Mar 1, 2011

Actual Primary Completion Date :

Dec 1, 2013

Actual Study Completion Date :

Dec 1, 2013

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Verum stimulation repetitive transorbital alternating current stimulation (rtACS)	Device: Verum stimulation 10 days (2x 5 working days), daily transorbital alternating current stimulation (rtACS) is applied with a device generating weak current pulses in predetermined firing bursts of 2 to 9 pulses. The amplitude of each current pulse is below 1000 µA. Current intensity is individually adjusted according to how well patients perceived phosphenes, e.g. any sensation of flickering light in response to the rtACS stimulation. Stimulation frequencies were between the individual alpha frequency peak and below flicker fusion.
Sham Comparator: Placebo stimulation compared to verum stimulation the same electrode montage set-up is used during placebo stimulation, except that placebo patients receive a minimal stimulation	Device: Placebo stimulation 10 days (2x 5 working days), daily sham-stimulation with the same electrode montage set-up that is used for verum transorbital alternating current stimulation (rtACS). Minimal sham-stimulation was performed with single bursts (approx. one per min) of electrical currents at a given frequency of 5Hz and individually adjusted current amplitude.

Arm

Intervention/Treatment

Experimental: Verum stimulation

repetitive transorbital alternating current stimulation (rtACS)

Device: Verum stimulation

10 days (2x 5 working days), daily transorbital alternating current stimulation (rtACS) is applied with a device generating weak current pulses in predetermined firing bursts of 2 to 9 pulses. The amplitude of each current pulse is below 1000 µA. Current intensity is individually adjusted according to how well patients perceived phosphenes, e.g. any sensation of flickering light in response to the rtACS stimulation. Stimulation frequencies were between the individual alpha frequency peak and below flicker fusion.

Sham Comparator: Placebo stimulation

compared to verum stimulation the same electrode montage set-up is used during placebo stimulation, except that placebo patients receive a minimal stimulation

Device: Placebo stimulation

10 days (2x 5 working days), daily sham-stimulation with the same electrode montage set-up that is used for verum transorbital alternating current stimulation (rtACS). Minimal sham-stimulation was performed with single bursts (approx. one per min) of electrical currents at a given frequency of 5Hz and individually adjusted current amplitude.

Outcome Measures

Primary Outcome Measures

detection accuracy (%) in visual field measures over baseline [baseline to 8 weeks after stimulation]
visual stimuli detection accuracy in residual and absolutely defect visual field will be assessed using computer-based high resolution perimetry (HRP)

Secondary Outcome Measures

detection accuracy (%) in the intact visual field over baseline [baseline to 8 weeks after stimulation]
visual stimuli detection accuracy in the intact visual field will be assessed using computer-based high resolution perimetry (HRP)
visual acuity (LogRAD) [baseline to 8 weeks after stimulation]
EEG parameters [baseline to 8 weeks after stimulation]
entrainment of stimulation frequencies (EEG power spectra) and measures of functional connectivity
conventional perimetry [baseline to 8 weeks after stimulation]
visual fields obtained by static and kinetic perimetry (average threshold in db, average excentricity in degrees)
reaction time (ms) [baseline to 8 weeks after stimulation]
average reaction time in ms, measured by computer-based high resolution perimetry (HRP)

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 75 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

lesion of the tractus opticus or of the visual cortex
lesion age > 6 months
stable visual field defect with residual vision

Exclusion Criteria:

electric or electronic implants, e.g. heart pacer
any metal artefacts in the head
Epilepsy
Auto-immune diseases in acute stage
mental diseases, e.g. schizophrenia etc.
diabetic retinopathy
addictive diseases
blood pressure above 160/100 mmHg
instable or high level of intraocular pressure above 27 mmHg
retinitis pigmentosa
pathological nystagmus
presence of an un-operated tumor or tumor relapse (patients with non-progressive tumor are eligible if study participation is recommended by medical authorities)
focal findings in EEG or photosensitivity (patients with single seizure more than 10 yrs ago may participate)
recurrent transitional ischemic attacks after stroke
arteriosclerosis of large blood vessels with stenosis >75%
severe coronary heart disease (CHD)
unstable angina pectoris
diabetes with blood glucose level > 9 mmol/l
myocard infarct/ cardiomyopathy
ventricular fibrillation
risk of vascular thrombosis
pregnant or breast-feeding women