Alternating and Direct Current Stimulation for Neuropathic Eye Pain

Neil Lagali

Status: Enrolling

Conditions: Eye Pain; Neuropathy, Optic; Cerebral Injury

Treatments: Device: DC-Stimulator Plus (NeuroConn GmbH, Germany); Device: Sooma direct current stimulator (Sooma, Finland)

Study type: Interventional

Funder types: Other

Identifiers

NCT05931250

20220727401

Details and patient eligibility

About

The goal of this clinical intervention is to test if two forms of transcranial current stimulation, transcranial direct current stimulation (tDCS) or transcranial alternating current stimulation (tACS) can alleviate neuropathic eye pain in a sample of 20 patients.

The main aims are:

• Test if tDCS/tACS can alleviate neuropathic eye pain and/or other cerebral symptoms: brain fatigue, migraine, light sensitivity, etc.
• Test if one stimulation method is superior to the other Patients will be treated for a total of fifteen 30-minute stimulation sessions, three times a day over a five-day period, each stimulation separated by approximately 4 hours, with either active tACS or tDCS over the scalp corresponding to primary sensory and motor areas.

The patients will have questionnaires to monitor subjective experiences and pupillometry before and after treatment to monitor experimental outcomes.

Full description

Brief Summary sufficient

Enrollment: 20 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• persistent eye pain for at least 6 months
• average eye pain intensity of 4 or more on a 0-10 numerical rating scale
• naive to transcranial stimulation
• eye pain having neuropathic-like characteristics

Exclusion criteria

• contraindication to transcranial stimulation (i.e., pacemaker, cardioverter defibrillator, neuro-stimulation (brain or spinal cord), bone growth stimulations, indwelling blood pressure monitors, epilepsy, pregnancy)
• presence of ocular diseases that are the likely cause of pain (i.e., corneal and conjunctival scarring, corneal edema, uveitis, iris transillumination defects, etc.)
• current participation in another study with an investigational drug or device within one month prior to screening

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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20 participants in 2 patient groups

Transcranial alternating current stimulation

Experimental group

Description:

Transcranial alternating current stimulation (tACS) device using 50x70 mm electrodes that are placed bilaterally between EEG coordinates C3/C5 for left hemisphere and C4/C6 for right hemisphere (corresponding to S1 and M1 of the eye). The alternating current electrodes are in-phase and have the same peak to peak stimulation 3mA, for 30 minutes duration at 10Hz. An impedance value under 15 ohms is required at all times to ensure patient comfort and safety.

Treatment:

Device: DC-Stimulator Plus (NeuroConn GmbH, Germany)

Transcranial direct current stimulation

Experimental group

Description:

Transcranial direct current stimulation (tDCS) device using 50x70 mm electrodes that has the anodal electrode placed contralateral to most prominent ocular pain or, in the case of bilateral pain symptoms, contralateral to the dominant hand between EEG coordinates C3/C5 for left hemisphere and C4/C6 for right hemisphere (corresponding to S1 and M1 of the eye), and the cathode placed on the patient's upper arm. A current peaking at 3mA will ramp up for 20 secs and be delivered for a total of 20 minutes, thereafter, ramping down for 20s. An impedance value under 15 ohms is required at all times to ensure patient comfort and safety.

Treatment:

Device: Sooma direct current stimulator (Sooma, Finland)