The effect of transcranial direct current stimulation (tDCS) on diabetes-related visual impairment (diabetic retinopathy)
| ISRCTN | ISRCTN70877737 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN70877737 |
- Submission date
- 12/01/2021
- Registration date
- 15/01/2021
- Last edited
- 08/03/2021
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Eye Diseases
Plain English summary of protocol
Background and study aims
Diabetic retinopathy is a complication of diabetes, caused by high blood sugar levels damaging the back of the eye (retina). It can cause blindness if left undiagnosed and untreated. Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes and the leading cause of preventable blindness.
In the present study, we explored the potential of transcranial direct current stimulation (tDCS) to enhance PDR patients' residual vision.
Transcranial direct current stimulation (tDCS) is a form of brain stimulation that uses constant, low direct current delivered via electrodes on the head.
Who can participate?
Patients clinically diagnosed with PDR who have the capacity to consent participated in this study. They are right-handed and at least 18 years of age during the experiment.
What does the study involve?
Patients were divided into two groups: tDCS and sham group. Patients in the tDCS group received 10 minutes of tDCS stimulation of the part of the brain that process visual information called the visual cortex. Patients in the sham group only received tDCS stimulation for 30 seconds. Visual acuity and ability to discriminate numbers of non-verbal stimuli such as dots (number acuity) were measured before and after stimulation.
What are the possible benefits and risks of participating?
tDCS is a safe and non-invasive method of stimulating the brain. The current is very low (1mA) and will not cause pain or skin burn. Skin irritation is only documented for an extended period of stimulation and higher current intensity. This study expected to improve visual and number acuity of patients who will receive negative current or cathodal tDCS.
Where is the study run from?
Nazareth General Hospital in Dagupan City, Pangasinan (Philippines)
When is the study starting and how long is it expected to run for?
October 2019 to February 2020
Who is funding the study?
Investigator initiated and funded
Who is the main contact?
Dr Shane Fresnoza, shane.fresnoza@uni-graz.at
Contact information
Scientific
Goethestrasse 21
Graz
8010
Austria
 ORCID ID |
0000-0002-9938-2285 |
|---|---|
| Phone | +43 6608474229 |
| shane.fresnoza@uni-graz.at |
Study information
| Study design | Double-blinded randomized sham-controlled study |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised controlled trial |
| Study setting(s) | Hospital |
| Study type | Treatment |
| Participant information sheet | No participant information sheet available |
| Scientific title | Visual cortex transcranial direct current stimulation for proliferative diabetic retinopathy patients: an exploratory randomized trial |
| Study acronym | VTDCSPDR |
| Study objectives | Retinal diseases, including the early stages of diabetic retinopathy, are characterized by high internal noise within the visual pathways which further aggravates impaired visual functions. Cathodal tDCS could reduce neural noise and improve the processing of impaired visual inputs from the damaged retinas of PDR patients. |
| Ethics approval(s) | The clinic where the study is conducted is located in a private, non-research and non-teaching hospital which do not have a formal ethics committee. The patients included in the study were all private patients, who provided informed consent for participation. The study protocol ( STUDY PROTOCOL Version 1.1) was approved by the chief of clinics of Nazareth General Hospital in Dagupan City, Pangasinan, Philippines. Dr Demosthenes Ydia (Chief of Clinics, Nazareth General Hospital, Perez Blvd Dagupan City, Pangasinan, 2433, Philippines; +6309175081288; docbutchydia@yahoo.com) |
| Health condition(s) or problem(s) studied | Improving the residual vision of proliferative diabetic retinopathy patients |
| Intervention | Participants were allocated into either the tDCS group or sham group using block randomization (online Study Randomizer Software (https://www.studyrandomizer.com)). Participants in the tDCS group received 10 minutes 1 mA cathodal tDCS stimulation of the primary visual cortex. Participants in the sham group were only stimulated for 30 seconds using the same stimulation parameters. Measures were taken immediately before and after the stimulation, there was no further follow up. |
| Intervention type | Device |
| Pharmaceutical study type(s) | |
| Phase | Not Applicable |
| Drug / device / biological / vaccine name(s) | Transcranial direct current stimulation (tDCS) |
| Primary outcome measure | Visual acuity is measured using the logarithm of the minimum angle of resolution (LogMAR) scores before and after stimulation |
| Secondary outcome measures | Number acuity measured before and after stimulation using a numerical discrimination task. (Patients were presented with an intermixed of 60 black and white dots. After the stimulus presentation time of 500ms, patients have to indicate whether there were more black or white dots by key presses) |
| Overall study start date | 15/10/2019 |
| Completion date | 20/02/2020 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | Both |
| Target number of participants | 22 |
| Total final enrolment | 22 |
| Key inclusion criteria | 1. Clinically diagnosed PDR patients 2. Voluntary participation and capacity to consent 3. Right-handedness (Edinburgh Handedness Test) 4. At least 18 years of age during the experiment |
| Key exclusion criteria | 1. Other co-morbid conditions such as chronic or residual neurological, psychological, and psychiatric disorders (esp. epilepsy, schizophrenia, mania or depression) 2. History of head injury with loss of consciousness 3. Intracerebral ischemia/history of cerebral bleeding 4. Metal implants in the head and neck area (e.g. post-operative clips) 5. Electronic implants (pacemakers, cochlear implant, deep brain stimulator) 6. Pregnancy or breastfeeding 7. Alcohol or drug addiction 8. Local or global aphasia 9. Any legal reason why the candidate cannot participate 10. Participation in another scientific or clinical study within the last 8 weeks |
| Date of first enrolment | 20/02/2020 |
| Date of final enrolment | 20/02/2020 |
Locations
Countries of recruitment
- Austria
- Philippines
Study participating centres
Pangasinan
Dagupan City
2433
Philippines
Universitätsplatz 2
Graz
8010
Austria
Sponsor information
University/education
Institute of Psychology
Universitätsplatz 2
Graz
8010
Austria
| Phone | +43 316 380 8541 |
|---|---|
| anja.ischebeck@uni-graz.at | |
| Website | https://psychologie.uni-graz.at/en/ |
"ROR" |
https://ror.org/01faaaf77 |
Funders
Funder type
Other
No information available
Results and Publications
| Intention to publish date | 20/02/2021 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Available on request |
| Publication and dissemination plan | Planned publication in a high-impact peer-reviewed journal. |
| IPD sharing plan | The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Protocol file | version v1.1 | 04/02/2021 | No | No | |
| Results article | results | 21/02/2021 | 08/03/2021 | Yes | No |
Additional files
- ISRCTN70877737_PROTOCOL_v1.1.pdf
- uploaded 04/02/2021
Editorial Notes
08/03/2021: Publication reference added.
04/02/2021: Uploaded protocol (not peer reviewed) Version 1.1, no date.
15/01/2021: Trial’s existence confirmed by Nazareth General Hospital
