Visual Field Defect Homonymous Bilateral
Conditions
Keywords
stroke, neurofeedback, network, EEG
Brief summary
Visual field defects are a common consequence of acquired brain injuries and affect people of all ages. These vision problems make everyday life more difficult-for example, when reading, driving, or moving around safely. However, there is currently no effective therapy to improve visual field defects. Previous training methods have focused on maximizing brain activity during a task. However, new findings show that the best performance is achieved when the brain is already in a state of high communication before the task. Our research shows that people can learn to increase communication between brain regions through neurofeedback. Studies have shown that neurofeedback can help people after a stroke: it improves the coordination of brain areas that are important for movement, thereby helping to increase mobility. Building on these findings, this study investigates whether EEG neurofeedback can support the visual centers in the brain to improve vision in patients with chronic visual field defects. The main objective of the study is to evaluate the effectiveness of neurofeedback in improving visual field defects. More specifically, the investigators are investigating the development of visual ability (expansion of the visual field, contrast sensitivity).
Interventions
PROCEDUREneurofeedback
The proposed neurofeedback approach relies on high-density electroencephalography (EEG) combined with advanced source localization algorithms. Data will be analyzed in real-time and simultaneously recorded for offline analysis. During each update, a data segment will be filtered between 1 and 20 Hz. The beamformer, computed at the beginning of the session, will be used to project the signal to the gray-matter voxels. The investigators will compute the alpha-band absolute imaginary coherence between a visual target area and the rest of the brain as index of functional connectivity. Global functional connectivity in the alpha band (8-13 Hz) between the voxels in the target region and the rest of the brain will be calculated.
Sponsors
Adrian Guggisberg
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
50 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* Chronic, stable HVFD (homologous lateral quadranopsia or hemianopsia) * 12 months or more after stroke * Age range 50-70 * Ability to provide informed consent
Exclusion criteria
* Inability to concentrate for long treatment sessions * Eye disease with impact on visual field or acuity * Presence of non-MRI safe metal in the body * New stroke during study period * Hemispatial neglect
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Visual field | Change from enrollment to post-test at 3 weeks and follow up at 7 weeks (repeated-measures ANOVA) | This will be evaluated using the Haag-Streit Octopus 900 perimetry device (Haag-Streit AG, Köniz, Switzerland). The device features advanced gaze-tracking capabilities that effectively control compensatory eye movements, ensuring accurate measurement of visual field improvements. The Central 30-2 protocol will be followed. The primary outcome will be the change in the Mean Deviation (MD) score in detection threshold (in dB) from baseline to the end of the intervention period within the target area of affected visual field. The MD score represents the overall deviation of the patient's visual field from age-matched normative data, with more negative values indicating greater visual field loss. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in alpha-band functional connecticity | Change from entrollment to the end of treatment at 3 weeks. | Neurophysiological changes reflected in alpha-band network communication between targeted area and the rest of the brain, as measured with EEG-based FC. For this, the investigators will record resting state EEG, which, together with individual MRI scans and beamforming techniques, will allow us to estimate FC in source space. |
| Questionnaire on daily-life impact of the visual impairment | Change from enrollment to treatment end at 3 weeks | Daily-life impact of the visual impairment (visual function questionnaire, VFQ25). It ranges from 0 (worst visual function) to 100 (best visual function)). |
| Reading speed | Change from enrollment to treatment end at 3 weeks and follow up at 7 weeks (repeated-measures ANOVA). | Reading speed (International Reading Speed Test, IReST). It is a continuous variable measured in words per minute with no predefined scale range (higher values indicate better performance). |
Countries
Switzerland
Contacts
CONTACTAdrian Guggisberg, MD
Outcome results
None listed