About this trial
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).
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Chronic, stable HVFD (homologous lateral quadranopsia or hemianopsia)
12 months or more after stroke
Age range 50-70
Ability to provide informed consent
Disqualifiers
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
Trial design
Crossover
Treatments tested in this trial
neurofeedback
Procedure/SurgeryThe 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.
Treatment groups
Trial outcomes
Primary outcomes
Visual field
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 outcomes
Changes in alpha-band functional connecticity
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
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
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).
Other outcomes
Test of Attentional Performance (TAP) Visual Scanning
Reaction time in the TAP Visual Scanning test is a continuous variable with no predefined bounds, with longer reaction times indicating poorer performance; omissions represent the number of missed targets, with higher values also indicating poorer performance.
Test of Attentional Performance (TAP) Sustained Attention
The reaction time of the TAP Sustained Attention is a continuous variable with no predefined bounds, with longer reaction times indicating poorer performance; omissions represent the number of missed targets, with higher values also indicating poorer performance.
Test of Attentional Performance (TAP) Visual field and Neglect test
The reaction time is a continuous variable with no predefined bounds, with longer reaction times indicating poorer performance; omissions represent the number of missed targets, with higher values also indicating poorer performance.
Sponsors and contacts
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Adrian Guggisberg
Lead sponsor
University Hospital, Geneva
Sponsor institution