Active not recruitingOBSERVATIONAL

Anatomical and Functional Predictions of Blindsight Capabilities in Patients With Lateral Hemianopsia

This study is for people who have lost half of their vision (hemianopia) after a stroke, particularly in the part of the brain that handles sight. We know that some people with this type of vision loss can still unconsciously detect movement or light in their 'blind' area, a phenomenon called blindsight. This research aims to understand why some people experience blindsight and others don't, and why there are different types. We're especially interested in how different parts of the brain communicate with each other after a stroke, and if this communication can predict who might have blindsight. The goal is to find better ways to assess vision problems and tailor support for patients.

At a glance

Status

Active not recruiting

Sponsor

Fondation Ophtalmologique Adolphe de Rothschild

Enrolment target

Start

21 Nov 2024

Estimated completion

01 Dec 2029

Homonymous Hemianopia Stroke Cortical Blindness Hemianopia

What is this study about?

If you've had a stroke that affected your vision, you might have a condition called homonymous hemianopia. This means you've lost the ability to see things on one side of your visual field. While this can be challenging, some scientific studies have shown that even without seeing consciously, some people can still react to things in their 'blind spot'. This surprising ability is called 'blindsight'.

There are a few different types of blindsight. Some people might unconsciously detect something moving, while others might just have a feeling that something is there without actually 'seeing' it. Around four in ten people with this condition don't experience any blindsight at all. The researchers in this study believe that these different experiences are linked to how the brain has been affected and how different parts of the brain are still working together after the stroke.

This study will use a special type of brain scan called an fMRI to look at how different parts of your brain communicate with each other when you're resting. The researchers are particularly interested in the connections between the healthy side of the brain and the side affected by the stroke. They want to see if the strength of these connections can predict whether someone will experience blindsight, and what kind of blindsight it might be. Understanding this could help doctors better assess a person's vision issues and offer more personalised support in the future.

Key takeaways

The study explores why some stroke survivors with vision loss can unconsciously 'see' things.
It uses brain scans (fMRI) to look at brain connections after a stroke.
Aims to understand different types of 'blindsight' and why they occur.
Could help doctors better assess and support people with vision problems after a stroke.
It's an observational study, not testing a new treatment.

Who may be eligible?

This study is looking for adults aged 18 and older who have experienced vision loss in half of their visual field (homonymous hemianopia) after a stroke. This stroke must have affected the back part of their brain, which is crucial for vision. You'll also need to be able to have follow-up brain scans as part of your regular treatment and be able to use a computer for some simple tasks. You must be willing to give your agreement to take part and be covered by a social security scheme.

There are also some reasons why you might not be able to join. For example, if you have other severe problems with your thinking, memory, attention, or language. If you have serious eye conditions that existed before your stroke, or ongoing eye conditions like cataracts or glaucoma, you might not be a good fit. Also, if you have major mental health or behavioural issues, or if you are pregnant or breastfeeding, you won't be able to participate.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you 18 years old or older?
Have you lost half of your vision after a stroke?
Did your stroke affect the back part of your brain (involved in sight)?
Are you able to have routine brain MRI scans?
Can you use a computer for simple tasks?
Do you have good overall thinking and memory abilities?

Answer every question to see your result.

What does participation involve?

The detailed involvement for participants isn't fully described, but based on the summary, you would likely participate in some computer-based tasks designed to test your vision and reactions. You would also undergo special brain scans (fMRI) while resting. The study aims to look at your brain's structure and activity. The total duration of your involvement isn't specified, but the study focuses on understanding existing conditions and brain activity rather than new treatments.

Potential risks and benefits

Potential benefits of participating include contributing valuable information that could lead to a better understanding of blindsight and potentially improved ways to assess and support people with vision loss after a stroke. Risks for this type of observational study are generally low, mainly related to the fMRI scan (e.g., spending time in an enclosed space, potential for noise). You are free to withdraw from the study at any time without giving a reason, and your medical care will not be affected.

Locations (1)

Hopital Fondation Adolphe de Rothschild
Verified postcode
Paris, France

Common questions

What is 'blindsight'?

Blindsight is when someone can react to things in their 'blind' spot even though they can't consciously see them. It's like having an unconscious awareness.

What is homonymous hemianopia?

This is a type of vision loss where you can't see things in one half of your visual field (e.g., the left half for both eyes) due to a problem in your brain, often caused by a stroke.

What is an fMRI scan?

An fMRI is a special type of brain scan that looks at blood flow changes, which helps to show which parts of your brain are active. It is safe and does not involve radiation.

Will this study cure my vision loss?

No, this is an observational study focused on understanding blindsight. It's not testing a new treatment or medication, but aims to improve future assessments and support.

Will I receive feedback on my results?

The study description doesn't specify if individual results will be shared. You should ask the research team if this is important to you.