When we think about a stroke, we usually picture its most visible effects: a weak arm, slurred speech, or difficulty walking. But one of the most challenging conditions a stroke survivor can face is actually invisible to the eye. It is a neurological phenomenon known as spatial neglect.
Imagine waking up and completely losing awareness of the left side of your world. You only eat food from the right side of your plate. You only shave the right side of your face. If someone stands to your left and speaks to you, your brain struggles to recognize they are there. This isn’t a vision problem—your eyes work perfectly fine. Instead, it is a localized breakdown in how the brain processes space and attention, typically occurring after a stroke injures the brain’s right hemisphere.
Traditional rehabilitation can take a long time to show results for spatial neglect, leaving many survivors looking for answers. However, a recent research study from our team at the Centre of Science Research Institute highlights a promising breakthrough that could drastically accelerate how we treat it.
Shifting Perspectives with Prism Goggles
One of the most effective tools we currently use to treat spatial neglect is called Prism Adaptation (PA).
During prism adaptation therapy, a patient wears specialized goggles fitted with wedge-shaped prism lenses. These lenses intentionally shift everything they see slightly to the right. When the patient tries to reach out and point at an object in front of them, they initially miss it, reaching too far to the right because their eyes are being tricked.
But the human brain is highly adaptable. Within about 120 pointing trials, the brain recognizes the error, recalibrates its internal map, and forces the arm to adjust by reaching further to the left to hit the target. When the goggles are taken off, a fascinating “aftereffect” happens: the brain keeps pointing to the left space it was previously ignoring. By forcing this physical adjustment, we are essentially training the brain to look left again.
The Power of Combination: Adding a Spark to Therapy
While prism adaptation works well on its own, our latest study looked at how we could make this rewiring process stronger and more permanent. We wanted to know: What happens if we stimulate the muscles while the brain is adapting?
To test this, we paired a single session of prism adaptation with non-invasive sensorimotor electrical stimulation. We applied gentle, safe electrical currents to the muscles while participants performed the pointing tasks, and then used advanced Transcranial Magnetic Stimulation (TMS) to look directly at the brain’s response.
The results were eye-opening. While both groups experienced the immediate behavioural benefit of pointing further to the left, the participants who received the electrical stimulation showed a significant increase in motor cortex excitability. In simple terms, adding electrical stimulation acted like an amplifier. It made the primary motor cortex more receptive to change, lighting up the neural pathways connected to both the upper limb (the hand) and, crucially, the lower limb (the ankle).
Why This Matters for the Future of Stroke Rehab
This finding is incredibly exciting for two main reasons:
Greater Neuroplasticity: The boost in brain excitability suggests that combining physical tricks (like the goggles) with sensory inputs (like electrical stimulation) can drive deeper, longer-lasting neuroplastic changes than traditional therapy alone.
Generalization to Walking: Spatial neglect doesn’t just affect how people look at the world; it affects how they walk, often causing balance issues because they aren’t aware of the left side of their body. Seeing these positive brain changes stretch all the way down to the lower limbs opens up massive possibilities for designing better walking therapies for stroke survivors.
Rehabilitating the brain after a severe neurological injury is a complex puzzle, but by combining innovative behavioural exercises with targeted technology, we are getting closer to solving it.
This write up if culled from Dr. Aloba’s research. You can reach more about Dr. Aloba’s work here:
Reference
Aloba F, Chen P, Hope J, Spencer J, Muthukumar M, Leone T, et al. Effects of Prism Adaptation Combined with Electrical Stimulation on Cortical Excitability of Upper and Lower Limb Muscles. Behavioural brain research. 2026:116263. doi: 10.1016/j.bbr.2026.116263.
