#363 ‒ A new frontier in neurosurgery: restoring brain function with brain-computer interfaces, advancing glioblastoma care, and new hope for devastating brain diseases | Edward Chang, M.D.
Dr. Edward Chang, Chair of Neurosurgery at UCSF, discusses the evolution of neurosurgery, awake brain surgery, and breakthroughs in brain-computer interfaces (BCIs) to restore speech and movement. He also touches on glioblastoma and the future of neurosurgical treatments.
Deep Dive Analysis
21 Topic Outline
Evolution of Modern Neurosurgery and Key Figures
Advances in Vascular and Minimally Invasive Neurosurgery
Understanding and Treating Glioblastoma Multiforme (GBM)
Challenges and Future of Blood-Brain Barrier Treatments
Personal Journey into Neurosurgery and Awake Brain Surgery
Brain Mapping and Decoding Neural Activity for Language
The Mechanics of Awake Brain Surgery
Brain Plasticity and Redundancy in Surgical Resection
Corpus Callosotomy and Split-Brain Syndrome
Neural Engineering for Neurodegenerative Diseases
Individual Variation in Brain Activity and Sensory Processing
Impact of Sensory Loss on Cognitive Function
Introduction to Brain-Computer Interfaces (BCI)
Comparing EEG, ECoG, and Intracortical Electrode Resolution
Clinical Trial: Restoring Speech to a Stroke Patient via ECoG BCI
Training and AI Decoding for BCI-Enabled Speech
Future Applications of BCI for Movement and Respiration
The Role of Bioengineering and Stem Cells in Brain Regeneration
2030-2040 Vision for Neurosurgery and Neurological Treatments
Risks of Vertebral Artery Dissections
Harvey Cushing's Perspective on Modern Neurosurgery
9 Key Concepts
Homunculus
A representation in the brain showing which part of the brain controls every muscle in our body and how it's laid out. This concept was popularized by Wilder Penfield in the context of epilepsy surgery.
Awake Brain Surgery
A surgical procedure where the patient is conscious for a portion of the operation, made possible because the brain itself lacks pain receptors. This allows surgeons to map and protect critical functions like language and movement in real-time.
Brain Plasticity
The brain's ability to reorganize itself by forming new synaptic connections or strengthening existing ones. This allows other redundant parts of the brain to compensate for lost function, especially in cases of slow-growing lesions or injury.
Corpus Callosum
A thick band of nerve fibers that serves as an information highway, connecting the left and right hemispheres of the brain. Its surgical transection can limit the spread of severe seizures but may lead to a dissociation syndrome.
Neural Engineering
A field that uses computers, sensors, and chips to interpret the electrical signals neurons use to communicate. The goal is to decode these signals and use that information to guide or restore normal brain signaling and function.
Brain-Computer Interface (BCI)
A system that records electrical activity from the brain (via non-invasive or invasive methods) and connects those signals to a computer. The computer analyzes, interprets, and transforms these signals into useful outputs, such as controlling a cursor or generating speech.
Electrocorticography (ECoG)
A method of recording brain activity using electrodes placed directly on the surface of the brain, underneath the dura mater. It offers significantly higher resolution than scalp EEG and avoids the immune reaction associated with electrodes penetrating brain tissue.
Functional Electrical Stimulation (FES)
A technique that couples brain-computer interface decoding with stimulating electrodes placed directly on muscles. This allows for the bypass of damaged nerves to restore coordinated movement, such as breathing or limb control.
Organoids
Miniature, self-organizing 3D tissue cultures derived from stem cells that mimic the structure and function of organs, such as the brain. They are used as models for disease, drug testing, and are envisioned to interface with brain-computer interfaces in the future.
12 Questions Answered
The main categories include tumors, vascular system issues (aneurysms, strokes), spine conditions, and functional neurosurgery, which involves understanding and intervening in brain circuits.
Many procedures that once required large open craniotomies, such as for aneurysms, are now often performed using minimally invasive techniques like catheters in the groin or laser probes, significantly reducing collateral damage and recovery time.
GBM is a highly aggressive brain tumor originating from glial support cells, characterized by rapid growth and necrosis. It is particularly lethal because it outstrips its blood supply, suppresses the immune system, and often has microscopic cells beyond what can be seen on MRI, leading to recurrence even after extensive resection.
The blood-brain barrier restricts drug delivery to the brain. Future solutions include designing drugs that can cross the barrier, direct intrathecal (spinal fluid) administration, and using technologies like focused ultrasound to temporarily open the barrier in targeted areas.
The brain itself does not contain pain receptors, although the scalp and dura (membrane covering the brain) do. Surgeons numb the scalp and use light sedation, allowing the patient to be awake for critical periods of brain mapping without feeling pain from the brain manipulation.
Yes, the brain exhibits plasticity, meaning it can reorganize itself over time. If a part of the brain is slowly compromised (e.g., by a tumor), other redundant areas can take over its functions through synaptic changes and new connections.
Severing the corpus callosum (corpus callosotomy) is performed in patients with severe, medically resistant seizures (like drop attacks) to prevent the rapid propagation of seizure activity from one brain hemisphere to the other, thereby reducing loss of consciousness and injury risk.
Unrecognized hearing loss can lead to social isolation and deprives the brain of necessary auditory signals, which has been shown to accelerate age-related memory loss and cognitive decline.
Non-invasive EEG (scalp electrodes) offers low resolution. ECoG (electrodes on the brain surface) provides significantly higher resolution (approx. 1000x EEG) with stable recordings and less immune reaction. Intracortical electrodes (inserted into the brain) offer the highest resolution (approx. 5000x EEG) for single-neuron activity but face challenges with stability and immune response.
In a clinical trial with a patient who had been unable to speak for 18 years, an ECoG-based BCI was able to decode her attempted speech into text at an average rate of about 80 words per minute, roughly half the rate of natural conversation.
By 2030, the goal is to have fully implantable, wireless BCI systems available to a broader market, helping patients with various neurological conditions like ALS, spinal cord injury, and stroke by optimizing existing proof-of-concept technologies.
Yes, certain chiropractic movements or high-velocity neck movements can cause injury to the vertebral artery wall, leading to dissection. While the incidence is low, it is a statistically proven and very dangerous risk.
18 Actionable Insights
1. Correct Hearing Loss to Preserve Cognition
Actively address and correct any hearing loss, even if unrecognized, because it can accelerate age-related memory loss and lead to cognitive decline due to sensory deprivation.
2. Avoid Aggressive Neck Adjustments
Refrain from severe aggressive movements or certain chiropractic neck adjustments, as they are statistically proven to cause vertebral artery dissection, a rare but highly severe injury.
3. Choose Medicine to Bend Civilization’s Arc
Consider a career in medicine, especially in fields like neurosurgery and neuroengineering, as it offers a unique opportunity to combine science, medicine, and technology to solve complex problems and significantly impact civilization.
4. Utilize BCI for Speech Restoration
For individuals with severe paralysis and loss of speech, explore brain-computer interfaces (BCI) that decode brain activity to restore communication through synthesized speech or text. This technology interprets brain signals to transform them into a useful communication form.
5. Pursue Early BCI Intervention
For conditions leading to speech loss, seek early intervention with BCI technology, as the brain’s original speech-related activity patterns are more preserved and easier to decode, leading to faster and more effective outcomes.
6. Use BCI for Rehabilitation
Consider BCI technology not only for prosthetic function but also as a tool to augment and accelerate rehabilitation. Direct brain feedback and repeated volitional attempts can strengthen affected muscles and aid in regaining natural function.
7. Combine BCI with FES
For conditions like ALS affecting motor function, explore combining brain-computer interfaces with functional electrical stimulation (FES). This approach bypasses damaged nerves to directly stimulate muscles for coordinated movement, such as breathing or limb control.
8. Explore Cell Transplant for Parkinson’s
Investigate advanced cell-based therapies for Parkinson’s disease, specifically the transplantation of stem cells or engineered cells into the substantia nigra. These therapies aim to replace degenerated dopaminergic neurons with better control over dopamine release and delivery.
9. Prioritize Brain Mapping in Surgery
When undergoing brain surgery for tumors or seizures in critical areas, ensure brain mapping is performed to precisely identify and protect vital language and motor function regions. This helps balance maximal resection with preserving neurological function.
10. Maximize Glioblastoma Resection
For glioblastoma, aim for the most extensive surgical resection possible, as studies have shown a direct correlation between the extent of tumor removal and prolonged patient survival.
11. Utilize Glioblastoma Genetic Profiling
For glioblastoma, seek genetic profiling of the tumor in academic medical centers to identify specific mutations. This information is crucial for tailoring and personalizing chemotherapy and other targeted treatments.
12. Explore Immune-Based Glioblastoma Therapies
Investigate emerging immune-based strategies that aim to overcome glioblastoma’s ability to suppress the immune system. Enabling the immune system to recognize and target the tumor could unlock future therapeutic options.
13. Utilize Focused Ultrasound for BBB Opening
Explore focused ultrasound as a non-invasive method to temporarily open the blood-brain barrier in targeted brain regions. This technique can enhance the delivery of molecularly specific therapeutic agents to the brain.
14. Consider Corpus Callosotomy for Seizures
For patients with severe, medically recalcitrant drop attack seizures, a partial corpus callosotomy can be considered. This procedure severs connections between hemispheres to prevent rapid seizure propagation, reducing loss of consciousness and injury risk.
15. Actively Vocalize During BCI Training
When training a brain-computer interface for speech restoration, it is critical to actively attempt to vocalize the desired words. This volitional intent to speak is the most important factor for the algorithm to effectively decode brain activity patterns.
16. Leverage Brain Plasticity for Recovery
Understand that the brain exhibits significant plasticity, allowing functions to reorganize and shift to other areas over time, especially with slow-growing lesions. This inherent adaptability can aid in recovery and influence surgical planning.
17. Investigate Bioengineering for Neurological Therapies
For future neurological therapies, consider exploring bioengineering solutions such as engineered cells and organoids. This approach moves beyond traditional electronics to leverage biological systems for computing and interfacing with the brain.
18. Advance Health Knowledge
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5 Key Quotes
The brain itself doesn't have any pain receptors.
Edward Chang
It's not like you're looking at a computer. You're looking at, essentially, an organ composed of biological cells, 86 billion to be precise, you know, how many neurons there are in the human brain.
Edward Chang
The history of neurosurgery was actually primarily about trying to avoid injury, stay outside of the brain, etc. Now it's much more inward looking, trying to understand actually how the system works, how the organ works.
Edward Chang
It's not a wives' tale. It's actually statistically proven that certain kind of chiropractic movements around the neck can cause an injury to the wall of the vertebral artery.
Edward Chang
The biggest thing you give up is 80% of the resolution, roughly.
Peter Attia
2 Protocols
Awake Brain Surgery Procedure
Edward Chang- Fix the patient's head using a head holder.
- Administer a light level of sedation (e.g., propofol, at a much lower dose than general anesthesia).
- Numb the scalp and areas around the dura with local anesthesia (e.g., lidocaine).
- Make an incision and perform a craniotomy (temporarily remove a piece of bone) to access the brain.
- Turn off sedation so the patient is fully awake for brain mapping.
- Use electrical stimulation or other recording technologies to map critical functions like language and motor control on the exposed brain.
- Perform the necessary surgical resection (e.g., tumor removal) while protecting mapped critical areas.
- Ramp up sedation to finish the procedure and close the incision.
Brain-Computer Interface (BCI) Training for Speech Restoration
Edward Chang- Implant an array of ECoG sensors (e.g., 253 sensors) on the part of the brain responsible for motor production of words (lips, jaw, larynx, tongue).
- Connect the implanted array to an external computer system, initially via a percutaneous port.
- Display text prompts (e.g., NATO code words or sentences) on a screen for the participant.
- Instruct the participant to *try* to say the words/sentences, even if no intelligible sound is produced.
- Record the brain activity patterns from the ECoG sensors during these attempted speech movements.
- Train a machine learning algorithm (decoder) to translate the brain activity patterns (in small 10-20 millisecond segments) into individual speech units (phonemes).
- Utilize a language model to infer the most likely sequence of words or phonemes, reconstructing full sentences from the decoded speech units.
- Provide real-time feedback to the participant on the accuracy of the decoded speech, allowing for rapid improvement and adaptation.