This document discusses a technical seminar on wireless intracortical brain-computer interfaces used by individuals with tetraplegia. It describes how intracortical BCIs implanted with microelectrode arrays have helped people with tetraplegia regain independence by decoding intended arm and hand movements. A new wireless transmitter system is presented as an alternative to external cables, allowing high-resolution recording of neural signals. The wireless system achieves similar signal quality as the wired system while offering advantages such as increased mobility and potential for in-home use.

1. A Technical Seminar
on
WIRELESS INTRACORTICAL BRAIN-COMPUTER INTERFACE
USED BY INDIVIDUALS WITH TETRAPLEGIA

2. CONTENTS
▪ Abstract
▪ Introduction
▪ Literature Survey
▪ What is tetraplegia?
▪ Brain–computer interfaces (BCIs)
▪ Brain–computer interfaces to restore function
▪ Standard cabled iBCI system
▪ Wireless iBCI system
▪ Comparing cabled and wireless signal fidelity
▪ Advantages and disadvantages
▪ Conclusion
▪ References

3. ABSTRACT
▪ People suffering from neurological disease, unable to speak, inability
to move parts of the body. In such absence of physical activity, brain-
computer interfaces are being built to help people regain their
independence and communicate.
▪ Intracortical brain-computer interfaces (iBCIs), which interpret
intended arm and hand movements from neural signals captured by
implanted microelectrode arrays, have helped people with
tetraplegia.
▪ Wireless transmitters are now being used to replace the external
cables of a 192-electrode iBCI, allowing for high-resolution recording
and decoding of broadband field potentials as well as spiking
activity from people with paralysis.

4. INTRODUCTION
▪ Individuals with neurological disease or injury such as amyotrophic
lateral sclerosis, spinal cord injury or stroke may become tetraplegic,
unable to speak or even locked-in. For people with these conditions,
current assistive technologies are often ineffective.
▪ Brain-computer interfaces are being developed to enhance
independence and restore communication in the absence of physical
movement.
▪ Over the past decade, individuals with tetraplegia have achieved
rapid on-screen typing and point and-click control of tablet apps using
Intracortical brain-computer interfaces (iBCIs) that decode intended
arm and hand movements from neural signals recorded by implanted
microelectrode arrays.

5. Literature Survey:
Author and Published year Title Key points
Gerwin Schalk et al
2018
Noninvasive Brain–Computer
Interfaces
 People with tetraplegia can
manipulate a robotic arm
with NIS-based control
J. L. Collinger et al
2013
High-performance
neuroprosthetic control by an
individual with tetraplegia
 Development of
neuroprosthetic limbs
L. R. Hochberg et al
2012
Reach and grasp by people with
tetraplegia using a neurally
controlled robotic arm
 NIS-based control of a
robotic arm to perform three-
dimensional reach and grasp
movements.
L. R. Hochberg et al
2006
Neuronal ensemble control of
prosthetic devices by a human
with tetraplegia
 Tetraplegic human (MN)
using a pilot NMP
Leuthardt et al
2003
Defining Surgical Terminology
and Risk for Brain Computer
Interface Technologies
 Invasive/non-invasive
distinction for BCI systems
 Describing BCI from a
procedural perspective

6. What is Tetraplegia?
▪ Tetraplegia, also known as quadriplegia,
is a paralysis that results in the partial or
complete loss of use of all four limbs and
the body as a result of illness or injury.
Sensory and motor failure is common,
which means that both sensation and
control are lost.
▪ Tetraplegia is a condition caused by
severe damage to the brain or spinal cord.
▪ Tetraplegia may be characterized in a
variety of ways; a C1–C4 injury typically
affects arm mobility more than a C5–C7
injury.

7. Symptoms:
The most common complications are:
• Respiratory problems such as atelectasis, hyper secretion, and
pneumonia.
• Pulmonary thromboembolism and other embolisms (blood clots).
• Urinary and pulmonary infections
• Pressure sores
• Spastic muscles
• Loss of bladder and bowel control
• Pain
Causes:
Possible causes of such damage include:
• Falls or injuries from vehicle or sporting accidents
• Neurological conditions, such as strokes
• Tumors and lesions in the brain or spinal cord
• Spinal cord infections, such as due to polio

8. Brain–computer interfaces (BCIs):
▪ Brain–computer interfaces (BCIs) tracks brain behavior,
collect features from it, and translate certain features into
outputs that substitute, repair, boost, complement, or
strengthen human functions.
▪ BCIs can be used to restore damaged roles like
communicating and driving. They can help you regain
control of your body by stimulating nerves or muscles that
move your hand.
▪ BCIs have also been used to enhance functions, such as
teaching users to improve the role of weakened pathways
that are needed for grasping.

9. BRAIN–COMPUTER
INTERFACES TO RESTORE
FUNCTION:
• A functional electrical stimulator
(FES) is a machine that stimulates
the muscles that regulate individual
motions like gripping, wrist
dorsiflexion, and knee flexion.
• Orthoses are noninvasive, external
instruments that are connected to
the body that help with movement
in a variety of ways.

10. Standard Cabled iBCI System
▪ The cabled iBCI used commercial hardware and software to
acquire and record neural signals.
▪ This system included a NeuroPort Patient Cable connecting
each percutaneous head-mounted pedestal to a Front End
Amplifier which applied a hardware filter (0.3 Hz – 7.5 kHz)
and digitized signals on each of 96 microelectrodes (30 kS/s,
16 bits per sample).
▪ The continuous serial stream of digital samples was relayed
over fiber optic cable to a Neural Signal Processor (NSP)
where they were time stamped and sent out as UDP packets
on a private local area network

11. Wireless iBCI System
In the wireless recording system, each
Neuro Port Patient Cable and Front End
Amplifier was replaced by four
components
▪ BrownWireless Device (BWD)
▪ One or more polarized planar
antennas (5” x 5”, 3 GHz – 4 GHz
reception, PA-333810-NF)
▪ AWireless Receiver (PN9323)
▪ Digital Hub (PN6973).

12. ▪ Each BWD digitized neural activity from one array and transmitted it at 3.3
GHz or 3.5 GHz (configured at time of manufacture) to the antennas.
▪ The corresponding Wireless Receiver was manually tuned to the appropriate
frequency and could detect valid data packets (frames) received by any of up
to 8 input antennas.
▪ Each Digital Hub relayed the digital data stream to its respective NSP over
fiber optic cable.
▪ The NSP, file recording system, and downstream hardware and software
were unchanged between the wired and wireless configurations.
▪ The BWD data stream from 20 kS/s to 30kS/s (via sample-and-hold) and
from 12 bits per sample to 16 bits per sample (four-bit up-shift).

13. Comparing Cabled and Wireless Signal Fidelity
▪ Transmission data loss is a concern for all
wireless systems.
▪ Wireless data (frame) loss occurred
whenever the receiver did not find the
expected digital sync word on the
incoming wireless data stream from at
least one antenna.
▪ The current samples from all 96
electrodes were invalid and the previous
valid frame was inserted into the data
stream.

14. Advantages and Disadvantages
Advantages:
▪ In-home mobile independent
▪ BWD uses a very low power transmitter
▪ Wireless iBCI to achieve point-and-click control of
computers.
Disadvantages:
▪ Transmission data loss
▪ Frame errors during iBCI decoding

15. CONCLUSION
▪ The feasibility of a wireless iBCI for real-time operation of a point-and-
select interface has been shown in two people with tetraplegia.
▪ The BWD records had characteristics that were somewhat similar to
wired recordings.
▪ This broadband wireless infrastructure also allows for continuing basic
research into cortical processing during every day human activity,
which will help to guide future neuroscience and BCI advances.
▪ This device removes some previous obstacles to in-home mobile
independence to help people with serious speech and/or motor
impairments and regain coordination and access to the internet

16. REFERENCES
John D. Simeral, et al, “Home Use of a Percutaneous Wireless Intracortical Brain-Computer
Interface by Individuals with Tetraplegia”, TBME.2021.3069119, IEEE Transactions on Biomedical
Engineering, 2021.
 Gerwin Schalk, et al,” Noninvasive Brain–Computer Interfaces” Neuromodulation, Second Edition,
2018.
L. R. Hochberg et al., “Neuronal ensemble control of prosthetic devices by a human with
tetraplegia,” Nature, vol. 442, no. 7099, pp. 164–171, 2006 .
J. L. Collinger et al., “High-performance neuroprosthetic control by an individual with tetraplegia,”
Lancet, vol. 381, no. 9866, pp. 557–64, 2013.
L. R. Hochberg et al., “Reach and grasp by people with tetraplegia using a neurally controlled
robotic arm,” Nature, vol. 485, no. 7398, pp. 372–5, 2012.
Leuthardt et al. “Defining Surgical Terminology and Risk for Brain Computer Interface
Technologies”, Frontiers in Neuroscience, March 2021. [12] Yoshio Tanimoto et al. “Evaluation
method of computer input ability of patients with tetraplegia”, WISP 2003, Budnpest,IEEE.