Introduction Evolution Battery-Powered BION System Applications
Proceedings of the IEEE
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* Low-level electrical current to nerves or reflex centers *
Triggered by single switch(open-loop) neuronal
activity(closed-loop) * Limb loss applications Reduce phantom pain
Restore functional movement
IntroductionEvolutionSystemApplications
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* Provide both stimulating and sensing capabilities * Be fully
implantable * Be minimally invasive * Have real-time communication
capability * Practically unlimited number of stimulation and
sensing channels * Function w/o external equipment or
interconnected leads btw components
IntroductionEvolutionSystemApplications
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Extensive surgery 20-plus channel Nucleus FES22 requires more
than 15h of surgery Infection of Large Continuous Implant Surfaces
Bacterial infection spread to the entire implant. The only remedy
is to explant the entire system. RF Powered Device Problems
Maintaining proper orientation of the power transmitting antenna
The discomfort of wearing an antenna and a battery powered
transmitter Lack of Coordinated Sensors and Stimulators Other than
demand pacemakers, very few attempts to use implantable sensors
Extensive Advanced Planning Each condition usually requires a
unique sensor system The number of channels, the type of sensors
and signal conditioning, and etc.
IntroductionEvolutionSystemApplications
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* As either stimulators or sensors * Minimally invasive
implantation * Wireless, real-time bidirectional communications *
Flexibility and functional expandability w/o leads * A large number
of channels * Self-powered operation
IntroductionEvolutionSystemApplications
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RF-powered Allow instantaneous control Prevent electrostatic
discharge Need to wear an external coil Battery-Powered To improve
patient acceptance To increase the reliability Operate for more
than ten years By Quallion. Capacity of 10mWH, operating at a
voltage of 3.6V IntroductionEvolutionSystemApplications
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* For urinary incontinence * The 1 st BION to have two- way
telemetry * Very short time for synchronization * Lack of sensing
capabilities * Slow communication response time * Wireless * Fully
implantable * Data processing for sensed signals * Rechargeable *
Long term immersion weakens ceramic improve longevity
IntroductionEvolutionSystemApplications
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* Improved IC Increase the compliance voltage of the RF-powered
microstimulator Modified the demodulation circuit * Combining the
IC and the ferrite Longer and more efficient coil in receiving
energy from the ac magnetic field * Ceramic case * Internal
capacitor Prevents continuous direct current from flowing into the
tissue IntroductionEvolutionSystemApplications
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* Defibrillator protection Prevents damages from static
electricity in the operating room * Eyelet Enables a simple removal
within about a week or more * Insertion System * Human experiments
42 RF microstimulators in six stroke patients Ultrasonic and
magnetic resonance image viewing
IntroductionEvolutionSystemApplications
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* Stimulating lead system failure Stimulation amplitude and low
current range was unstable * Automatic tuning of AC powering coils
Need a very precise tuning frequency in coil to save battery power
A crystal controlled oscillator and a bank of about eight
capacitors in the external control unit * Hermetic and electrolytic
corrosion free braze joints
IntroductionEvolutionSystemApplications
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* Arm coil system Microstimulators btw the wrist and elbow To
produce a magnetic field, two coil pairs are connected in series *
Clinicians automatic test system The fitting notebook station an
automatic microstimulator tester Test regime will verify nearly
every connection in the microstimulator
IntroductionEvolutionSystemApplications
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Communication and control hub External MCU: a few controls
accessible to the patient Implantable MCU: small patient control
unit (PCU) IntroductionEvolutionSystemApplications
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* Transmits and receives data up to 850 BPBs within 1/100s *
Basic user interface System ON/OFF control, alarms, program
selection and limited parameter control * During fitting, enables
the setup and the coordination * Manages the recharging subsystem *
Safety mechanisms Emergency STOP button When BPB overheats or
overcharges * Stores patient usage data and the approximate
location of BPBs IntroductionEvolutionSystemApplications
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Allows the clinician to configure and test
IntroductionEvolutionSystemApplications
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* During the fitting, CP & MCU facilitate measurement and
storage of the stimulation and sensor calibration parameters *
During the stand-alone mode, essential information is stored in the
MCU * Clinicians programmer Gather basic personal information
Establish the stimulation range and allow selection of the
stimulation parameters Specify the activity sequences Gather the
trigger information Compose the Finite State Machine functions
IntroductionEvolutionSystemApplications
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Place the coil close to the area Battery Depend on the
frequency and stimulation levels Run in 1 to 8 days Charging for
about 5 to 20 min per day
IntroductionEvolutionSystemApplications
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Transmits only power Each BPB Charging and battery status
IntroductionEvolutionSystemApplications
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* 12-kHz signal to generates a magnetic field * MCU Determines
which BPB to be charged and when to charge Indicates to the patient
where the coil must be moved Selects the most discharged device *
Temperature sensor that stops the process when the external coil
overheating IntroductionEvolutionSystemApplications
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Safety feature when Undesired manner No access of the patient
to control unit Magnet is positioned On the body holds off the
stimulation On the other part stimulation turns on Small, light
weight, very strong magnetic signal
IntroductionEvolutionSystemApplications
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* Single-channel, constant- current, charge-balanced stimulator
* Capacitance-coupled output prevents direct connection btw battery
and tissue. * Pulse amplitude, width, and frequency * Triggering
events * Dipole antenna * Crystal-controlled transmitter, receiver,
& digital processing unit * Digital processing unit Corrects
errors in data and communication Decodes the MCU commands Generates
the responses to the MCU
IntroductionEvolutionSystemApplications
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For frame synchronization and frame control data Stimulation
and/or sensing control data Forward error correction (FEC) bits
Information to MCU FEC for 1 or 2bit errors
IntroductionEvolutionSystemApplications
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* 10-mW-hr rechargeable lithium-ion battery * Recharging via
127kHz magnetic link * Provide 100 hours of operation * Deep
discharge lifetime of more than ten years * Miniature magnetic
sensor * Temperature sensor for terminating charging * Battery
safety circuitry Overvoltage, overdischarge, and overcharging * For
themselves for maximum charging
IntroductionEvolutionSystemApplications
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* Oscilloscope mode during fitting * Data analysis Count
pulses: accumulated pulses every 10ms Rectify and integrate every
10 ms * Along the axial dimension of the BPB * 400~900 mmHg * AC/DC
coupled * Altitude changes reference sensor in the MCU
IntroductionEvolutionSystemApplications
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* Distance btw two BPBs Intensity of the received magnetic
field One BPB as a transmitter, and other BPBs as a receiver
Receiver BPB detects and measures the signal strength No limit to
the number of BPB receivers Measure distances btw 1~20cm * 8
parallel systems whose frequencies are around 127kHz * As a safety
mechanism * Accurate to within 0.33 C * Range 16~50 C * Taken once
per second IntroductionEvolutionSystemApplications
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* Minimally invasive procedure 1 st test during the
implantation 2 nd test right after the implantation 3 rd test one
week after implantation A: Probe Electrode B: Dilator C: Sheath D:
Ejection Tool E: 3ml Syringe
IntroductionEvolutionSystemApplications
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* As a stimulator, biopotential signal sensor, goniometry
sensor, pressure or temperature sensor Multiple BPBs; up to 850
BPBs Near motor-points or nerves of muscles in the arm, forearm,
and hand * To extend the arm and forearm, and open the hand to
grasp an object As goniometry sensors and pressure sensors *
Sensing of the muscle activities acts as triggers to other BPBs to
stimulate the motor-points Standing, ambulation, swallowing,
bladder control, and respiration * Measuring pressure and
triggering motor-point or stopping a FES sequence At the heel, the
buttock, or hand IntroductionEvolutionSystemApplications
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* As biopotential sensors * Inserted in the stump * Pick up
motor nerve signals to control movement
IntroductionEvolutionSystemApplications
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* Voluntary motion is regained * By monitoring the motor cortex
* By feeding back sensed response signals to the sensory cortex *
Cortical interface device (CID) * Base unit implanted in the skull
monitors up to several hundred electrodes * Electrode arrays placed
on the sensory or motor cortices
IntroductionEvolutionSystemApplications
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* CID base unit Equivalent to a group of sixty-four BPBs
Sixty-four biopotential sensing modules Either unipolar or bipolar
Same technology developed for the BPB * Sensing electrode array
Include signal processing capability like biopotential sensing
module in the BPB same stimulation electronics like the BPB
stimulation module IntroductionEvolutionSystemApplications