Transcript Pain Stimulator

Pain Stimulator
Adam Platt
Biz Slyziuk
Bryan Eckerle
Jen Wells
Kalee McFadden
April 13, 2004
Dr. Stephen Bruehl
 Research Interests
 Endogenous Pain Regulatory Systems,
Psychobiology of Emotions
 Focus: Understanding endogenous pain
regulatory systems and dysfunction
associated with chronic pain.
 Interaction between cardiovascular and
pain regulatory systems to maintain
homeostasis during painful stimuli
compared to interaction in chronic pain
patients
Baroreceptor
Input
Intermediolateral
Cell Column
(SNS Preganglionic
Neurons)
Nucleus Tractus
Solitarius
NE Neurons and
α-2 receptors
Periaqueductal
Gray
α-2 receptors
Locus Coeruleus
NE Neurons and
α-2 receptors
A5 Cell Group
NE Neurons and
α-2 receptors
Caudal
Ventrolateral
Medulla
NE Neurons
Nucleus Raphe
Magnus
Dorsal Horn
Laminae I-IV
α-2 Postsynaptic
Rostal Ventrolateral
Medulla
NE Neurons and
α-2 receptors
Primary Afferent
Fiber Terminals
α-2 Presynaptic
Spinal Sites of Descending Modulation
Rostal Ventromedial
Medulla
α-2 receptors
Peripheral
SNS Terminals
(α-2Presynaptic
Autoreceptors)
Blood Pressure
Experimental Importance
 NIH funded
 120 subjects
 Two research sessions one week apart
 Stimulation of C-fibers
 Placebo vs. drug

Measures level of activity of receptors
 Draw conclusions on natural pain
systems in humans
Experimental Method
 Dinamap Compact-T automated oscillometric
BP monitor
 Finapres 2300
 ECG
 Cannula inserted into dominant arm
 Blood drawn to assess natural stress hormones
and inflammatory substances
 Forgione-Barber Finger Pressure Stimulator
 McGill Pain Questionnaire
Drugs to be Tested
 Yohimbine
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Blocks 2 adrenergic receptors which inhibit release
of norepinephrine
Used clinically for erectile dysfunction (orally)
For Dr. Bruehl’s purposes, the FDA has only
approved injections
 Naloxone

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Blocks opiate receptors
Used clinically for heroine overdose
Injected into patient
Problems with Existing Device
 No electronic output
 Oral reading
 No accurate
measurement of pressure
 Lever system with
constant weight
 No adjustability for height
or hand dominance

Adjustable only for finger
placement
Our Design
 Device
Maintain lever system
Most stable design
 Reposition weight to be placed
vertically above finger
Adjustable Weight
2 – 5 lbs
 Contact Point
 Between top two joints on
index finger of dominant hand
 Middle Phalanx #2
Our Design… Cont.
 Table
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Provided by Dr. Bruehl
Transportation
Positioning
 Adjustable Height
 Sliding Tracks
 Forearm length
 Slider scale mounted to table displaying “No Pain”
to “Worst Pain Imaginable”
 Scale mounted on each side of device
Schematic
Slider Scale
Device
(Pressure
Transducer)
PC
Computer
A/D
Converter
LabVIEW
Device with Measurements
Materials
 Aluminum
 Lucite
 Steel
Device Construction
 In process
 Featheringill machine shop
LabView
 Timer
 Sliding Scale
 Digital Display
 Graphical Output
 Audiovisuals
 Digital Data Storage
 Patient
 Administrator
 Date
 Experimental Data
LabVIEW Interface
Potentiometers
 Circuit sensitivity
≈ .62V/cm @ Vs=5V
 Potentiometer sensitivity
≈ 1500Ω/cm
Questions?