Probing Pain Perception Client: Christopher Coe, Ph.D. Department of Psychology Advisor: Professor Willis Tompkins Team Members: Stacey Hoebel, Jeff Swift, Anna Karas

FIBROMYALGIA Chronic musculoskeletal pain and fatigue disorder Cause of the disease is still unknown Associated sleep disorder called the alpha-EEG anomaly Treatments THERMO GRILL ILLUSION OF PAIN Pain is a homeostatic emotion Neurons and Central Nervous System

Previous Design Created by A.D. Craig (Univ. of Arizona) Alternating warm (40 C) and cool rods (20 C) About 8” x 8” with 0.5” diameter thermal rods Presumed to be electric Ominous Looking

Problem Statement Design a device to test pain sensitivity in patients with generalized pain disorders. The alternating warm and cool components of the device activate sensory receptors and neurological thermal pathways to create the illusion of pain.

Design Constraints Consistent temperature components –Warm: 40°CCool: 20°C Reach temperatures in 1 sec. SafeReusable On/off power temperature control Non threatening appearance Easy to operate

Design 1: Peltier Device Peltier device –Peltier effect –Internal Mechanism Temperature control –Surface 1 –Surface 2 Parallel arrangment of Peltier devices

Design 1: Peltier Device Advantages –Friendly user-interface –Electrical components minimize space –Replicable Disadvantages –Time constraint –Custom made Peltier devices

Design 2: Water and Copper Tubing

Design 2: Water and Copper rods Advantages –Constant water temperature –Copper tubing conduction –Construction Disadvantages –Device Setup –Aesthetics

Design 3: Electronic Heater and Copper Rods Warm component –Electric resistance heaters –Portable on/off switch –Temperature controller Asymptotic heating Cool component –Solid copper rods Thermal Conductivity Maintain relatively constant temperature

Design 3: Electronic Heater and Copper Rods Advantages –Temperature and time constraints satisfied –Safe due to asymptotic temperature control –Simple user interface Disadvantages –Material selection –Cost

Decision Matrix Design Water & tubing Peltier Heaters & tubing Time to reach temp. 819 Temp. Control 5910 Cost957 Ease of Manufacturing 865 User interface Total Rating: 0=worst, 10=best

Chosen Design: Electronic Heater and Copper Rods User friendly –Simple electric switch Aesthetically pleasing Compact Low maintenance Replicable experiments Meets specifications for temperature and time

Future Work Heat transfer calculations –Power, size necessary for electric heating components –Thickness of cool copper rods to maintain constant temperature Research on temperature controllers Experiments to determine optimal configuration

Questions??