Assessing Autonomous nerve function

Abstract

This thesis proposes a method of detecting autonomic neuropathy in low-income countries using an infrared camera. Access to healthcare is often limited in low-income countries delaying the detection of neuropathy. If neuropathy can be detected in the earliest stage, often the autonomic state, damage to motor and sensory nerves can be prevented. To develop the method for detecting autonomic neuropathy, first the autonomic system was researched, followed by looking into the effects of neuropathy on the autonomic system to discover what physical properties might be measured with the detection device.
Four affected physical properties were determined through literature research: blood flow, blood pressure, skin resistance, and skin temperature. Of these properties, skin temperature was found to be the most promising based on a literature study, as it seemed to be both easily measurable and relatively independent of other bodily functions. Then the constraints of healthcare in low-income countries were examined and devices that work within these constraints were identified. Of these, the infrared camera showed the most promise, because of its ease of use and cost to accuracy ratio.
A single-subject study was performed to test the restorative capacity of the autonomous system by deliberately changing the temperature of the hand with a heating and cooling agent. Four locations were used on both hands, and both palmar and dorsal side of the hand, using different doses of the agents. The temperature change of the skin was measured using an InfraRed (IR) camera.
A large variation in results was found, but the results did show some evidence for structural differences in the temperature normalization between the affected and unaffected hand. The palmar side shows a stronger reaction than the dorsal side. The cooling agent seems to be more effective, but there are some caveats attached to its use. An interesting observation is that the most noticeable difference between left and right was measured in an area of low circulation. This gives some indication that this area has the most difficulty with returning to the neutral state.
Conclusion: This research shows that skin temperature variation as a result of applying heating or cooling agents to the skin can be measured using an infrared camera, suggesting that minor variations in skin temperature as a result of neuropathy can also be measured, further research with more test subjects should be done.