Design, development, and validation of vibrotactile threshold evaluator for workplace screening of carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the number one cause of disability at work in the United States. Loss of time at work and worker's compensation expenditure caused by CTS is more than that caused by any other condition. However, workplace surveillance is likely to help in detecting CTS at a stage that is treatable at a significantly lower cost. Vibrotactile threshold (VT) testing can be used for this purpose. The VT is the smallest displacement applied (as a sinusoid) to a finger innervated by the median nerve that can be detected by the patient. Vibrotactile threshold evaluation can be a versatile tool for applications involving haptics interfaces, for evaluating peripheral neuropathies, and for studying the effects of chemotherapy induced neuropathies.;This dissertation presents the prototype design of a vibrotactile threshold evaluator for the workplace (VTEW), which is portable, and configurable in terms of the probe diameter (1-6 mm), surround diameter (8-10 mm), applied frequency (1-250 Hz), angle of probe (0-1200), and displacement of probe (1-1500 mum) and is operated with a customizable LabView interface. The VTEW also incorporates a special mount for the probe stimulus to test the subjects in at least two distinctive postures of the hand.;Subjects were tested using an existing validated device, Vibrotactile Threshold Tester (VTT) and VTEW. Subjects were tested at 50 Hz with VTT and VTEW for validation. The effect of flexion on VT was observed by testing the subjects on VTEW at 50 Hz with their dominant hand in neutral posture and again with their dominant hand in provocative flexion. Use of low frequency for testing in VT studies is uncommon due to hardware constraints. However, low frequency studies could be potentially useful for investigating the effects of chemotherapy on the perception of pain. Thus, subjects were also tested at 4 Hz using VTEW to obtain preliminary data. Finally, an age regression model was developed to correct for the changes occurring in VT with age.