Range of Motion Device for Evaluating Somatic Dysfunction




Purcell, Maureen
Patterson, Rita


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Introduction: An integral part of the osteopathic medical education is the palpation exam, but few tools exist to provide an objective measure of appropriate force applied to find the soft tissue resistance at the end of the range of motion. The educational range of motion device utilized in this study is a hand-held tool with sensors to record the applied force during a range of motion test. This device can allow students to observe differences in technique among motions and trails for a more rapid understanding of proper palpation exam techniques. It was hypothesized that first year medical students utilizing the device would apply less force during palpation exams than experienced physicians (gold standard), and that the group allowed to train with the device would apply force closer to the “gold standard” in the post-assessment period. Methods: First year medical students were recruited for this study, with a total of 208 participants. Expert examiners established a “gold standard” of the force applied when determining the force at end feel. The participants performed three trials on each arm of three different motions of the shoulder on their fellow students participants (extension, internal rotation, and external rotation), for a total of nine peaks of applied force. One group was provided access to train with the device, while another control group was not given access. Two assessment periods - one before training with the device, another two months after training – measured the usefulness of the device in an educational setting. The raw data was collected from MatLab and analyzed using SPSS software. Analysis focused on dependent variables including gender, side, motion, trials, and the overall force means compared to the “gold standard”. Results: Mean force of the student participants during the pre-assessment period was 2.11 kg with a standard deviation of 1.27 kg. For the student participants, an ANOVA of the three trials revealed no significant differences (p = 0.594). Women had a significantly lower (p = 0.00) mean than men (1.75 kg and 2.31 kg respectively). The three motions also had significant (p = 0.000) differences in values. Extension had the greatest applied force (2.38 kg), while external rotation had the least (1.78 kg). After two months of training to meet the “gold standard” of 3 kg of force, the trained group had a mean closer to that than the control (3.16 kg for trained, 2.58 kg for controls). No significant difference was found between left and right arm trials in pre or post assessment data. Discussion: The first hypothesis that the sample of medical students would have a lower mean of applied force that the gold standard was supported. The greater applied force in extension suggests that the movement’s range motion has a firmer and more sudden end feel. The second hypothesis that the trained group would achieve a mean applied force closer to the standard was also supported.