Shawn Roll, PhD, OTR/L, CWCE

Assistant Professor

Room: CHP 133
Phone: (323) 442-1850
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Web: http://www-hsc.usc.edu/~sroll

Biography

Shawn C. Roll received his B.S. in Occupational Therapy from The Ohio State University, graduating magna cum laude with distinction. He continued his post-secondary education at OSU, obtaining an M.S. in Allied Health Education with a Minor in Research Methods and received his Ph.D. in Health and Rehabilitation Sciences, with an Interdisciplinary Specialization in College and University Teaching. Dr. Roll has significant clinical experience in work programs, focusing on assessment, prevention, and rehabilitation of work-related injuries. He has developed an interdisciplinary research career combining his clinical occupational therapy skills with specialization in musculoskeletal sonography and industrial engineering/ergonomics. He has collaborated with rehabilitation providers, radiologic sciences, industrial and systems engineering, neurology and orthopedics.

Research Interests

Dr. Roll’s research strives to advance the understanding of musculoskeletal disorders through a holistic approach, to effectively evaluate and provide prevention or rehabilitation interventions within the adult population. His research focus includes:

Use of diagnostic sonography in the evaluation, prevention, and treatment of musculoskeletal disorders with a primary focus on the upper extremities
Investigation of physical exposures, stress, psychosocial factors and personality traits as each relate to the development of musculoskeletal disorders and how each mitigate or promote successful prevention and rehabilitation efforts
Investigation of tools and approaches for determining functional capacity in healthy and injured workers

Education

Doctor of Philosophy (Ph D) in Health-Related Professions
Ohio State University
2011

Master of Science (MS) in Health-Related Professions
Ohio State University
2006

Bachelor of Science (BS) in Health-Related Professions
Ohio State University
2002

Publications

Journal Articles

Evans, K. D., Roll, S. C., & Volz, K. R. (2013). Reply. Journal of Ultrasound in Medicine, 32, 188-189.

Roll, S. C., & Kutch, J. J. (2013). Transperineal sonography evaluation of muscles and vascularity of the male pelvic floor. Journal of Diagnostic Medical Sonography, 29, 3-10. doi:10.1177/8756479312472394. Abstract →← Abstract

Idiopathic chronic male pelvic pain is difficult to diagnose and treat. Currently, diagnosis relies on subjective symptoms; objective measures of neuromuscular mechanisms have not been investigated. Sonographic imaging has been used to investigate these neuromuscular mechanisms in the female pelvic floor, but neither research nor books describe sonography evaluation of the male pelvic floor. The purpose of this study was to develop and evaluate a perineal sonographic technique for the examination of the male pelvic floor muscles. Anatomic landmarks were identified with images collected from two subjects, one with intermittent reports of pelvic pain and one with no history of pain in the pelvic region. A description of the equipment settings, the examination protocol, and the resulting comparative image analysis is included. A validated protocol such as this may be useful in documenting differences in the soft tissue structures between asymptomatic individuals and patients with chronic pelvic pain to aid in diagnosis and treatment. This is the first known study to report sonographic findings of the individual muscles in the male pelvic floor, and additional research is needed to validate the techniques that have been deemed feasible.

Roll, S. C., Evans, K. D., Li, X., Sommerich, C. M., & Case-Smith, J. (2013). Importance of tissue morphology relative to patient reports of symptoms and functional limitations resulting from median nerve pathology. American Journal of Occupational Therapy, 67(1), 64-72. doi:10.5014/ajot.2013.005785. Abstract →← Abstract

Significant data exist for the personal, environmental, and occupational risk factors for carpal tunnel syndrome. Few data, however, explain the interrelationship of tissue morphology to these factors among patients with clinical presentation of median nerve pathology. Therefore, our primary objective was to examine the relationship of various risk factors that may be predictive of subjective reports of symptoms or functional deficits accounting for median nerve morphology. Using diagnostic ultrasonography, we observed real-time median nerve morphology among 88 participants with varying reports of symptoms or functional limitations resulting from median nerve pathology. Body mass index, educational level, and nerve morphology were the primary predictive factors. Monitoring median nerve morphology with ultrasonography may provide valuable information for clinicians treating patients with symptoms of median nerve pathology. Sonographic measurements may be a useful clinical tool for improving treatment planning and provision, documenting patient status, or measuring clinical outcomes of prevention and rehabilitation interventions.

Roll, S. C. (2012). Injuries and prevention in health care providers. WORK: A Journal of Prevention, Assessment & Rehabilitation, 42(3), 309-310. doi:10.3233/WOR-2012-1439.

Roll, S. C., Evans, K. D., Hutmire, C. D., & Baker, J. P. (2012). An analysis of occupational factors related to shoulder discomfort in diagnostic medical sonographers and vascular technologists. WORK: A Journal of Prevention, Assessment & Rehabilitation, 42(3), 355-365. doi:10.3233/WOR-2012-1434. Abstract →← Abstract

OBJECTIVE: Three-fourths of diagnostic medical sonographers (DMS) and vascular technologists (VT) experiencing discomfort due to job demands indicate having discomfort in the shoulder region. An analysis of factors related to shoulder discomfort highlighted salient factors requiring further investigation and intervention.

METHODS: The responses of 2,163 DMS and VT from a survey of a representative sample were analyzed to determine personal factors, work demands, and workstation design characteristics of those experiencing discomfort in the shoulder region. Frequencies and response distributions were calculated and cross tabulation with chi-square analysis was completed.

RESULTS: A majority of respondents with shoulder discomfort have co-morbid reports of discomfort in other locations. While overall sonographer discomfort is linked to age and years of experience, shoulder discomfort was also noted to be linked to specific workstation characteristics. A lack of adjustability in equipment, PACS workstations, and positions required to complete bedside exams contributes to discomfort due to sustained and repetitive shoulder abduction and twisting of the neck and trunk.

CONCLUSIONS: There is a need for studies investigating redesign of equipment and workstations or interventions with DMS and VT specifically focused on improving adjustability and improved positioning of sonographers in order to reduce shoulder discomfort while performing job demands.

Evans, K. D., Roll, S. C., Volz, K. R., & Freimer, M. (2012). Relationship between intraneural vascular flow measured with ultrasound and carpal tunnel syndrome diagnosis based on electro diagnostic testing. Journal of Ultrasound in Medicine, 31, 729-736. Abstract →← Abstract

OBJECTIVES: The purpose of this study was to document and analyze intraneural vascular flow within the median nerve using power and spectral Doppler sonography and to determine the relationship of this vascular flow with diagnosis of carpal tunnel syndrome based on electrodiagnostic testing.

METHODS: Power and spectral Doppler sonograms in the median nerve were prospectively collected in 47 symptomatic and 44 asymptomatic subjects. Doppler studies were conducted with a 12-MHz linear transducer. Strict inclusion criteria were established for postexamination assessment of waveforms; routine quality assurance was completed; electrodiagnostic tests were conducted on the same day as sonographic measurements; and the skin temperature was controlled. Included waveforms were categorized by location and averaged by individual for comparative analysis to electrodiagnostic testing.

RESULTS: A total of 416 waveforms were collected, and 245 were retained for statistical analysis based on strict inclusion criteria. The mean spectral peak velocity among all waveforms was 4.42 (SD, 2.15) cm/s. At the level of the pisiform, the most consistent data point, mean peak systole, was 3.75 cm/s in symptomatic patients versus 4.26 cm/s in asymptomatic controls. Statistical trending showed an initial increase in the mean spectral peak velocity in symptomatic but diagnostically negative cases, with decreasing velocity as diagnostic categories progressed from mild to severe.

CONCLUSIONS: An inverse relationship may exist between intraneural vascular flow in the median nerve and an increasing severity of carpal tunnel syndrome based on nerve conduction results. Randomized controlled trials are needed to determine whether spectral Doppler sonography can provide an additive benefit for diagnosing the severity of carpal tunnel syndrome.

Evans, K. D., Volz, K. R., Hutmire, C., & Roll, S. C. (2012). Morphologic characterization of intraneural flow associated with median nerve pathology. Journal of Diagnostic Medical Sonography, 28, 11-19. doi:10.1177/8756479311426777. Abstract →← Abstract

A prospective cohort of 47 symptomatic patients who reported for nerve conduction studies and 44 asymptomatic controls was examined with sonography to evaluate the median nerve. Doppler studies of the median nerve were collected with handheld sonography equipment and a 12-MHz linear broadband transducer. Strict inclusion criteria were established for assessing 435 waveforms from 166 wrists. Two sonographers agreed that 245 waveforms met the a priori criteria and analyzed the corresponding data. Spectral Doppler waveforms provided direct quantitative and qualitative data for comparison with indirect provocative testing results. These Doppler data were compared between the recruitment groups. No statistical difference existed in waveforms between the groups (P < .05). Trending of the overall data indicated that as the number of positive provocative tests increased, the mean peak systolic velocity within the carpal tunnel (mid) also increased, whereas the proximal mean peak systolic velocity decreased. However, by using multiple provocative tests as an indirect comparative measure, researchers may find mean peak spectral velocity at the carpal tunnel inlet a helpful direct measure in identifying patients with carpal tunnel syndrome.

Roll, S. C., Case-Smith, J., & Evans, K. D. (2011). Diagnostic accuracy of ultrasonography versus electromyography in carpal tunnel syndrome: A systematic review of literature. Ultrasound in Medicine and Biology, 37, 1539-1553. doi:10.1016/j.ultrasmedbio.2011.06.011. Abstract →← Abstract

A plethora of research evaluates the utility of ultrasonography versus electrodiagnostic testing for diagnosis of carpal tunnel syndrome. Two limited reviews of literature were completed, but a full, systematic review has not been completed. We identified 582 abstracts published 1999-2009 through database searches, hand searches, and communication with authors, resulting in 23 high quality studies that met our inclusion criteria based on a rigorous, independent review. Significant discrepancies and methodological limitations in the description of ultrasonography protocols and diagnostic thresholds limited the ability to combine data and identify specific thresholds. The cross-sectional area of the median nerve within the carpal tunnel is the most stable measure and has high potential to correctly diagnose severe carpal tunnel syndrome. Further investigation of measures, especially those that can diagnose mild cases of CTS, is needed. Suggestions for clinical protocols and the utility of ultrasonography as a screening tool to compliment electrodiagnostic testing are reviewed.

Roll, S. C., & Evans, K. D. (2011). Sonographic representation of bifid median nerve and persistent median artery. Journal of Diagnostic Medical Sonography, 27(2), 89-94. doi:10.1177/8756479311399763. Abstract →← Abstract

Bifid median nerve and persistent median arteries are natural anatomic variants that exist in a small percentage of the population. This case describes a young woman who was referred for electrodiagnostic (EDX) testing of her right upper extremity because of a one-year history of numbness, tingling, and discomfort in her right upper extremity consistent with carpal tunnel syndrome. Careful sonographic scanning (gray scale and power Doppler) and dynamic investigation revealed a bifid median nerve and associated persistent median artery (PMA). The awareness of a bifid median nerve and PMA is important when evaluating patients sonographically for diagnosis of upper extremity pathology, including enlargement due to carpal tunnel syndrome. Furthermore, as musculoskeletal sonography increases in clinical practice, it is important to raise awareness of this dual anatomic variant to ensure that appropriate evaluation and treatment are provided. The sonographic presentation of anatomic variations in this case along with a review of these anomalies is provided for translational clinical use.

Roll, S. C., Evans, K. D., Li, X., Freimer, M., & Sommerich, C. M. (2011). Screening for carpal tunnel syndrome using ultrasonography. Journal of Ultrasound in Medicine, 30, 1657-1667. Abstract →← Abstract

OBJECTIVE: The use of ultrasonography in musculoskeletal research and clinical applications is increasing; however, measurement techniques for diagnosing carpal tunnel syndrome (CTS) with ultrasonography continue to be inconsistent. Novel methods of measurement utilizing internal comparisons to identify swelling of the median nerve (MN) require investigation and comparison to currently used techniques.

METHODS: Flattening ratio of the MN, bowing of the flexor retinaculum, and cross-sectional area (CSA) of the MN were collected at the forearm, at the radio-carpal joint, and at the level of the pisiform in both symptomatic patients and asymptomatic controls. Electrodiagnostic testing (EDX) was completed in symptomatic patients as a diagnostic standard.

RESULTS: MN measurements were collected from 166 wrists of symptomatic and asymptomatic subjects. Flattening ratio did not show any correlation to EDX and was identical between both symptomatic and asymptomatic subjects. Moderate to strong correlations were noted between EDX results and ultrasonographic measures of CSA at the pisiform, retinacular bowing, and both ratio and change of CSA between the forearm and pisiform. Area under the curve was large for all receiver operating curves for each measure [.759-.899] and sensitivity was high [80.4%-82.4%].

CONCLUSIONS: Measurement of swelling through a ratio or absolute change had similar diagnostic accuracy as individual measurement of CSA within the carpal tunnel. These measures may be useful to improve accuracy in more diverse clinical populations. Further refinement of protocols to identify the largest CSA within the carpal tunnel region and statistical methods to analyze clustered, multi-level outcome data is recommended to improve diagnostics.

Evans, K. D., Roll, S. C., Li, X., & Sammet, S. (2010). A holistic evaluation of risk factors for work related musculoskeletal distress among asymptomatic sonographers performing neurosonology: A pilot study. Journal of Diagnostic Medical Sonography, 26, 64-78. doi:10.1177/8756479309352360. Abstract →← Abstract

A pilot study was conducted to gather holistic data points on female sonographers who executed neonatal neurosonography over four portable scanning sessions. The hypothesis was that specific risk factors contributed to work-related musculoskeletal distress in the hand and wrist as a result of neonatal neurosonography. A preexperimental pre-post research design was used to gather data on work demands, self-rated physical and mental health, posture/position during scanning, physiologic change, and pain scores. No statistically significant changes were detected between pre-post measures for work demands, physical and mental health, or pain scores as a result of portable scanning sessions. The physiologic changes, between scanning sessions, were recorded with the use of a hand-carried sonographic unit. Sonographic measures were less than the published criteria for carpal tunnel syndrome with a proximal cross-sectional area ≥10 mm2 and an anterior bulge of the retinaculum of >4 mm. Sonography documented a statistically significant cross-sectional area change, within the median nerve, at the distal radius only after the first scanning session. Power and spectral Doppler was used to document perineural vascular flow within the median nerve, but it was not consistently obtained to allow for a rigorous comparison between pre- and post-scanning sessions. This is the first pilot study to explore using a hand-carried sonographic unit to document change in the median nerve for an isolated sonographic examination. The results are only reflective of these particular participants, but much larger N and shorter scanning sessions are needed to confirm the hypothesis proposed.

Evans, K. D., Roll, S. C., Hutmire, C. D., & Baker, J. P. (2010). Factors that contribute to wrist-hand-finger discomfort in diagnostic medical sonographers and vascular technologists. Journal of Diagnostic Medical Sonography, 26, 121-129. doi:10.1177/8756479310366471. Abstract →← Abstract

A cross-sectional representative sample of 1722 sonographers and vascular technologists was analyzed using quantitative/qualitative methods to reveal that 60% are experiencing wrist-hand-finger discomfort, believed to be from work-related repetitive injury. The years of scanning accumulated by the participants was chosen as a variable to determine the relationship to the range of discomforts reported. A strong statistical correlation was noted between years of experience and the side of discomfort as well as the severity of hand-wrist-finger discomfort. In this study, a strong statistical association was also noted between increasing years of scanning and decreasing aggravation due to the transducer. A complete linkage between work-related exposure and hand-wrist-finger discomfort is difficult to make because of the contribution of leisure-time activities. A controlled experimental study is needed to determine the contribution that grip and pushing on the transducer may have on the incidence of hand-wrist-finger discomfort, leading to diagnoses such as carpal tunnel syndrome.

Evans, K. D., Roll, S. C., & Baker, J. (2009). Work-related musculoskeletal disorders (WRMDS) among registered diagnostic medical sonographers and vascular technologists: A representative sample. Journal of Diagnostic Medical Sonography, 25, 287-299. doi:10.1177/8756479309351748. Abstract →← Abstract

Literature indicates a significant history of workr-elated musculoskeletal disorders (WRMSD) among diagnostic medical sonographers (DMS) and vascular technologist (VTs). To gather current data related to this historical trend, the authors administered a survey to a random and convenient sample of 5200 registered DMS and VTs. The invitation to complete the survey on a secure Web site yielded the largest participant sample to date of 2963 completed surveys (57% response). Data relative to the prevalence of WRMSD were analyzed and compared to other WRMSD research over the past decade. Results indicated that 90% of respondents were scanning in pain, a 9% increase since the last large scale survey in 1997. Across all demographics, shoulder pain is most common, with older and more experienced sonographers having more finger, hand, and wrist pain than other groups. Pain continues to be related to pressure applied to the transducer, abduction of the arm, and twisting of the neck and trunk. Ergonomic equipment and education are provided by application specialists, but the incidence of WRMSD appears to be unabated. Higher order research, including randomized trials, with education and ergonomic interventions is needed to protect DMS and VTs who are necessary to meet increasing health care demands.

Roll, S. C., & Evans, K. D. (2009). Feasibility of using a hand-carried sonographic unit for investigating median nerve pathology. Journal of Diagnostic Medical Sonography, 25, 241-249. doi:10.1177/8756479309345284. Abstract →← Abstract

Numerous research studies describe the prevalence of work-related musculoskeletal disorders (WRMSD) in diagnostic medical sonographers, but little research has investigated contributing factors and biological changes in symptomatic individuals. Improved image quality and portability, combined with lower cost and dynamic capabilities, have led to increased use of sonography over magnetic resonance imaging (MRI) in musculoskeletal evaluations. The purpose of this pilot study was to develop a valid and reliable sonographic protocol for the evaluation of work-related median nerve pathology with a hand-carried sonographic unit. A GE Logiq I (Milwaukee, Wisconsin) hand-carried unit with a 12-MHz linear transducer was used to collect nine longitudinal and transverse images of the median nerve at various anatomical locations in the distal upper extremity of three healthy volunteers. Doppler waveforms were also collected in the median nerve sheath. Qualitative review indicated high-quality images with well-defined structures, resulting in valid measures between multiple researchers of anteriorposterior diameter, cross-sectional area, anterior transverse carpal ligament bulge, and Doppler flow. The use of a hand-carried sonographic unit appears to be a feasible alternative to MRI to detect musculoskeletal changes in symptomatic sonographers. Additional basic and clinical studies are necessary to validate the use of hand-carried sonography as a measure of biological changes in longitudinal WRMSD research.

Conference Proceedings

Roll, S. C., Evans, K. D., Volz, K. R., & Sommerich, C. M. (2013). Longitudinal analysis of grayscale imaging and electromyography in an animal model of carpal tunnel syndrome. In Journal of Ultrasound in Medicine.

Evans, K. D., Roll, S. C., Volz, K. R., & Sommerich, C. M. (2011). Ultrasound contrast enhanced interrogation of the median nerve to document peripheral vascular flow in an animal model. In Proceedings of the 13th Congress of the World Federation for Ultrasound in Medicine & Biology. Vienna, Austria.

Roll, S. C., Evans, K. D., Freimer, M. L., Case-Smith, J., & Sommerich, C. M. (2011). Relationship of median nerve ultrasonographic measures to anthropometric and demographic factors for diagnosis of carpal tunnel syndrome. In Proceedings of the 13th Congress of the World Federation for Ultrasound in Medicine & Biology. Vienna, Austria.

Evans, K. D., Roll, S. C., Volz, K. R., & Sommerich, C. M. (2011). Spectral Doppler measurement of perineural flow within the median nerve compared to nerve conduction studies. In Proceedings of the 13th Congress of the World Federation for Ultrasound in Medicine & Biology. Vienna, Austria.

Sommerich, C. M., Gumpina, R., Roll, S. C., Le, P., & Chandler, D. (2009). Investigating effects of controller algorithm on torque tool operator. In Proceedings of the 2009 Industrial Engineering Research Conference.