Palmer Center for Chiropractic Research

Davenport, IA, United States

Palmer Center for Chiropractic Research

Davenport, IA, United States
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Reed W.R.,Palmer Center for Chiropractic Research | Long C.R.,Palmer Center for Chiropractic Research | Kawchuk G.N.,University of Alberta | Pickar J.G.,Palmer Center for Chiropractic Research
Manual Therapy | Year: 2015

Background: Systematic investigations are needed identifying how variability in the biomechanical characteristics of spinal manipulation affects physiological responses. Such knowledge may inform future clinical practice and research study design. Objective: To determine how contact site for high velocity, low amplitude spinal manipulation (HVLA-SM) affects sensory input to the central nervous system. Design: HVLA-SM was applied to 4 specific anatomic locations using a no-HVLA-SM control at each location randomized in an 8. ×. 8 Latin square design in an animal model. Methods: Neural activity from muscle spindles in the multifidus and longissimus muscles were recorded from L6 dorsal rootlets in 16 anesthetized cats. A posterior to anterior HVLA-SM was applied through the intact skin overlying the L6 spinous process, lamina, inferior articular process and L7 spinous process. HVLA-SMs were preceded and followed by simulated spinal movement applied to the L6 vertebra. Change in mean instantaneous discharge frequency (δMIF) was determined during the thrust and the simulated spinal movement. Results: All contact sites increased L6 muscle spindle discharge during the thrust. Contact at all L6 sites significantly increased spindle discharge more than at the L7 site when recording at L6. There were no differences between L6 contact sites. For simulated movement, the L6 contact sites but not the L7 contact site significantly decreased L6 spindle responses to a change in vertebral position but not to movement to that position. Conclusions: This animal study showed that contact site for an HVLA-SM can have a significant effect on the magnitude of sensory input arising from muscle spindles in the back. © 2015 Elsevier Ltd.


Bovee B.,Palmer Center for Chiropractic Research
Chiropractic Journal of Australia | Year: 2016

Objective: High-stakes testing environments may lead to test anxiety in college students and may negatively impact college performance. Learning strategies related to test taking, test administration and test preparation may reduce test anxiety. Collaborative testing is one possible method for reducing test anxiety. A decrease in test anxiety may also lead to other positive benefits such as improved test scores, increased confidence, critical thinking and student satisfaction. This paper examines collaborative testing's effect on test anxiety in students at professional health institutions. Data Sources: The literature was searched using PubMed, google scholar Ebscohost and Science Direct. Indexing terms included collaborative testing and test anxiety in the English language only. Study Selection: Studies were selected if they examined test anxiety and collaborative testing at professional health institutions. Seven articles were initially selected. After reviewing, 4 articles were eventually chosen. Data Synthesis: Results were similar in the 4 studies. Students who took tests collaboratively had a reduction in test anxiety compared to students who took tests individually. Other interesting findings were improved test scores, increased confidence, critical thinking skills and student satisfaction. Conclusion: Collaborative testing may help reduce test anxiety. Faculty and administrators may want to incorporate this testing strategy into their classrooms to help reduce test anxiety. Findings of improved test scores, increased confidence, increased critical thinking skills and positive student's attitudes may result from a decrease in test anxiety, collaborative testing or both. Further evaluation of collaborative testing's impact on test anxiety and academic performance is needed. (Chiropr J Australia 2016;44:214-221).


Pickar J.G.,Palmer Center for Chiropractic Research | Pickar J.G.,University of Iowa | Bolton P.S.,University of Newcastle | Bolton P.S.,Hunter Medical Research Institute
Journal of Electromyography and Kinesiology | Year: 2012

Manually-applied movement and mobilization of body parts as a healing activity has been used for centuries. A relatively high velocity, low amplitude force applied to the vertebral column with therapeutic intent, referred to as spinal manipulative therapy (SMT), is one such activity. It is most commonly used by chiropractors, but other healthcare practitioners including osteopaths and physiotherapists also perform SMT. The mechanisms responsible for the therapeutic effects of SMT remain unclear. Early theories proposed that the nervous system mediates the effects of SMT. The goal of this article is to briefly update our knowledge regarding several physical characteristics of an applied SMT, and review what is known about the signaling characteristics of sensory neurons innervating the vertebral column in response to spinal manipulation. Based upon the experimental literature, we propose that SMT may produce a sustained change in the synaptic efficacy of central neurons by evoking a high frequency, bursting discharge from several types of dynamically-sensitive, mechanosensitive paraspinal primary afferent neurons. © 2012 Elsevier Ltd.


Bronfort G.,University of Minnesota | Hondras M.A.,Palmer Center for Chiropractic Research | Schulz C.A.,Northwestern Health Sciences University | Evans R.L.,University of Minnesota | And 2 more authors.
Annals of Internal Medicine | Year: 2014

Objective: To determine whether spinal manipulative therapy (SMT) plus home exercise and advice (HEA) compared with HEA alone reduces leg pain in the short and long term in adults with BRLP.Design: Controlled pragmatic trial with allocation by minimization conducted from 2007 to 2011. (ClinicalTrials.gov: NCT00494065).Setting: 2 research centers (Minnesota and Iowa).Patients: Persons aged 21 years or older with BRLP for least 4 weeks.Intervention: 12 weeks of SMT plus HEA or HEA alone.Results: Of the 192 enrolled patients, 191 (99%) provided follow-up data at 12 weeks and 179 (93%) at 52 weeks. For leg pain, SMT plus HEA had a clinically important advantage over HEA (difference, 10 percentage points [95% CI, 2 to 19]; P = 0.008) at 12 weeks but not at 52 weeks (difference, 7 percentage points [CI, -2 to 15]; P = 0.146). Nearly all secondary outcomes improved more with SMT plus HEA at 12 weeks, but only global improvement, satisfaction, and medication use had sustained improvements at 52 weeks. No serious treatment-related adverse events or deaths occurred.Measurements: The primary outcome was patient-rated BRLP at 12 and 52 weeks. Secondary outcomes were self-reported low back pain, disability, global improvement, satisfaction, medication use, and general health status at 12 and 52 weeks. Blinded objective tests were done at 12 weeks.Limitation: Patients and providers could not be blinded.Conclusion: For patients with BRLP, SMT plus HEA was more effective than HEA alone after 12 weeks, but the benefit was sustained only for some secondary outcomes at 52 weeks.Background: Back-related leg pain (BRLP) is often disabling and costly, and there is a paucity of research to guide its management. © 2014 American College of Physicians.


Ge W.,Palmer Center for Chiropractic Research | Pickar J.G.,Palmer Center for Chiropractic Research
Journal of Electromyography and Kinesiology | Year: 2012

In the lumbar spine, muscle spindle responsiveness is affected by the duration and direction of a lumbar vertebra's positional history. The purpose of the present study was to determine the relationship between changes in the magnitude of a lumbar vertebra's positional history and the responsiveness of lumbar muscle spindles to a subsequent vertebral position and subsequent vertebral movement. Neural activity from multifidus and longissimus muscle spindle afferents in deeply anesthetized cats was recorded while creating positional histories of the L6 vertebra. History was induced using a displacement-controlled feedback motor. It held the L6 vertebra for 4s at an intermediate position (hold-intermediate at 0mm) and at seven positions from 0.07 to 1.55mm more ventralward and dorsalward which lengthened (hold-long) and shortened (hold-short) the lumbar muscles. Following the conditioning hold positions, L6 was returned to the intermediate position. Muscle spindle discharge at this position and during a lengthening movement was compared between hold-intermediate and hold-short conditionings and between hold-intermediate and hold-short conditionings. We found that regardless of conditioning magnitude, the seven shortening magnitudes similarly increased muscle spindle responsiveness to both vertebral position and movement. In contrast, the seven lengthening magnitudes produced a graded decrease in responsiveness to both position and movement. The decrease to position became maximal following conditioning magnitudes of ~0.75mm. The decrease to movement did not reach a maximum even with conditioning magnitudes of ~1.55mm. The data suggest that the fidelity of proprioceptive information from muscle spindles in the low back is influenced by small changes in the previous length history of lumbar muscles. © 2012 Elsevier Ltd.


Cao D.-Y.,Palmer Center for Chiropractic Research | Pickar J.G.,Palmer Center for Chiropractic Research
Journal of Neurophysiology | Year: 2011

Proprioception is considered important for maintaining spinal stability and for controlling posture and movement in the low back. Previous studies demonstrate the presence of thixotropic properties in lumbar muscle spindles, wherein a vertebra's positional history alters spindle responsiveness to position and movement. This study investigated whether a vertebra's movement history affects the velocity sensitivity of paraspinal muscle spindles in the low back. Afferent activity from multifidus and longissimus muscle spindles was recorded in the L6 dorsal root in 30 anesthetized cats. To alter movement history, a feedback-controlled motor attached to the L6 spinous process held (conditioned for 4 s) the L6 vertebra at an intermediate position or at positions that either lengthened or shortened the muscles. With the vertebra returned to the intermediate position, resting spindle discharge was measured over the next 0.5 s (static test) and then during a dynamic test consisting of ramp vertebral movement at four velocities (0.2, 0.5, 1.0, 2.0 mm/s). Spindle activity during the tests was measured relative to hold-intermediate. For both tests, hold-long decreased and hold-short increased muscle spindle responsiveness. For the static test position responsiveness was not different among the velocity protocols for either hold-long or hold-short (P = 0.42 and 0.24, respectively). During the dynamic test, hold-long conditioning significantly decreased [F(3,119) = 7.99, P < 0.001] spindle responsiveness to increasing velocity. Mean velocity sensitivity was 4.44, 3.39, and 1.41 (impulses/s)/(mm/s) for the hold-short, hold-intermediate, and hold-long protocols, respectively. The nearly 2.5-fold decrease in velocity sensitivity following hold-long was significantly less than that for either hold-intermediate (P = 0.005) or hold-short conditioning (P < 0.001). Hold-short conditioning had little effect on velocity responses during the dynamic test [F(3,119) = 0.23, P = 0.87]. In conclusion, only movement histories that stretch but not shorten muscle spindles alter their velocity sensitivity. In the low back, forward flexion and lateral bending postures would likely be the most provocative Copyright © 2011 The American Physiological Society.


Lyons S.S.,Palmer Center for Chiropractic Research
Gerontologist | Year: 2010

Purpose: Although nursing homes (NHs) are criticized for offering poor quality continence care, little is known about the organizational processes that underlie this care. This study investigated the influence of organizational culture on continence care practices in two NHs.Design and Methods: This ethnographic study explored continence care from the perspectives of NH stakeholders, including residents and interdisciplinary team members. Data were collected through participant observation, interviews, and archival records.Results: Human relations dimensions of organizational culture influenced continence care by affecting institutional missions, admissions and hiring practices, employee tenure, treatment strategies, interdisciplinary teamwork, and group decision making. Closed system approaches, parochial identity, and an employee focus stabilized staff turnover, fostered evidence-based practice, and supported hierarchical toileting programs in one facility. Within a more dynamic environment, open system approaches, professional identity, and job focus allowed flexible care practices during periods of staff turnover. Neither organizational culture fully supported interdisciplinary team efforts to maximize the bladder and bowel health of residents.Implications: Organizational culture varies in NHs, shaping the continence care practices of interdisciplinary teams and leading to the selective use of treatments across facilities. Human relations dimensions of organizational culture, including open or closed systems, professional or parochial identity, and employee or job focus are critical to the success of quality improvement initiatives. Evidence-based interventions should be tailored to organizational culture to promote adoption and sustainability of resident care programs. © The Author 2009. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved.


Henderson C.N.R.,Palmer Center for Chiropractic Research
Journal of Electromyography and Kinesiology | Year: 2012

It is reasonable to think that patients responding to spinal manipulation (SM), a mechanically based therapy, would have mechanical derangement of the spine as a critical causal component in the mechanism of their condition. Consequently, SM practitioners routinely assess intervertebral motion, and treat patients on the basis of those assessments. In chiropractic practice, the vertebral subluxation has been the historical raison d'etre for SM. Vertebral subluxation is a biomechanical spine derangement thought to produce clinically significant effects by disturbing neurological function. This paper reviews the putative mechanical features of the subluxation and three theories that form the foundation for much of chiropractic practice. It concludes with discussion of subluxation as an indicator for SM therapy, particularly from the perspective that subluxation may be one contributory cause of ill-health within a "web of causation". © 2012 Elsevier Ltd.


Gudavalli M.R.,Palmer Center for Chiropractic Research
Journal of Manipulative and Physiological Therapeutics | Year: 2014

Objective The objective of this study was to determine the instantaneous rate of loading during manual high-velocity, low-amplitude spinal manipulations (HVLA SMs) in the lumbar and thoracic regions and compare to the average rates of loading. Methods Force-time profiles were recorded using a hand force transducer placed between the hand of a doctor of chiropractic and the subject's back during 14 HVLA SM thrusts on asymptomatic volunteers while 3 doctors of chiropractic delivered the spinal manipulations. Doctors also delivered 36 posterior to anterior thoracic manipulations on a mannequin. Data were collected at a sampling rate of 1000 Hz using Motion Monitor software. Force-time profile data were differentiated to obtain instantaneous rates of loading. The data were reduced using a custom-written MathCad program and analyzed descriptively. Results The instantaneous rates of loading were 1.7 to 1.8 times higher than average rates of loading, and instantaneous rates of unloading were 2.1 to 2.6 times the average rates of unloading during HVLA SMs. Maximum instantaneous rates of loading occurred 102 to 111 milliseconds prior to peak load. Maximum instantaneous rates of unloading occurred 121 to 154 milliseconds after the peak load. These data may be useful for further understanding of HVLA SMs. Conclusions The instantaneous rates of loading and where they occurred may be useful data for understanding and describing HVLA SMs. © 2014 National University of Health Sciences.


Low back pain (LBP) is a major health issue due to its high prevalence rate and socioeconomic cost. While spinal manipulation (SM) is recommended for LBP treatment by recently published clinical guidelines, the underlying therapeutic mechanisms remain unclear. Spinal stiffness is routinely examined and used in clinical decisions for SM delivery. It has also been explored as a predictor for clinical improvement. Flexion-relaxation phenomenon has been demonstrated to distinguish between LBP and healthy populations. The primary objective of the current study is to collect preliminary estimates of variability and effect size for the associations of these two physiological measures with patient-centered outcomes in chronic LBP patients. Additionally biomechanical characteristics of SM delivery are collected with the intention to explore the potential dose-response relationship between SM and LBP improvement. This is a prospective, observational study applying side-lying, high velocity, low amplitude SM as treatment for patients with LBP over a course of 6 weeks. Approximately 80 participants will be enrolled if they present with chronic LBP of 1, 2 or 3 in Quebec Task Force Classification for spinal disorders, a Roland-Morris Disability Questionnaire (RMDQ) score ≥ 6, and persistent LBP ≥ 2 with a maximum ≥ 4 using numerical rating scale. Patient-centered outcomes include LBP using visual analog scale, RMDQ, and PROMIS-29. Lumbar spine stiffness is assessed using palpation, a hand-held instrumented device, and an automated device. Flexion-relaxation is assessed using surface electromyography at the third level of the lumbar spine. Biomechanical characteristics of SM are assessed using a self-reported, itemized description system, as well as advanced kinetic measures that will be applied to estimate forces and moments at the lumbar segment level targeted by SM. Beside alterations in material properties of the passive components of the spine, increased neuromuscular activity may also contribute to a stiffened spine. Examining changes in both spinal stiffness and flexion-relaxation along the course of the treatment provides an opportunity to understand if the therapeutic effect of SM is associated with its action on active and/or passive components of the spine. NCT01670292 on clinicaltrials.gov.

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