Barry Kim Humphreys

Are Swiss Chiropractors Different Than Other Chiropractors? Results of the Job Analysis Survey 2009

OBJECTIVE With the start of a new chiropractic program in the faculty of medicine, University of Zürich, an in-depth look at chiropractic practice in Switzerland was needed to help direct the undergraduate and postgraduate education. The purposes of this study were (1) to identify specific characteristics of chiropractic practice in Switzerland to ensure that relevant key competencies particular to practice in this country are covered in the undergraduate and postgraduate chiropractic programs and (2) to compare chiropractic practice in Switzerland to other countries who have completed similar surveys. METHODS Using the National Board of Chiropractic Examiners (United States) job analysis survey as a template and adapting questions from the General Chiropractic Council United Kingdom survey, a Swiss questionnaire was created and tested for face and content validity before being placed online for completion by the 260 members of the Swiss Association for Chiropractors. Participation was voluntary and anonymous. Data were entered into an Excel spreadsheet, and descriptive statistics were calculated. RESULTS The response rate was 70%. Similarities between Swiss chiropractors and their international counterparts were found in the most common conditions treated, the common etiologies of these conditions, the most common age groups seen, and the most common treatment methods used. Differences were found in the high proportion of patients referred directly to chiropractors from varying medical specialists in Switzerland, the fact that the most common category of patient to be seen by chiropractors in Switzerland is the acute followed by the subacute patient, the much higher requirement for continuing education hours in Switzerland, and the reduced use of diagnostic imaging compared with practitioners from the United States. CONCLUSIONS Chiropractic practice in Switzerland is a government-recognized medical profession with significant interprofessional referrals resulting in earlier chiropractic treatment for many patients. However, Swiss chiropractic practitioners still retain their professional identity and focus of practice.

Neural Correlates of Fear of Movement in Patients with Chronic Low Back Pain vs. Pain-Free Individuals

Fear of movement (FOM) can be acquired by a direct aversive experience such as pain or by social learning through observation and instruction. Excessive FOM results in heightened disability and is an obstacle for recovery from acute, subacute, and chronic low back pain (cLBP). FOM has further been identified as a significant explanatory factor in the Fear Avoidance (FA) model of cLBP that describes how individuals experiencing acute back pain may become trapped into a vicious circle of chronic disability and suffering. Despite a wealth of evidence emphasizing the importance of FOM in cLBP, to date, no related neural correlates in patients were found and this therefore has initiated a debate about the precise contribution of fear in the FA model. In the current fMRI study, we applied a novel approach encompassing: (1) video clips of potentially harmful activities for the back as FOM inducing stimuli; and (2) the assessment of FOM in both, cLBP patients (N = 20) and age- and gender-matched pain-free subjects (N = 20). Derived from the FA model, we hypothesized that FOM differentially affects brain regions involved in fear processing in patients with cLBP compared to pain-free individuals due to the recurrent pain and subsequent avoidance behavior. The results of the whole brain voxel-wise regression analysis revealed that: (1) FOM positively correlated with brain activity in fear-related brain regions such as the amygdala and the insula; and (2) differential effects of FOM between patients with cLBP and pain-free subjects were found in the extended amygdala and in its connectivity to the anterior insula. Current findings support the FOM component of the FA model in cLBP.

Neural responses of posterior to anterior movement on lumbar vertebrae: a functional magnetic resonance imaging study.

OBJECTIVE The purpose of this study was to develop and test a clinically relevant method to mechanically stimulate lumbar functional spinal units while recording brain activity by means of functional magnetic resonance imaging (MRI). METHODS Subjects were investigated in the prone position with their face lying on a modified stabilization pillow. To minimize head motion, the pillow was fixed to the MRI headrest, and supporting straps were attached around the shoulders. An experienced manual therapist applied controlled, nonpainful pressure stimuli to 10 healthy subjects at 3 different lumbar vertebrae (L1, L3, and L5). Pressure applied to the thumb was used as a control. The stimulation consisted of posterior to anterior (PA) pressure movement. The therapist followed a randomized stimulation protocol projected onto a screen in the MRI room. Blood oxygenation level-dependent responses were analyzed in relation to the lumbar and the thumb stimulations. The study was conducted by the Chiropractic Department, Faculty of Medicine, University of Zürich, Switzerland. RESULTS No participant reported any discomfort due to the prone-lying position or use of the pillow. Importantly, PA-induced pressure produced only minimal head movements. Stimulation of the lumbar spinous processes revealed bilateral neural responses in medial parts of the postcentral gyrus (S1). Additional activity was observed in the secondary somatosensory cortex (S2), posterior parts of the insular cortex, different parts of the cingulate cortex, and the cerebellum. Thumb stimulations revealed activation only in lateral parts of the contralateral S1. CONCLUSION The current study demonstrates the feasibility of the application of PA pressure on lumbar spinous processes in an MRI environment. This approach may serve as a promising tool for further investigations regarding neuroplastic changes in chronic low back pain subjects.

Fear avoidance beliefs in back pain-free subjects are reflected by amygdala-cingulate responses

In most individuals suffering from chronic low back pain, psychosocial factors, specifically fear avoidance beliefs (FABs), play central roles in the absence of identifiable organic pathology. On a neurobiological level, encouraging research has shown brain system correlates of somatic and psychological factors during the transition from (sub) acute to chronic low back pain. The characterization of brain imaging signatures in pain-free individuals before any injury will be of high importance regarding the identification of relevant networks for low back pain (LBP) vulnerability. Fear-avoidance beliefs serve as strong predictors of disability and chronification in LBP and current research indicates that back pain related FABs already exist in the general and pain-free population. Therefore, we aimed at investigating possible differential neural functioning between high- and low fear-avoidant individuals in the general population using functional magnetic resonance imaging. Results revealed that pain-free individuals without a history of chronic pain episodes could be differentiated in amygdala activity and connectivity to the pregenual anterior cingulate cortex by their level of back pain related FABs. These results shed new light on brain networks underlying psychological factors that may become relevant for enhanced disability in a future LBP episode.

Reorganization in secondary somatosensory cortex in chronic low back pain patients

Study Design. A cross-sectional comparative study between chronic low back pain (CLBP) patients and healthy control subjects. Objective. The aim of this study was to investigate reorganization in the sensory cortex by comparing cortical activity due to mechanosensory stimulation of the lumbar spine in CLBP patients versus a control group by using functional magnetic resonance imaging (fMRI). Summary of Background Data. LBP is now the number 1 condition across the world in terms of years living with a disability. There is growing evidence that maladaptive changes in the processing of sensory input by the central nervous system are central to understanding chronic (back) pain. Methods. Nonpainful, posterior-anterior (PA) movement pressure was applied manually to lumbar vertebrae at L1, L3, and L5 in 13 healthy subjects and 13 CLBP patients. The manual pressure (30 N) was monitored and controlled using sensors. A randomized stimulation protocol was used consisting of 51 pressure stimuli of 5 seconds duration. fMRI data analysis was performed for the group activation within the primary and secondary sensory cortices (S1 and S2, respectively) and the representation of the individual vertebrae was extracted and statistically analyzed. Results. Nonpainful PA pressure revealed no cortical reorganization in S1. In contrast, the extent of S2 activation in the CLBP group was significantly reduced in both hemispheres. In the control group, a somatotopy was identified for the lumbar vertebrae between L1 and L3, respectively, and L5 in S2 of the right hemisphere. Most importantly, a blurring of the somatotopic representation of the lumbar spine in S2 was observed in the patient group. Conclusion. Together, these maladaptive changes suggest a reorganization of higher-order processing for sensory information in CLBP patients that might have implications for a decreased sensory acuity, also related to body perception and subsequent altered functioning of the lumbar spine. Level of Evidence: 2

The impact of pain-related fear on neural pathways of pain modulation in chronic low back pain

Introduction: Pain-related fear plays a substantial role in chronic low back pain (LBP) by amplifying the experienced disability. Related dysfunctional emotions and cognitions may also affect sensory aspects of pain through a modulatory pathway in which the periaqueductal gray (PAG) and the amygdala play key roles. Objectives: We therefore hypothesized a differential amygdala-PAG functional connectivity (FC) in patients with chronic LBP that is modulated by the degree of pain-related fear. Methods: We used data of a previously reported fMRI study where 20 chronic LBP patients (7 females, mean age = 39.35) and 20 healthy controls (12 females, mean age = 32.10) were asked to observe video clips showing potentially harmful and neutral activities for the back. Pain-related fear was assessed using the Tampa Scale of kinesiophobia (TSK) and Fear Avoidance Beliefs questionnaires (FABQ). Generalized psychophysiological interactions were used to reveal task-based FC. Results: Compared to controls, patients exhibited a significant decrease in amygdala-PAG-FC (P = 0.022) during observation of harmful activities, but not of neutral activities. Furthermore, amygdala-PAG-FC correlated negatively with Tampa Scale of kinesiophobia scores in patients (R2 = 0.28, P = 0.01) but not with Fear Avoidance Beliefs questionnaires scores. Discussion: Our findings might indicate a maladaptive psychobiological interaction in chronic LBP patients characterized by a disrupted amygdala-PAG-FC that is modulated by the degree of pain-related fear. These results shed new light on brain mechanisms underlying psychological factors that may have pronociceptive effects in chronic LBP.

Cortical Sensorimotor Processing of Painful Pressure in Patients with Chronic Lower Back Pain—An Optical Neuroimaging Study using fNIRS

In this study we investigated sensorimotor processing of painful pressure stimulation on the lower back of patients with chronic lower back pain (CLBP) by using functional near-infrared spectroscopy (fNIRS) to measure changes in cerebral hemodynamics and oxygenation. The main objectives were whether patients with CLBP show different relative changes in oxy- and deoxyhemoglobin ([O2Hb] and [HHb]) in the supplementary motor area (SMA) and primary somatosensory cortex (S1) compared to healthy controls (HC). Twelve patients with CLBP (32 ± 6.1 years; range: 24–44 years; nine women) and 20 HCs (33.5 ± 10.7 years; range 22–61 years; eight women) participated in the study. Painful and non-painful pressure stimulation was exerted with a thumb grip perpendicularly to the spinous process of the lumbar spine. A force sensor was attached at the spinous process in order to control pressure forces. Tactile stimulation was realized by a one-finger brushing. Hemodynamic changes in the SMA and S1 were measured bilaterally using a multi-channel continuous wave fNIRS imaging system and a multi-distant probe array. Patients with CLBP showed significant stimulus-evoked hemodynamic responses in [O2Hb] only in the right S1, while the HC exhibited significant [O2Hb] changes bilaterally in both, SMA and S1. However, the group comparisons revealed no significant different hemodynamic responses in [O2Hb] and [HHb] in the SMA and S1 after both pressure stimulations. This non-significant result might be driven by the high inter-subject variability of hemodynamic responses that has been observed within the patients group. In conclusion, we could not find different stimulus-evoked hemodynamic responses in patients with CLBP compared to HCs. This indicates that neither S1 nor the SMA show a specificity for CLBP during pressure stimulation on the lower back. However, the results point to a potential subgrouping regarding task-related cortical activity within the CLBP group; a finding worth further research.

Different mechanosensory stimulations of the lower back elicit specific changes in hemodynamics and oxygenation in cortical sensorimotor areas-A fNIRS study.

This study aimed at investigating the feasibility of functional near‐infrared spectroscopy (fNIRS) to measure changes in cerebral hemodynamics and oxygenation evoked by painful and nonpainful mechanosensory stimulation on the lower back. The main objectives were to investigate whether cortical activity can be (1) detected using functional fNIRS, and (2) if it is possible to distinguish between painful and nonpainful pressure as well as a tactile brushing stimulus based on relative changes in oxy‐ and deoxyhemoglobin ([O2Hb] and [HHb]).

ECU convention 2017 research presentations

O-01 Care seeking patterns during one year after visiting a chiropractor Alice Kongsted, Lise Hestbaek Nordic Institute of Chiropractic and Clinical Biomechanics, University of Southern Denmark, 5230 Odense M, Denmark; Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, 5230 Odense M, Denmark Correspondence: Alice Kongsted (a.kongsted@nikkb.dk) Chiropractic & Manual Therapies 2017, 25(Suppl 1):O-01

Pain-related fear - From different fear constructs to dissociable neural sources

Fear of pain demonstrates significant prognostic value regarding the development of persistent musculoskeletal pain and disability. Its assessment often relies on self-report measures of pain-related fear by a variety of questionnaires. However, based either on “fear of movement/(re)injury/kinesiophobia”, “fear avoidance beliefs” or “pain anxiety”, pain-related fear constructs seemingly differ while the potential overlap of the questionnaires is unclear. Furthermore, the relationship to other anxiety measures such as state or trait anxiety remains ambiguous. Because the neural bases of fearful and anxious states are well described, advances in neuroimaging such as machine learning on brain activity patterns recorded by functional magnetic resonance imaging might help to dissect commonalities or differences across pain-related fear constructs. We applied a pattern regression approach in 20 non-specific chronic low back pain patients to reveal predictive relationships between fear-related neural information and different pain-related fear questionnaires. More specifically, the applied Multiple Kernel Learning approach allowed generating models to predict the questionnaire scores based on a hierarchical ranking of fear-related neural patterns induced by viewing videos of potentially harmful activities for the back. We sought to find evidence for or against overlapping pain-related fear constructs by comparing the questionnaire prediction models according to their predictive abilities and associated neural contributors. The results underpin the diversity of pain-related fear constructs by demonstrating evidence of non-overlapping neural predictors within fear processing regions. This neuroscientific approach might ultimately help to further understand and dissect psychological pain-related fear constructs. Significance Pain-related fear, often assessed through self-reports such as questionnaires, has shown prognostic value and clinical utility for a variety of musculoskeletal pain disorders. However, it remains difficult to determine a common underlying construct of pain-related fear due to several proposed constructs among questionnaires. The current study describes a novel neuroscientific approach using machine learning of neural patterns within the fear circuit of chronic low back pain patients that has the potential to identify neural commonalities or differences among the various pain-related fear constructs. Ultimately, this approach might afford a deeper understanding of the suggested constructs and might be also applied to other domains where ambiguity exists between different psychological constructs.The ability to infer emotional states through self-reports is often limited. Their measurement becomes even more challenging when considering emotional phenomena such as pain-related fear where different associated fear constructs have been proposed. Demonstrating significant predictive value regarding disability in patients with persistent musculoskeletal pain, pain-related fear is often assessed by questionnaires focusing on either fear of movement/(re)injury/kinesiophobia, fear avoidance beliefs or pain anxiety. Furthermore, the relationship of general anxiety measures such as trait anxiety to pain-related fear remains ambiguous. Advances in neuroimaging might help to support potential commonalities or differences across psychological constructs using appropriate machine learning techniques with the ability to reveal predictive relationships between neural information and questionnaire scores. Here, we applied a pattern regression approach using functional magnetic resonance imaging data of 20 non-specific chronic low back pain (LBP) patients. More specifically, we applied a novel approach using Multiple Kernel Learning that allows investigating the contribution of experimental conditions and regional neural information to a prediction model. We hypothesized to find evidence for or against a common fear construct by computing and comparing the prediction model of each questionnaire according to the contribution of fear-related neural information and conditions. The current results underpin the diversity of fear constructs among self-report measures of pain-related fear by demonstrating evidence of non-overlapping and differentially contributing neural sources within fear processing regions. Thus, the current approach might ultimately help to further understand and dissect the fear constructs captured by the various pain-related fear questionnaires.