A pilot study was conducted to evaluate the application of sEMG, as recorded with the Insight 7000 TM Subluxation Station, to the chiropractic clinical setting as an objective measure of change in assessing patient progress. The study revealed that intra-examiner reliability could be demonstrated through a paired two-tailed t-test which takes variation into consideration, rather than using correlation coefficients which could mask examiner error. Thirty patients under the care of 19 different supervised interns in a clinical teaching setting, were, over a four week period, administered a wide range of adjustments in accordance with a planned regimen of care. Findings revealed that all patients experienced a gradual to significant decline in sEMG activity in either the right and/or left side, in 14 of the 15 paraspinal muscular segments evaluated. This suggested a long term effect in sEMG activity changes, as opposed to a short term physiological response. Additional study is underway to evaluate inter-examiner reliability of the Insight 7000 Subluxation Station in the clinical teaching setting. Investigation is also planned to couple sEMG changes to other physical finding. This level of study is expected to contribute to an understanding of the clinical significance of the effects of the chiropractic adjustment on paraspinal muscular activity.
Objective: To provide occurrence rates for anomalies discovered on radiographs in patients seeking chiropractic care.
Methods: One thousand four random patient files dated between 1997 and 2001 were obtained from the records of the outpatient clinic at the New Zealand College of Chiropractic. In cases in which radiographs were taken, the radiographic reports were analyzed by the authors for the presence of a number of anomalies.
Results: Eight hundred forty-seven full-spine radiographs were included in the study. Anomalies were found in 68% of patients who had radiographs taken. The 5 most frequently occurring anomalies in descending order were degenerative joint disease (23.8%), posterior ponticle (13.6%), soft tissue abnormalities (13.5%), transitional segments (9.8%), and spondylolisthesis (7.8%). Other noteworthy occurrences because of their generalized status as absolute contraindications to adjustment are fracture (6.6%), malignant tumor (0.8%-3.1%), abdominal aortic aneurysm (0.8%) and atlantoaxial instability (0.6%).
Conclusion: A large percentage of patients presenting for chiropractic care have anomalies present on spinal radiographs. Further research and analysis is necessary to investigate the risk-verses-benefit ratio of spinal radiographs for chiropractic patients.
Key Indexing Terms: Chiropractic; Radiography; Anomaly; Bone Diseases
Chiropractic patients presenting to the New Zealand College of Chiropractic teaching clinic: A short description of patients and patient complaints
Objective: To report the basic characteristics of new chiropractic patients presenting to the New Zealand College of Chiropractic teaching clinic.
Design and Outcome Variables: Retrospective analysis of 1,004 new patient files opened between 1997 and 2001. Age, gender and chief complaint were recorded.
Results: Some 51.9% of patients were female. The mean age was 32.3 years, and age range was 0-85 years. The most common chief complaint was low back pain (38.1%). Overall spinal problems accounted for 64.4% of chief complaints, and 11.6% of patients presented for wellness care with no complaint present.
Conclusion: Patients presenting to the New Zealand College of Chiropractic teaching clinic showed many similarities with teaching clinics in the United States of America and Australia. Some discrepancies were noted, however, between the patient characteristics at the teaching clinic and the general New Zealand population.
The Effect of Altered Peripheral Input on Sensorimotor Integration (Doctoral dissertation, Sport and Exercise Science)
The study of neural plasticity has expanded rapidly in the past decades, and has revealed the remarkable ability of the adult human central nervous system (CNS) to adapt to altered peripheral input from its ever-changing environment. However, this adaptive ability may not always represent a behavioral benefit for a given individual. Certain movement disorders may develop due to maladaptive changes in sensorimotor integration due to prolonged periods of repetitive movement. Joint dysfunction following injury may also lead to maladaptive central changes that cause ongoing pain and loss of function. This thesis has investigated the effects of altering peripheral input with two specific tasks (20 minutes of motor training and spinal manipulation) on sensorimotor integration.
Both single and dual peripheral nerve stimulation somatosensory evoked potential (SEP) techniques, as well as single and paired pulse transcranial magnetic stimulation (TMS) protocols were used to measure sensorimotor integration. The first studies demonstrated that motor training reduced the CNS’s ability to suppress dual input at the cortical level (increased N20-P27 and P22-N30 SEP ratios) and selectively altered short interval intracortical inhibition (SICI) and I-wave facilitation in both utilized and non-utilized muscles (increased SICI and reduced IwF in a non-utilized muscle, and the opposite effect in the trained muscle). The next set of experiments demonstrated selective changes in cortical processing in somatosensory and sensorimotor integration areas, and altered motor control of a thumb muscle following spinal manipulation (reduced N20 and N30 SEP peak amplitudes and a shortening of the TMS induced cortical silent period in the abductor pollicis brevis).
The final experiments demonstrated that cervical manipulation also altered cortical filtering of peripheral input utilizing the dual peripheral nerve stimulation SEP technique (decreased P22 – N30 SEP ratio). Furthermore, spinal manipulation prior to motor training altered the outcome of motor training alone (reduced P22-N30 SEP ratio post motor training as apposed to increased). These results suggest that the CNS at the cortical level had a greater ability to suppress the dual input following spinal manipulation and improves “sensory gating” following motor training when it is preceded with manipulation of dysfunctional cervical segments.
This thesis has significant implications for understanding the role of altered afferent input from joints and muscles on the ability to appropriately integrate somatosensory input.
Cervical spine manipulation alters sensorimotor integration: A somatosensory evoked potential study
Objective: To study the immediate sensorimotor neurophysiological effects of cervical spine manipulation using somatosensory evoked potentials (SEPs).
Methods: Twelve subjects with a history of reoccurring neck stiffness and/or neck pain, but no acute symptoms at the time of the study were invited to participate in the study. An additional twelve subjects participated in a passive head movement control experiment. Spinal (N11, N13) brainstem (P14) and cortical (N20, N30) SEPs to median nerve stimulation were recorded before and for 30 min after a single session of cervical spine manipulation, or passive head movement.
Results: There was a significant decrease in the amplitude of parietal N20 and frontal N30 SEP components following the single session of cervical spine manipulation compared to pre-manipulation baseline values. These changes lasted on average 20 min following the manipulation intervention. No changes were observed in the passive head movement control condition.
Conclusions: Spinal manipulation of dysfunctional cervical joints can lead to transient cortical plastic changes, as demonstrated by attenuation of cortical somatosensory evoked responses.
Significance: This study suggests that cervical spine manipulation may alter cortical somatosensory processing and sensorimotor integration. These findings may help to elucidate the mechanisms responsible for the effective relief of pain and restoration of functional ability documented following spinal manipulation treatment.
The adult human central nervous system (CNS) retains its ability to reorganize itself in response to altered afferent input. Intracortical inhibition is thought to play an important role in central motor reorganization. However, the mechanisms responsible for altered cortical sensory maps remain more elusive.
The aim of the current study was to investigate changes in the intrinsic inhibitory interactions within the somatosensory system subsequent to a period of repetitive contractions. To achieve this, the dual peripheral nerve stimulation somatosensory evoked potential (SEP) ratio technique was utilized in 14 subjects. SEPs were recorded following median and ulnar nerve stimulation at the wrist (1 ms square wave pulse, 2.47 Hz, 1 x motor threshold). SEP ratios were calculated for the N9, N11, N13, P14–18, N20–P25 and P22–N30 peak complexes from SEP amplitudes obtained from simultaneous median and ulnar (MU) stimulation divided by the arithmetic sum of SEPs obtained from individual stimulation of the median (M) and ulnar (U) nerves. There was a significant increase in the MU/M + U ratio for both cortical SEP components following the 20 min repetitive contraction task, i.e. the N20–P25 complex, and the P22–N30 SEP complex. These cortical ratio changes appear to be due to a reduced ability to suppress the dual input, as there was also a significant increase in the amplitude of the MU recordings for the same two cortical SEP peaks (N20–P25 and P22–N30) following the typing task. No changes were observed following a control intervention. The N20 (S1) changes may reflect the mechanism responsible for altering the boundaries of cortical sensory maps, changing the way the CNS perceives and processes information from adjacent body parts. The N30 changes may be related to the intracortical inhibitory changes shown previously with both single and paired pulse TMS. These findings may have implications for understanding the role of the cortex in the initiation of overuse injuries.
Transient modulation of intracortical inhibition following spinal manipulation
Objective: To study the immediate sensorimotor neurophysiological effects of cervical spine manipulation using transcranial magnetic stimulation (TMS).
Design: Experimental design.
Setting: This study was carried out at the Human Neurophysiology Laboratory at the University of Auckland in Auckland, New Zealand.
Participants: Thirteen (13) subjects with a history of recurring neck stiffness and/or neck pain, but no acute symptoms at the time of the study were invited to participate in the study.
Intervention: Three (3) interventions were carried out in a randomised order: a control with no intervention, a passive head movement control condition, and a session of spinal manipulation of dysfunctional cervical joints.
Main Outcome Measures: Motor evoked potentials (MEP) and cortical silent periods (CSP) in the abductor pollicis brevis (APB) muscle of the dominant hand following transcranial magnetic stimulation (TMS) over the motor cortex.
Results: The major finding of this study was that the TMS-induced CSP measured in APB was significantly decreased for the first 20 minutes following spinal manipulation. No such changes were observed following either control condition, i.e. following no intervention or following passive head movement.
Conclusion: Spinal manipulation of dysfunctional cervical joints can lead to transient central neural plastic changes, as demonstrated by shortening of the TMS-induced CSP. This study suggests that cervical spine manipulation may alter sensorimotor integration. These findings may help to elucidate the mechanisms responsible for the effective relief of pain and restoration of functional ability documented following spinal manipulation treatment.