Upright Balance Control in Individuals with Cervical Myelopathy Following Cervical Decompression Surgery: A Prospective Cohort Study.

Patients with cervical myelopathy may manifest impairments in functional activities and balance control caused by compression of the spinal cord. The objective of the current study was to determine long-term changes in the upright balance control of patients with cervical myelopathy who had undergone cervical decompression surgery. This is a prospective cohort study from the preoperative phase to 3 months, 6 months, and 1 year postsurgery. Fifty-three patients with cervical myelopathy were recruited for the cervical myelopathy group and 22 age-matched healthy controls were recruited for the control group. Functional assessments including Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire-Lower Extremity Function (JOACMEQ-LEF) and 10-second step test; as well as balance assessments including postural sway (center-of-pressure: COP) were performed for both groups. The JOACMEQ-LEF (p = 0.036) scores of the myelopathy group improved postoperatively, and a significant decrease in COP variables of postural sway was observed. The upright posture was less stable in the myelopathy group than in the control group (p < 0.05) both before and after surgery. The effect size and standard response mean of the COP variables ranged from -0.49 to 0.03 at 3 months, 6 months, and 1 year postsurgery. The upright balance control had improved significantly 6 months after decompression surgery. However, the balance control of the patients who had undergone decompression surgery remained less stable than that of the age-matched healthy controls. Balance training should be initiated before 6 months postsurgery to accelerate balance control recovery in patients with cervical myelopathy.

Perturbation-Based Balance Training in Postoperative Individuals With Degenerative Cervical Myelopathy.

Degenerative cervical myelopathy (DCM) is a common aging condition caused by spinal cord compression. Individuals with DCM often presented with residual balance and functional impairments postoperatively. Perturbation-based balance training (PBT) has been shown to have positive effects on populations with neurological disorders but has yet to be investigated in DCM. The objective of this study was therefore to evaluate the effects of PBT on balance and functional performance in postoperative individuals with DCM. Fifteen postoperative individuals with DCM (DCM group) and 14 healthy adults (healthy control group) were recruited. The DCM group received a 4-weeks PBT using a perturbation treadmill. The outcome measures included mean velocity of center of pressure (COP) during quiet standing; center of mass (COM) variance and reaction time to balance perturbation during standing with forward and backward perturbation; gait speed during level ground walking; Timed Up and Go Test (TUG) and disability questionnaire scores including Visual Analog Scale, Neck Disability Index, and Lower Extremity Function of Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire. The assessments were conducted pre- and post-training postoperatively for the DCM group but only once for the healthy control group. Significant improvements were observed in the mean velocity of COP, COM variance, reaction time, gait speed, and TUG in the DCM group. Disability questionnaire scores were not significantly different after training in DCM group. For between-group comparisons, significant differences that were observed pre-training were not observed post-training. The 4-weeks PBT is a potential rehabilitation strategy for addressing balance and functional impairment in postoperative individuals with DCM. In addition, the post-training performance in the DCM group exhibited trends comparable to those of age-matched healthy controls. Furthermore, the training regimens offer a practical reference for future studies on populations with balance disorders. Future studies complemented with neurophysiological assessments could reveal more information of the underlying mechanisms of PBT.

Reweighting of the sensory inputs for postural control in patients with cervical spondylotic myelopathy after surgery.

BACKGROUND: Cervical spondylotic myelopathy (CSM) is a degenerative cervical disease in which the spinal cord is compressed. Patients with CSM experience balance disturbance because of impaired proprioception. The weighting of the sensory inputs for postural control in patients with CSM is unclear. Therefore, this study investigated the weighting of sensory systems in patients with CSM. METHOD: Twenty-four individuals with CSM (CSM group) and 24 age-matched healthy adults (healthy control group) were analyzed in this observational study. The functional outcomes (modified Japanese Orthopaedic Association Scale [mJOA], Japanese Orthopaedic Association Cervical Myelopathy Questionnaire [JOACMEQ], Nurick scale) and static balance (eyes-open and eyes-closed conditions) were assessed for individuals with CSM before surgery, 3 and 6 months after surgery. Time-domain and time-frequency-domain variables of the center of pressure (COP) were analyzed to examine the weighting of the sensory systems. RESULTS: In the CSM group, lower extremity function of mJOA and Nurick scale significantly improved 3 and 6 months after surgery. Before surgery, the COP mean velocity and total energy were significantly higher in the CSM group than in the control group for both vision conditions. Compared with the control group, the CSM group exhibited lower energy content in the moderate-frequency band (i.e., proprioception) and higher energy content in the low-frequency band (i.e., cerebellar, vestibular, and visual systems) under the eyes-open condition. The COP mean velocity of the CSM group significantly decreased 3 months after surgery. The energy content in the low-frequency band (i.e., visual and vestibular systems) of the CSM group was closed to that of the control group 6 months after surgery under the eyes-open condition. CONCLUSION: Before surgery, the patients with CSM may have had compensatory sensory weighting for postural control, with decreased weighting on proprioception and increased weighting on the other three sensory inputs. After surgery, the postural control of the patients with CSM improved, with decreased compensation for the proprioceptive system from the visual and vestibular inputs. However, the improvement remained insufficient because the patients with CSM still had lower weighting on proprioception than the healthy adults did. Therefore, patients with CSM may require balance training and posture education after surgery. TRIAL REGISTRATION: Trial Registration number: NCT03396055 Name of the registry: ClinicalTrials.gov Date of registration: January 10, 2018 - Retrospectively registered Date of enrolment of the first participant to the trial: October 19, 2015.

Changes of balance control in individuals with lumbar degenerative spine disease after lumbar surgery: a longitudinal study.

BACKGROUND CONTEXT: Lumbar degenerative spine disease (DSD) with neurological symptoms is the most common indication requiring lumbar surgery when nonoperative treatment is not effective. Individuals with lumbar DSD have sensory, proprioception, and musculoskeletal system alterations, which may result in balance impairment. However, evidence regarding balance recovery in individuals with lumbar DSD after lumbar surgery is limited. PURPOSE: To evaluate balance control, pain, and functional activities in individuals with lumbar DSD after lumbar surgery. STUDY DESIGN/SETTING: A prospective study with a cross-sectional control group. PATIENT SAMPLE: Seventy individuals with lumbar DSD (DSD group) and 30 age-matched healthy adults (control group) were recruited. Participants in the DSD group were diagnosed by a neurological surgeon and received lumbar surgery according to relevant imaging findings and neurological symptoms. OUTCOME MEASURES: Clinical assessments, including a visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the Roland-Morris Disability Questionnaire (RMDQ), were performed in the DSD group only. Balance control was assessed in all participants using the root mean square (RMS) distance of the center of pressure (COP) in anteroposterior and mediolateral directions. METHODS: All participants were instructed to stand in natural stance and Romberg stance with eyes open and eyes closed on a force platform for 35 seconds, respectively. The assessments were performed in the DSD group at four time points: preoperative phase (baseline), 3 months, 6 months, and 12 months postoperatively. In the age-matched healthy control group, only one assessment on the recruitment day was performed. RESULTS: The VAS, ODI, and RMDQ scores of the DSD group significantly improved after lumbar surgery (p<.001). The RMS distance of COP in the DSD group significantly decreased after lumbar surgery (p<.017) compared with baseline in most of the testing conditions. However, the RMS distance of the COP in the DSD group after surgery was significantly greater than in the healthy control group (p<.05), especially 6 months and 12 months postoperatively. CONCLUSIONS: Balance control, pain, and functional activities of individuals with lumbar DSD showed improvement after lumbar surgery. However, balance control in individuals with lumbar DSD was still less stable than in age-matched healthy adults from 6 to 12 months after surgery. Therefore, individuals with lumbar DSD require fall prevention programs after lumbar surgery, including balance assessments and postoperative balance training.

Asymmetric Thickness of Oblique Capitis Inferior and Cervical Kinesthesia in Patients With Unilateral Cervicogenic Headache.

OBJECTIVE: The purpose of this study was to compare the thickness of the oblique cervical inferior (OCI) and the error of the head reposition test between the painful and nonpainful sides of patients with cervicogenic headache (CeH) and between the patients and the asymptomatic group. METHODS: Thirteen patients (24.5 ± 4.8 years) and 14 asymptomatic participants (23.9 ± 2.7 years) were included. The head reposition test was recorded by a 3-dimensional motion analysis system. The thickness of the OCI was recorded by ultrasonography. The measured outcomes were compared between the painful and nonpainful sides and with the asymptomatic participants. RESULTS: The thickness of the OCI in the rest condition on the painful side (9.92 ± 2.31 mm) was smaller than that of the nonpainful side (10.56 ± 2.24 mm). The constant error of the head-to-target test toward the nonpainful side was smaller in the patients with CeH (-1.6 ± 4.3°) than in the asymptomatic group (3.3 ± 3.7°, P = 0.005). CONCLUSION: Asymmetric OCI and cervical proprioception were demonstrated in patients with CeH.

Asymmetrical responses of skin blood flow in ischemic hindlimbs to electrical stimulation of the unilateral forelimb.

The regulation of skin blood flow (SBF) is primarily mediated by the sympathetic nervous system, but the effects of electrical stimulation (ES) of one limb on SBF in the other limbs remain unknown. The present study investigated the effects of unilateral forelimb ES on SBF in the bilateral hindlimbs in anesthetized rats. Bilateral hindlimb ischemia was induced by tourniquet application for 60min. After reperfusion for 24h, ES (3 or 125Hz) was applied to the upper one-fourth of the triceps brachii muscle of the left or right forelimb for 30min. Rats that did not receive ES were used as the controls. Bilateral hindlimb SBF was measured by a laser Doppler line scanner for 20min before ES, 30min during ES, and 9min after ES. The results showed significant differences in SBF in the right but not left hindlimb between the control group and experimental group that received 125-Hz ES of the right forelimb. Right hindlimb SBF significantly increased within 3min following the application of 125-Hz ES to the right forelimb. No significant changes in SBF were observed in the left or right hindlimb when 125-Hz ES was applied to the left forelimb. Moreover, 3-Hz ES of the left or right forelimb did not significantly change SBF in either hindlimb compared with the control group. These results indicate that unilateral forelimb ES causes a differential SBF response in the hindlimb via a specific somatosympathetic reflex, and ES-induced SBF improvements in the ischemic hindlimb are frequency-dependent.

Mechanical deformation of posterior thoracolumbar fascia after myofascial release in healthy men: A study of dynamic ultrasound imaging.

BACKGROUND: Myofascial release (MR) on the posterior thoracolumbar fascia (PLF) is one of the manual techniques aim to restore the normal length and tension of restricted fasciae and muscles. OBJECTIVES: The present study aimed to quantify the immediate effects of MR on fascial properties of the PLF in healthy men. DESIGN: Cross-sectional study. METHOD: Participants (N = 10, aged 22.8 ± 2.0 years) performed a press-down to maximal voluntary contraction (MVC) in the prone position. Deformation of the PLF was measured using an ultrasonographic apparatus. Force output was simultaneously measured. The stiffness index and hysteresis index were then represented by the slope of the loading curve, and the percentage of the area within the loading-unloading curve. One-way ANCOVA was used to compare differences in the stiffness index or hysteresis index of the PLF before and after MR. Two-way repeated ANOVA was used to compare deformation of the PLF or force output after MR. RESULTS: The primary findings included a decrease (before: 24.1 ± 8.3 vs. after: 18.9 ± 5.3 N/mm; mean difference, -5.2 ± 4.9 N/mm, p = 0.002 < 0.05) in the stiffness index of the PLF and a greater difference in deformation of the PLF between 50% and 100% MVC (before: Def50% = 6.5 ± 1.8 mm and Def100% = 9.8 ± 1.9 mm vs. after: Def50% = 6.4 ± 2.5 mm and Def100% = 10.2 ± 2.4 mm; p = 0.037 < 0.05, power = 58.5%). CONCLUSION: After MR, stiffness of the PLF decreased in healthy men.

Comparison of Cervical Kinematics, Pain, and Functional Disability Between Single- and Two-level Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: A prospective, time series design. OBJECTIVE: The purpose of this study is two-fold: firstly, to investigate the impact of altered cervical alignment and range of motion (ROM) on patients' self-reported outcomes after anterior cervical discectomy and fusion (ACDF), and secondly, to comparatively differentiate the influence of single- and two-level ACDF on the cervical ROM and adjacent segmental kinematics up to 12-month postoperatively. SUMMARY OF BACKGROUND DATA: ACDF is one of the most commonly employed surgical interventions to treat degenerative disc disease. However, there are limited in vivo data on the impact of ACDF on the cervical kinematics and its association with patient-reported clinical outcomes. METHODS: Sixty-two patients (36 males; 55.63 ±â€Š11.6 yrs) undergoing either a single- or consecutive two-level ACDF were recruited. The clinical outcomes were assessed with the Pain Visual Analogue Scale (VAS) and the Neck Disability Index (NDI). Radiological results included cervical lordosis, global C2-C7 ROM, ROM of the Functional Spinal Unit (FSU), and its adjacent segments. The outcome measures were collected preoperatively and then at 3, 6, and 12-month postoperatively. RESULTS: A significant reduction of both VAS and NDI was found for both groups from the preoperative to 3-month period (P < 0.01). Pearson correlation revealed no significant correlation between global ROM with neither VAS (P = 0.667) nor NDI (P = 0.531). A significant reduction of global ROM was identified for the two-level ACDF group at 12 months (P = 0.017) but not for the single-level group. A significant interaction effect was identified for the upper adjacent segment ROM (P = 0.024) but not at the lower adjacent segment. CONCLUSION: Current study utilized dynamic radiographs to comparatively evaluate the biomechanical impact of single- and two-level ACDF. The results highlighted that the two-level group demonstrated a greater reduction of global ROM coupled with an increased upper adjacent segmental compensatory motions that is independent of patient-perceived recovery. LEVEL OF EVIDENCE: 3.

Increased sliding of transverse abdominis during contraction after myofascial release in patients with chronic low back pain.

PURPOSE: Recent evidence suggested the significance of integrity of the tension balance of the muscle-fascia corset system in spinal stability, particularly the posterior musculofascial junction which is adjacent to dorsal located paraspinal muscles joining each other at lateral raphe (LR). The purpose of this study was to compare the contraction of the transversus abdominis (TrA) at both anterior and posterior musculofascial muscle-fascia junctions in patients with low back pain (LBP) and asymptomatic participants before and immediately after a sustained manual pressure to LR. METHODS: The present observational cohort study used a single-instance, test-retest design. The outcome variables included the resting thickness (Tr), the thickness during contraction (Tc), change in thickness (ΔT), sliding of musculofascial junction (ΔX), muscle length at rest (L) and displacement pattern (ΔD) of the TrA using ultrasonography. Vertical tolerable pressure at the LR was applied manual for 1 min. Tr, Tc, ΔT, and ΔX were analyzed by three-way ANOVA (musculofascial junction sites*group* pre-post manual release). ΔL and ΔD were analyzed by two-way ANOVA (group* pre-post manual release). RESULTS: Participants with LBP revealed less Tc, ΔT and ΔX at both sites (p < 0.005). After myofascial release, LBP group demonstrated a positive ΔD of the musculofascial junctions at both end (p < 0.001). Nevertheless, both groups increased the ΔT and ΔX at both sites (p < 0.001 and 0.001, respectively). CONCLUSION: The result indicated immediately effect of sustained manual pressure on musculofascial junction of TrA and supported the concept that the possible imbalanced tension of the myofascia corset of TrA in patients with LBP.

Exercise training for non-operative and post-operative patient with cervical radiculopathy: a literature review.

[Purpose] Cervical radiculopathy is a clinical condition associated with pain, numbness and/or muscle weaknesses of the upper extremities due to a compression or irritation of the cervical nerve roots. It is usually managed conservatively but surgical intervention is sometimes required for those who fail to respond adequately. This study performed a literature review to determine the effects of exercise on non-operative and post-operative cervical radiculopathy patients. [Methods] The PubMed, MEDLINE, CINAHL and Scopus databases were searched to identify relevant articles published from January 1997 to May 2014, which explicitly stated that an exercise program was employed as an intervention for cervical radiculopathy. The therapeutic effectiveness and outcomes were then classified based on the International Classification of Functioning, Disability and Health (ICF) model. [Results] Eleven studies were identified and included in the final analysis. In these studies, the main forms of exercise training were specific strengthening and general stretching exercises. Levels of evidence were graded as either I or II for all studies according to the Oxford Centre for Evidence-based Medicine. The PEDro Scale score of these studies ranged from 5 to 8. [Conclusion] A review of eleven high-level evidence and high-quality studies revealed that, based on the ICF model, exercise training is beneficial for improving the body function as well as activity participation of cervical radiculopathy patients.

Reliability and Validity of Transversus Abdominis Measurement at the Posterior Muscle-Fascia Junction with Ultrasonography in Asymptomatic Participants.

OBJECTIVE: The purposes of this study were (1) to establish the intrarater sliding and change in thickness of the transversus abdominis (TrA) measurement at the posterior muscle-fascia junction and (2) to examine the relationship between the muscle thickness and sliding of the TrA at the anterior and posterior sites. METHODS: Asymptomatic participants (n = 20) were placed into the hook-lying position to perform the abdominal drawing-in maneuver viewed in B-mode with a 5- to 12-MHz linear ultrasound transducer. The outcome variables included the resting thickness, the thickness during contraction, the change of thickness, and the change of sliding length. Both intraclass correlation coefficient and Pearson correlation were used for analysis. RESULTS: Measuring the thickness and sliding of the TrA at the posterior muscle-fascia junction showed good reliability (intraclass correlation coefficient (3,3), 0.89-0.98). The correlations between the sliding measurements of the TrA at the anterior and posterior sites were moderate to good (r = 0.41-0.74). CONCLUSION: This study found that measuring the musculofascial corset from the posterior site using ultrasonography is reliable, allowing for ultrasound measurements at both the anterior and posterior sites of the TrA to provide a comprehensive evaluation of the TrA fascia.

Responsiveness of the Chinese versions of the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire and Neck Disability Index in postoperative patients with cervical spondylotic myelopathy.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To evaluate the postoperative responsiveness of the Chinese versions of the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) and the Neck Disability Index (NDI) in a cohort of patients with cervical spondylotic myelopathy. SUMMARY OF BACKGROUND DATA: We have recently completed the translation and cross-cultural adaptation of a Chinese version of JOACMEQ. However, the postoperative responsiveness of the Chinese JOACMEQ and how it compares with the more commonly used NDI remain undetermined. METHODS: Forty-five patients with cervical spondylotic myelopathy undergoing surgical decompression were recruited. All patients completed the Chinese JOACMEQ and the NDI preoperatively and again at 3-month follow-up together with an 11-point Global Rating of Change scale. Patients were dichotomized either as "Improved" or "Stable" on the basis of Global Rating of Change. Paired t test, standardized effect sizes, and Guyatt responsiveness index were used to determine internal responsiveness. External responsiveness was evaluated by the area under the receiver operating characteristic curve and the minimal clinically important change was determined as the optimal cutoff point for patient discrimination anchor-based on Global Rating of Change classification. RESULTS: Bladder function and quality of life (QOL) domains (P < 0.03) of the JOACMEQ and the NDI (P = 0.004) reached statistically significant difference with the paired t test. After the dichotomization, the standardized effect size was strong for the QOL domain in the improved group (0.85) and the Cervical spine function (0.97) in the stable group, respectively. Based on the Guyatt responsiveness index, strong responsiveness was found for the Bladder function (0.88) and QOL (0.76) domains of the JOACMEQ and moderate responsiveness (0.55) for the NDI. The Bladder function (area = 0.82; minimal clinically important change = 6) and QOL (0.83; minimal clinically important change = 8.5) also produced largest area under the receiver operating characteristic curve. CONCLUSION: Bladder function and QOL domains of the JOACMEQ seem to demonstrate the strongest postoperative responsiveness and thus may be more appropriate than NDI when attempting to determine treatment efficacy in cervical spondylotic myelopathy. LEVEL OF EVIDENCE: 3.

Differential segmental motion contribution of single- and two-level anterior cervical discectomy and fusion.

PURPOSE: To determine and compare the biomechanical effects of single- and two-level anterior cervical decompression and fusion (ACDF) on the re-distribution of the segmental contribution to total cervical range of motion (ROM) in a prospective longitudinal design. METHODS: Fifty-one patients undergoing either a single- or two-level ACDF due to cervical disc disease were recruited. Functional radiographs were taken preoperatively and then at 3, 6 and 12-month follow-ups. Global ROM of C2-C7, ROM of the treated functional spinal unit (FSU) and the superior and inferior segmental ROMs were then measured. The relative contribution from the FSU and each of the adjacent segments to total cervical ROM were compared pre- and post-operatively within and between the two groups at each of the time points. RESULTS: Single-level ACDF patients demonstrated a significantly greater total cervical ROM at 6 and 12 months compared with the two-level ACDF group (p = 0.021 and 0.045, respectively). A significantly greater contribution from the FSU to the total ROM was found at 3 months in the two-level ACDF group (p = 0.016), but the greater contribution shifted to the superior adjacent segment at 6 and 12 months (p = 0.025 and 0.046). The two-level ACDF group did not demonstrate a significant difference at 3 months (p = 0.087), but a significant increase in contribution was found at 6 and 12 months (p < 0.01). CONCLUSIONS: Single-level ACDF maintains and restores a more physiological re-distribution of segmental contribution of ROM compared with two-level ACDF, which required longer time to achieve stable FSU immobilization and coupled with significantly increased superior segment contribution.

Translation, cross-cultural adaptation, and validation of a Chinese version of the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire.

STUDY DESIGN: Translation and psychometric testing of a questionnaire. OBJECTIVE: To adapt the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) cross-culturally to Chinese language and to investigate the psychometric properties of the translated Chinese JOACMEQ. SUMMARY OF BACKGROUND DATA: The recently developed JOACMEQ is a self-reported questionnaire used to assess the severity of the cervical spondylotic myelopathy. Despite its acceptance in the literature, the JOACMEQ has not been translated and validated for Chinese-speaking patients. METHODS: Translation and cross-cultural adaptation of the original JOACMEQ was performed according to published guidelines. A total of 105 patients with a predominant complain of neck pain that included but not limited to patients with a clinically confirmed cervical spondylotic myelopathy were included. Psychometric testing of the responses included construct validity (factor analysis), internal consistency (Cronbach α), test-retest reproducibility (intraclass correlation coefficient), and concurrent validity (Spearman ρ). The discriminatory power of differentiating those with myelopathy from those without was assessed by the area under the receiver operating characteristic curve and with the optimal cutoff points determined. RESULTS: Construct validity testing revealed a comparable factorial structure of the Chinese JOACMEQ with the original JOACMEQ. The Cronbach α of the Chinese JOACMEQ was 0.88, indicating good internal consistency. Good to excellent test-retest reliability was demonstrated for all 5 domain scores (intraclass correlation coefficient range = 0.79-0.90). A significant strong association between the Chinese Neck Disability Index and the quality of life domain of the Chinese JOACMEQ (Spearman ρ= -0.76, P < 0.01) was identified. The upper and lower extremity function domain scores were found to be significant, with the area under the receiver operating characteristic curve found to be 0.75 (P = 0.04) and 0.82 (P = 0.02), respectively. CONCLUSION: The results indicated that the Chinese JOACMEQ successfully retained the psychometric properties of the original JOACMEQ and support the usefulness of the Chinese JOACMEQ as an appropriate supplementary diagnostic and outcome measure for Chinese patients suspected of cervical spondylotic myelopathy.

Altered Co-contraction of Cervical Muscles in Young Adults with Chronic Neck Pain during Voluntary Neck Motions.

[Purpose] Muscle co-contraction is important in stabilizing the spine. The aim of this study was to compare cervical muscle co-contraction in adults with and without chronic neck pain during voluntary movements. [Subjects and Methods] Surface electromyography of three paired cervical muscles was measured in fifteen young healthy subjects and fifteen patients with chronic neck pain. The subjects performed voluntary neck movements in the sagittal and coronal plane at slow speed. The co-contraction ratio was defined as the normalized integration of the antagonistic electromyography activities divided by that of the total muscle activities. [Results] The results showed that the co-contraction ratio of patients was greater during flexion movement, lesser during extension movement, slightly greater during right lateral bending, and slightly lesser during left lateral bending compared with in the controls. [Conclusion] The results suggested that neck pain patients exhibit greater antagonistic muscle activity during flexion and dominate-side bending movements to augment spinal stability, while neuromuscular control provides relatively less protection in the opposite movements. This study helps to specify the changes of the stiffness of the cervical spine in neck pain patients and provides a useful tool and references for clinical assessment of neck disorders.

Inter-session reliability of the measurement of the deep and superficial layer of lumbar multifidus in young asymptomatic people and patients with low back pain using ultrasonography.

STUDY DESIGN: Reliability study. OBJECTIVE: To investigate the inter-session reliability of measuring the thickness of deep (dMF) and superficial layer of lumbar multifidus (sMF) using ultrasonography for participants with and without low back pain (LBP). BACKGROUND: The lumbar multifidus is an important muscle in maintaining spinal stability. The dMF is considered important in maintaining tonic contraction and joint stability. Motor control impairment is also discovered in patients with LBP. However, no study to date has investigated the method of observing both the sMF and dMF through ultrasound imaging (USI). METHODS: Twenty subjects aged 18-35 years old with LBP (N=10) and without LBP (N=10) were recruited. Every subject extended the upper trunk in prone lying with maximal isometric contraction. Simultaneously, the examiner measured the thickness of the dMF and the sMF using ultrasonography after ensuring the muscle belly was located. The participants performed three trials of isometric trunk extension in each session, with 30 min between each session. The reliability of measuring the change of thickness is represented by the intra-class correlation coefficient (ICC). RESULTS: Through averaging three trials of measurement, the reliability of measuring the thickness of the dMF or the sMF in static or in the contracted condition, and the change of the thickness during contraction, is reliable (ICC=0.84-1.00). CONCLUSIONS: The intra-rater inter-session reliability of measurement of the dMF and the sMF with USI has been established. This method could be applied to the qualification of the activation level of the dMF and the sMF with specific tasks.

Increasing acclimation period improves the reproducibility of short-heating local thermal hyperemia.

OBJECTIVES: The axon reflex (AR) can be induced by the activation of afferent C-fibers during local skin heating. The previously used long-heating local thermal hyperemia (LTH) protocols tested AR flare by normalizing to endothelial-mediated maximal vasodilatation to adjust capillary heterogeneity when the recording sites were randomly selected. The AR flare induced by short local heating can be reproducible without using the data from subsequent longer heating for normalization when the recording sites were fixed with holders in the same session. The aim of this study was to investigate the effect of acclimation period on the intersession reproducibility of short-heating LTH when the recording sites were relocated after a longer interval of 1-3 days. METHODS: After 30 or 60 min acclimation, LTH with 5 min heating was assessed on bilateral human forearms using single-point laser Doppler flowmetry. The test was repeated at the same recording sites again at the same time 1-3 days later. Baseline and heating blood flux were analyzed and the data were expressed as different forms. Reproducibility of two tests was assessed using coefficient of variation (CV) and intra-class correlation coefficient (ICC) statistics. RESULTS: The intersession reproducibility of peak cutaneous vascular conductance (CVC) (CV=18.38%, ICC=0.82), peak CVC change (CV=20.38%, ICC=0.83) and 4 min area-under-the-curve (AUC) (CV=18.66%, ICC=0.75) of the right forearm and time to peak (CV=16.84%, ICC=0.52) of the left forearm were acceptable after 30 min acclimation. When the acclimation period was increased to 60 min, all of these data except 4 min AUC of both sides reached an acceptable level. CONCLUSIONS: The AR flare induced by short local heating is reproducible when the recording sites are relocated by a predefined rule. The reproducibility of LTH on right forearm is different from that on left forearm, and increasing acclimation period improves the reproducibility.

Axon reflex-related hyperemia induced by short local heating is reproducible.

OBJECTIVES: The axon reflex (AR) flare is induced by antidromic activation of afferent C-fibers during nociceptive stimulation. This response has been suggested to be modulated by sympathetic activity and basal level of nitric oxide. In previously used protocols of local thermal hyperemia (LTH), AR flare has been used in combination with maximal vasodilatation to study the integrated endothelial function. The aim of this study was to investigate the intra-session reproducibility of short heating-induced AR flare, the specific neural-mediated portion of LTH, and to compare the reproducibility between different forms of data expression. METHODS: Short-heating LTH was assessed using single-point laser Doppler flowmetry (LDF) on bilateral volar surface of the forearm in 10 men and 10 women. The blood flux measurement included a non-heating process for 5 min, followed by a quick heating process from 33°C to 42°C for 5 min. The test was repeated 45 min later at the same recording sites with fixed holders. Baseline and heating blood flux were recorded and expressed as different forms of data. Reproducibility was assessed using coefficient of variation (CV) and intra-class correlation coefficient (ICC) statistics. RESULTS: The reproducibility of peak cutaneous vascular conductance (CVC) (CV=16.02-17.31%, ICC=0.77-0.78), peak CVC change (CV=14.30-18.12%, ICC=0.80-0.86), and the 4 min area-under-the-curve (CV=18.37-18.70%, ICC=0.60-0.78) was acceptable. The time to peak flux of each recording site ranged from 90 to 209 s and all the peak fluxes have been achieved before 4 min of heating. CONCLUSIONS: Single-point LDF is a reproducible technique of assessing AR flare on volar surface of the forearm when the heating period is reduced to 5 min and the recording sites are fixed. Using this new protocol, short-heating LTH has a potential to be used to evaluate the effects of acute physical or chemical interventions between two short-heating LTH tests to further explore the pathophysiological meaning of heating-induced AR flare.

Reliability and relationship between 2 measurements of transversus abdominis dimension taken during an abdominal drawing-in maneuver using a novel approach of ultrasound imaging.

STUDY DESIGN: Reliability study of clinical measurement. OBJECTIVES: The primary purpose was to develop a reliable method for measuring muscle length changes of the transversus abdominis (TrA) during contraction. The secondary purpose was to investigate the relationship between changes in thickness and length (as indicated by the lateral sliding of the anterior muscle-fascia junction) of the TrA muscle during an abdominal drawing-in maneuver. We also provide data on between-day reliability of change in thickness (ΔT) of the TrA. BACKGROUND: Ultrasound imaging measurements of TrA thickness at rest (Thr) and during maximal contraction (Thm) have been shown to be reliable. However, limited data exist on quantifying changes in TrA length (as indicated by the lateral sliding of the muscle-fascia junction [Δx]) and ΔT during contraction. METHODS: Eighteen healthy adults (mean ± SD age, 22.6 ± 2.5 years) participated in this study. Brightness mode ultrasound images of the TrA were collected at rest and during an abdominal drawing-in maneuver. Subjects were examined by the same examiner twice within a 48-hour period. ΔT, ΔT/Thr, Thr, Thm, and Δx of the TrA were calculated. Medial-lateral movement of the transducer during measurement was corrected through a custom-written program that used an internal marker created by an echo-absorptive thread attached to the skin. Intraclass correlation coefficients (ICC3,1), within-subject coefficient of variance, and standard error of measurement were calculated. The relationship between ΔT and adjusted Δx of the TrA muscle was investigated. RESULTS: The ICC values for Thr, Thm, and ΔT of the TrA muscle were greater than 0.75, with the exception of the left ΔT (0.62) and left ΔT/Thr (0.49). After adjusting for medial-lateral motion of the transducer, the ICC values of adjusted Δx were above 0.75, and the within-subject coefficient of variance was below 10%. There was no significant correlation between ΔT and adjusted Δx of the TrA. CONCLUSION: Ultrasound imaging measurements of TrA thickness and length change were shown to be reliable using a novel method to control for medial-lateral transducer motion. Measuring different but unrelated dimensional changes in the TrA might provide further insight as to the function of the TrA.

Position accuracy and electromyographic responses during head reposition in young adults with chronic neck pain.

The head reposition test is traditionally used to examine the proprioceptive sensitivity of the neck. The aim of this study was to investigate the position accuracy and corresponding cervical electromyographic (EMG) responses of the neck pain subjects during sagittal head-to-neutral tasks. Twelve young subjects with chronic neck pain and twelve young healthy subjects were recruited. The position accuracy was measured by the constant error, variable error, and root mean square error of joint angles during head-to-neutral tasks in flexion and extension directions. Surface EMG of neck flexors and extensors were analyzed by the voluntary response index, including the similarity index (SI) and electromyographic magnitude (MAG) of muscle groups. The normalized average integration of EMG activity (NAIEMG) of individual muscle was also calculated. The results showed: (1) significantly larger constant error and root mean square error but similar variable error in patients compared with controls, (2) smaller SI but similar MAG in patients compared with controls, (3) greater synergistic/antagonistic NAIEMG in patients than controls. The findings suggested that young adults with chronic neck pain exhibit proprioceptive dysfunction and altered EMG pattern during voluntary sagittal neck motions. This study provides guidelines which could lead to the development of therapeutic exercise programs.