Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles

Sway detection in hypertension as a novel tool to anticipate risk and morbidity due to postural instability

Objectives:

Hypertension contributes substantially to poor physical function and autonomic imbalance. It may cause instability in posture that limits daily activities and can lead to devastating falls. Centre of pressure (CoP) is a commonly used index of postural stability while standing and is a measure of the activity of the motor system, which may be altered in hypertension. It is also observed that the fall incidence is higher in women than men, which may be due to postural instability. The pilot study was conducted to see whether the presence of essential hypertension further contributes to postural instability in women and compared with age-matched normotensive controls.

Materials and Methods:

Sixteen hypertensive women on regular treatment for hypertension and 16 age-matched normotensive women with a mean age of 51.9 ± 9.1 years were included in the study. The WII balance board was used to measure the CoP and displacement to sway. PowerLab 8/35 (AD instruments) with LabChart software was used to measure the parameters.

Results:

Displacement of CoP in the mediolateral direction was studied in the trials. The CoP was measured in eyes closed and eyes open conditions and was displaced in both groups, with significant displacement in hypertensive women. With voluntary sway to their right and left sides, hypertensive women have shown significantly less sway displacement compared to normotensive women. In hypertensives, during right sway, the error of correction was 13%. During left sway, overcorrection was high in both hypertensive and normotensive.

Conclusion:

Postural instability is observed in hypertension, and posturography can be used as a routine screening tool to predict postural instability in hypertensives. Balance training exercise biofeedback protocols and the use of sensory augmentation devices may prove to be useful in improving postural stability.

The key role of muscle spindles in the pathogenesis of myofascial trigger points according to ramp-and-hold stretch and drug intervention in a rat model

This study investigated whether abnormal peak inversion spontaneous potentials (PISPs) recorded at resting myofascial trigger points (MTrPs) stem from the discharge of muscle spindles. Forty-eight male Sprague-Dawley rats were randomly divided into six groups. Five groups underwent MTrP modeling intervention, whereas one group did not receive intervention and was duly designated as the blank control. After model construction, five rat models were randomly subjected to ramp-and-hold stretch tests, succinylcholine injection, eperisone hydrochloride injection, saline injection, and blank drug intervention. By contrast, the rats in the blank control group were subjected to ramp-and-hold stretch tests as a control. Frequencies and amplitudes of PISPs were recorded pre- and post-interventions and compared with those of the blank group. Stretch tests showed that the depolarization time and amplitude of PISPs ranged from 0.4 ms to 0.9 ms and from 80 uV to 140 μV, respectively. However, no PISPs were observed in the control rats. The frequency of PISPs in the ramp and hold phases and the first second after the hold phase was higher than that before stretching (p < 0.01). Succinylcholine and eperisone exerted excitatory and inhibitory effects on PISPs, respectively. In the group injected with 0.9% saline, no considerable differences of the PISPs were observed during the entire observation period. In conclusion, PISPs recorded at resting MTrPs are closely related to muscle spindles. The formation of MTrPs may be an important factor that regulate dysfunctional muscle spindles.

Impact of lumbar delayed-onset muscle soreness on postural stability in standing postures

BACKGROUND

Similar impact on proprioception has been observed in participants with lumbar delayed-onset muscle soreness (DOMS) and chronic low back pain (LBP), raising questions about the relevance of lumbar DOMS as a suitable pain model for LBP when assessing back pain-related postural stability changes.

RESEARCH QUESTION

Does lumbar DOMS impact postural stability?

METHODS

Twenty healthy adults participated in this experimental study and underwent a posturographic examination before and 24 to 36 h after a protocol designed to induce lumbar DOMS. Posturographic examination was assessed during quiet standing on both feet with eyes opened (EO), with eyes closed (EC), and on one-leg (OL) standing with eyes opened. Postural stability was assessed through center of pressure (COP) parameters (COP area, velocity, root mean square, mean power frequency) which were compared using repeated measure ANOVA. Moreover, pain, soreness and pressure pain threshold (PPT) on specific muscles were assessed.

RESULTS

There was a significant main effect of the postural condition on all COP variables investigated. More specifically, each COP variable reached a significantly higher value in the OL stance condition than in both EO and EC bipedal conditions (all with p < 0.001). In addition, the COP velocity and the mean power frequency along the anteroposterior direction both reached a significantly higher value in EC than in EO (p < 0.001). In contrast, there was no significant main effect of the DOMS nor significant DOMS X postural condition interaction on any of the COP variables. There was a significant decrease in the PPT value for both the left and right erector spinae muscles, as well as the left biceps femoris.

SIGNIFICANCE

Lumbar DOMS had no impact on postural stability, which contrasts findings in participants with clinical LBP. Although DOMS induces similar trunk sensorimotor adaptations to clinical LBP, it does not appear to trigger similar postural stability adaptations.

Prevalence of Static Balance Impairment and Associated Factors of University Student Smartphone Users with Subclinical Neck Pain: Cross-Sectional Study

The aim of this study was to assess the prevalence of static balance impairment in university student smartphone users with subclinical neck pain and identify the associated risk factors. Because of rapid and widespread smartphones use, and the subsequent effect on neck pain in university students, it is essential to determine the prevalence of balance impairment and associated factors in this population. Simple random sampling was completed among eighty-one participants in this cross-sectional study. A self-reported questionnaire, fitted precisely for smartphone users, was used prior to clinical assessment by the Balance Error Scoring System. Both simple and multiple logistic regressions were used to analyze the prevalence of static balance impairment and associated factors. The prevalence of static balance impairment in university student smartphone users with subclinical neck pain was 74.07% (95% CI: 64.32 to 83.82). The significant risk factors were "daily smartphone use ≥ 4 h'' (AOR: 19.24 (95% CI 4.72 to 78.48) p = 0.000), "≥4 years of smartphone use" (AOR: 5.01 (95% CI 1.12 to 22.38) p = 0.035), and "≥7 neck disability index score'' (AOR: 12.91 (95% CI 2.24 to 74.45) p = 0.004). There was a high prevalence of static balance impairment in university smartphone users with subclinical neck pain. University student smartphone users with subclinical neck pain who met at least one of the risk factors should realize their static balance impairment.

A Comprehensive Review of Pain Interference on Postural Control: From Experimental to Chronic Pain

Motor control, movement impairment, and postural control recovery targeted in rehabilitation could be affected by pain. The main objective of this comprehensive review is to provide a synthesis of the effect of experimental and chronic pain on postural control throughout the available literature. After presenting the neurophysiological pathways of pain, we demonstrated that pain, preferentially localized in the lower back or in the leg induced postural control alteration. Although proprioceptive and cortical excitability seem modified with pain, spinal modulation assessment might provide a new understanding of the pain phenomenon related to postural control. The literature highlights that the motor control of trunk muscles in patient presenting with lower back pain could be dichotomized in two populations, where the first over-activates the trunk muscles, and the second under-activates the trunk muscles; both generate an increase in tissue loading. Taking all these findings into account will help clinician to provide adapted treatment for managing both pain and postural control.

A clinical study on the incidence of internal derangement of the temporomandibular joint following harvesting of temporalis fascia

OBJECTIVE

The aim of the current clinical study was to reveal whether harvesting of a temporalis fascia graft would be associated with a higher incidence of temporomandibular joint (TMJ) internal derangement.

METHODS

The study group involved 104 patients who had middle-ear operations, 67 of which involved harvesting of temporalis fascia and 37 that did not. The TMJs were clinically examined in each group.

RESULTS

The total incidence of internal derangement of the TMJ was significantly higher in the group that had temporalis fascia harvesting (79.1%), compared to the group that did not have temporalis fascia harvesting (29.7%), (p= 0.001).

CONCLUSION

Harvesting of temporalis fascia probably alters mandibular kinematics and predisposes to internal derangement of the TMJs.

Effects of experimental pain on the cervical spine reposition errors

BACKGROUND

Healthy subjects showed normal variance of cervical spine reposition errors of approximately 2 degrees. Effects of experimental pain on cervical spine reposition errors were unknown; thus, the purpose of this study was to investigate the effects of experimental pain on cervical spine reposition errors.

METHODS

A repeated measured study design was applied. Thirty healthy subjects (12 males) were recruited. Reposition errors were extracted from upright cervical positions before and after cervical flexion movement in healthy subjects before and during experimental neck pain. Cervical spine reposition errors were calculated based on anatomical landmarks of each cervical joint. Reposition errors were extracted in degrees as constant errors and absolute errors for further statistical analysis. Repeated measures analysis of variance (RM-ANOVA) was applied to analyse experimental pain effects on either constant errors or absolute errors of different cervical joints.

RESULTS

The cervical spine showed non-significant difference in reposition errors regarding the constant errors (P>0.05) while larger reposition errors regarding the absolute errors during experimental pain compared to before experimental pain (P<0.001). In addition, the pain level joint (C4/C5) and its adjacent joints (C3/C4 and C5/C6) indicated larger reposition errors regarding absolute errors (P=0.035, P=0.329 and P=0.103, respectively).

CONCLUSIONS

This study firstly investigated the cervical spine reposition errors in experimental neck pain and further found the joints adjacent to the pain level showed larger errors compared to the distant joints regarding absolute errors. It may imply that the larger reposition errors in specific cervical joint indicate probable injury or pain existed adjacent to the joints.

Comparison and correlation of cervical proprioception and muscle endurance in general joint hypermobility participants with and without non-specific neck pain-a cross-sectional study

Background

Cervical proprioception and muscle endurance are essential for maintaining cervical functional joint stability. Proprioception and muscle endurance may be impaired in those with general joint hypermobility (GJH). Examining these aspects is crucial. This study's aims are to (1) compare the cervical joint position error (JPE) and muscle endurance holding capacities in GJH individuals with and without non-specific neck pain (NSNP) (2) to assess the relationship between hypermobility Beighton scores, cervical JPE's, and muscle endurance in GJH individuals with and without NSNP.

Methods

In this cross-sectional comparative study, 33 GJH participants with NSNP (mean age 21.7 ± 1.8 years) and 35 asymptomatic participants GJH (mean age 22.42 ± 1.7 years) participated. Beighton's score of ≥4 of 9 tests was used as criteria to diagnose GJH. Cervical JPEs were estimated in degrees using a cervical range of motion device, and muscle endurance (flexor and extensor) were estimated in seconds using a stopwatch.

Results

GJH participants with NSNP showed significantly larger cervical JPEs (p < 0.001) and decreased muscle endurance holding times (p < 0.001) compared to asymptomatic participants. Beighton hypermobility scores showed a significant moderate positive correlation with cervical JPEs (flexion: r = 0.43, p = 0.013), left rotation: r = 0.47, p = 0.005, right rotation: r = 0.57, p = 0.001) in NSNP individuals. Also, Beighton hypermobility scores showed a moderate negative correlation with muscle endurance in NSNP (flexor muscles: r = -0.40, p = 0.020, extensor muscles: r = -0.41, p = 0.020, and asymptomatic individuals (flexor muscles: -0.34, p = 0.045, extensor muscles: r = -0.45, p = 0.007).

Conclusion

GJH individuals with NSNP showed increased cervical JPEs and reduced muscle endurance compared to asymptomatic. Individuals with GJH with higher Beighton scores demonstrated increased cervical JPEs and reduced neck muscle endurance holding ability. In clinical practice, therapists should be aware of these findings, incorporate proprioceptive and muscle endurance assessments, and formulate rehabilitation strategies for NSNP individuals with GJM.

A Study on the Relationship between Postural Control and Pain-Related Clinical Outcomes in Patients with Chronic Nonspecific Low Back Pain

Objectives

To explore the relationship between postural control and pain-related clinical outcomes in patients with chronic nonspecific low back pain (cNLBP).

Methods

Participants with cNLBP and healthy individuals were recruited. Muscle activities were recorded during internal and external perturbation tasks. Postural control capacity was assessed by muscle onset time and integrals of electromyography (iEMGs) of postural muscles during the phases of anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs). Correlation analysis was employed to investigate the relationship between postural control capacity, pain, and disability.

Results

Twenty-seven patients with cNLBP and 27 healthy participants were recruited. Gastrocnemius (GA) muscle onset time was earlier in the cNLBP group than in the control group in the internal perturbation task. The onset time of GA and erector spinae (ES) of the cNLBP group was later than that of the controls in the external perturbation task. Disability level moderately correlated with the iEMGs of rectus abdominis (RA), GA, and external oblique (EO) during APAs. Pain score moderately correlated with the iEMGs of RA, EO, and ES during CPAs of perturbation tasks.

Conclusion

cNLBP participants had altered muscle activation strategy to maintain postural stability in response to perturbation. This study further discovered that pain-related disabilities of cNLBP participants were likely related to the APAs capacity, whereas the pain intensity may relate to the CPAs capacity. Pain and disability may therefore be related to the control process of the posture-related muscles.

Impairments in grip and pinch force accuracy and steadiness in people with osteoarthritis of the hand: A case-control comparison

BACKGROUND

Symptomatic hand osteoarthritis (OA) is severely disabling condition. Limited evidence has focused on force control measures in this population.

OBJECTIVES

It was the aim of the present study to determine whether force matching accuracy and steadiness are impaired in people with hand OA. In addition, the relationship between force control measures (accuracy and steadiness) and measures of hand function and pain in people with symptomatic hand OA was explored.

DESIGN

Case-control study.

METHOD

Sixty-two participants with symptomatic hand OA and 26 healthy pain-free controls undertook an isometric grip and pinch force matching task at 50 % of their maximum voluntary contraction. Average pain hand pain was recorded. In addition, the Disability of the Arm Shoulder and Hand Questionnaire (DASH), and the Functional Index of Hand Osteoarthritis were collected.

RESULTS

Grip force-matching accuracy and steadiness were significantly impaired in the hand OA group compared to controls (P < 0.05). Pinch force-matching error was greater in people with hand OA (P < 0.05), however, pinch force steadiness was not different between groups. There was a learning effect in people with hand OA, with resolution of force matching impairments with task repetition. A small positive correlation was identified between grip force control and the DASH. No association was found between other measures of force control and self-reported measures of function or pain.

CONCLUSIONS

People with hand OA presented with greater impairments in measures of submaximal force control. These were correlated with self-reported hand function but not pain. Future studies may wish to examine whether objective measures of functional performance are related to force-matching error and steadiness.

Does piriformis muscle syndrome impair postural balance? A case control study

BACKGROUND AND PURPOSE

While patients with musculoskeletal disorders reported postural balance impairments, it is unknown whether patients with piriformis muscle syndrome (PMS) may exhibit postural balance disorders compared to controls. The aim was to compare postural balance in patients with PMS to controls in static and dynamic conditions.

MATERIAL AND METHODS

Twelve patients with PMS and twelve controls were enrolled. Static postural balance was assessed by calculating the symmetry index (SI) in the unipedal posture. To measure vision contribution, the Romberg index (RI) was computed. Dynamic postural balance was evaluated with the Timed up and go test (TUGT). Besides, inter-limb strength asymmetry (SA), pain and the short form-36 (SF-36) were assessed.

RESULTS

The PMS group (PMSG) exhibited significant (p < 0.001) higher SI in eyes opened (EO) and eyes closed (EC) conditions compared to the control group (CG). Besides, PMSG had significant higher RI (p < 0.05), TUGT scores (p < 0.001), SA values (p < 0.05), pain intensity (p < 0.001), and worse SF-36 scores on all physical health (p < 0.05) and psychological health (only in vitality and mental health [p < 0.05]), compared to CG.

CONCLUSION

Our data revealed impaired static and dynamic postural balance, and reduced quality of life in PMSG compared to CG. Postural balance impairments could explain the poor quality of life, which are likely due to the higher SA and higher pain intensity. Clinicians and physiotherapists should consider postural balance disorders while designing rehabilitation programs in these patients.

Dizziness and localized pain are often concurrent in patients with balance or psychological disorders

Background and aims Symptoms of dizziness and pain are both common complaints and the two symptoms often seem to coincide. When symptoms appear concomitant for sustained periods of time the symptoms might maintain and even exacerbate each other, sometimes leading to psychological distress. In order to evaluate such comorbidity we studied patients referred to a vestibular unit and to a psychiatric outpatient clinic with respectively balance disorders and psychological issues. Methods Consecutive patients referred to a vestibular unit (n = 49) and a psychiatric outpatient clinic (n = 62) answered the Dizziness Handicap Inventory (DHI) questionnaire and a questionnaire detailing occurrence of dizziness and pain. Results The experience of dizziness and pain often coincided within individuals across both clinical populations, especially if the pain was located to the neck/shoulder or the back (p = 0.006). Patients who reported dizziness had significantly more often pain (p = 0.024); in the head (p = 0.002), neck/shoulders (p = 0.003) and feet (p = 0.043). Moreover, patients who reported dizziness stated significantly higher scoring on emotional (p < 0.001) and functional (p < 0.001) DHI sub-scales. Furthermore, patients who reported an accident in their history suffered significantly more often from dizziness (p = 0.039) and pain (p < 0.001); in the head (p < 0.001), neck/shoulders (p < 0.001) and arms (p = 0.045) and they scored higher on the emotional (p = 0.004) and functional (p = 0.002) DHI sub-scales. Conclusions The findings suggest comorbidity to exist between dizziness and neck/shoulder or back pain in patients seeking health care for balance disorders or psychological issues. Patients suffering from dizziness and pain, or with both symptoms, also reported higher emotional and functional strain. Thus, healthcare professionals should consider comorbidity when determining diagnosis and consequent measures. Implications Clinicians need to have a broader "receptive scope" in both history and clinical examinations, and ask for all symptoms. Although the patients in this study visited a vestibular unit respectively a psychological clinic, they commonly reported pain conditions when explicitly asked for this symptom. A multimodal approach is thus to favor, especially when the symptoms persist, for the best clinical management.

Short-term effects of spinal thrust joint manipulation on postural sway in patients with chronic mechanical neck pain: a randomized controlled trial

PURPOSE

Our aim was to compare the efficacy of spinal manipulation of the upper cervical spine (C1-C2) on postural sway in patients with chronic mechanical neck pain with the application of a combination of cervical (C3-C4), cervicothoracic (C7-T1) and thoracic spine (T5-T6) thrust joint manipulation.

METHODS

One hundred eighty-six (n = 186) individuals with chronic mechanical neck pain were randomised to receive an upper cervical spine manipulation (n = 93) or three different spinal manipulation techniques applied to the cervical spine, cervicothoracic joint and thoracic spine (n = 93). Measures included the assessment of stabilometric parameters using the Medicapteurs S-Plate platform. Secondarily, neck pain was analysed using the Numeric Pain Rating Scale.

RESULTS

We observe a decrease in the length of the centre of pressure path, average speed, medio-lateral and antero-posterior displacement with statistically significant results (p < 0.05) in the upper cervical manipulation group. Both interventions are equally effective in reducing neck pain after fifteen days (p < 0.001).

CONCLUSION

The application of upper cervical thrust joint manipulation is more effective in improving stabilometric parameters in patients with chronic mechanical neck pain. Trial registration: The study was registered in the Australian and New Zealand Clinical Trial Registry (no. ACTRN12619000546156).Implications for rehabilitationPatients who suffer from neck pain exhibit increased postural sway than asymptomatic subjects.Both spinal manipulation treatments applied in this study are equally effective in reducing neck pain.Spinal manipulation treatment on the upper cervical spine improves postural stability parameters.

Multimodal Sensory Stimulation of the Masseter Muscle Reduced Precision but Not Accuracy of Jaw-Opening Movements

A functional integration between the trigeminal and craniocervical sensorimotor systems has been demonstrated, with simultaneous jaw and head–neck movements during jaw opening–closing. We previously showed that pain induction in the masseter muscle increased the relative contribution of the neck component of integrated jaw–neck movements. Induced pain or manipulation of proprioception by vibration did not affect accuracy during a jaw-opening task in men. It is not known how multimodal sensory stimulation, with a combination of pain induction and vibration, affects jaw-opening accuracy and precision. The aim was to investigate how jaw–neck movements, and specifically accuracy and precision of jaw-opening, are affected during concomitant nociceptive and proprioceptive stimulation of the masseter muscle. Twenty-one healthy men performed jaw-opening to a target position, defined as 75% of individual maximum jaw opening, during control (Ctr), vibration of masseter muscles (Vib), pain induction in the masseter (Pain), and concomitant vibration and pain induction in the masseter muscle (VibPain). Simultaneous jaw and head movements were recorded with an optoelectronic system and amplitudes calculated for each jaw opening–closing cycle. Accuracy of jaw movements was defined as the achievement of the target position. Precision of jaw movements was defined as the cycle-to-cycle variability from the mean of cycles 2–10 (coefficient of variation, CV). Differences between the trials were analyzed with Friedman’s test, Dunn’s test, and Benjamini–Hochberg correction. There were no significant differences between the trials for jaw movement amplitudes. For head movements, amplitudes for cycles 2–10 were larger during Pain compared to Ctr and Vib (both p = 0.034), and larger during VibPain compared to Ctr (p = 0.034) and Vib (p = 0.035). There were no differences in accuracy of jaw movements between the trials. For precision of jaw movements, the cycle-to-cycle variability was larger during VibPain compared to Ctr (p = 0.027) and Vib (p = 0.018). For integrated jaw–neck motor strategy, there was a difference between pain and non-pain trials, but no differences between unimodal and multimodal stimulation trials. For achievement of jaw-opening to a target position, the results show no effect on accuracy, but a reduced precision of jaw movements during combined proprioceptive and nociceptive multimodal stimulation.

Cervical proprioception and its relationship with neck pain intensity in subjects with cervical spondylosis

Background

Cervical proprioception is critical in the maintenance of posture and movements, so its assessment in different cervical conditions has gained importance in recent clinical practice. Studies reporting this assessment in subjects with cervical spondylosis (CS) have not previously been investigated. The goals of the study are (1) comparison of joint position error (JPE) in subjects with CS to healthy control group. (2) Correlation of neck pain intensity to cervical proprioception in patients with CS.

Methods

In a Cross-sectional study, 132 subjects with CS and 132 healthy age-matched control subjects were evaluated for cervical JPE with the cervical range of motion device. The subjects were blindfolded and repositioned their heads to a target position, which was determined by the examiner previously and their repositioning accuracy (absolute error in degrees) was measured in the frontal (flexion and extension) and transverse planes (left rotation and right rotation). The CS subjects resting neck pain intensity was assessed using visual analog scale (VAS).

Results

CS subjects showed statistically significantly larger JPEs compared to healthy control subjects in all the directions tested (flexion - 95% CI = 2.38–3.55, p < 0.001, extension - 95% CI =3.26–4.33, p < 0.001, left rotation - 95% CI = 2.64 - 3.83, p < 0.001, right rotation − 95% CI = 3.77–4.76, p < 0.001). The mean JPE errors in the CS group ranged from 6.27° to 8.28° and in the control group ranged from 2.36° to 4.48°. Pearson’s correlation coefficient showed a significant and positive relationship between neck pain intensity and cervical proprioception (p ≤ 0.001).

Conclusions

Proprioception is impaired in subjects with CS when compared to healthy control group. Higher pain intensity was associated with greater cervical JPE in patients with CS.

Changes in Knee Vastii Muscle Activity in Women with Patellofemoral Pain Syndrome During the Menstrual Cycle

BACKGROUND

Changes in hormonal levels during the menstrual cycle are known to affect muscle electromyographic (EMG) activity, but no studies have investigated the effect of hormonal changes on the EMG activity of muscles around the knee in patients with patellofemoral pain syndrome (PFPS).

OBJECTIVE

To evaluate the EMG activity of the vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles during toe rise and heel rock tasks in different phases of the menstrual cycle in women with PFPS.

DESIGN

Cross sectional study.

SETTING

Rehabilitation Research Center at the School of Rehabilitation Sciences of Shiraz University of Medical Sciences.

PARTICIPANTS

Ten women with PFPS between 18 and 40 years of age.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

The VL/VMO amplitude ratio and differences between onset (onset VL-onset VMO) of vastii muscle activity were measured in the affected limb during rise and rock tasks in the follicular and ovulatory phases of the menstrual cycle. The signals were analyzed with MATLAB software.

RESULTS

During both tasks, there were no significant changes in onset differences in vastii muscles between the ovulatory and follicular phases. However, the amplitude ratio (VL/VMO) was significantly lower in the ovulatory phase compared to the follicular phase (P = .035 for rise tasks and .010 for rock tasks).

CONCLUSION

The menstrual cycle may affect some EMG parameters. These factors can be taken into account when planning sports and rehabilitation training programs.

Postural control in subclinical neck pain: a comparative study on the effect of pain and measurement procedures

BACKGROUND AND AIMS

This study investigated whether young university students with neck pain (NP) have postural control deficits when compared to sex and age-matched asymptomatic subjects.

METHODS

Centre of pressure (COP) sway area, velocity, anterior-posterior and mediolateral distances were measured in participants with (n=27) and without (n=27) neck pain for different combinations of static standing (narrow stance, tandem stance and single leg stance) and measurement time (90, 60, 30 and 15 s) with eyes closed using a force plate. Additionally, static and dynamic clinical tests of postural control were used.

RESULTS

No significant between group differences were found for the COP measurements (p>0.05). However, individuals with subclinical NP were more likely to fail the 90 s tandem test (p<0.05) in the force plate and univariate comparisons revealed significant between group differences in the tandem and single leg stance clinical test measurements.

CONCLUSIONS

Taken together, the inconsistent results might suggest an emerging postural control deficit in university students with low disability and low intensity chronic idiopathic NP.

Motor impairment in patients with chronic neck pain: does the traumatic event play a significant role? A case-control study

BACKGROUND CONTEXT

Motor impairment is a key sign in patients with traumatic (whiplash-associated disorder [WAD]) and non-traumatic (idiopathic neck pain [INP]) neck pain.

PURPOSE

This study aimed to analyze differences in motor impairment between two patient groups and to assess the association between motor performance and self-reported symptoms.

STUDY DESIGN

This is a case-control study.

PATIENT SAMPLE

A total of 38 patients with chronic INP, 35 patients with chronic WAD, and 30 healthy pain-free controls were included in the study.

OUTCOME MEASURES

Outcome measures used in this study were mobility (°), strength (N), repositioning accuracy (°), endurance (seconds), sway velocity (cm/s), sway area (cm²), and neuromuscular control.

METHODS

Group differences of motor impairment, together with questionnaires to evaluate pain intensity, fear avoidance, pain catastrophizing, symptoms of central sensitization, and disability, were analyzed with analysis of covariance, including age as a covariate.

RESULTS

Motor impairment was observed in both patient groups with a higher degree in patients with chronic WAD. These impairments were moderately linked to self-reported disability and were in most cases associated with pain, fear avoidance, and symptoms of central sensitization (|ρ| ranging from 0.28 to 0.59).

CONCLUSIONS

Motor impairment should be addressed when treating both groups of patients, keeping in mind the association with self-reported pain and disability, fear-avoidance, and central sensitization.

Effects of lumbosacral orthoses on postural control in individuals with or without non-specific low back pain

OBJECTIVE

To investigate the effect of lumbosacral orthoses (LSOs) on postural control in individuals with or without non-specific low back pain (NSLBP).

METHODS

Individuals with NSLBP (n = 28) and healthy controls (n = 28) were enrolled to assess the postural control with or without LSOs. Postural control was tested using the Balance Master^® NeuroCom system by the modified clinical test of sensory interaction and balance.

RESULTS

Relative to controls, patients with NSLBP had deficits in postural control with greater center of pressure (COP) sway velocity when standing on firm surface (with eyes open: p = 0.002; with eyes closed: p = 0.002) and standing on foam surface (with eyes open: p = 0.024; with eyes closed: p < 0.001). In the braced condition, the COP sway decreased in all subjects with or without NSLBP when standing on foam surface. There was no significant difference in the effect of LSOs on postural control between NSLBP group and healthy controls.

CONCLUSION

Individuals with NSLBP have poorer postural control than controls. LSOs seem to improve postural control when standing on unstable surfaces in subjects with or without NSLBP. The effect of LSOs on postural control may not depend on the level of baseline.

Effects of Prolonged and Acute Muscle Pain on the Force Control Strategy During Isometric Contractions

Musculoskeletal pain is associated with multiple adaptions in movement control. This study aimed to determine whether changes in movement control acquired during acute pain are maintained over days of pain exposure. On day 0, the extensor carpi radialis brevis muscle of healthy participants was injected with nerve growth factor (NGF) to induce persistent movement-evoked pain (n = 13) or isotonic saline as a control (n = 13). On day 2, short-lasting pain was induced by injection of hypertonic saline into extensor carpi radialis brevis muscles of all participants. Three-dimensional force components were recorded during submaximal isometric wrist extensions on day 0, day 4, and before, during, and after saline-induced pain on day 2. Standard deviation (variation of task-related force) and total excursion of center of pressure (variation of force direction) were assessed. Maximal movement-evoked pain was 3.3 ± .4 (0-10 numeric scale) in the NGF-group on day 2 whereas maximum saline-induced pain was 6.8 ± .3 cm (10-cm visual analog scale). The difference in centroid position of force direction relative to day 0 was greater in the NGF group than in the control group (P < .05) on day 2 (before saline-induced pain) and day 4, reflecting changes in tangential force direction used to achieve the task. During saline-induced pain in both groups, tangential and task-related force variation was greater than before and after saline-induced pain (P < .05).

PERSPECTIVE

Persistent movement-evoked pain changes force direction from the pain-free direction. Acute pain leads to increased variation in force direction irrespective of persistent movement-evoked pain preceding the acutely painful event. These differences provide novel insight into the search for and consolidation of new motor strategies in the presence of pain.

Is There a Relationship Between Lumbar Proprioception and Low Back Pain? A Systematic Review With Meta-Analysis

OBJECTIVE

To systematically review the relationship between lumbar proprioception and low back pain (LBP).

DATA SOURCES

Four electronic databases (PubMed, EMBASE, CINAHL, SPORTDiscus) and reference lists of relevant articles were searched from inception to March-April 2014.

STUDY SELECTION

Studies compared lumbar proprioception in patients with LBP with controls or prospectively evaluated the relationship between proprioception and LBP. Two reviewers independently screened articles and determined inclusion through consensus.

DATA EXTRACTION

Data extraction and methodologic quality assessment were independently performed using standardized checklists.

DATA SYNTHESIS

Twenty-two studies (1203 participants) were included. Studies measured lumbar proprioception via active or passive joint repositioning sense (JRS) or threshold to detection of passive motion (TTDPM). Data from 17 studies were pooled for meta-analyses to compare patients with controls. Otherwise, descriptive syntheses were performed. Data were analyzed according to measurement method and LBP subgroup. Active JRS was worse in patients compared with controls when measured in sitting (standard mean difference, .97; 95% confidence interval [CI], .31-1.64). There were no differences between groups measured via active JRS in standing (standard mean difference, .41; 95% CI, -.07 to .89) or passive JRS in sitting (standard mean difference, .38; 95% CI, -.83 to 1.58). Patients in the O'Sullivan flexion impairment subgroup had worse proprioception than the total LBP cohort. The TTDPM was significantly worse in patients than controls. One prospective study found no link between lumbar proprioception and LBP.

CONCLUSIONS

Patients with LBP have impaired lumbar proprioception compared with controls when measured actively in sitting positions (particularly those in the O'Sullivan flexion impairment subgroup) or via TTDPM. Clinicians should consider the relationship between sitting and proprioception in LBP and subgroup patients to guide management. Further studies focusing on subgroups, longitudinal assessment, and improving proprioception measurement are needed.

Proprioceptive use and sit-to-stand-to-sit after lumbar microdiscectomy: The effect of surgical approach and early physiotherapy

BACKGROUND

Individuals with non-specific low back pain show decreased reliance on lumbosacral proprioceptive signals and slower sit-to-stand-to-sit performance. However, little is known in patients after lumbar microdiscectomy.

METHODS

Patients were randomly assigned into transmuscular (n=12) or paramedian lumbar surgery (n=13). After surgery, the same patients were randomly assigned into individualized active physiotherapy starting 2 weeks after surgery (n=12) or usual care (n=13). Primary outcomes were center of pressure displacement during ankle and back muscles vibration (to evaluate proprioceptive use), and the duration of five sit-to-stand-to-sit movements, evaluated at 2 (baseline), 8 and 24 weeks after surgery.

FINDINGS

Two weeks after surgery, all patients showed smaller responses to back compared to ankle muscles vibration (P<0.05). Patients that underwent a transmuscular surgical procedure and patients that received physiotherapy switched to larger responses to back muscles vibration at 24 weeks, compared to 2 weeks after surgery (P<0.005), although not seen in the paramedian group and usual care group (P>0.05). Already 8 weeks after surgery, the physiotherapy group needed significantly less time to perform five sit-to-stand-to-sit movements compared to the usual care group (P<0.05).

INTERPRETATION

Shortly after lumbar microdiscectomy, patients favor reliance on ankle proprioceptive signals over lumbosacral proprioceptive reliance to maintain posture, which resembles the behavior of patients with non-specific low back pain. However, early active physiotherapy after lumbar microdiscectomy facilitated higher reliance on lumbosacral proprioceptive signals and early improvement of sit-to-stand-to-sit performance. Transmuscular lumbar surgery favoured recovery of lumbosacral proprioception 6 months after surgery.

CLINICAL TRIAL NUMBER

NCT01505595.

Can pain influence the proprioception and the motor behavior in subjects with mild and moderate knee osteoarthritis?

Background

Osteoarthritis (OA) is a chronic disease, usually characterized by pain, which is associated with reduced muscle strength, disability and progressive loss of function. However, the pain influence over proprioception and motor behaviour remains unclear. Thus, the purpose of the study was to identify the levels of pain, the proprioceptive acuity and the pattern of muscle recruitment during stair ascent and descent in elderly patients with mild and moderate osteoarthritis (OA) compared to healthy subjects.

Methods

The study participants included 11 healthy elderly subjects (7 women and 4 men) and 31 elderly patients with knee OA (19 women and 12 men). The functional capacity was assessed by the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index; the pain was evaluated by Wong-Baker faces pain rating scale (WBS) and pressure pain threshold (PPT); the proprioceptive acuity was based on the joint position sense evaluated by electrogoniometer; and the electromyographic (EMG) activity of the major muscles of the lower limb were evaluated during a task of stair ascent and descent of 15 cm. For statistical analysis it was used Statistic for Windows software (StatSoft Inc., version 5.0). Data from the WOMAC index, WBS, the proprioceptive acuity and IEMG (for each muscle in each phase) were analyzed using the Mann–Whitney U test and data from PPT was used Kruskal-Wallis test.

Results

Higher scores were found in the WOMAC index and WBS whereas lower scores were seen in PPT in patients with knee OA compared to healthy subjects. In contrast, there were no significant differences in the proprioceptive acuity and EMG results of most muscles analyzed between the groups.

Conclusion

The presence of pain does not influence the proprioception and the motor behavior of the thigh muscles during stair ascent and descent in subjects with mild and moderate knee OA.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-321) contains supplementary material, which is available to authorized users.

The effect of experimentally-induced subacromial pain on proprioception

Shoulder injuries may be associated with proprioceptive deficits, however, it is unknown whether these changes are due to the experience of pain, tissue damage, or a combination of these. The aim of this study was to investigate the effect of experimentally-induced sub-acromial pain on proprioceptive variables. Sub-acromial pain was induced via hypertonic saline injection in 20 healthy participants. Passive joint replication (PJR) and threshold to detection of movement direction (TTDMD) were assessed with a Biodex System 3 Pro isokinetic dynamometer for baseline control, experimental pain and recovery control conditions with a starting position of 60° shoulder abduction. The target angle for PJR was 60° external rotation, starting from 40°. TTDMD was tested from a position of 20° external rotation. Repeated measures ANOVAs were used to determine differences between PJR absolute and variable errors and TTDMD for the control and experimental conditions. Pain was elicited with a median 7 on the Numeric Pain Rating Scale. TTDMD was significantly decreased for the experimental pain condition compared to baseline and recovery conditions (≈30%, P = 0.003). No significant differences were found for absolute (P = 0.152) and variable (P = 0.514) error for PJR. Movement sense was enhanced for the experimental sub-acromial pain condition, which may reflect protective effects of the central nervous system in response to the pain. Where decreased passive proprioception is observed in shoulders with injuries, these may be due to a combination of peripheral tissue injury and neural adaptations that differ from those due to acute pain.

Postural control in individuals with and without non-specific chronic low back pain: a preliminary case-control study

STUDY DESIGN

A preliminary case-control study.

OBJECTIVE

To assess postural control in individuals with and without non-specific chronic low back pain (cLBP) during quiet standing. cLBP affects 12-33 % of the adult population. Reasons for pain chronicity are yet poorly known. Change in postural control may be a risk factor for cLBP, although available studies are not conclusive.

METHODS

Sample consisted of 21 individuals with cLBP and 23 controls without cLBP. Balance was assessed using a force plate (Balance Master, NeuroCom) by the modified clinical test of sensory interaction and balance, pain severity by the visual analogue scale, quality of life with the SF-36 Questionnaire, and functional disability with the Roland-Morris Questionnaire.

RESULTS

Groups were homogeneous for age, weight, height and body mass index. Relative to controls, participants in the cLBP group had deficits in the postural control, with greater postural sway in the quiet standing condition with closed eyes closed on unstable surfaces (p < 0.05) for the following parameters: total COP oscillation [cLBP 1,432.82 (73.27) vs CG 1,187.77 (60.30)], root mean square sagittal plane [cLBP 1.21 (0.06) vs CG 1.04 (0.04)], COP area [cLBP 24.27 (2.47) vs CG 16.45 (1.79)] and mean speed of oscillation [cLBP 12.97 (0.84) vs CG 10.55 (0.70)].

CONCLUSION

Postural control, as evidenced by increased oscillation of COP, is impaired in individuals with cLBP relative to controls. Differences are magnified by visual deprivation and unstable surface conditions.

Does knee joint proprioception alter following medial patellofemoral ligament reconstruction?

BACKGROUND

This study firstly aimed to determine whether proprioception deficits, as measured by joint position sense (JPS), occur in people following recurrent patellar dislocations. Secondly, to determine whether JPS changes following medial patellofemoral ligament reconstruction (MPFL) reconstruction for patellar instability.

METHODS

Thirty people following recurrent patellar dislocation were recruited. Pre-operative JPS was assessed using the passive angle reproduction test. Through this, an assessor moved a participant's limb to a target position. This was returned to neutral, before finally moving the limb again, whilst requiring the participant to indicate when they thought the target angle was reached. The actual angular error (AAE) was calculated as the difference between the perceived angle and target angle. Clinical outcomes included the Kujala Patellofemoral Disorder Score, the International Knee Documentation Committee (IKDC) form, pain, knee motion, extensor muscle strength and frequency of patellar dislocation. Outcomes were assessed pre-operative, 6 weeks, 3 and 12 months.

RESULTS

Mean AAE was 2.2° (inner range) to 3.9° (mid-range); this was not clinically significant. There was no statistically significant difference between the baseline-and-6 week, 6 week-and-3 month or baseline-and-12 month AAE measures (p=0.38 to 1.00). There was a statistically significant improvement in functional outcomes as measured by the Kujala score, IKDC form, reduced pain and increased extension strength from baseline to 12 months (p<0.01).

CONCLUSIONS

Following recurrent patellar dislocation, patients exhibit minimal deficits in JPS. Whilst MPFL reconstruction significantly improved clinical and functional outcomes for this population, this operation did not significantly alter JPS during the first post-operative year.

Balance ability and postural stability among patients with painful shoulder disorders and healthy controls

Background

In therapeutic settings, patients with shoulder pain often exhibit deficient coordinative abilities in their trunk and lower extremities. The aim of the study was to investigate 1) if there is a connection between shoulder pain and deficits in balance ability and postural stability, 2) if pain intensity is related to balance ability and postural stability, and 3) if there is a connection between body mass index (BMI) and balance ability and postural stability.

Methods

In this case–control study, patients (n = 40) with pathological shoulder pain (> 4 months) were matched with a healthy controls (n = 40) and were compared with regard to their balance ability and postural stability. Outcome parameters were postural stability, balance ability and symmetry index which were measured using the S3-Check system. In addition, the influence of shoulder pain intensity and BMI on the outcome parameters was analysed.

Results

Patients with shoulder pain showed significantly worse results in measurements of postural stability right/left (p < 0.01) and front/back (p < 0.01) as well as balance ability right/left (p = 0.01) and front/back (p < 0.01) compared to healthy controls. There were no significant group differences with regard to symmetry index. However, there was a significant (p < 0.01) symmetry shift towards the affected side within the shoulder pain group. There was no correlation between pain intensity and measurements of balance ability or postural stability. Likewise, no correlation between BMI and deficiencies in balance ability and postural stability was established.

Conclusions

Patients with pathological shoulder pain (> 4 months) have deficiencies in balance ability and postural stability; however the underlying mechanisms for this remain unclear. Neither pain intensity nor BMI influenced the outcome parameters. Patients with shoulder pain shift their weight to the affected side. Further research is needed to determine if balance training can improve rehabilitation results in patients with shoulder pathologies.

Experimentally induced deep cervical muscle pain distorts head on trunk orientation

PURPOSE

We wanted to explore the specific proprioceptive effect of cervical pain on sensorimotor control. Sensorimotor control comprises proprioceptive feedback, central integration and subsequent muscular response. Pain might be one cause of previously reported disturbances in joint kinematics, head on trunk orientation and postural control. However, the causal relationship between the impact of cervical pain on proprioception and thus on sensorimotor control has to be established.

METHODS

Eleven healthy subjects were examined in their ability to reproduce two different head on trunk targets, neutral head position (NHP) and 30° target position, with a 3D motion analyser before, directly after and 15 min after experimentally induced neck pain. Pain was induced by hypertonic saline infusion at C2/3 level in the splenius capitis muscle on one side (referred to as "injected side").

RESULTS

All subjects experienced temporary pain and the head repositioning error increased significantly during head repositioning to the 30° target to the injected side (p = 0.011). A post hoc analysis showed that pain interfered with proprioception to the injected side during acute pain (p < 0.001), but also when the pain had waned (p = 0.002). Accuracy decreased immediately after pain induction for the 30° target position to the side where pain was induced (3.3 → 5.3°, p = 0.033), but not to the contralateral side (4.9 → 4.1°, p = 0.657). There was no significant impact of pain on accuracy for NHP. A sensory mismatch appeared in some subjects, who experienced dizziness.

CONCLUSIONS

Acute cervical pain distorts sensorimotor control with side-specific changes, but also has more complex effects that appear when pain has waned.

Nociception affects motor output: a review on sensory-motor interaction with focus on clinical implications

OBJECTIVES

Research has provided us with an increased understanding of nociception-motor interaction. Nociception-motor interaction is most often processed without conscious thoughts. Hence, in many cases neither patients nor clinicians are aware of the interaction. It is aimed at reviewing the scientific literature on nociception-motor interaction, with emphasis on clinical implications.

METHODS

Narrative review.

RESULTS

Chronic nociceptive stimuli result in cortical relay of the motor output in humans, and a reduced activity of the painful muscle. Nociception-induced motor inhibition might prevent effective motor retraining. In addition, the sympathetic nervous system responds to chronic nociception with enhanced sympathetic activation. Not only motor and sympathetic output pathways are affected by nociceptive input, afferent pathways (proprioception, somatosensory processing) are influenced by tonic muscle nociception as well.

DISCUSSION

The clinical consequence of the shift in thinking is to stop trying to restore normal motor control in case of chronic nociception. Activation of central nociceptive inhibitory mechanisms, by decreasing nociceptive input, might address nociception-motor interactions.

Standing balance in patients with whiplash-associated neck pain and idiopathic neck pain when compared with asymptomatic participants: A systematic review

Neck proprioception is one of the information sources that helps regulate postural balance. However, it is believed to be impaired as patients with both idiopathic neck pain (INP) and whiplash-associated disorders (WAD) have been shown to have a more unstable balance than healthy controls. This systematic review aims to determine if there are significant differences in balance between patients with INP and healthy controls and between patients with WAD and healthy controls. Studies were sought from PubMed, Cinahl, Physiotherapy Evidence Database, Web of Science, Academic Search Complete, Science Direct, and Scielo. Two reviewers independently screened titles and abstracts, assessed full reports for potentially eligible studies, and extracted information on participants' characteristics, pain characteristics, study methods, study results, and study quality. Twelve studies were included in this systematic review. Of these, six compared INP and healthy controls and eight compared WAD and healthy controls. All but one study (11/12) found a statistically significant difference for at least one measurement between patients with INP and WAD and healthy controls. The results of this systematic review suggest that both patients with INP and patients with WAD have poorer balance than healthy controls.

Pain relief is associated with decreasing postural sway in patients with non-specific low back pain

Background

Increased postural sway is well documented in patients suffering from non-specific low back pain, whereby a linear relationship between higher pain intensities and increasing postural sway has been described. No investigation has been conducted to evaluate whether this relationship is maintained if pain levels change in adults with non-specific low back pain.

Methods

Thirty-eight patients with non-specific low back pain and a matching number of healthy controls were enrolled. Postural sway was measured by three identical static bipedal standing tasks of 90 sec duration with eyes closed in narrow stance on a firm surface. The perceived pain intensity was assessed by a numeric rating scale (NRS-11). The patients received three manual interventions (e.g. manipulation, mobilization or soft tissue techniques) at 3-4 day intervals, postural sway measures were obtained at each occasion.

Results

A clinically relevant decrease of four NRS scores in associated with manual interventions correlated with a significant decrease in postural sway. In contrast, if no clinically relevant change in intensity occurred (≤ 1 level), postural sway remained similar compared to baseline. The postural sway measures obtained at follow-up sessions 2 and 3 associated with specific NRS level showed no significant differences compared to reference values for the same pain score.

Conclusions

Alterations in self-reported pain intensities are closely related to changes in postural sway. The previously reported linear relationship between the two variables is maintained as pain levels change. Pain interference appears responsible for the altered sway in pain sufferers. This underlines the clinical use of sway measures as an objective monitoring tool during treatment or rehabilitation.

Is there a relationship between pain intensity and postural sway in patients with non-specific low back pain?

Background

Increased center of pressure excursions are well documented in patients suffering from non-specific low back pain, whereby the altered postural sway includes both higher mean sway velocities and larger sway area. No investigation has been conducted to evaluate a relationship between pain intensity and postural sway in adults (aged 50 or less) with non-specific low back pain.

Methods

Seventy-seven patients with non-specific low back pain and a matching number of healthy controls were enrolled. Center of pressure parameters were measured by three static bipedal standing tasks of 90 sec duration with eyes closed in narrow stance on a firm surface. The perceived pain intensity was assessed by a numeric rating scale (NRS-11), an equal number of patients (n = 11) was enrolled per pain score.

Results

Generally, our results confirmed increased postural instability in pain sufferers compared to healthy controls. In addition, regression analysis revealed a significant and linear increase in postural sway with higher pain ratings for all included COP parameters. Statistically significant changes in mean sway velocity in antero-posterior and medio-lateral direction and sway area were reached with an incremental change in NRS scores of two to three points.

Conclusions

COP mean velocity and sway area are closely related to self-reported pain scores. This relationship may be of clinical use as an objective monitoring tool for patients under treatment or rehabilitation.

Altered postural sway in patients suffering from non-specific neck pain and whiplash associated disorder - A systematic review of the literature

Study design

Systematic literature review.

Objectives

To assess differences in center of pressure (COP) measures in patients suffering from non-specific neck pain (NSNP) or whiplash-associated disorder (WAD) compared to healthy controls and any relationship between changes in postural sway and the presence of pain, its intensity, previous pain duration and the perceived level of disability.

Summary of Background data

Over the past 20 years, the center of pressure (COP) has been commonly used as an index of postural stability in standing. While several studies investigated COP excursions in neck pain and WAD patients and compared these to healthy individuals, no comprehensive analysis of the reported differences in postural sway pattern exists.

Search methods

Six online databases were systematically searched followed by a manual search of the retrieved papers.

Selection Criteria

Papers comparing COP measures derived from bipedal static task conditions on a force plate of people with NSNP and WAD to those of healthy controls.

Data collection and analysis

Two reviewers independently screened titles and abstracts for relevance. Screening for final inclusion, data extraction and quality assessment were carried out with a third reviewer to reconcile differences.

Results

Ten papers met the inclusion criteria. Heterogeneity in study designs prevented pooling of the data and no direct comparison of data across the studies was possible. Instead, a qualitative data analysis was conducted. There was broad consensus that patients with either type of neck pain have increased COP excursions compared to healthy individuals, a difference that was more pronounced in people with WAD. An increased sway in antero-posterior direction was observed in both groups.

Conclusions

Patients with neck pain (due to either NSNP or WAD) exhibit greater postural instability than healthy controls, signified by greater COP excursions irrespective of the COP parameter chosen. Further, the decreased postural stability in people with neck pain appears to be associated with the presence of pain and correlates with the extent of proprioceptive impairment, but appears unrelated to pain duration.

Avaliação dos distúrbios do controle sensório-motor em pessoas com dor cervical mecânica: uma revisão

INTRODUÇÃO: A dor cervical mecânica é problema comum na população em geral e engloba a dor cervical aguda, as lesões em chicote, as disfunções cervicais e a dor cervical-ombro. A limitação da amplitude de movimento, a sensação de aumento da tensão muscular, a cefaleia, a braquialgia, a vertigem e outros sinais e sintomas são manifestações comuns e podem ser agravados por movimentos ou pela manutenção de posturas da coluna cervical. Estudos recentes mostram comprometimento no controle sensório-motor em pessoas com dor cervical manifestando-se por alterações da cinestesia cervical com dificuldade no reconhecimento da posição da cabeça, do movimento dos olhos e do equilíbrio. OBJETIVOS: Descrever, com base na revisão da literatura, as manifestações e os métodos de avaliação dos distúrbios sensório-motores relacionados à dor cervical mecânica. MÉTODOS: Para a revisão foram utilizadas as bases de dados de literatura científica indexada no período de 1965 a 2009. Considerou-se para a inclusão os artigos que abordassem a dor cervical mecânica e os distúrbios da propriocepção cervical, da coordenação dos movimentos dos olhos e do equilíbrio. Não houve restrição quanto à língua de publicação. O processo de seleção foi realizado por dois examinadores independentes, considerando a evidência científica em ordem decrescente, havendo preferência para as meta-análises e os estudos randomizados controlados. RESULTADOS: Dos 119 artigos encontrados, 69 preenchiam os critérios de inclusão. DISCUSSÃO: A presença de alterações dos músculos e das articulações cervicais, o processo de envelhecimento e a presença de dor cervical são descritos como fatores que alteram o sistema somatossensorial cervical e devem ser considerados também como perpetuantes. CONCLUSÃO: As alterações dos sistemas visual, do equilíbrio e proprioceptivo não podem ser desprezadas e devem ser consideradas durante a avaliação fisioterapêutica dos distúrbios cervicais, visto que existe uma integração entre os sistemas.

Center of pressure excursion as a measure of balance performance in patients with non-specific low back pain compared to healthy controls: a systematic review of the literature

Over the past 20 years, the center of pressure (COP) has been commonly used as an index of postural stability in standing. While many studies investigated COP excursions in low back pain patients and healthy individuals, no comprehensive analysis of the reported differences in postural sway pattern exists. Six online databases were systematically searched followed by a manual search of the retrieved papers. The selection criteria comprised papers comparing COP measures derived from bipedal static task conditions on a force-plate of non-specific low back pain (NSLBP) sufferers to those of healthy controls. Sixteen papers met the inclusion criteria. Heterogeneity in study designs prevented pooling of the data so only a qualitative data analysis was conducted. The majority of the papers (14/16, 88%) concluded that NSLBP patients have increased COP mean velocity and overall excursion as compared to healthy individuals. This was statistically significant in the majority of studies (11/14, 79%). An increased sway in anteroposterior direction was also observed in NSLBP patients. Patients with NSLBP exhibit greater postural instability than healthy controls, signified by greater COP excursions and a higher mean velocity. While the decreased postural stability in NSLBP sufferers further appears to be associated with the presence of pain, it seems unrelated to the exact location and pain duration. No correlation between the pain intensity and the magnitude of COP excursions could be identified.

Trigeminal electrophysiology: a 2 x 2 matrix model for differential diagnosis between temporomandibular disorders and orofacial pain

Background

Pain due to temporomandibular disorders (TMDs) often has the same clinical symptoms and signs as other types of orofacial pain (OP). The possible presence of serious neurological and/or systemic organic pathologies makes differential diagnosis difficult, especially in early disease stages. In the present study, we performed a qualitative and quantitative electrophysiological evaluation of the neuromuscular responses of the trigeminal nervous system. Using the jaw jerk reflex (JJ) and the motor evoked potentials of the trigeminal roots (_bR-MEPs) tests, we investigated the functional and organic responses of healthy subjects (control group) and patients with TMD symptoms (TMD group).

Method

Thirty-three patients with temporomandibular disorder (TMD) symptoms and 36 control subjects underwent two electromyographic (EMG) tests: the jaw jerk reflex test and the motor evoked potentials of the trigeminal roots test using bilateral electrical transcranial stimulation. The mean, standard deviation, median, minimum, and maximum values were computed for the EMG absolute values. The ratio between the EMG values obtained on each side was always computed with the reference side as the numerator. For the TMD group, this side was identified as the painful side (pain side), while for the control group this was taken as the non-preferred masticatory side (non-preferred side). The 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles were also calculated.

Results

Analysis of the ratios (expressed as percentages) between the values obtained on both sides revealed a high degree of symmetry in the _bR-MEPs ^% in the control (0.93 ± 0.12%) and TMD (0.91 ± 0.22%) groups. This symmetry indicated organic integrity of the trigeminal root motor fibers and correct electrode arrangement.

A degree of asymmetry of the jaw jerk's amplitude between sides (_ipJJ%), when the mandible was kept in the intercuspal position, was found in the TMD group (0.24% ± 0.14%) with a statistically significant difference in relation to the control group (0.61% ± 0.2%). This asymmetry seemed to be primarily due to a failure to facilitate the reflex on the painful side in intercuspal position.

Conclusions

In this 2 × 2 matrix diagnostic model, three different types of headache may be identified: 1) those due to organic pathologies directly and indirectly involving the trigeminal nervous system denoted as "Organic Damage"; 2) those in TMD patients; 3) other types of orofacial pain in subjects who could erroneously be considered healthy, denoted as Orofacial Pain "OP". This category of patient should be considered at risk, as organic neurological pathologies could be present and yet not directly affect the trigeminal system, at least in the early stages of the disease.

Targeted ablation of mesenteric projecting sympathetic neurons reduces the hemodynamic response to pain in conscious, spinal cord-transected rats

Individuals with spinal cord injuries above thoracic level 6 (T(6)) experience episodic bouts of life-threatening hypertension as part of a condition termed autonomic dysreflexia. The paroxysmal hypertension can be caused by a painful stimulus below the level of the injury. Targeted ablation of mesenteric projecting sympathetic neurons may reduce the severity of autonomic dysreflexia by reducing sympathetic activity. Therefore, cholera toxin B subunit (CTB) conjugated to saporin (SAP; a ribosomal inactivating protein that binds to and inactivates ribosomes) was injected into the celiac ganglion to test the hypothesis that targeted ablation of mesenteric projecting sympathetic neurons reduces the pressor response to pain in conscious, spinal cord-transected rats. Nine Sprague-Dawley male rats underwent a spinal cord transection between thoracic vertebrae 4 and 5. Following recovery (5 wk), all rats were instrumented with a radio telemetry device for recording arterial pressure and bilateral catheters in the gluteus maximus muscles for the infusion of hypertonic saline (hNa(+)Cl(-)). Subsequently, the hemodynamic responses to intramuscular injection of hNa(+)Cl(-) (100 microl and 250 microl, in random order) were determined. Following the experiments in the no celiac ganglia injected condition (NGI), rats received injections of CTB-SAP (n = 5) or CTB (n = 3) into the celiac ganglia. CTB-SAP rats, compared with NGI and CTB rats, had reduced pressor responses to hNa(+)Cl(-). Furthermore, the number of stained neurons in the celiac ganglia and spinal cord (segments T(6)-T(12)), was reduced in CTB-SAP rats. Thus, CTB-SAP retrogradely transported from the celiac ganglia is effective at ablating mesenteric projecting sympathetic neurons and reducing the pressor response to pain in spinal cord-transected rats.

Stretch Reflex and Pressure Pain Thresholds in Chronic Tension-Type Headache Patients and Healthy Controls

To compare the jaw-stretch reflex and pressure pain thresholds (PPT) in chronic tension-type headache (CTTH) patients and healthy controls, 30 patients (15 male and 15 female) and 30 age- and sex-matched healthy subjects were investigated. Stretch reflexes were recorded in the temporalis and masseter muscles and PPT was determined in the anterior temporalis, splenius capitis and masseter muscles. The results showed that the amplitude of the stretch reflex in CTTH patients was higher compared with control subjects ( P < 0.045), and higher in women compared with men in the right and left anterior temporalis muscles ( P < 0.009). There were no differences in the PPT value between CTTH and control subjects ( P > 0.509), whereas women showed significantly lower PPT measurements ( P < 0.046). The results demonstrated a facilitation of the stretch reflex pathways in CTTH patients that is unrelated to measures of pericranial sensitivity.

Rehabilitation program for traumatic chronic cervical pain associated with unsteadiness: a single case study

BACKGROUND

Neck problems are often recurring or chronic. After pain, unsteadiness and balance problems are among the most frequent symptoms reported by chronic neck pain (CNP) patients. Altered sensorimotor control of the cervical spine and sensorimotor integration problems affecting postural control have been observed in CNP patients. Very few data are available regarding the post-intervention effects of rehabilitation programs on postural control in CNP.

CASE PRESENTATION

This is a case study of a traumatic CNP patient (a 45-year old female) with postural unsteadiness who participated in an 8-week rehabilitation program combining therapeutic exercises with spinal manipulative therapy. Pre-intervention data revealed that the postural control system was challenged when postural control sensory inputs were altered, particularly during the head-extended-backward condition. Post-intervention centre of pressure measurements indicated a drastic reduction in postural sway during trials with changes in neck orientation.

CONCLUSION

This case report indicates that an 8-week rehabilitation program combining therapeutic exercises with spinal manipulative therapy may have had an effect on improvement of postural control in a trauma CNP patient with unsteadiness. These results warrant further studies to investigate the relationships between pain amelioration, sensorimotor control of the cervical spine, muscle fitness and postural steadiness.