McKenzie neck exercise versus cranio-cervical flexion exercise on strength and endurance of deep neck flexor muscles, pain, disability, and craniovertebral angle in individuals with chronic neck pain: a randomized clinical trial

PURPOSE

To compare the effectiveness of McKenzie neck exercise and cranio-cervical flexion (CCF) exercise on strength and endurance of deep neck flexor (DNF) muscles, pain, disability, and craniovertebral angle (CVA) in individuals with chronic neck pain.

METHODS

Forty individuals with chronic neck pain were randomly allocated to the McKenzie neck or CCF exercise group. Each group performed exercises at home daily. The strength and endurance of DNF muscles were measured at baseline, immediately after the first exercise session, and each week follow-up for six weeks. Average pain over the past week was measured at baseline and each week follow-up for six weeks. Disability and CVA were measured at baseline and the end of six weeks.

RESULTS

At six weeks, both groups exhibited significant improvements across all outcome variables (p < 0.001) but there were no differences between groups (p > 0.05). The significant difference from baseline in the strength of DNF muscles was observed as early as the second week of each intervention (p ≤ 0.001). The significant difference from baseline in the endurance of DNF muscles was observed as early as the first week in the CCF exercise group (p < 0.05) and the second week in the McKenzie neck exercise group (p < 0.05). A significant decrease in pain intensity from baseline was observed after the first week in the McKenzie neck exercise group (p < 0.001) while it was after the second week in the CCF exercise group (p < 0.05).

CONCLUSION

Both the McKenzie neck exercise and CCF exercise produced similar effects in enhancing the strength and endurance of the DNF muscles, decreasing pain, alleviating neck disability, and improving the CVA.

Joint position sense testing at the wrist and its correlations with kinesiophobia and pain intensity in individuals who have sustained a distal radius fracture: A cross-sectional study

BACKGROUND

Sensorimotor impairment following distal radius fracture (DRF) has been associated with a significant decline in function. Joint position sense (JPS) testing is a meaningful and responsive way to assess sensorimotor impairment for individuals who have sustained a DRF; however, there are factors that may influence the results of JPS testing, including kinesiophobia and pain intensity.

PURPOSE

This study aimed to evaluate the influence kinesiophobia may have on wrist JPS testing and if pain intensity impacts kinesiophobia and JPS in individuals with a DRF.

STUDY DESIGN

This was a cross-sectional study.

METHODS

Participants referred from two medical centers with a diagnosis of DRF treated with at least 3 weeks of immobilization were enrolled in the study. Data were collected at 1 week and 6 weeks postimmobilization period. Demographics were summarized with descriptive statistics, and linear relationships between kinesiophobia, pain intensity, and wrist JPS were examined using Pearson correlation coefficient.

RESULTS

Forty-eight participants were included in this study (mean age 42.9 years). Significant positive correlations were found between the Tampa Scale for Kinesiophobia (TSK) and Numeric Rating Scale (NRS; r = 0.951, p < 0.001), TSK and JPS error (r = 0.942, p < 0.001), as well as NRS and JPS error (r = 0.898, p < 0.001). These correlations indicate that higher levels of kinesiophobia are associated with increased pain intensity and greater JPS error. T-tests reveal no significant difference between male and female for the TSK, NRS, or JPS scores.

CONCLUSIONS

There is an association for individuals with high levels of kinesiophobia and both greater pain and errors with JPS testing.

Evaluating the Accuracy of Upper Limb Movement in the Sagittal Plane among Computer Users during the COVID-19 Pandemic

(1) Background: The most common musculoskeletal pathology among healthcare professionals is neck and/or shoulder pain. The aim of this study was to determine the dominant upper limb functionality concerning the ability to replicate a given movement pattern among employees reporting neck or upper limb pain while using a computer during the COVID-19 pandemic. (2) Methods: The study was conducted from March to April 2021 on a group of 45 medical employees who used a computer workstation for 4 to 6 h of their working time. In the design of this study, three study groups were created: a group of patients with pain syndrome of segment C5/C7 of the spine, a group of patients with shoulder pain syndrome, and a control group of healthy volunteers. (3) Results: The examined groups significantly differed in the correctness of performing the given movement (p = 0.001) and the minimum value of inclination during the exercise session (p = 0.026), as well as the maximum lowering (p = 0.03) in relation to the control group. (4) Conclusions: The VECTIS device can be used to assess the accuracy of reflecting the prescribed movement of the upper limb in rehabilitation programs for patients with cervical spine pain syndrome and shoulder pain syndrome.

Cervical proprioception in Parkinson's disease and its correlation with manual dexterity function

OBJECTIVE

Cervical proprioception plays a crucial role in posture and movement control. This study aimed to determine the relationships of cervical proprioception, cervical muscle strength and endurance with manual dexterity and hand strength in individuals with idiopathic Parkinson's disease (PD).

METHODS

Twenty individuals with PD (mean age: 63.9 years) and 20 healthy individuals as a control group (mean age: 61.9 years) were recruited. Cervical joint position error (JPE), static endurance of neck muscles, activation of deep cervical flexor muscles (Craniocervical Flexion Test, CCFT), manual dexterity (Purdue Pegboard Test, PPT), cognitive and motor tasks of the PPT, finger tapping test (FTT), pinch strength, and grip strength were assessed.

RESULTS

Cervical JPE was significantly higher in individuals with PD than in controls (p < 0.05). The strength and endurance of the cervical muscles were significantly decreased in individuals with PD (p < 0.05). Cervical JPE measurements were negatively correlated with PPT, cognitive and motor tasks of the PPT in individuals with PD (all p < 0.05). The endurance of cervical flexor muscles was negatively correlated with PPT and cognitive PPT scores in the PD group (p < 0.05). In addition, a significant positive correlation was found between cervical flexor endurance and hand strength in the PD group (p < 0.05).

CONCLUSION

Cervical proprioception and the strength and endurance of cervical muscles decrease in individuals with PD compared to healthy individuals. Impairment of cervical proprioception appears to be associated with poorer upper extremity performance. Detailed evaluation of the cervical region in PD may help determine the factors affecting upper extremity function.

Reliability and Validity of the Double Inclinometer Method for Assessing Thoracolumbar Joint Position Sense and Range of Movement in Patients with a Recent History of Low Back Pain

The study was aimed at examining the reliability of the Double Inclinometer (DI) method for the assessment of thoracolumbar Range of Movement (ROM) and Joint Position Sense (JPS) in patients with a recent history of Low Back Pain (LBP). Twenty patients with a history of LBP in the last three months participated. The thoracolumbar ROM and JPS were examined from a standing position by using both the DI and the tape measure method. The DI method was found to have moderate to good intra-rater (ICC = 0.68-0.79, SEM = 2.20-2.77°, SDD = 6.09-7.67°), moderate inter-rater (ICC = 0.59-0.62, SEM = 2.96-3.35°, SDD = 8.19-9.27°) and poor test-retest reliability (ICC = 0.13-0.17, SEM = 3.98-4.32°, SDD = 11.02-11.96°) for the assessment of thoracolumbar JPS. For the assessment of thoracolumbar ROM, the DI method was found to have good to excellent intra-rater (ICC = 0.88-0.94, SEM = 4.25-6.20°, SDD = 11.77-17.17°), excellent inter-rater (ICC = 0.90-0.91, SEM = 7.26-7.74°, SDD = 20.11-21.43°) and excellent test-retest reliability (ICC = 0.91-0.93, SEM = 6.03-6.87°, SDD = 16.70-19.02°). The concurrent validity of the DI method with the tape measure method was found to be very weak for the assessment of thoracolumbar JPS (r = 0.02, p = 0.93) and strong for the assessment of thoracolumbar ROM (r = 0.66, p = 0.001). The DI method seems to be a very reliable method for the assessment of thoracolumbar ROM in individuals with a recent history of LBP.

Pain-side related difference in cross-sectional area of the longus colli muscle and its relationship with standing balance in persons with non-specific neck pain

BACKGROUND

Longus colli muscle has a significant role in postural control. A reduction of longus colli cross-sectional area (CSA) has been demonstrated in neck pain patients. However, pain-side related difference and its relationship with clinical features and standing balance remain unclear.

OBJECTIVE

To investigate side-to-side difference in the longus colli CSA and to determine the relationships of the CSA with clinical characteristics and standing balance in neck pain patients.

STUDY DESIGN

Cross-sectional study.

MATERIALS AND METHODS

Fifty participants with chronic non-specific neck pain (20 unilateral and 30 bilateral) were recruited. CSA of the longus colli muscle was measured using ultrasound imaging. Balance was measured using a force platform during a narrow stance with eyes open, eyes closed, and neck torsion (left and right). Balance outcomes were sway area and displacement in anterior-posterior (AP) and medial-lateral (ML) directions. Clinical characteristics were neck pain intensity, disability, and duration.

RESULTS

The longus colli CSA was reduced on the painful side in patients with unilateral neck pain (p < 0.01). There was a trend towards reduced CSA on the more painful side in those with bilateral neck pain (p = 0.08). The reduced CSA was mostly correlated with the greater AP sway displacement and sway area (r ranged from -0.27 to -0.54, p < 0.05). The longus colli CSA was not correlated with pain intensity, disability, and duration (p > 0.05).

CONCLUSION

The longus colli CSA was reduced on the painful side of neck pain. The reduced CSA was correlated with impaired standing balance, but not with clinical characteristics of neck pain.

Fat Infiltration of Multifidus Muscle Is Correlated with Neck Disability in Patients with Non-Specific Chronic Neck Pain

Background: Chronic non-specific neck pain (CINP) is common, but the etiology remains unclear. This study aimed to examine the relationship between cervical muscle composition (cervical multifidus and longus capitis/longus colli), morphometry, range of movement, muscle function, and disability severity (Neck Disability Index) in patients with CINP. Methods: From September 2020 to July 2021, subjects underwent cervical MRI and clinical tests (cervical range of motion, cranio-cervical flexion test, neck flexor, and extensor muscle endurance). MRI analysis comprised muscle cross-sectional area, volume, and fat infiltration of multifidus and longus colli between C4 and C7 levels. Results: Twenty-five participants were included. Multiple linear regression analysis indicated that NDI was positively correlated with the volume percentage of fat infiltration of the multifidus (B = 0.496), negatively correlated with fat-free muscle volume of the multifidus normalized by subject height (B = −0.230), and accounted for 32% of the variance. There was no relationship between neck disability and longus capitis/longus colli morphology. We also found no relationship between neck disability scores, neck flexor or extensor muscle endurance, or the outcome motor control test of craniocervical flexion (p > 0.05). Conclusions: Neck disability was moderately correlated with the percentage of fat volume in the multifidus muscle and fat-free volume of the multifidus. There was no relationship between NDI scores and muscle function test outcomes or any fat or volume measures pertaining to the longus colli muscle.

Reliability of Cervicocephalic Proprioception Assessment: A Systematic Review

OBJECTIVE

The purpose of this systematic review was to determine the reliability and, where possible, the validity of cervicocephalic proprioceptive (CCP) tests in healthy adults and clinical populations.

METHODS

A systematic search, utilizing 7 databases from the earliest possible date to April 14, 2021, identified studies that measured reliability of CCP tests. Studies were screened for eligibility, and included studies were appraised using Quality Appraisal Tool for Studies of Diagnostic Reliability (QAREL) and Quality Assessment and Diagnostic Accuracy Studies-2 Tool (QUADAS-2) tools. Validity outcomes were assessed for included studies.

RESULTS

Of 34 included studies, 29 investigated reliability for sense of position tests, 10 involved sense of movement tests, and 1 used a sense of force test. The head to neutral test was reliable and valid when 6 or more repetitions were performed within the test, discriminating between those with and without neck pain. Head tracking tests were reliable with 6 repetitions, and 1 study found discriminative validity in a whiplash population. Studies that found discriminative validity in sense of position reported mean joint position error generally >4.5° in the neck pain group and <4.5° in the asymptomatic group. No sense of force test was applied to a clinical population. Convergent validity analysis showed that these proprioceptive tests have low correlations with each other.

CONCLUSION

The reliability and validity of CCP tests for sense of position and movement are dependent upon equipment and repetitions. Six repetitions are generally required for good reliability, and joint position error >4.5° is likely to indicate impairment in sense of position.

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.

Sex and posture dependence of neck muscle size-strength relationships

Neck muscle size and strength have been linked to lower injury risk and reduced pain. However, prior findings have been inconclusive and have failed to clarify whether there are sex differences in neck muscle size-strength relationships. Such differences may point to an underlying cause for the reported sex difference in neck pain prevalence. Thirty participants (13 males, 17 females) who underwent neck strength testing and MR imaging were analyzed. Strength was measured in three conditions that differed in posture and exertion direction. Muscle size was quantified by three metrics: anatomical cross-sectional area (ACSA), muscle volume (MV), and an estimate of physiological cross-sectional area-reconstruction-based cross-sectional area (RCSA). Inter-posture strength correlations, muscle size-strength correlations, and sex differences were analyzed with linear regression. Males were approximately 65% stronger and had significantly larger muscles. Strength varied significantly across postures, but only female strength values for different postures were significantly correlated. Observed in males only, the sternocleidomastoid (SCM) was a strong predictor of flexion strength in the neutral posture while the anterior scalene (AS) was more involved in the extended. No extensor's size was significantly linked to extension strength. A greater amount of force variation is unexplained by muscle size alone in females than in males. Males and females exhibited distinct size-strength relationships, highlighting the need for sex-specific models and analyses and the greater potential effect of non-morphometric factors on force generating capacity in females. No advantage of one muscle size metric over another in strength prediction was evidenced.

Kinesiophobia and its correlations with pain, proprioception, and functional performance among individuals with chronic neck pain

Chronic neck pain (CNP) incidence in the general population is high and contributes to a significant health problem. Kinesiophobia (fear of pain to movement or re-injury) combined with emotions and physical variables may play a vital role in assessing and managing individuals with CNP. The study’s objectives are 1) to evaluate the relationship between kinesiophobia, neck pain intensity, proprioception, and functional performance; 2) to determine if kinesiophobia predicts pain intensity, proprioception, and functional performance among CNP individuals. Sixty-four participants with CNP (mean age 54.31 ± 9.41) were recruited for this cross-sectional study. The following outcome measures were evaluated: Kinesiophobia using the Tampa Scale of Kinesiophobia (TSK), neck pain intensity using the visual analog scale (VAS), cervical proprioceptive joint position errors (in flexion, extension, and rotation directions) using cervical range of motion (CROM) device and handgrip strength as a measure of functional performance using the Baseline® hydraulic hand dynamometer. Kinesiophobia showed a strong positive correlation with neck pain intensity (r = 0.81, p<0.001), a mild to a moderate positive correlation with proprioception joint position errors (JPE) in extension, rotation left and right directions (p<0.05), but no correlation in flexion direction (p = 0.127). Also, there was a moderate negative correlation with handgrip strength (r = -0.65, p<0.001). Regression analysis proved that kinesiophobia was a significant predictor of pain intensity, proprioception, and functional performance (p<0.05). This study infers that kinesiophobia in individuals with CNP predicts pain, proprioception, and functional performance. Kinesiophobia assessment should be considered in regular clinical practice to understand the barriers that can influence rehabilitation outcomes in CNP individuals.

Effects of Proprioceptive and Craniocervical Flexor Training on Static Balance in University Student Smartphone Users with Balance Impairment: A Randomized Controlled Trial

Purpose

University student smartphone users adopt flexed neck postures during smartphone use, creating an increased compressive load on their neck structures. This study was conducted to compare the effects of proprioceptive and craniocervical flexor training with a control group on static balance in a group of university student smartphone users with balance impairment.

Methods

A double-blinded, randomized controlled trial was conducted involving 42 university students (19.67±1.68 years old) with balance impairment. Participants were randomized into a proprioceptive training (ProT) group (n=14), a craniocervical flexor training (CCFT) group (n=14), and a control group (CG; n=14) for a 6-week intervention. The balance error scoring system (BESS), cervical joint position sense (CJPS), craniocervical flexion (CCF) test, and visual analog scale (VAS) for neck pain were evaluated using univariate analysis of covariance (ANCOVA).

Results

After 6 weeks of intervention, the ProT group showed significantly greater improvement of CJPS than the CG (p=0.000) and the CCFT group significantly improved of CCF test than CG (p=0.002). Findings, at 4 weeks after intervention, were (i) the ProT group had significantly more improvement in BESS than the CCFT group (p=0.014) and CG (p=0.003), (ii) the ProT group had significantly more improvement of CJPS than the CG (right and left rotate) (p=0.001, p=0.016, respectively) and CCFT group (right rotate) (p=0.004), (iii) the CCFT group had significantly more improvement of craniocervical flexor strength than CG (p=0.004), and (iv) the ProT group and CCFT group had significantly more decreased pain than CG (p=0.015, p=0.033, respectively). No adverse effects occurred during or after training in any group.

Conclusion

ProT is important for regaining static balance and CJPS, while CCFT improved craniocervical flexor strength. Moreover, both ProT and CCFT can reduce neck pain. We recommend performing ProT to improve static balance, CJPS and to reduce neck pain in smartphone users with static balance impairment.

Clinical Trail Registration Number

TCTR20190909003.

Comparison and Association of Neck Extensor Muscles’ Endurance and Postural Function in Subjects with and without Chronic Neck Pain – A Cross-Sectional Study

Purpose Neck extensor endurance (NEE) and position sense are vital for maintaining cervical spine function and defects in these processes may be associated with impaired postural control in chronic neck pain (CNP) subjects. The study’s objectives are 1) to compare the cervical extensor endurance capability and postural control of CNP subjects with those of asymptomatic controls; 2) to investigate the association between NEE and postural control.

Materials and Methods Sixty-four participants (38 asymptomatic, 38 with CNP) participated in this cross-sectional study. NEE was assessed using a clinical extensor endurance test. Under open and closed eyes conditions, postural control measures were tested with the Good Balance system. The postural control parameters were AP-velocity (mm/s), ML-velocity (mm/s) and Velocity moment (mm2). NEE capacity and postural control parameters were compared and correlated between asymptomatic and CNP subjects.

Results and Discussion CNP subjects showed lower NEE capacity (p<0.001) and significantly larger AP-velocity (p<0.001), ML-velocity (p<0.001) and Velocity moment (p<0.001) than asymptomatic participants. NEE negatively correlated with AP-velocity (r=−0.51, p=0.001), ML-velocity (r=0.46, p=0.003) and velocity moment (r=0.38, p=0.020) in asymptomatic subjects in eyes open condition and no correlations in subjects with CNP. CNP subjects showed increased postural sway velocities and lowered extensor endurance capacity compared to asymptomatic participants. No correlations existed between NEE and postural control parameters in CNP subjects.

Comparison of neck extensor muscle endurance and cervical proprioception between asymptomatic individuals and patients with chronic neck pain

INTRODUCTION

Neck extensor endurance (NEE) and cervical proprioception are vital for maintaining cervical spine function and defects in these processes have been associated with chronic neck pain (CNP). The objectives of the study are 1) To investigate the association between NEE and cervical joint position error (JPE) in subjects with CNP; 2) to compare the cervical extensor endurance and cervical JPE of CNP subjects with those of asymptomatic controls; and 3) to determine the relationship between Pain Catastrophizing Scale (PCS) scores, NEE, and cervical JPE in subjects with CNP.

METHOD

Sixty-four participants (32 asymptomatic, 32 with CNP) participated in this comparative cross-sectional study. Cervical proprioception was assessed by measuring the absolute JPE in the sagittal and transverse directions. NEE was assessed using a clinical extensor endurance test. NEE capacity and JPE were compared and correlated between asymptomatic and CNP subjects. Pain catastrophic behavior was assessed using the Pain Catastrophizing Scale (PCS) in CNP subjects.

RESULTS

CNP subjects showed lower NEE capacity (p < 0.001) and significantly larger JPEs (p < 0.001) than asymptomatic participants. NEE negatively correlated with JPEs in all directions (p < 0.001) in asymptomatic subjects and only neck extension errors showed a correlation in CNP subjects (r = -0.45, p = 0.009). PCS scores were negatively correlated with endurance capacity (r = -0.42, p = 0.017) and positively correlated with JPE (flexion: r = 0.57, p = 0.001).

CONCLUSION

CNP subjects showed impaired proprioception and lower endurance capacity compared to asymptomatic participants. Neck extension errors alone correlated with JPE in CNP subjects. PCS scores negatively correlated with NEE in subjects with CNP.

The brain and behavioral correlates of motor-related analgesia (MRA)

The human motor system has the capacity to act as an internal form of analgesia. Since the discovery of the potential influence of motor systems on analgesia in rodent models, clinical applications of targeting the motor system for analgesia have been implemented. However, a neurobiological basis for motor activation's effects on analgesia is not well defined. Motor-related analgesia (MRA) is a phenomenon wherein a decrease in pain symptoms can be achieved through either indirect or direct activation of the motor axis. To date, research has focused on (a) evaluating the pain-motor interaction as one focused on the acute protection from painful stimuli; (b) motor cortex stimulation for chronic pain; or (c) exercise as a method of improving chronic pain in animal and human models. This review evaluates (1) current knowledge surrounding how pain interferes with canonical neurological performance throughout the motor axis; and (2) the physiological basis for motor-related analgesia as a means to reduce pain symptom loads for patients. A proposal for future research directions is provided.

Interactive Association Between Mechanical and Sensorimotor Aspects of Cervical Extensor Muscles: Implications for Chronic Neck Pain

While proprioceptive functioning of the cervical extensor muscles has been proposed to be associated with chronic neck pain (NP), the mechanism by which such impairment might contribute to NP is not clear. The aim of this cross-sectional study was to investigate the relevance of proprioception, extensor muscles size, and endurance to chronic NP. A total of 60 participants with (n = 30) or without (n = 30) chronic NP participated in this cross-sectional study. Joint repositioning error (JRE), ultrasonographic parameters of the cervical extensors, and clinical extensor endurance were assessed. Multivariate analysis of variance and logistic regression tests were used to compare the groups and test the predictive value of the dependent variables for chronic NP, respectively. Patients showed comparable JRE scores but smaller multifidus size and lower extensor endurance (Cohen d = 0.66 for both). JRE in the transverse plane (β = 1.20), multifidus muscle size (β = 0.02), and endurance (β = 0.99) were significant predictors for chronic NP odds ratio. The results found multifidus size as the most relevant factor to NP by showing both between-groups difference and considerable odds ratio. As JRE in transverse plane was not different between the groups and extensor endurance demonstrated minimal odds ratio, these 2 factors may be considered as less relevant to NP comparing multifidus muscle size.

Widespread impairment of tactile spatial acuity and sensory-motor control in patients with chronic nonspecific neck pain with neuropathic features

OBJECTIVE

To assess differences in tactile spatial acuity and in sensory-motor control between patients with chronic nonspecific neck pain (CNSNP) with and without neuropathic features (NF), as well as asymptomatic.

METHODS

183 participants were included, 135 had CNSNP classified by the Self-report version of Leeds Assessment of Neuropathic Symptoms and Signs scale in order to identify pain with NF: (1) CNSNP with NF (n = 67), (2) CNSNP with No-NF (n = 68), and (3) asymptomatic subjects (n = 48). The following tests in the following order were assessed after determining the participants' clinical characteristics: 1) two-point discrimination, 2) joint position error, and 3) craniocervical flexion test.

RESULTS

Both neck pain groups showed a significant reduction in their ability to discriminate two points in the trapezium and masseter, as well as a significant deficit of a moderate to large magnitude in craniocervical motor control compared with the asymptomatic group. However, only the CNSNP with NF group showed a significant impairment of the two-point discrimination in the tibia (d = 0.57) and a significant impairment of the kinesthetic sense (neck rotation, d = 0.73; neck lateroflexion, d = 0.69), compared with the asymptomatic group. Significant differences in pain intensity, disability and psychological factors between the CNSNP groups were also found, observing the poorest results in the NF group.

CONCLUSIONS

Patients with CNSNP with NF have a greater sensory, motor and psychological impairment than those without NF, more pain intensity, disability and negative psychological factors, as well as more impaired tactile spatial acuity in areas remote to the pain and impaired cervical kinesthetic sense.

Examination of Regional Interdependence Theory in Chronic Neck Pain: Interpretations from Correlation of Strength Measures in Cervical and Pain-Free Regions

OBJECTIVE

Impairments present in chronic pain conditions have been reported not to be limited to the painful region. Pain-free regions have also been proposed to be adversely affected as a cause or consequence of the painful condition. The aim of this study was to investigate the association between muscle strength in painful and pain-free regions and chronic neck pain.

DESIGN

A cross-sectional study.

SETTING

Rehabilitation hospital laboratory.

SUBJECTS

One hundred twenty-two patients with chronic neck pain (87 female) and 98 asymptomatic volunteers (52 female) were included in the study.

METHODS

Maximal isometric strength measures of the neck, scapulothoracic, shoulder, trunk, and hip muscles were assessed using a hand-held dynamometer in all participants. Pain intensity and pain-related disability were also assessed in patients through visual analog scale and Neck Disability Index scores, respectively.

RESULTS

Principal component analysis revealed one component for each of the studied regions. Multivariate analysis of variance found neck (d = 0.46), scapulothoracic (d = 0.46), shoulder (d = 0.60), trunk flexor (d = 0.38), extensor (d = 0.36), and hip (d = 0.51) strength components to be lower in the neck pain patients compared with asymptomatic participants (P < 0.01). Logistic and linear regression analyses found the shoulder strength component both to be a significant predictor for neck pain occurrence (β = 0.53, P < 0.01) and to have a considerable effect on pain intensity score (β=-0.20, P = 0.02), respectively.

CONCLUSIONS

The results found that some pain-free regions in addition to the cervical spine to exhibit lower levels of muscular strength in neck pain patients. These findings support the regional interdependence theory, which proposes that impairments are not limited to the painful area and are possibly mediated by central mechanisms.

Reliability, measurement error and construct validity of four proprioceptive tests in patients with chronic idiopathic neck pain

BACKGROUND

There are different neck proprioceptive tests that are believed to be targeting different sources of proprioceptive information.

OBJECTIVE

To assess the reliability, measurement error, discriminative validity and convergent validity of four proprioceptive tests (head repositioning to neutral - HRNT, torsion test - TT, head repositioning to 30° rotation - HR30T and figure of eight relocation test - F8T) in individuals with chronic idiopathic neck pain and asymptomatic individuals. A secondary aim was to assess the divergent validity of these tests by correlating them against measures of disability, pain catastrophizing and fear of movement.

DESIGN

- Reliability and validity study.

METHODS

- 66 participants (33 with chronic neck pain and 33 asymptomatic) were assessed using four proprioceptive tests, pain catastrophizing scale, neck disability index, tampa scale of kinesiophobia and visual analogue scale.

RESULTS

Proprioceptive tests showed moderate to good reliability (ICC: 0.55 to 0.85), but high measurement error. All tests but the HR30T were significantly different between participants with and without neck pain (p < 0.05). Only the HRNT showed an area under the curve above 0.5 (AUC95% CI = 0.51; 0.78, p ≤ 0.042). Between test correlations ranged between 0.35 and 0.61 and correlations between proprioceptive tests and catastrophizing, fear of movement and disability were, in general, lower than 0.3.

CONCLUSION

The four proprioceptive tests showed reliability and measurement errors good enough for group comparisons but of limited utility for individual comparisons. They seem to measure related but dissimilar constructs and the HRNT seemed better at discriminating individuals with and without NP and easier to perform in clinical practice.

Is forward head posture relevant to cervical muscles performance and neck pain? A case-control study

BACKGROUND

Forward head posture (FHP) and muscular dysfunction are likely contributing factors to chronic neck pain (CNP) but there are inconsistent findings on the relevance of these factors to clinical CNP characteristics.

OBJECTIVE

To compare FHP, cervical muscles size and endurance between CNP and asymptomatic participants and to investigate their association with pain and disability and relative involvement of deep/superficial and flexor/extensor muscles.

METHODS

Thirty-two patients with CNP and 35 asymptomatic participants were included in this case-control study. FHP in standing, extensor and flexor muscles endurance and dimensions were assessed using digital photography, clinical tests and ultrasonographic imaging, respectively. The visual analog scale and neck disability index were also used to evaluate CNP patients' clinical characteristics.

RESULTS

Deep flexor (mean difference=0.06, 95% CI=0.02-0.11) and extensor muscles size (mean difference=0.07, 95% CI=0.01-0.12) were found to be significantly smaller in CNP patients. CNP patients also demonstrated lower levels of flexor (mean difference=14.68, 95% CI=3.65-25.72) and global extensor endurance capacity. FHP was neither different between the groups nor correlated with any of the dependent variables. Neither FHP nor endurance was correlated with pain/disability. Extensor endurance in both groups and flexor endurance in the asymptomatic group showed significant correlations with muscles size.

CONCLUSIONS

FHP was found neither different between groups nor correlated with muscle performance or CNP clinical characteristics. While cervical endurance was found lower in CNP patients, it did not show any association with pain/disability. The muscular size-endurance relationship seems to become more complex in the presence of NP. While deep muscles seem to be differentially affected in the presence of CNP, the alterations do not seem to be uniform in the flexor and extensor groups.

Neck-specific exercise improves impaired interactions between ventral neck muscles in chronic whiplash: A randomized controlled ultrasound study

Chronic pain and disability is common in whiplash-associated disorders (WAD), leading to personal suffering, sick leave, and social cost. The cervical spine is heavily dependent on muscular support and whiplash injury can cause damage to the neck muscles, but diagnostic tools to measure neck muscle impairment and evaluate exercise interventions are lacking. Therefore, the present study investigated ventral neck muscle interactions in 26 individuals with chronic WAD randomized to neck-specific exercise (NSE) or remaining on a waiting list (WL) in 3 months. We performed real-time, non-invasive ultrasound measurements with speckle tracking analysis and calculated the deformation area and deformation rate in three ventral neck muscles. Multivariate statistics were used to analyse interactions between the muscles. After 3 months of NSE, significant improvements were observed in neck muscle interactions and pain intensity in the NSE group compared to the WL group. Thus, this study demonstrates that non-invasive ultrasound can be a diagnostic tool for muscle impairment and used to evaluate exercise interventions in WAD and stands to make a breakthrough for better management in chronic WAD.