Lack of visual information alters lower limb motor coordination to control center of mass trajectory during walking.

Vision, as queen of the senses, plays a critical role in guiding locomotion. Little is known about the effects of vision on gait coordination in terms of variability. The uncontrolled manifold (UCM) approach offers a window to the structure of motor variability that has been difficult to obtain from the traditional correlation analysis. In this study, we used the UCM analysis to quantify how the lower limb motion is coordinated to control the center of mass (COM) while walking under different visual conditions. We also probed how synergy strength evolved along the stance phase. Ten healthy participants walked on the treadmill with and without visual information. Leg joint angle variance with respect to the whole-body COM was partitioned into good (i.e., the one that kept the COM) and bad (i.e., the one that changed the COM) variances. We observed that after vision was eliminated, both variances increased throughout the stance phase while the strength of the synergy (the normalized difference between the two variances) decreased significantly and even reduced to zero at heel contact. Thus, walking with restricted vision alters the strength of the kinematic synergy to control COM in the plane of progression. We also found that the strength of this synergy varied across different walking phases and gait events in both visual conditions. We concluded that the UCM analysis can quantify altered coordination of COM when vision is blocked and sheds insights on the role of vision in the synergistic control of locomotion.

Self-Compassion: The Factor That Explains a Relationship between Perceived Social Support and Emotional Self-Regulation in Psychological Well-Being of Breast Cancer Survivors.

Objective: Perceived social support (PSS) and emotional self-regulation have customarily been related to greater psychological well-being, but the pathways via which perceived social support and emotional self-regulation increase psychological well-being have not been revealed. We investigated how much self-compassion mediated the association between perceived social support and emotional self-regulation in psychological well-being of breast cancer sufferers. Method : A cross-sectional study design was used. Participants were recruited from three oncology departments in Zanjan, Iran. Data was collected from breast cancer patients (n = 300). Participants completed self-report measures, the short Ryff scale Psychological Well-being (RSPWB), Emotion Regulation Questionnaire (ERQ), Multidimensional Scale of Perceived Social Support (MSPSS) and Self-Compassion Scale (SCS). Pearson correlation coefficient was used to assess association among the study variables and multivariable regression analysis was used to assess linear relationships among predictor variables (emotional self-regulation, perceived social support and self-compassion) and criterion variable (psychological well-being). Bootstrapping analyses were used to test the significance on indirect effects. Results: Bootstrapping analyses revealed significant indirect effects of perceived social support (ß = 0.055, SE = 0.45, P = 0.049, 0.95 CI: LL = 0.0092, UL = 0.1345) and emotional self-regulation (ß = 0.079, SE = 0.079, P = 0.004, 0.95 CI: LL = -0.0331, UL = -0.1358) on psychological well-being through self-compassion. Conclusion: These findings present new evidence that self-compassion may be a target for psychological interventions attempted at enhancing psychological well-being in cancer populations, particularly breast cancer survivors.

Rehabilitative ultrasound imaging of the levator scapula muscle at rest and during contraction: Technical description and reliability.

BACKGROUND: Altered scapular muscle activity is associated with abnormal scapular motions and shoulder pain. Hence, quantification of these activities is a challenging issue. OBJECTIVES: The purposes of this study were to establish the reliability of measuring levator scapula muscle thickness and to examine how thickness of this muscle changes with contraction. METHODS: Twenty-one asymptomatic individuals (mean age 22.29 ± 2.17 years) participated in this study. Three separate ultrasound images of the levator scapula muscle were captured at the neck-shoulder junction at rest and during a loaded isometric contraction. The procedures were repeated twice, four to seven days apart to establish intra-rater test-retest reliability. Interclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to determine the reliability, and a paired t-test was performed to examine the difference in muscle thickness between two conditions. RESULTS: The results demonstrated that intra-examiner reliability was good at rest (ICC = 0.88, SEM = 1.16 mm) and excellent during loaded isometric contraction (ICC = 0.95, SEM = 0.91 mm). Furthermore, the thickness of levator scapula muscle significantly increased from rest to the loaded isometric contraction (Effect size = 1.99, P < 0.001). CONCLUSION: This study demonstrates that the thickness of the levator scapula muscle can be measured reliably at the neck-shoulder junction. Furthermore, ultrasound measures can reliably detect changes in muscle thickness from rest to a contracted state. Therefore, if the need exists to evaluate muscle morphology before and after any treatment strategy, thickness measurement of levator scapula can be determined reliably using ultrasound.

Different Effects of Aerobic Exercise and Diaphragmatic Breathing on Lower Esophageal Sphincter Pressure and Quality of Life in Patients with Reflux: A Comparative Study.

BACKGROUND Gastroesophageal reflux disease (GERD) is a worldwide disorder with an increasing prevalence. The quality of life (QOL) of the patients may be influenced by reflux disease. Diaphragmatic breathing (DB), as well as aerobic exercise (AE), may improve the symptoms of reflux disease, although it remains a controversial issue. The aim of this study was to compare the effects of AE and DB on QOL and lower esophageal sphincter (LES) pressure of patients with moderate to severe reflux. METHODS This was a case-control study that was conducted for 8 weeks among patients with moderate to severe GERD. The block randomization method was designed to randomize patients into three groups (AE, DB, and control) to achieve equal sample sizes. The control group received omeprazole 20 mg once daily. The other groups, in addition to omeprazole, received AE and DB. QOL and LES pressure were measured before and after the study by Questionary and Manometry method, respectively. RESULTS 75 patients were enrolled in this study. Positive effects of DB on LES pressure was approved (p = 0.001). DB had significantly more effects on QOL than aerobic exercise (p = 0.003). AE can significantly improve QOL in patients (p = 0.02) but no significant change in LES pressure (p = 0.38). There was no change in the control group for both variables. CONCLUSION AE had no effects on LES pressure but can improve QOL of the patients. DB had more effects on QOL than AE, so injured or disable patients with reflux who cannot do AE, can benefit from DB to improve their reflux symptoms.

Coenzyme Q0 immobilized on Magnetic Nanoparticle: Synthesis and Antitumoral Effect on Saos, MCF7 and Hela Cell Lines.

Many attempts in medical community focused on the preparation of anticancer agents. Various Coenzyme Q such as CoQ0 analogs have been reported as anti-inflammatory, anticancer, and antioxidant substances. In this study a novel derivatives of Coenzyme Q as an anticancer agent have been introduced. The prepared magnetic nanoparticle, containing CoQ0 were prepared using common chemical methods and also characterized by means of nuclear magnetic resonance (NMR), fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA), and differential scanning calorimetric (DSC). To evaluate the antiproliferative effects of the nanoparticle, the prepared compound was treated with cell lines such as Hela, MCF-7 and Saos. Moreover, the outcomes were compared with normal fibroblast cell line. These assessments were performed by means of MTT assay. Investigation on the capability of this prepared nanoparticle showed some reliable results including cytotoxicities against MCF7, Saos and Hela cancer cell lines which were illustrated by displaying the morphology of the treated cells using AO/EB dual staining fluorescent technique. Employing simple method for preparation as well as the promising cytotoxic results makes it as a promising candidate for further bioexperiments.

An ultrasonographic investigation of deep neck flexor muscles cross-sectional area in forward and normal head posture.

BACKGROUND: As one of the most common work-related musculoskeletal disorders and postural deviations, forward head posture (FHP), is considered to lead to muscle imbalance. OBJECTIVES: The aim of this study is to investigate the bilateral cross-sectional area (CSA) of the deep neck flexor muscles at rest and during five stages of the craniocervical flexion (CCF) test in individuals with FHP and the controls with normal head posture. METHODS: Eighteen students with FHP and 18 controls with normal head posture, all females aged 18-35 years, participated in this study. Participants were categorized into two groups based on their craniovertebral angle. The CSA of the deep neck flexors was measured using ultrasonography while participants lay supine on the table with a pressure biofeedback unit placed under their necks in order to let the examiner measure the CSA of the muscles during rest and five stages of the CCF test including 22, 24, 26, 28, and 30 mmHg of the pressure biofeedback unit. RESULTS: A significant effect of contraction level was observed in both groups, indicating significant increases of the CSA of the deep neck flexors during contraction (F = 64.37, P < 0.001). No significant difference was evident for the CSA of the deep neck flexors between the groups, although the increase in the CSA of the deep neck flexors was up to 28 mmHg in the normal head posture group compared to 26 mmHg in the FHP group. CONCLUSIONS: The results of the present study showed no significant difference between the performance of the deep neck flexors during the CCF test in FHP and normal head posture individuals, which challenge the common belief of the deep neck flexors weakness in individuals sustaining FHP.

Automatic activity of deep and superficial abdominal muscles during stable and unstable sitting positions in individuals with chronic low back pain.

OBJECTIVE: The purpose of this study was to assess muscle thickness changes in the deep and superficial abdominal muscles, during sitting on stable and unstable surfaces in subjects with and without chronic low back pain (CLBP). METHOD: A cross-sectional study was conducted involving 40 participants (20 CLBP and 20 healthy). Ultrasound imaging was used to assess changes in the thickness of the Transversus abdominis (TrA), Internal Oblique (IO), Rectus abdominis (RA) and External oblique (EO) muscles. Muscle thickness under two different sitting postures; (sitting on a chair and sitting on a Swiss ball), was normalized to actual muscle thickness at rest in the supine lying position and was expressed as a percentage of thickness change of muscles. RESULT: The results showed significantly greater thickness changes in RA muscle in the CLBP patients compared to the healthy subjects, during both stable and unstable sitting positions. Also, significantly lower thickness changes in TrA muscle was observed in subjects with CLBP compared to those without CLBP, during unstable sitting position. CONCLUSION: There was an imbalance between the automatic activity of TrA and RA muscles in the subjects with CLBP, compared to the pain-free controls, during an unstable sitting position. Therefore, it is necessary to pay attention, to the altered automatic activity of the abdominal muscles while utilizing a Swiss ball, for rehabilitation of subjects with CLBP.

Parental training and externalizing behaviors of children with severe hearing loss.

Background: Externalizing behavior in deaf children causes many psychological problems for their parents. Aggression and rule breaking behaviors in children with severe hearing loss may cause psychological problems in parents and in managing children's behavior. Consequently, the present study aimed at investigating the effect of parental behavioral training of mothers on reducing the externalized behaviors (aggression and rule breaking behavior) of their 9- to 10- year old children with severe hearing loss. Methods: This was an experimental study with pretest, posttest, and a control group. The research population included all students with severe hearing loss and their mothers. Thus, 30 mothers whose children had the most severe hearing loss were selected as our main sample among 80 mothers who had completed the Child Behavior Checklist. Then, they were placed into the experimental (n=15) and control groups (n=15) after being matched based on age, educational level, and socioeconomic status. The research tool was Child Behavior Checklist-Persian Version. The parental behavior training was provided for the experimental group in nine 90- minute sessions. Results: The results of the present study indicated the effectiveness of experimental treatment on decreasing the aggressive behaviors of children of mothers in the experimental group compared to mothers of the control group (p=0.001). Moreover, the results revealed a decrease in rule breaking behaviors (p= 0.007) in children of mothers of the experimental group compared to mothers of the control group. Conclusion: Parents' behavioral training is important in decreasing the aggressive and offensive behaviors in children with severe hearing loss who are at risk of behavioral problems. Furthermore, some research has highlighted the necessity of such trainings for parents of these children. Thus, the present study, emphasizing the importance of childhood problems, found that mothers' behavioral training could prevent behavioral problems of school-aged children with hearing loss and reduce the recurrence of such problems.

The effect of different exercise programs on cervical flexor muscles dimensions in patients with chronic neck pain.

OBJECTIVE: The effect of different exercise programs on cervical flexor muscles dimensions in patients with chronic neck pain is yet to be demonstrated. The purpose of this study was to assess the effect of two exercise programs; craniocervical flexion (CCF) and cervical flexion (CF), on flexor muscles dimensions in patients with chronic neck pain. METHODS: Following ethical approval, 60 patients were randomly assigned into either a CCF group or a CF group. Patients in the CCF group were given CCF exercises and those in the CF group received CF exercises. All patients received interventions for a period of ten weeks. Pain intensity and functional disability were assessed using numerical pain rate scale and neck disability index, respectively. Dimensions of longus colli (LC) and sternoclidomastoid (SCM) muscles were measured using ultrasonography (US). All measurements were taken before and after interventions. RESULTS: Following intervention, the CCF group demonstrated a significant increase in LC muscle dimensions including cross sectional area, width and thickness compared with the CF group. A statistically significant increase was found on SCM thickness in the CF group. Following intervention, SCM thickness measurement in the CCF group showed no significant changes. Statistically significant decrease on pain intensity and disability were also found in both groups. CONCLUSION: Present findings demonstrated that craniocervical flexion program which specifically recruiting deep cervical flexor muscles increased LC muscle dimension significantly and CF program as an endurance training program increased SCM thickness.

Relationship between cross sectional area of Longus Colli muscle and pain laterality in patients with cervicogenic headache.

BACKGROUND AND OBJECTIVES: Cervicogenic headache (CGH) originated from impaired cervical musculoskeletal structures. Dysfunction of deep neck flexor muscles has been reported in CGH subjects. The purpose of this study was to assess relationship between the size of these muscles and headache laterality in CGH subjects. MATERIAL AND METHOD: A cross sectional single blind study designed to investigate 37 CGH subjects compared with 37 healthy controls. Longus colli (LC) muscle Cross Sectional Area (CSA) in both sides was measured in supine position utilizing diagnostic ultrasonography. RESULTS: The mean CSA of LC muscle in healthy subjects was 0.74 ± 0.06 cm2 and in patients suffering from CGH was 0.74 ± 0.06 cm2 in left and 0.75 ± 0.06 cm<2 in right side. No significant difference was found between subjects suffering from CGH compared with healthy controls. Also no difference was found between muscle size of affected and non-affected side in unilateral CGH subjects. CONCLUSIONS: Results indicated that there was no relationship between size of LC muscle and pain laterality in patients with CGH.

Application of CdO nanoparticle ionic liquid modified carbon paste electrode as a high sensitive biosensor for square wave voltammetric determination of NADH.

In this paper we report the synthesis and application of CdO nanoparticle (CdO/NPs) and 1,3-dipropylimidazolium bromide as high sensitive sensors for voltammetric determination of nicotinamide adenine dinucleotide (NADH) using carbon paste electrode. The cyclic voltammogram showed an irreversible oxidation peak at 0.68 V (vs. Ag/AgClsat), which corresponded to the oxidation of NADH. Compared to common carbon paste electrode, the electrochemical response was greatly improved for NADH electrooxidation at a surface of CdO/NP modified ionic liquid carbon paste electrode (IL/CdO/NP/CPE). The linear response range and detection limit were found to be 0.09-750 µmol L(-1) and 0.05 µmol L(-1), respectively. Result shows that other physiological species did not interfere in the determination of NADH at the surface of the proposed sensor in the optimum condition. The proposed sensor was successfully applied for the determination of NADH in tap water, urine and pharmaceutical serum samples.

Reliability and validity of the Persian versions of the fear avoidance beliefs questionnaire and Tampa Scale of Kinesiophobia in patients with neck pain.

STUDY DESIGN: Validation of 2 self-report questionnaires. OBJECTIVE: To evaluate the internal consistency, reliability, and construct validity of the Persian versions of the fear avoidance beliefs questionnaire (FABQ) and the Tampa Scale of Kinesiophobia (TSK) in patients with acute and chronic neck pain. SUMMARY OF BACKGROUND DATA: The FABQ and TSK are 2 important measures to evaluate fear of pain and fear avoidance beliefs in patients with spinal pain. To date, the psychometric properties of these questionnaires have not been demonstrated in Persian-speaking patients with neck pain in Iran. METHODS: One hundred sixty-six patients with acute and chronic neck pain participated in the study. The construct validity of the questionnaires was evaluated by measuring convergent and known-groups validity. The visual analogue scale measure of pain, neck disability index, hospital anxiety and depression scale, and the physical (PCS-12) and mental (MCS-12) summary scores of the Short Form health survey (SF-12) were used to test construct validity of the Persian FABQ and TSK. In addition, 50 randomly selected patients with chronic neck pain were asked to complete the questionnaires 48 hours later for the second time. RESULTS: Cronbach α coefficient for the FABQ and TSK in patients with acute and chronic pain was in the range from 0.77 to 0.92 and 0.77 to 0.78, respectively. The Persian FABQ and TSK showed satisfactory test-retest reliability with intraclass correlation coefficient of more than 0.80. There were moderate to strong correlations between the Persian FABQ and TSK scores and the neck disability index (r = 0.44-0.55), Depression subscales of the hospital anxiety and depression scale (r = 0.42-0.48), and PCS-12 (r =-0.34 to -0.62). CONCLUSION: The Persian FABQ and TSK have acceptable reliability and validity for measuring pain related fear and avoidance beliefs among Persian-speaking patients with acute and chronic neck pain. However, considering the study limitations, the findings should be interpreted with caution. LEVEL OF EVIDENCE: 3.

Work related neck pain in Iranian dentists: an epidemiological study.

OBJECTIVE: The purpose of this study was to determine the prevalence of and risk factors for neck pain in dentists of Tehran province and to analyze the association of neck pain with individual and occupational characteristics. DESIGN: Following ethical approval, a cross sectional study was conducted on 300 randomly selected dentists at Tehran city. Different questionnaires were used to collect personal and occupational characteristics as well as the prevalence and risk factors of neck pain. The Iranian validated version of visual analogue scale and neck disability questionnaires were also used to assess the pain intensity and functional disability of neck, respectively. RESULTS: Point, last month, last year and lifetime prevalence of neck pain were 19.3%, 27.3%, 29.9% and 34.7%, respectively. The prevalence of neck pain was significantly correlated with regular exercise, general health condition and having an assistant (P< 0.05 in all instances) and was not significantly correlated with body mass index, age and gender. Prolonged sitting, awkward postures and repeated movements were the most significant aggravating factors. CONCLUSIONS: Results indicated that the prevalence of neck pain in dentists appears to be high. Therefore, further studies on different preventive strategies in dentists' population seem necessary.

The Effects of Stabilization and Mckenzie Exercises on Transverse Abdominis and Multifidus Muscle Thickness, Pain, and Disability: A Randomized Controlled Trial in NonSpecific Chronic Low Back Pain.

[Purpose] This study compared the effectiveness of stabilization and McKenzie exercises on pain, disability, and thickness of the transverse abdominis and multifidus muscles in patients with nonspecific chronic low back pain. [Subjects] Thirty patients were randomly assigned into two groups: the McKenzie and stabilization exercise groups. [Methods] Before and after intervention, pain, disability, and thickness of the transverse abdominis and multifidus muscles were evaluated by visual analogue scale, functional rating index, and sonography, respectively. The training program was 18 scheduled sessions of individual training for both groups. [Results] After interventions, the pain score decreased in both groups. The disability score decreased only in the stabilization group. The thickness of the left multifidus was significantly increased during resting and contracting states in the stabilization group. The thickness of the right transverse abdominis during the abdominal draw-in maneuver, and thickness of the left transverse abdominis during the active straight leg raising maneuver were significantly increased in the stabilization group. The intensity of pain, disability score, thickness of the right transverse abdominis during the abdominal draw-in manouver, and thickness of the left transverse abdominis during active straight leg raising in the stabilization group were greater than those on the Mackenzie. [Conclusion] Stabilization exercises are more effective than McKenzie exercises in improving the intensity of pain and function score and in increasing the thickness of the transverse abdominis muscle.

Reliability of ultrasound measurement of automatic activity of the abdominal muscle in participants with and without chronic low back pain.

BACKGROUND: Ultrasound (US) imaging has been considered as a non-invasive technique to measure thickness and estimate relative abdominal muscle activity. Although some studies have assessed the reliability of US imaging, no study has assessed the reliability of US measurement of automatic activity of abdominal muscles in positions with different levels of stability in participants with chronic low back pain (cLBP). The purpose of this study was to investigate within-day and between-days reliability of US thickness measurements of automatic activity of the abdominal muscles in asymptomatic participants and within-day reliability in those with cLBP. METHODS: A total of 20 participants (10 with cLBP, 10 healthy) participated in the study. The reliability of US thickness measurements at supine lying and sitting positions (sitting on a chair, sitting on a gym ball with both feet on the ground or lifting one foot off the floor) were assessed. We evaluated within-day reliability in all participants and between-days reliability in asymptomatic participants. RESULTS: We found high ICC scores (0.85-0.95) and also small SEM and MDC scores in both groups. The reliability of the measurements was comparable between participants with and without LBP in each position but the SEMs and MDCs was slightly higher in patient group compared with healthy group. It indicates high intra-tester reliability for the US measurement of the thickness of abdominal muscles in all positions. CONCLUSION: US imaging can be used as a reliable method for assessment of automatic activity of abdominal muscles in positions with low levels of stability in participants with and without LBP.

Ultrasound measurement of deep abdominal muscle activity in sitting positions with different stability levels in subjects with and without chronic low back pain.

The purpose of this study was to investigate the changes in the thickness of the transversus abdominis (TrA) and internal oblique (IO) muscles in three sitting postures with different levels of stability. The technique of ultrasound imaging was used for individuals with and without chronic low back pain (LBP). A sample of 40 people participated in this study. Subjects were categorised into two groups: with LBP (N = 20) and without LBP (N = 20). Changes in the thickness of tested muscles were normalized under three different sitting postures to actual muscle thickness at rest in the supine lying position and were expressed as a percentage of thickness change. The percentage of thickness change in TrA and IO increased as the stability of the sitting position decreased in both groups. However, the percentages of thickness change in all positions were less in subjects with LBP. There was a significant difference in thickness change in TrA when sitting on a gym ball between subjects with and without LBP but no difference was found when sitting on a chair. There was no significant difference in thickness change in IO in all positions between the two groups. Our findings indicate that difference in the percentage of thickness change in TrA between subjects with and without LBP increases as the stability of sitting position decreases.

Ultrasonography of longus colli muscle: A reliability study on healthy subjects and patients with chronic neck pain.

In this study, the reliability of the longus colli muscle (LCM) size was assessed in a relaxed state by a real time ultrasonography (US) device in a group of healthy subjects and a group of patients with chronic neck pain. Fifteen healthy subjects (19-41 years old) and 10 patients with chronic neck pain (27-44 years old) were recruited for the purpose of this study. LCM size was measured at the level of thyroid cartilage. Two images were taken on the same day with an hour interval to assess the within day reliability and the third image was taken 1 week later to determine between days reliability. Cross sectional area (CSA), anterior posterior dimension (APD), and lateral dimension (LD) were measured each time. The shape ratio was calculated as LD/APD. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were computed for data analysis. The ICC of left and right CSA for within day and between days reliability in healthy subjects were (0.90, 0.93) and (0.85, 0.82), respectively. The ICC of left and right CSA for within day and between days reliability in patients with neck pain were (0.86, 0.82) and (0.76, 0.81), respectively. The results indicated that US could be used as a reliable tool to measure the LCM dimensions in healthy subjects and patients with chronic neck pain.

Ultrasound assessment of bilateral longus colli muscles in subjects with chronic bilateral neck pain.

OBJECTIVE: The aim of this study was to investigate bilateral differences in the cross-sectional area (CSA) and shape ratio of the longus colli muscle between subjects with mechanical neck pain and healthy controls. DESIGN: A case-control cohort study was conducted. Bilateral ultrasound images of the longus colli muscle at the thyroid (C5-C6) level were conducted in 20 patients with mechanical bilateral chronic neck pain and 20 controls by an assessor blinded to the subjects' condition. CSA, anterior-posterior dimension (APD), lateral dimension (LD), and shape ratio (LD/APD) were measured. RESULTS: The intraclass correlation coefficients (3,1) were above 0.86 for within-day and above 0.81 for between-day intraexaminer reliability. Patients with mechanical neck pain showed bilateral smaller CSA (P < 0.001) and APD (P = 0.004) as compared with controls. Muscle shape and LD were not different between groups (P = 0.092 and P = 0.963, respectively). Women exhibited smaller bilateral CSA as compared with men (P < 0.01). CSA was negatively associated with self-reported disability, whereas APD was negatively associated with intensity of neck pain: the greater the self-reported disability or the pain intensity, the smaller the bilateral CSA or APD of the longus colli muscle. CONCLUSIONS: The longus colli muscle exhibited smaller bilateral CSA and APD, but not LD and shape ratio, in subjects with bilateral chronic neck pain as compared with healthy controls. Reduced CSA was negatively associated with self-reported disability and APD was negatively associated with the intensity of pain.

Ultrasonography of the cervical muscles: a critical review of the literature.

OBJECTIVE: This article presents a review of the literature concerning size measurement of cervical muscles using real-time ultrasound imaging (RUSI) in patients with neck pain and in healthy populations. METHODS: A literature search from 1996 to December 2009 making use of Science Direct and PubMed databases was conducted. Medical Subject Headings and other terms were as follows: ultrasonography, cervical, muscle, neck, size, pain, validity, reliability, neck pain, and healthy subjects. We included studies using RUSI for assessing cervical paraspinal muscles both in healthy subjects and in patients with neck pain. We assessed muscles investigated and the reliability and validity of the method used. RESULTS: The literature search yielded 16 studies. Twelve (75%) studies assessed the posterior muscles, whereas in the remaining 4 (25%), the anterior muscles were studied. Three studies quantified the size of the muscles during contraction; 3 assessed the relationship between cross-sectional area, linear dimensions, and anthropometric variables; 1 evaluated the training-induced changes in muscle size; 1 assessed the differences in muscle shape and cross-sectional area of cervical multifidus between patients with chronic neck pain and controls; 8 studies looked at the reliability of using RUSI in patients with neck pain or healthy subjects; and 3 studies evaluated the validity of RUSI compared with magnetic resonance imaging. CONCLUSIONS: This literature review has shown that there are not sufficient studies for assessing neck muscles with RUSI. It seems that using constant landmarks, knowledge of anatomy and function of target muscle, and a proper definition of muscle borders can help to take a clear image. Standardized position of the subject, correct placement of the transducer, and using multiple RUSI for statistical analyses may improve results.