Standing balance: a comparison between idiopathic and whiplash induced neck pain
From: Manual Therapy. 2008 Jun;13(3):183-91. Epub 2007 Feb 15
Disturbances of balance have been found both in patients with whiplash associated disorders and idiopathic neck pain. This study directly compared balance between these groups to determine if neck pain precipitated by trauma resulted in greater or different balance impairments. The study was a comparative, observational design. Thirty subjects with whiplash, 30 with idiopathic neck pain and 30 healthy controls, took part in the study. Subjects performed balance tests in comfortable, narrow and tandem stances. Balance disturbances (sway energy and/or root mean squared (RMS) amplitude) were evident in several tests between subjects with neck pain and controls. Direct comparison between the neck pain groups revealed that the whiplash group had significantly greater sway energy and RMS amplitude than the idiopathic group in comfortable stance tests on a soft surface. Further, the whiplash group had greater RMS, but significantly less sway energy than the idiopathic group in most narrow stance tests in the anterior posterior direction. Both neck pain groups were also significantly less able to complete the eyes closed, tandem test compared to control subjects.
The study has found that balance deficits exist in both subjects with whiplash associated disorders and idiopathic neck pain compared to controls; however, differences in balance strategies may exist between the neck pain groups. Overall, subjects who have experienced trauma appear to have greater balance disturbances.
Self reported driving habits in subjects with persistent whiplash associated disorder: relationship to sensorimotor and psychologic features
From: Archives of Physical Medicine and Rehabilitation. 2008 Jun;89(6):1097-102
Self reported driving habits after whiplash injury and to determine any relation among self reported driving habits, selected sensorimotor impairments, and psychologic features. Subjects (n=30) with chronic whiplash and 30 asymptomatic controls. The Driving Habits Questionnaire (composite driving tasks score), Neck Disability Index, 28-item General Health Questionnaire, Impact of Events Scale-Revised, Tampa Scale for Kinesiophobia, neck range of motion, neck joint position error, and smooth pursuit neck torsion test.
Subjects in the whiplash group had equal driving exposure and driving spaces (distances, locations) compared with control subjects but reported significantly more driving difficulty with most driving tasks. There were no significant correlations between the composite driving tasks score and any of the sensorimotor impairments, but there were significant and moderate correlations between the composite driving task score and both pain and disability (Neck Disability Index score, .518) and anxiety (General Health Questionnaire score -28, .518; Impact of Events Scale-Revised score, .524). Persons with chronic whiplash have greater self reported driving difficulty than controls, which appears to relate more to reported levels of pain and disability and psychologic stress than laboratory measures of features of neck sensorimotor control.
Quality of sleep in patients with chronic low back pain: a case-control study
From: European Spine Journal. 2008 Apr 4. [Epub ahead of print]
Animal experiments and studies in humans clearly show that the relation between pain (acute and chronic) and sleep quality is two-way: sleep disorders can increase pain, which in turn may cause sleep disorders. Sleep disorders and chronic low back pain are frequent health problems and it is unsurprising that the two can co-exist. This study was conducted to evaluate if sleep disorders and chronic pain associated are more frequently than one would expect. The objective of the study was to compare sleep quality in a population of patients with chronic low back pain and a control population. Sleep quality was assessed in 101 patients with chronic low back pain (chronic low back pain) and in 97 sex and age matched healthy control subjects using the Pittsburgh Sleep Quality Index [score from 0 (no disorder) to 21]. The French version of the Dallas Pain Questionnaire was used to assess the impact of low back pain on patients’ quality of life. This impact was taken as nil in the healthy controls. The patients with chronic low back pain and the controls were comparable in age, sex, and height, but mean bodyweight was higher in the chronic low back pain group. The patients with chronic low back pain were also more frequently on sick leave than the controls. Coffee, tea, and cola intakes were comparable in the two groups. Patients with chronic low back pain had statistically higher scores in all items of the Pittsburgh Sleep Quality Index than the healthy controls. The mean Pittsburgh Sleep Quality Index was 4.7 +/- 3.2 for the healthy controls and 10.9 +/- 7.9 for the patients with chronic low back pain. Sleep disorders were greater when the impact of chronic low back pain on daily life (the four aspects of the Dallas Pain Questionnaire) was greater. The sleep of the patients with chronic low back pain was significantly altered compared with that of the healthy controls, in proportion to the impact of low back pain on daily life. Our findings do not indicate whether sleep disorders are a cause or a consequence of chronic low back pain.
Biomechanical model study of pelvic belt influence on muscle and ligament forces
From: Journal of Biomechanics. 2008 May 21; [Epub ahead of print]
Many patients with low back and/or pelvic girdle pain feel relief after application of a pelvic belt. External compression might unload painful ligaments and joints, but the exact mechanical effect on pelvic structures, especially in (active) upright position, is still unknown. In the present study, a static three-dimensional (3-D) pelvic model was used to simulate compression at the level of anterior superior iliac spine and the greater trochanter. The model optimised forces in 100 muscles, 8 ligaments and 8 joints in upright trunk, pelvis and upper legs using a criterion of minimising maximum muscle stress. Initially, abdominal muscles, sacrotuberal ligaments and vertical sacroiliac joints shear forces mainly balanced a trunk weight of 500N in upright position. Application of 50N medial compression force at the anterior superior iliac spine (equivalent to 25N belt tension force) deactivated some dorsal hip muscles and reduced the maximum muscle stress by 37%. Increasing the compression up to 100N reduced the vertical SIJ shear force by 10% and increased sacroiliac joint compression force with 52%. Shifting the medial compression force of 100N in steps of 10N to the greater trochanter did not change the muscle activation pattern but further increased sacroiliac joint compression force by 40% compared to coxal compression. Moreover, the passive ligament forces were distributed over the sacrotuberal, the sacrospinal and the posterior ligaments. The findings support the cause-related designing of new pelvic belts to unload painful pelvic ligaments or muscles in upright posture.
Head repositioning accuracy to neutral: A comparative study of error calculation
From: Manual Therapy. 2008 May 23; [Epub ahead of print]
Deficits in cervical proprioception have been identified in subjects with neck pain through the measure of head repositioning accuracy. Nevertheless there appears to be no general consensus regarding the construct of measurement of error used for calculating head repositioning accuracy. This study investigated four different mathematical methods of measurement of error to determine if there were any differences in their ability to discriminate between a control group and subjects with a whiplash associated disorder. The four methods for measuring cervical joint position error were calculated using a previous data set consisting of 50 subjects with whiplash complaining of dizziness, 50 subjects with whiplash not complaining of dizziness and 50 control subjects. The results indicated that no one measure of head repositioning accuracy uniquely detected or defined the differences between the whiplash and control groups. Constant error was significantly different between the whiplash and control groups from extension. Absolute errors and root mean square errors demonstrated differences between the two whiplash associated disorder groups in rotation trials. No differences were seen with variable error. The results suggest that a combination of absolute errors or root mean square error and constant error are probably the most suitable measures for analysis of head repositioning accuracy.
A field comparison of neck and shoulder postures in symptomatic and asymptomatic office workers
From: Applied Ergonomics. 2002 Jan;33(1):75-84
Poor neck and shoulder postures have been suggested to be a cause of neck and shoulder pain in computer workers. The present study aimed to evaluate and compare the head, neck and shoulder postures of office workers with and without symptoms in these regions, in their actual work environments. The two all female subject groups reported significantly different discomfort scores across five trials repeated in a single working day. The results of repeated video capture and two-dimensional motion analysis showed that there were trends for increased head tilt and neck flexion postures in the symptomatic subjects (n = 8), compared to the asymptomatic subjects (n = 8). Symptomatic subjects also tended to have more protracted acromions compared with asymptomatic subjects and showed greater movement excursions in the head segment and the acromion. All subjects demonstrated an approximately 10% increase in forward head posture from their relaxed sitting postures when working with the computer display, but there were no significant changes in posture as a result of time-at-work.
Individual and work related risk factors for neck pain among office workers
From: European Spine Journal. 2007 May; 16(5): 679–686.
Work related neck disorders are common problems in office workers, especially among those who are intensive computer users. It is generally agreed that the etiology of work related neck disorders is multidimensional which is associated with, and influenced by, a complex array of individual, physical and psychosocial factors.
The results of this study indicate that physical and psychosocial work factors, as well as individual variables, are associated with the frequency of neck pain. These association patterns suggest also opportunities for intervention strategies in order to stimulate an ergonomic work place setting and increase a positive psychosocial work environment.
Work related neck disorders are common problems in office workers, especially among those who are intensive computer users The worldwide trend is for people to use computers for longer periods daily, due to increased computer-based tasks at work as well as during leisure activities. Introduction of the computer into the workplace has meant changes in work organization, and a different use of worker physical and mental potential. It is generally agreed that the etiology of work related neck disorders is multidimensional which is associated with, and influenced by, a complex array of individual, physical and psychosocial factors. Among these various risk factors, work-related psychosocial factors appear to play a major role. Work-related psychosocial variables may include aspects of the work content, organization, and interpersonal relationships at work, finances and economics. Individual factors are considered as confounding factors that influence the relation between psychosocial demands and the occurrence of neck pain. Furthermore, psychosocial demands may be highly correlated with physical demands, which also indicate a confounding effect of physical factors on the relation between work-related psychosocial variables and the occurrence of neck pain.
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Post trauma ratings of pre collision pain and psychological distress predict poor outcome following acute whiplash trauma: A 12-month follow-up study
From: Pain. 2008 May 20; [Epub ahead of print]
Patients with acute whiplash trauma were followed to examine if post trauma ratings of pre collision pain and psychological distress were associated with reduced work capability and neck pain at 12 months follow-up. The study included 740 consecutive patients (474 females, 266 males) referred from emergency departments or primary care after car accidents in four counties in Denmark. After the collision patients received a questionnaire on psychological distress, unspecified pain and socio-demographics and 12 months later a follow-up on work capability and neck pain was performed. Risk factors were identified by multiple logistic regression analysis.
Factors associated with affected work capacity at the 12 month follow-up were pre collision unspecified pain condition and socio-demographic characteristics: female gender, low educational level, unemployment and blue collar worker. Factors associated with considerable neck pain at follow-up were pre collision unspecified pain, pre collision high psychological distress and socio-demographic characteristics: female gender and formal education > 4years. Pre collision neck pain and severity of accident were not associated with poor outcome.
Unspecified as opposed to specified pain (neck pain) before the collision is associated with poor recovery and high accumulation of pre-collision psychological distress is associated with considerable neck pain at follow-up. However, no conclusions on causality can be drawn. Personal characteristics before the collision are important for recovery and attention to pre collision characteristics may contribute to the prevention of poor recovery after acute whiplash trauma.
Decreased isometric neck strength in women with chronic neck pain and the repeatability of neck strength measurements
From: Archives of Physical Medicine and Rehabilitation. 2004 Aug;85(8):1303-8
To evaluate neck flexion, extension, and, especially, rotation strength in women with chronic neck pain compared with healthy controls and to evaluate the repeatability of peak isometric neck strength measurements in patients with neck pain. Twenty-one women with chronic neck pain and healthy controls matched for sex, age, anthropometric measures, and occupation. Peak isometric strength of the cervical muscles was tested in rotation, flexion, and extension.
Significantly lower flexion (29%), extension (29%), and rotation forces (23%) were produced by the chronic neck pain group compared with controls. When the repeated test results were compared pairwise against their mean, considerable variation was observed in the measures on the individual level. Intratester repeatability of the neck muscle strength measurements was good in all the 4 directions tested in the chronic neck pain group. The coefficient of repeatability was 15N, both in flexion and extension, and 1.8 Nm in rotation. On the group level, improvement up to 10% due to repeated testing was observed.
The group with neck pain had lower neck muscle strength in all the directions tested than the control group. This factor should be considered when planning rehabilitation programs. Strength tests may be useful in monitoring training progress in clinical settings, but training programs should be planned so that the improvement in results is well above biologic variation, measurement error, and learning effect because of repeated testing.
Predicting persistent pregnancy related low back pain
From: Spine. 2008 May 20;33(12):E386-93
A cohort study to examine the course of subtypes of low back pain experienced [no low back pain, pelvic girdle pain, lumbar pain, and combined pelvic girdle pain and lumbar pain (combined pain)] during gestational weeks 12 to 18 and 3 months postpartum, and to explore potential predictors for persistent pelvic girdle pain or pelvic girdle pain and lumbar pain postpartum.
Low back pain is more prevalent in pregnant women (25%) than in the general population (6.3%). Persistent low back pain postpartum (16%) is usually studied as a single entity. However, only one subgroup of low back pain, pelvic girdle pain, is associated with pregnancy. Several studies have suggested an association between muscular dysfunction and pregnancy-related low back pain, however, muscle dysfunction has not been evaluated as potential predictor of persistent low back pain postpartum. Possible subgroup differences in the course and predictors of persistent low back pain are unknown.
Pregnant women (n = 308) were classified into low back pain subgroups by mechanical assessment of the lumbar spine, pelvic pain provocation tests, standard history, and pain drawings. Trunk muscle endurance, hip muscle strength (dynamometer) and gait speed were evaluated. Multiple logistic regression was used to identify predictors from self-reports and clinical examination. RESULTS: Women with combined pain recovered to a lower degree 33% (17 of 51) than those with pelvic girdle pain 66% (56 of 85) or lumbar pain 72% (21 of 29). Predictors for having persistent pelvic girdle pain or combined pain after delivery were low endurance of back flexors, older age, combined pain in early pregnancy and work dissatisfaction (explained variance 30%).
Women with pelvic girdle pain and lumbar pain were identified to be a target group since they had the most unfavorable course and since the classification of pelvic girdle pain and lumbar pain pain was found to be a predictor for persistent pain postpartum. Identification of women at risk for persistent pain postpartum seems possible in early pregnancy and requires physical examination and self-reports. Pregnancy had low impact on the course of lumbar pain.
