An upper body musculoskeletal assessment instrument for patients with work-related musculoskeletal disorders: a pilot study.

OBJECTIVES: To examine the reliability and validity of a new outcome measure, the Upper Body Musculoskeletal Assessment (UBMA). DESIGN: Twenty subjects physician-diagnosed as having work-related musculoskeletal disorders (WRMD) and ten healthy subjects were assessed using the UBMA on three separate occasions. All subjects with WRMD attributed their injury to equipment use on their job. RESULTS: The WRMD group had significantly higher UBMA scores on the side of equipment use than on the other side (p <0.01), whereas the healthy group had similar scores on both sides (p> 0.05). UBMA scores for the WRMD group were significantly greater on both sides of the body than scores for the healthy group (p<0.01). Only one test occasion was required to produce excellent reliability coefficients (ICCs>0.88). Although group reliability was excellent, changes of 24% for patients with WRMD and 44% for healthy subjects would be required for confidence that UBMA scores for individual patients on the side of equipment use had changed from baseline. CONCLUSIONS: Although testing on one occasion produced reliable UBMA scores, healthy subjects could be distinguished from patients with WRMD, and the side of equipment use could be distinguished from the other side in patients with WRMD, prediction of individual UBMA scores was poor. In its present form, the UBMA is useful for making decisions about groups but not about individual patients. Modifications of the current UBMA are required to reduce measurement error.

Cumulative trauma disorders in the upper extremities: reliability of the postural and repetitive risk-factors index.

OBJECTIVE: This study addresses test-retest reliability of the Postural and Repetitive Risk-Factors Index (PRRI) for work-related upper body injuries. This assessment was developed by the present authors. DESIGN: A repeated measures design was used to assess the test-retest reliability of a videotaped work-site assessment of subjects' movements. SUBJECTS: Ten heavy users of video display terminals (VDTs) from a local banking industry participated in the study. SETTING: The 10 subjects' movements were videotaped for 2 hours on each of 2 separate days, while working on-site at their VDTs. MAIN OUTCOME MEASURE: The videotaped assessment, which utilized known postural risk factors for developing musculoskeletal disorder, pain, and discomfort in heavy VDT users (ie, repetitiveness, awkward and static postures, and contraction time), was called the PRRI. The videotaped movement assessments were subsequently analyzed in 15-minute sessions (five sessions per 2-hour videotape, which produced a total of 10 sessions over the 2 testing days), and each session was chosen randomly from the videotape. The subjects' movements were given a postural risk score according to the criteria in the PRRI. Each subject was therefore tested a total of 10 times (ie, 10 sessions), over two days. The maximum PRRI score for both sides of the body was 216 points. RESULTS: Reliability coefficients (RCs) for the PRRI scores were calculated, and the reliability of any one session met the minimum criterion for excellent reliability, which was .75. A two-way analysis of variance (ANOVA) confirmed that there was no statistically significant difference between sessions (p < .05). Calculations using the standard error of measurement (SEM) indicated that an individual tested once, on one day and with a PRRI score of 25, required a change of at least 8 points in order to be confident that a true change in score had occurred. The significant results from the reliability tests indicated that the PRRI was a reliable measurement tool that could be used by occupational health practitioners on the job site.

Preferential activation of the vastus medialis oblique, vastus lateralis, and hip adductor muscles during isometric exercises in females.

Disagreement exists as to whether the individual components of the quadriceps femoris can be preferentially activated, i.e., that one muscle component is activated to a greater degree of its maximum voluntary contraction ability than the remaining components. Preferential activation of the vastus medialis (VM) might be useful in the treatment of knee patients demonstrating VM atrophy. The purpose of the present investigation was to determine if the vastus medialis oblique (VMO), vastus lateralis (VL), and hip adductor (HA) muscles were preferentially activated in females during the following maximal voluntary isometric exercises: 1) unilateral quadriceps setting (QS) with the ankle positioned in neutral, 2) unilateral quadriceps setting combined with ankle dorsiflexion (QS + D), and 3) maximal bilateral hip adduction. Integrated electromyography (IEMG in mV.sec) was determined for the VMO, VL, and HA muscles of the preferred leg (i.e., that used to kick a ball) of 20 healthy females. Data were normalized using QS exercise as the reference exercise. Nonnormalized IEMG (+/-SD) of the VMO and VL was similar during QS [i.e., VMO = 1050 (+/-802) mV.sec, VL = 1075 (+/-738) mV. sec] and QS + D exercises [i.e., VMO = 1191 (+/-738) mV.sec, VL = 1202 (+/-836) mV.sec], but significantly less than these values during hip adduction exercise [i.e., VMO = 174 (+/-62) mV. sec, VL = 194 (+/-70) mV.sec]. Nonnormalized IEMG of the HA muscles was similar during both QS and QS+D [i.e., 286 (+/-405) mV.sec and 195 (+/-432) mV.sec], but significantly higher than these values during hip adduction exercise [i.e., 413 (+/-235) mV.sec]. Normalized IEMG (+/-SD)(%) demonstrated similar patterns, i.e., the ratios for the VMO and the VL muscles did not differ from one another under either QS + D [i.e., VMO = 121 (+/-60)%, VL = 116 (+/-40)%] or hip adduction conditions [i.e., VMO = 33 (+/-24)%, VL = 36 (+/-25)%]. As a result, the degree of activation of the two muscles was considered the same. These results suggest no preferential activation of the quadriceps femoris component muscles during QS, QS + D, and hip adduction exercises in the nonweight-bearing position. The use of hip adduction to preferentially activate the VMO over the VL compared with QS exercises was not substantiated. A mean increase of 20% in the VMO and VL myoelectric activity during QS (as demonstrated by the normalized IEMG), by the addition of dorsiflexion, may be clinically significant. However, further study is required.

Reliability of non-normalized and normalized integrated EMG during maximal isometric contractions in females.

The purpose of this investigation was to examine the test-retest reliability of non-normalized (absolute or raw units of mV . s) and normalized (percentage ratio) scores using integrated electromyography (IEMG) in voluntary maximal isometric contractions. Bipolar surface electrodes on the vastus medialis (VM) and vastus lateralis (VL) muscles were used to record IEMG (mV . s) on two occasions, 2-8 days apart. While, positioned supine, 20 healthy young women (mean age 24 +/- 2 yr) performed: (a) maximal voluntary unilateral quadriceps setting (QS) (i.e. isometric knee extension with the knee in 0 degrees ) with the ankle joint in a neutral position and the ankle musculature relaxed, and (b) maximal unilateral OS with the ankle joint in maximal dorsiflexion and the ankle dorsiflexors maximally contracted (QSD). The QS exercise was used to normalize IEMG (QSD: QS ratio for each of the two muscle heads) and the VM muscle was also used to normalize IEMG to the other head of the vasti (VL: VM ratio for each exercise). Reliability coefficients were excellent for test-retest reliability of non-normalized IEMG (mV . s) and for IEMG normalized to another muscle: (intraclass correlation coefficients (ICCs) > 0.86). However, IEMG normalized to another exercise was characterized by poor reliability (ICCs < 0.34), even when determined as the reliability of data averaged over two occasions. Regardless of whether absolute or normalized IEMG was used, 95% confidence intervals were wide, suggesting that precise, interday prediction of an individual's performance using the present protocol is questionnable.

Clinical applicability and test-retest reliability of an external perturbation test of balance in stroke subjects.

We address the test-retest reliability and clinical applicability of an adapted external perturbation balance assessment, ie, the Postural Stress Test (PST). Repeated-measures were designed to assess the clinical features of a component of balance disorder in stroke. Twenty ambulatory stroke patients and 20 age-, gender-, height-, and weight-matched healthy control subjects participated in this study. Stroke patients were tested (using the adapted PST) on 4 separate days; matched control subjects were tested on one occasion. With the subject standing, backward perturbation forces were applied at the level of the center of gravity. Postural reactions to the test were scored in real-time and from videotape, from two different viewing angles, ie, 45 degrees and 90 degrees to the saggital plane. Scores (out of a maximal of 81) were ascertained using a 10-point subjective-observational scale. None of the control subjects fell during testing; four of the hemiplegic subjects fell. Subjects were protected from potential injury by a custom-designed safety harness system. For the hemiplegic subjects, intraclass correlation coefficients (ICCs), calculated as the reliability of any one occasion, ranged from 0.71 to 0.77, whereas those calculated as the reliability of the mean of the first two occasions ranged from 0.83 to 0.93. Although scores on the fourth occasion were significantly greater than those on the third occasion, both being significantly greater than those on the first and second test occasions (p < .05), differences were less than 5 points on the 81-point scale.(ABSTRACT TRUNCATED AT 250 WORDS)

A reflex technique to measure presynaptic inhibition in cerebral stroke.

The purpose of this study was to evaluate the feasibility of reflex excitability measurement techniques in the partial measurement of spasticity related to cerebral stroke. Techniques involved the testing of the soleus H-reflex at specific ankle positions during passive dorsiflexing movements with and without background plantarflexing contractions; conditions attempted to simulate the terminal stance phase of gait. Testing of 12 stroke subjects, having cerebrovascular lesions related only to occlusion of the middle cerebral artery, demonstrated significantly (p < 0.01) less inhibition of the H-reflex during passive ankle dorsiflexion compared to 12 matched, healthy controls. However, evocation of the H-reflex during a low-level, voluntary plantarflexing contraction concomitant with passive dorsiflexion, did not reflect a statistical difference between the two groups. The two conditions were thought to each represent measures of faulty presynaptic inhibition as indicators of cerebral spasticity. A Chi-square calculation of sensitivity for the passive ankle movement without background plantarflexing contraction condition, was shown to significantly differentiate (p < 0.05) between the stroke and normal groups. A positive, but weak, correlation was found for stroke subjects between this reflex measure and the Ashworth clinical measure of spasticity (r = 0.49). Although stroke subjects exhibited increased joint stiffness when the full range of passive ankle dorsiflexion movement was considered, in comparison to the matched healthy control subjects, no significant increase in passive stiffness was found at the joint position of the reflex evocation. Size of the cerebral lesion, as determined from CT or MRI scan, was not related to the spasticity measures. Therefore, in a homogeneous stroke sample, a component of cerebral spasticity i.e., faculty Ia presynaptic inhibition, has been measured during a simulated functional movement in the lower extremity and was shown to differentiate this group from a matched, healthy, control sample. Joint stiffness did not contaminate the measures.

An overhead harness and trolly system for balance and ambulation assessment and training.

Safe assessment of standing balance and gait is often jeopardized by the potential for falls, which may have major physical and legal consequences. This article describes the design and use of a system that enhances the safety of the patient and clinician during balance and gait assessment and training. The system consists of an overhead track and moveable trolly that allows the patient, while secured in a simple body harness, the freedom to ambulate, perform functional types of activities, and fall with minimal risk of injury. As a result, a single therapist can more readily assess balance and ambulation, as well as provide training for these skills. In addition, the therapist is free to observe the patient's movements from any position, without direct physical contact. Practically, the system described may allow ambulation training sooner after injury or surgery, permit training in weight-bearing or partial weight-bearing activities with or without assistive devices, and allow the clinician to focus on assessment and training, rather than on patient safety.

Spasticity measurement in stroke: a pilot study.

The ability to objectively measure spasticity, related to cerebral stroke, is important in the rehabilitation therapies since many therapeutic modalities have been developed over the years to reduce spasticity. The unproven clinical expectation is that function would be improved were spasticity to be reduced. Unfortunately, the ability to measure spasticity to conduct efficacy studies of spasticity-reducing therapies is not possible. This relates to the multi-variable nature of the spastic syndrome with the result that no clinical measurement technique has been proven to be sensitive, valid and reliable. Therefore, it is important to develop a research-oriented spasticity measurement system to meet this need. We describe the current development of such a system. Details of our pilot study of a reflex excitability technique, designed to measure certain components of cerebral spasticity, are presented. The technique combined biomechanical and electrophysiological measures to investigate a homogenous stroke sample (n = 6); it incorporated the H-reflex in soleus, during passive ankle movements, as a measure of faulty neural inhibition. This component significantly (p < .05) differentiated the stroke sample from a matched, healthy control group (n = 6). Evocation of a cutaneous reflex in soleus was a condition that was problematic and it had to be dropped from the protocol. Joint stiffness, which is thought to affect measures of spasticity during passive movement, did not contaminate the measures. Further research in this direction is required to delineate and measure other neural components of spasticity while taking into account related non-neural variables. The final objective in this line of research is to develop a valid, reliable and sensitive spasticity measurement system that could be used to judge the efficacy of physical neurorehabilitation treatments currently employed to reduce spasticity following stroke.

Periodicity in the Hoffmann reflex recovery curve.

Hoffmann (H) reflex recovery curves were recorded from the soleus muscles of 10 healthy adult subjects with a view to further elucidating the pattern of facilitation of the motoneuron pool. Specific consideration was given to the possible existence of periodicity in facilitation of the motoneuron pool following a subthreshold conditioning H-reflex stimulus. The reliability of the recovery curves was also examined. The recovery curves, which utilized a 50% maximal test response, revealed the well established early facilitation (peak at 10 ms) followed by a later facilitation commencing 50 to 70 ms after the conditioning stimulus. In addition, there was evidence of peaks in excitability of the motoneuron pool occurring at 70 to 75 ms, 125 to 150 ms, and about 250 ms. The reliability of the periodicity in the recovery curve was established by examining the subjects on two separate occasions and investigating the effect of the number of measurements made within each day. Although there was considerable inter- and intrasubject variability in the form of the recovery curves, both within days, and between days, the overall group data showed a remarkably consistent periodicity for the first 350 ms following the conditioning stimulus. Methodological considerations that are important for observing the periodicity in the recovery curve were identified. These included an adequate number of measurements (test reflexes) per data point in the recovery curve, adequate sampling rate, and conditioning and test stimulus intensity. The clinical significance of these results resides in the possible contributions of the peripherally triggered periodic facilitation to rhythmic phenomena such as clonus and physiologic tremor.

Muscle activity in the spinal cord-injured during wheelchair ambulation.

Right shoulder complex muscles of nondisabled, paraplegic, and quadriplegic subjects were monitored with electromyography (EMG) during standardized wheelchair ambulation. It was shown that wheelchair ambulation required the recruitment of large amounts of available motor units in spinal cord-injured persons. Motor unit recruitments differed for the groups: recruitment was minimal for the nondisabled subjects, moderate for paraplegics, and often maximal for quadriplegics. In addition, large intra- and intergroup variabilities were found in the pattern of muscle recruitment during the standardized wheelchair ambulation movement. The high variability shown in the muscle recruitment patterns of the normal individuals was unexpected, because the ambulation movement had been standardized as much as possible. The technique used to monitor muscle activity in this study reflects an example of how EMG can be employed to analyze activity during a movement. Using this technique one can objectively determine if assumptions about what is occurring in a muscle group during activity are correct.