Classifying subgroups of chronic low back pain patients based on lifting patterns.

OBJECTIVE: To compare self-reported measures of chronic lower back pain (CLBP) patients who were assigned to 2 subgroups based on their lifting patterns performed during a repetitive lifting task. DESIGN: Cross-sectional study. SETTING: Research laboratory PARTICIPANTS: CLBP subjects (n=81) and pain-free controls (n=53). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Measures of lifting patterns and self-reported disability, pain, and psychosocial aspects. RESULTS: Two CLBP subgroups were found: 1 group that lifts similarly to control subjects (n=35) and 1 group that lifts very differently from controls (n=46). The CLBP group that lifted differently than controls reported higher pain intensity (P=.005), higher pain severity (P=.025), and lower self-efficacy (P=.013) than the CLBP group that lifted similarly to controls. CONCLUSIONS: A classification system based on lifting patterns identified 2 CLBP subgroups that were significantly different on lifting and self-reported measures, indicating the importance of physical functioning measures in classification systems.

An interdisciplinary expert consensus statement on assessment of pain in older persons.

This paper represents an expert-based consensus statement on pain assessment among older adults. It is intended to provide recommendations that will be useful for both researchers and clinicians. Contributors were identified based on literature prominence and with the aim of achieving a broad representation of disciplines. Recommendations are provided regarding the physical examination and the assessment of pain using self-report and observational methods (suitable for seniors with dementia). In addition, recommendations are provided regarding the assessment of the physical and emotional functioning of older adults experiencing pain. The literature underlying the consensus recommendations is reviewed. Multiple revisions led to final reviews of 2 complete drafts before consensus was reached.

The use of splines to calculate jerk for a lifting task involving chronic lower back pain patients.

Motion differences in a repetitive lifting task have been described previously using differences in the timing of body angle changes during the lift. These timing changes relied on small differences of motion and are difficult to measure. The purpose of this study was to evaluate shoulder jerk (rate of change of acceleration) in a repetitive lifting task as an alternative parameter to detect differences of motion between controls and chronic lower back pain (CLBP) patients and to measure the impact of a rehabilitation program on jerk. The jerk calculation was a noisy measure, since jerk is the third derivative of position; consequently a simulation was performed to evaluate smoothing methods. Woltring's generalized cross-validation spline produced the best estimates of the third derivative and was fit to subject data. The root mean square (rms) amplitude of jerk was used for comparison. Significant group differences were found. CLBP patients performed lifts with lower jerk values than controls and, as the task progressed, both groups increased jerk. After completion of a rehabilitation program, CLBP patients performed lifts with greater rms jerk. In general, patients performed lifts with lower jerk values than controls, suggesting that pain impacts lifting style.

Body motion during repetitive isodynamic lifting: a comparative study of normal subjects and low-back pain patients.

To quantify performance differences between patients with low-back pain (LBP) and a control group during their performance of a repetitive isodynamic lifting task. Case-control study was done. LBP patients were recruited and tested at an outpatient ambulatory chronic pain rehabilitation program before treatment was begun. Fifty-three LBP patients who had prolonged back pain and 53 age and gender matched pain-free control subjects. Overall lifting performance measures included weight lifting and number of lifts completed; kinematic measures of hip and knee movements during lifting were described by hyperbolic tangent models, and included static measures of starting and ending angles, and dynamic measures of midpoint, falltime, and lift speed. Control subjects completed significantly more lifts and lifted more weight than patients. Starting hip flexion was greater for controls and starting knee flexion was greater for patients, indicating that patients used more of a leg lift. Patients and controls also differed significantly on dynamic measures, particularly lifting speed and hip and knee temporal midpoints. Major static and dynamic motion differences were found between LBP patients and controls as they performed repetitive lifting under a constant load. These findings indicate that body motion parameters, in addition to more common strength and endurance measures, are necessary to describe the impact of persistent LBP on a person's lifting abilities.

Efficacy of percutaneous electrical nerve stimulation for the treatment of chronic low back pain in older adults.

OBJECTIVES: To determine the efficacy of a complementary analgesic modality, percutaneous electrical nerve stimulation (PENS), for the treatment of chronic low back pain (CLBP) in community-dwelling older adults. DESIGN: Randomized, controlled clinical trial. SETTING: University of Pittsburgh Pain Evaluation and Treatment Institute. PARTICIPANTS: Thirty-four English speaking, community-dwelling adults aged 65 and older with CLBP of at least moderate intensity experienced every day or almost every day. INTERVENTION: Subjects were randomized to receive twice-weekly PENS and physical therapy (PT) or sham PENS and physical therapy for 6 weeks. MEASUREMENTS: At baseline, immediately after the 6-week intervention period, and 3 months later, the primary outcome measures pain intensity and pain-related disability were assessed. The secondary outcome measures physical performance (timed chair rise, functional reach, gait speed, static and isoinertial lifting), psychosocial factors (mood, sleep, and life control), and cognitive function (measures of attention, concentration, and mental flexibility) were also collected. RESULTS: Subjects randomized to PENS plus PT displayed significant reductions in pain intensity measures from pre- to posttreatment (P <.001), but the sham PENS plus PT group did not (P =.94). These pain reduction effects were maintained at 3-month follow-up. Similarly, significant reductions in pain-related disability were observed at posttreatment (P =.002) for the PENS plus PT group and were maintained at follow-up, but the sham PENS plus PT group did not show reductions in pain-related disability (P =.81). Of the secondary outcome measures, psychosocial function, timed chair rise, and isoinertial lifting endurance also improved significantly at posttreatment for the PENS plus PT group, and their improvement was sustained at 3-month follow-up, but the sham PENS plus PT did not display significant changes on these measures after treatment. CONCLUSION: This preliminary study suggests that PENS may be a promising treatment modality for community-dwelling older adults with CLBP, as demonstrated by reduction in pain intensity and self-reported disability, and improvement in mood, life control, and physical performance. Larger studies with longer duration of follow-up are needed to validate these findings and support the use of PENS in clinical practice.

The influence of weight and starting height on lifting mechanics in lower extremity amputees.

This study compares the lifting mechanics of lower extremity amputees to controls and describes the influence of weight lifted and starting height on lifting style. Subjects included three individuals with transtibial amputation (TTA), two individuals with transfemoral amputation (TFA), and three able-bodied controls (CO). Amputee subjects performed six repetitions of six weights, randomly ordered, from two starting heights. TTA lifted from 30 cm and knee height, TFA from knee and thigh height, and controls from all three heights. Data were obtained from a work simulator, force plate, and a motion analysis system, with starting posture index, lateral sway index, lift duration, synchrony index, and hip moments and elbow moments as dependent measures. The results for each lifting height were analyzed using a mixed model repeated measures MANOVA to test for group and weight differences and post hoc tests were applied when appropriate. Results suggest that healthy lower extremity amputees who have had a number of years to adjust to their prosthesis and develop compensatory strategies can complete a repetitive lifting task at a performance level very similar to able-bodied controls. The most consistent group differences detected were in the timing parameters: synchrony and duration. TTA and TFA tended to lift with less synchronization of hip and knee movements than able-bodied controls and to initiate the lift with their upper bodies. In contrast, able-bodied controls tended to move their upper and lower bodies more synchronously during the lift. TTA had longer lift durations than CO. In terms of stability and moments generated, TTA lifted very similarly to controls. TFA used a different lifting style that involved higher moments and more use of the upper body, particularly for lifts of heavier weights. TFA appeared to be less stable than CO, while TTA did not appear to be less stable than CO.

Psychosocial predictors of physical performance in disabled individuals with chronic pain.

OBJECTIVES: First, to identify what physical performance differences existed between a group of disabled individuals with chronic pain and a control group of pain-free individuals with comparable disabilities; and second, to test a psychosocial model designed to evaluate which psychosocial constructs were predictive of performance in disabled individuals with chronic pain. DESIGN: Case-comparison study. SETTING: Ambulatory university laboratory. PARTICIPANTS: A community sample of 62 individuals with lower limb amputations or paraplegia, 31 with chronic pain and 31 pain-free. INTERVENTION: Standardized lifting and wheel-turning tasks. MAIN OUTCOME MEASURES: Static strength, endurance, lifting speed, lateral and anterior-posterior sway, and multidimensional psychosocial measures. RESULTS Disabled individuals with chronic pain had decreased endurance for both the lifting (p <0.001) and the wheel-turning (p <0.05) tasks. A psychosocial model of physical performance also was evaluated. Using confirmatory factor analysis, 31 measures were used to validate 8 theoretical constructs: emotional functioning, pain intensity, pain cognitions, physical functioning, social functioning, task-specific self-efficacy, performance outcome, and performance style. Regression analyses indicated that more than 90% of the variance in performance was predicted by psychosocial factors, with self-efficacy, perceived emotional and physical functioning, pain intensity, and pain cognitions showing the highest associations. CONCLUSIONS: Chronic pain was found to significantly reduce the performance in individuals with lower limb amputations and paraplegia. A strong association was found between performance and psychosocial factors in disabled individuals with chronic pain. These findings extend the existing literature by validating that psychosocial models of chronic pain can be applied to the disabled population, with results similar to those of other chronic pain samples.

The impact of chronic low back pain on older adults: a comparative study of patients and controls.

Chronic low back pain (CLBP) is one of the most common, poorly understood, and potentially disabling chronic pain conditions from which older adults suffer. Many older adults remain quite functional despite CLBP, and because age-related comorbidities often exist independently of pain (e.g., medical illnesses, sleep disturbance, mobility difficulty), the unique impact of CLBP is unknown. We conducted this research to identify the multidimensional factors that distinguish independent community dwelling older adults with CLBP from those that are pain-free. Three hundred twenty cognitively intact participants (162 with moderate pain for 3 months, and 158 pain-free) underwent comprehensive assessment of pain severity, medical comorbidity (illnesses, body mass index, medications), severity of degenerative disc and facet disease, lumbar flexion, psychological constructs (self-efficacy, mood, overall mental health), and self-reported as well as performance-based physical function. Significant differences were ascertained for all 22 measures. Discriminant function analysis revealed that eight measures uniquely maximized the separation between the two groups (self-reported function with the Functional Status Index and the SF-36, performance-based function with repetitive trunk rotation and functional reach, mood with the Geriatric Depression Scale, comorbidity with the Cumulative Illness Rating Scale and BMI, and severity of degenerative disc disease). These results should help to guide investigators that perform studies of CLBP in older adults and practitioners that want an easily adaptable battery for use in clinical settings.