Susan J Lieber

University of Pittsburgh, Pittsburgh, PA, United States

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Publications (17)37.2 Total impact

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    ABSTRACT: 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. Cross-sectional study. Research laboratory CLBP subjects (n=81) and pain-free controls (n=53). Not applicable. Measures of lifting patterns and self-reported disability, pain, and psychosocial aspects. 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. 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.
    Archives of physical medicine and rehabilitation 09/2008; 89(8):1542-9. · 2.18 Impact Factor
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    ABSTRACT: 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.
    Pain 11/2007; 131(3):293-301. · 5.64 Impact Factor
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    ABSTRACT: 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.
    Clinical Journal of Pain 02/2007; 23(1 Suppl):S1-43. · 2.55 Impact Factor
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    ABSTRACT: Chronic pain and cognitive impairment are prevalent and disabling in older adults (OA), but their interrelationship has not been rigorously tested. We did so in OA with chronic low back pain (CLBP). A total of 323 OA (160 pain-free, 163 CLBP; mean age 73.5 years, 45% female) had neuropsychological (NP) testing with the Repeatable Battery for the Assessment of Neuropsychological Status, Trail Making Test, and the Grooved Pegboard Test. Pain intensity was measured with the McGill Pain Questionnaire Short Form. Physical performance (gait speed, functional reach, chair rise, trunk rotation, and static/dynamic lifting), psychosocial disruption (Geriatric Depression Scale, the Short Form-36 Mental Health and Role Limitations-Emotional Composite scale), and self-reported disability (Functional Status Index, the Short From-36 Physical Functioning/Role-Physical Composite scale) were also measured. Outpatient research laboratory. There were no group differences in age, gender, or educational level, but significant differences in NP scores (P = 0.01) were found. Five scales accounted for the differences: immediate memory (P = 0.002), language (P = 0.004), delayed memory (P = 0.04), mental flexibility (Trails B [P = 0.02]), and Grooved Pegboard (P = 0.05). NP scores were significantly correlated with physical performance (R2= 0.30, P < 0.001), but not self-reported disability (R2= 0.04, P = 0.52) or psychosocial disruption (R2= 0.05, P = 0.46). NP function was correlated with pain intensity (R2= 0.17, P < 0.001), and NP function mediated the relationship between pain and physical performance. OA with CLBP demonstrated impaired NP performance as compared with pain-free OA. Further, pain severity was inversely correlated with NP performance, and NP performance mediated the relationship between pain and physical performance. Future research should examine whether cognitive function and impaired physical performance can be improved with pain reduction.
    Pain Medicine 01/2006; 7(1):60-70. · 2.46 Impact Factor
  • European Journal of Pain - EUR J PAIN. 01/2006; 10.
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    ABSTRACT: 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.
    IEEE Transactions on Neural Systems and Rehabilitation Engineering 10/2005; 13(3):406-14. · 3.26 Impact Factor
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    ABSTRACT: The purpose of this study was to determine if jerk, (rate of change of acceleration) differs in elderly control and CLBP patients during a lifting task. Jerk was calculated for the shoulder trajectory, since shoulder motion depends on motion at both the hips and knees. To reduce noise, Woltring's GCV hepatic spline was fitted to the data and derivatives were calculated through differentiation of the spline coefficients. A root mean square (rms) measure of jerk was used for comparison. The rms jerk values for the lifts were designated as early, middle or late based on the number of repetitions completed by the subject, and a repeated measures analysis of variance allowed testing for changes over time during the task. Lift duration was also analyzed. Significant group differences were found for lift duration and rms jerk, with controls lifting faster and generating greater values of jerk than CLBP patients. Changes over time were also observed in which lift duration decreased and jerk increased with task time. A group by time interaction occurred for lift duration but not for jerk. In general, patients had slower lifts with lower jerk values than controls, suggesting that pain impacts lifting style.
    Engineering in Medicine and Biology Society, 2003. Proceedings of the 25th Annual International Conference of the IEEE; 10/2003
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    ABSTRACT: 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.
    Pain 10/2003; 105(1-2):319-26. · 5.64 Impact Factor
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    ABSTRACT: 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. Randomized, controlled clinical trial. University of Pittsburgh Pain Evaluation and Treatment Institute. 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. Subjects were randomized to receive twice-weekly PENS and physical therapy (PT) or sham PENS and physical therapy for 6 weeks. 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. 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. 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.
    Journal of the American Geriatrics Society 06/2003; 51(5):599-608. · 3.98 Impact Factor
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    ABSTRACT: The purpose of this study was to determine if the same differences in lifting observed in a younger population of chronic lower back pain (CLBP) patients are present in an elderly CLBP patient population. The parameters used to quantify the lifting patterns included lift duration, starting posture, coordination parameters, maximum hip and shoulder moments and anterior-posterior sway. The lifts performed by controls and CLBP patients were designated as early, middle or late based on the number of repetitions completed by the subject, and a repeated measures analysis allowed testing for changes over time during the task. Significant group differences were shown in lift duration and anterior-posterior (AP) body sway with controls lifting faster with more AP sway than CLBP patients. Changes over time were observed in lift duration and starting posture. Group-by-time interactions were seen in coordination parameters, maximum hip moment, lift duration, and starting posture. In general, these results show patterns of lifting like those seen in younger subjects, with similar differences between groups with and without CLBP. This test appears to have utility for evaluating the effects of CLBP on functional performance in elderly subjects.
    Engineering in Medicine and Biology, 2002. 24th Annual Conference and the Annual Fall Meeting of the Biomedical Engineering Society EMBS/BMES Conference, 2002. Proceedings of the Second Joint; 11/2002
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    ABSTRACT: 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.
    IEEE Transactions on Neural Systems and Rehabilitation Engineering 07/2002; 10(2):109-17. · 3.26 Impact Factor
  • C. Kuzkaya, J R Boston, T E Rudy, S.J. Lieber
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    ABSTRACT: Proposes that, in a dynamic lifting task, individuals adjust their lifting style to minimize a cost function involving some combination of work performed and forces generated in the spine. This proposal is to be evaluated with data previously obtained in a large experimental study of low-back pain patients before and after treatment. Because of limitations in the data collected for this study, an approximate three-segment model of the body is to be used to estimate the total work performed per lift and the moment generated at the hip, using as inputs the hip and knee angles as functions of time during the lift and the patient's height and weight. Simulation results are presented to illustrate the effects of lift type and dynamics on work and hip moment. The model then is applied to a sample of 15 patients and 15 controls. The results show that controls lift heavier loads than the patients do, but at a cost of incurring higher moments at the hip. Assuming that these moments reflect greater forces in the spine, the results suggest that controls are willing to tolerate greater spinal forces than patients in order to perform efficient lifts
    Engineering in Medicine and Biology Society, 1997. Proceedings of the 19th Annual International Conference of the IEEE; 01/1997
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    ABSTRACT: This study evaluated performance differences between patients with chronic low back pain and a control group during their performance of a novel functional capacity task. To 1) evaluated strength and endurance differences between patients and control subjects, 2) test for movement pattern differences between these groups, and 3) evaluate how these patterns changed with repetitive performance of the wheel-turning task. Despite increased emphasis on quantifying functional capacities, few well-controlled studies comparing the performances of patients with low back pain with those of control subjects have appeared in the literature, particularly for movement patterns. Forty patients with low back pain and 40 control subjects performed a sustained isodynamic wheel turning task. This task was selected because it simultaneously combined several common pain-related movements. A set of kinematic measures to characterize the basic movement patterns during this task were developed. Control subjects produced significantly higher levels of static torque and completed significantly more wheel-turning repetitions. Patients with low back pain exhibited significantly less upper torso and pelvic motion, upper torso rotation, and lateral trunk flexion than those in the control group. The dissimilar movement strategies found between the patient and control groups suggests that factors beyond more global physical explanations (e.g., deconditioning) may be important in accounting for the large discrepancy between these groups regarding the amount of work performed. These findings, along with the basic kinematic patterns developed in this study, may have important implications for determining the efficacy of instruction in body mechanics and treatment outcome for patients with chronic low back pain.
    Spine 01/1996; 20(23):2547-54. · 2.16 Impact Factor
  • T E Rudy, S J Lieber, J R Boston
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    ABSTRACT: The environment surrounding the functional capacity evaluation (FCA) is complex and determined by both external factors as well as those specific to the testing situation. In this paper we (1) briefly review existing models of pain, (2) highlight how current FCAs of pain patients adhere in general to behavioral conceptualizations of chronic pain, (3) review some inadequacies of current conceptualizations of FCA when it applies to chronic pain, (4) review the many internal and external environmental factors that can significantly influence FCAs, and (5) consider some psychosocial factors that play an important role in patients' performances. We conclude that not only should evaluators more carefully consider the central influences of psychosocial factors when interpreting the results of FCAs, but that an alternate conceptual model that emphasizes both environmental and psychological factors is also needed to more adequately describe the physical performances obtained during FCAs.
    Journal of Back and Musculoskeletal Rehabilitation 01/1996; 6(3):277-88. · 0.61 Impact Factor
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    ABSTRACT: The purpose of this study was to determine changes in the amount of work performed and lifting speed, style, and coordination during a repetitive dynamic-lifting task for patients with chronic low back pain (CLBP) after an intensive 3 1/2-week pain rehabilitation program. Subjects included 57 CLBP patients and an age- and gender-matched control group (n = 57). Patients' work indices increased by 71%, but remained significantly less than those observed for controls. Similarly, their lifting speed also increased significantly after treatment, but remained slower than the lifting speed of controls. Patients' posttreatment coordination indices, however, were not significantly different from those of controls. This finding suggests that treatment effectively normalized the dynamic lifting motion used by the patients. These findings, along with the basic kinematic patterns developed in this study, have important implications for determining improvements in functional capacity in the treatment of patients with CLBP.
    Journal of Spinal Disorders 11/1995; 8(5):342-51. · 1.21 Impact Factor
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    ABSTRACT: 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. Case-comparison study. Ambulatory university laboratory. A community sample of 62 individuals with lower limb amputations or paraplegia, 31 with chronic pain and 31 pain-free. Standardized lifting and wheel-turning tasks. 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. 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.
    Clinical Journal of Pain 19(1):18-30. · 2.55 Impact Factor
  • S J Lieber, T E Rudy, J R Boston
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    ABSTRACT: To measure the efficacy of body mechanics instruction (BMI) in patients with low back pain. The effect of BMI was measured in four participants with back injuries using a standardized lifting protocol. Static strength, weight lifted, number of lifts completed, and motion analysis data to describe the body mechanics were measured before and after work hardening to evaluate treatment effects. The participants' performances were compared with 52 controls from an earlier study. Starting postures, characterized by degrees of hip and knee flexion, varied by participant but favored a squat lift in three participants when compared with the controls. Dynamic motion synchrony of the hip and knee joints was similar to controls in three of the four participants. Posttest data revealed significant changes in static strength, dynamic endurance, and lifting speed. Intensive instruction in body mechanics provided during the work-hardening treatment produced major changes in lifting styles, in terms of both starting postures and dynamic aspects of repetitive lifting. The computerized measurement procedures used in this study permitted more careful and detailed analyses of body mechanics, particularly dynamic aspects, than is possible with observational methods. This study demonstrated some of the inherent intricacies in isodynamic lifting and suggests additional areas of performance that may be important to address in BMI.
    The American journal of occupational therapy.: official publication of the American Occupational Therapy Association 54(2):166-75. · 1.70 Impact Factor