Samuel S Wu

University of Florida, Gainesville, Florida, United States

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Publications (121)370.17 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: As the U.S. population ages, efficacious interventions are needed to manage pain and maintain physical function among older adults with osteoarthritis (OA). Skeletal muscle weakness is a primary contributory factor to pain and functional decline among persons with OA, thus interventions are needed that improve muscle strength. High-load resistance exercise is the best-known method of improving muscle strength; however high-compressive loads commonly induce significant joint pain among persons with OA. Thus interventions with low-compressive loads are needed which improve muscle strength while limiting joint stress. This study is investigating the potential of an innovative training paradigm, known as Kaatsu, for this purpose. Kaatsu involves performing low-load exercise while externally-applied compression partially restricts blood flow to the active skeletal muscle. The objective of this randomized, single-masked pilot trial is to evaluate the efficacy and feasibility of chronic Kaatsu training for improving skeletal muscle strength and physical function among older adults. Participants aged≥60years with physical limitations and symptomatic knee OA will be randomly assigned to engage in a 3-month intervention of either (1) center-based, moderate-load resistance training, or (2) Kaatsu training matched for overall workload. Study dependent outcomes include the change in 1) knee extensor strength, 2) objective measures of physical function, and 3) subjective measures of physical function and pain. This study will provide novel information regarding the therapeutic potential of Kaatsu training while also informing about the long-term clinical viability of the paradigm by evaluating participant safety, discomfort, and willingness to continually engage in the intervention. Copyright © 2015. Published by Elsevier Inc.
    Contemporary clinical trials 06/2015; DOI:10.1016/j.cct.2015.06.016 · 1.99 Impact Factor
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    ABSTRACT: Study Design Literature review and cross-sectional study. Objective To describe the development of a review of systems screening tool appropriate for use by orthopaedic physical therapists. Background Direct access to physical therapy necessitates greater responsibility to determine appropriateness of care by recognizing the potential for concomitant disease or systemic involvement. Recent research has identified excessive variability in reporting of red flag symptoms. An initial step to improving identification of red flag symptoms is the development of a standardized screening tool. Methods First, a red flag symptom item bank was compiled from a systematic literature review to allow for further psychometric testing and development of a screening tool. Second, physical therapists in 11 outpatient clinics recruited patients presenting with primary complaints of neck, shoulder, low back, or knee pain. Patients completed the red flag symptom item bank and standard questionnaires for comorbidities, negative mood, quality of life, pain, and function. The development of the screening tool involved identifying and combining different three-item sets that characterized the highest number of patients reporting at least one positive symptom response (operationally defined as "red flag symptom responder"). Results The literature search yielded 103 studies meeting inclusion criteria and the final item bank consisted of 97 items representing 8 body systems. 431 patients with primary complaints of neck (n=93), shoulder (n=108), low back (n=119), or knee (n=111) disorders contributed to the cross-sectional study. The number of red flag symptom responders was 393/431 (91.2%). These patients were older, more likely to be female, had lower income, and were more likely to report neck or back pain (all P values < 0.05). A 10 item review of systems screening tool correctly identified 372/393 (94.7%) and a 23 item version identified 393/393 (100%) of responders. The review of systems screening tools and the complete 97 item bank had similar correlations with concurrent clinical measures, except for depressive symptoms. Conclusions Concise red flag symptom identification appears to be feasible in outpatient orthopaedic physical therapy settings. Future research will determine how this review of systems screening tool needs refinement for different patient populations and whether it predicts clinical outcomes or the need for referral to other providers. J Orthop Sports Phys Ther, Epub 21 May 2015. doi:10.2519/jospt.2015.5900.
    05/2015; DOI:10.2519/jospt.2015.5900
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    ABSTRACT: Initial management decisions following a new episode of low back pain (LBP) are thought to have profound implications for health care utilization and costs. The purpose of this study was to evaluate the impact of early and guideline adherent physical therapy for low back pain on utilization and costs within the Military Health System (MHS). Patients presenting to a primary care setting with a new complaint of LBP from January 1, 2007 to December 31, 2009 were identified from the MHS Management Analysis and Reporting Tool. Descriptive statistics, utilization, and costs were examined on the basis of timing of referral to physical therapy and adherence to practice guidelines over a 2-year period. Utilization outcomes (advanced imaging, lumbar injections or surgery, and opioid use) were compared using adjusted odds ratios with 99% confidence intervals. Total LBP-related health care costs over the 2-year follow-up were compared using linear regression models. 753,450 eligible patients with a primary care visit for LBP between 18-60 years of age were considered. Physical therapy was utilized by 16.3% (n = 122,723) of patients, with 24.0% (n = 17,175) of those receiving early physical therapy that was adherent to recommendations for active treatment. Early referral to guideline adherent physical therapy was associated with significantly lower utilization for all outcomes and 60% lower total LBP-related costs. The potential for cost savings in the MHS from early guideline adherent physical therapy may be substantial. These results also extend the findings from similar studies in civilian settings by demonstrating an association between early guideline adherent care and utilization and costs in a single payer health system. Future research is necessary to examine which patients with LBP benefit early physical therapy and determine strategies for providing early guideline adherent care.
    BMC Health Services Research 04/2015; 15(1). DOI:10.1186/s12913-015-0830-3 · 1.66 Impact Factor
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    ABSTRACT: To ascertain the existence of discordance between perceived and measured balance in persons with stroke and to examine the impact on walking speed and falls. A secondary analysis of a phase three, multicentered randomized controlled trial examining walking recovery following stroke. A total of 352 participants from the Locomotor Experience Applied Post-Stroke (LEAPS) trial. Participants were categorized into four groups: two concordant and two discordant groups in relation to measured and perceived balance. Number and percentage of individuals with concordance and discordance were evaluated at two and 12 months. Walking speed and fall incidence between groups were examined. Perceived balance was measured by the Activities-Specific Balance Confidence scale, measured balance was determined by the Berg Balance Scale and gait speed was measured by the 10-meter walk test. Discordance was present for 35.8% of participants at two months post stroke with no statistically significant change in proportion at 12 months. Discordant participants with high perceived balance and low measured balance walked 0.09 m/s faster at two months than participants with concordant low perceived and measured balance (p < 0.05). Discordant participants with low perceived balance and high measured balance walked 0.15 m/s slower than those that were concordant with high perceived and measured balance (p ⩽ 0.0001) at 12 months. Concordant participants with high perceived and measured balance walked fastest and had fewer falls. Discordance existed between perceived and measured balance in one-third of individuals at two and 12 months post-stroke. Perceived balance impacted gait speed but not fall incidence. © The Author(s) 2015.
    Clinical Rehabilitation 03/2015; DOI:10.1177/0269215515578294 · 2.18 Impact Factor
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    ABSTRACT: Background: Parkinson's disease (PD) patients with 20 years or more survival (PD-20) are not well characterized. Objective: To evaluate PD-20 patient characteristics and identify areas for improvement of their health care. Methods: The international, multicenter National Parkinson's Foundation Quality Improvement Initiative (NPF-QII) study database was queried to identify PD-20 subjects. Demographic and clinical data were analyzed. Results: We identified 187 PD-20 subjects (55% men) representing 4% (187/4,619) of all NPF-QII participants. Subjects were mean age 69.5 years; mean age at PD onset was 44.0 years. The majority (75%) had 20-25 years of PD duration, the longest duration being 49 years. They were median Hoehn and Yahr stage 3, and 75% had motor fluctuations. Half (54%) reported exercising. The majority (89%) were living at home and required a caregiver (88%). They were mildly cognitively impaired for age (Montreal Cognitive Assessment estimate 22.6 ± 3.7), with most deficits in verbal fluency and delayed recall. Quality of life (Parkinson's Disease Quality of Life Questionnaire index 36 ± 15%) was mild to moderately impaired, with most impairment in mobility and activities of daily living. Caregiver strain measured by the Multidimensional Caregiver Strain Index (27 ± 16%), recorded highest subscores in social constraint. PD-20 subjects aged <70 years versus ≥$70 only differed significantly by worse cognition (P < 0.0001). Conclusions: PD-20 subjects reflect an elite group of PD survivors with early-onset disease and relatively mild cognitive disability despite long disease duration. Interventions for caregivers, mobility, and activities of daily living are areas that could improve caregiver burden and patient quality of life.
    Journal of Parkinson's Disease 02/2015; 5(2). DOI:10.3233/JPD-140515 · 1.10 Impact Factor
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    ABSTRACT: Tailored treatment based on individual risk factors is an area with promise to improve options for pain relief. Musculoskeletal pain has a biopsychosocial nature, and multiple factors should be considered when determining risk for chronic pain. This study investigated whether subgroups comprised genetic and psychological factors predicted outcomes in preclinical and clinical models of shoulder pain. Classification and regression tree analysis was performed for an exercise-induced shoulder injury cohort (n = 190) to identify high-risk subgroups, and a surgical pain cohort (n = 150) was used for risk validation. Questionnaires for fear of pain and pain catastrophizing were administered before injury and preoperatively. DNA collected from saliva was genotyped for a priori selected genes involved with pain modulation (COMT and AVPR1A) and inflammation (IL1B and TNF/LTA). Recovery was operationalized as a brief pain inventory rating of 0/10 for current pain intensity and <2/10 for worst pain intensity. Follow-up for the preclinical cohort was in daily increments, whereas follow-up for the clinical cohort was at 3, 6, and 12 months postoperatively. Risk subgroups comprised the COMT high pain sensitivity variant and either pain catastrophizing or fear of pain were predictive of heightened shoulder pain responses in the preclinical model. Further analysis in the clinical model identified the COMT high pain sensitivity variant and pain catastrophizing subgroup as the better predictor. Future studies will determine whether these findings can be replicated in other anatomical regions and whether personalized medicine strategies can be developed for this risk subgroup.
    Pain 01/2015; 156(1):148-56. DOI:10.1016/j.pain.0000000000000012 · 5.84 Impact Factor
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    ABSTRACT: To study mood and behavioral effects of unilateral and staged bilateral subthalamic nucleus (STN) and globus pallidus internus (GPi) deep brain stimulation (DBS) for Parkinson's disease (PD). There are numerous reports of mood changes following DBS, however, most have focused on bilateral simultaneous STN implants with rapid and aggressive post-operative medication reduction. A standardized evaluation was applied to a subset of patients undergoing STN and GPi DBS and who were also enrolled in the NIH COMPARE study. The Unified Parkinson Disease Rating Scale (UPDRS III), the Hamilton depression (HAM-D) and anxiety rating scales (HAM-A), the Yale-Brown obsessive-compulsive rating scale (YBOCS), the Apathy Scale (AS), and the Young mania rating scale (YMRS) were used. The scales were repeated at acute and chronic intervals. A post-operative strategy of non-aggressive medication reduction was employed. Thirty patients were randomized and underwent unilateral DBS (16 STN, 14 GPi). There were no baseline differences. The GPi group had a higher mean dopaminergic dosage at 1-year, however the between group difference in changes from baseline to 1-year was not significant. There were no differences between groups in mood and motor outcomes. When combining STN and GPi groups, the HAM-A scores worsened at 2-months, 4-months, 6-months and 1-year when compared with baseline; the HAM-D and YMRS scores worsened at 4-months, 6-months and 1-year; and the UPDRS Motor scores improved at 4-months and 1-year. Psychiatric diagnoses (DSM-IV) did not change. No between group differences were observed in the cohort of bilateral cases. There were few changes in mood and behavior with STN or GPi DBS. The approach of staging STN or GPi DBS without aggressive medication reduction could be a viable option for managing PD surgical candidates. A study of bilateral DBS and of medication reduction will be required to better understand risks and benefits of a bilateral approach.
    PLoS ONE 12/2014; 9(12):e114140. DOI:10.1371/journal.pone.0114140 · 3.53 Impact Factor
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    ABSTRACT: Background Coronary artery disease is highly prevalent in patients with stroke, but because revascularization does not improve major clinical outcomes in patients with stable coronary artery disease relative to intensive medical therapy, routine evaluation for this disease is not warranted in stroke patients. However, it might be warranted in patients destined to undergo vigorous physical therapy. The Locomotor Experience Applied Post-Stroke study, a randomized controlled trial of 408 participants that tested the relative efficacy of two rehabilitation techniques on functional walking level, provided the opportunity to address this question.AimThe study aims to test the efficacy of screening for cardiovascular disease and an exercise tolerance test in assuring safety among patients undergoing vigorous rehabilitation for gait impairment.Methods All participants were screened for serious cardiovascular and pulmonary conditions. At six-weeks poststroke, they also completed a cardiovascular screening inventory and underwent an exercise tolerance test involving bicycle ergometry. Participants received 36, 90-min sessions of a prescribed physical therapy (three per week), initiated at either two-months or six-months poststroke.ResultsTwenty-nine participants were excluded on the basis of the cardiac screening questionnaire, and 15 failed the exercise tolerance test for cardiovascular reasons. No participant experienced a cardiac event during a treatment session. Two participants experienced myocardial infarctions, but continued in the trial. In three additional participants, myocardial infarctions caused or contributed to death.Conclusions The combination of a negative cardiac screen and the absence of exercise tolerance test failure appeared to have a high negative predictive value for cardiac events during treatment, despite the likelihood of a high prevalence of coronary artery disease in our population.
    International Journal of Stroke 09/2014; 9(8). DOI:10.1111/ijs.12354 · 4.03 Impact Factor
  • Samuel S Wu, Yi-Hsuan Tu, Ying He
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    ABSTRACT: Adaptive design of clinical trials has attracted considerable interest because of its potential of reducing costs and saving time in the clinical development process. In this paper, we consider the problem of assessing the effectiveness of a test treatment over a control by a two-arm randomized clinical trial in a potentially heterogenous patient population. In particular, we study enrichment designs that use accumulating data from a clinical trial to adaptively determine patient subpopulation in which the treatment effect is eventually assessed. A hypothesis testing procedure and a lower confidence limit are presented for the treatment effect in the selected patient subgroups. The performances of the new methods are compared with existing approaches through a simulation study. Copyright © 2014 John Wiley & Sons, Ltd.
    Statistics in Medicine 07/2014; 33(16). DOI:10.1002/sim.6127 · 2.04 Impact Factor
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    ABSTRACT: Age-related impairment of neuromuscular activation has been shown to contribute to weakness in older adults. However, it is unclear to what extent impaired neuromuscular activation independently accounts for decline of mobility function. The hypothesis of this study is that capability to produce rapid neuromuscular activation during maximal effort leg muscle contractions will be shown to be an independent predictor of mobility function in older men and women after accounting for muscle size and adiposity, body composition and age. Twenty six older men and eighteen older women (aged 70-85 years) participated in this study. Mobility function was assessed by the 400-meter walk test. Neuromuscular activation of the quadriceps muscle group was assessed by surface electromyography (“rate of EMG rise”). Thigh muscle cross sectional area and adiposity was assessed by computed tomography. In males, univariate regression analysis revealed strong associations between walking speed and a number of predictors including age (p < 0.01), muscle area (p < 0.01), intermuscular adipose tissue area (p < 0.01), and rate of EMG rise (p < 0.001). Subsequent multiple regression analysis with all variables accounted for 72% of the variability in walking speed (p < .0001), with age and rate of EMG rise as the dominant variables in the model. In females, univariate analysis showed a significant association only between walking speed and subcutaneous adipose tissue area (p < 0.05). Multiple regression analysis accounted for only 44% of the variability in walking speed, and was not statistically significant (p = 0.18). The present findings indicate that the capability to rapidly activate the quadriceps muscle group is an important factor accounting for inter-individual variability of walking speed among older men, but not among older women. This research is important for informing the design of assessments and interventions that seek to detect and prevent impairments that contribute to age-related mobility disability.
    Experimental gerontology 07/2014; 55. DOI:10.1016/j.exger.2014.03.019 · 3.53 Impact Factor
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    ABSTRACT: We previously reported a randomized, sham-controlled trial of 5 Hz dorsolateral prefrontal left- and right-side repetitive transcranial magnetic stimulation (rTMS) in 48 participants with a medically refractory major depressive disorder. Depression improved most with right-side cranial stimulation, both rTMS and sham, and to a lesser degree with left rTMS. Because depression is often associated with cognitive impairment, in this study we sought to determine whether our earlier participants had treatment-induced changes in cognition, which cognitive domains (language, executive, visuospatial, verbal episodic memory, attention) were affected, and whether treatment-induced cognitive changes were related either to improvement in depression or to other treatment variables, such as right versus left treatment and rTMS versus sham.
    Cognitive and behavioral neurology: official journal of the Society for Behavioral and Cognitive Neurology 06/2014; 27(2):77-87. DOI:10.1097/WNN.0000000000000031 · 1.14 Impact Factor
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    ABSTRACT: Phase III trials of rehabilitation of paresis after stroke have proven the effectiveness of intensive and extended task practice, but they have also shown that many patients do not qualify, because of severity of impairment, and that many of those who are treated are left with clinically significant deficits. To test the value of 2 potential adjuvants to normal learning processes engaged in constraint-induced movement therapy (CIMT): greater distribution of treatment over time and the coadministration of d-cycloserine, a competitive agonist at the glycine site of the N-methyl-D-aspartate glutamate receptor. A prospective randomized single-blind parallel-group trial of more versus less condensed therapy (2 vs 10 weeks) and d-cycloserine (50 mg) each treatment day versus placebo (in a 2 × 2 design), as potential adjuvants to 60 hours of CIMT. Twenty-four participants entered the study, and 22 completed it and were assessed at the completion of treatment and 3 months later. Neither greater distribution of treatment nor treatment with d-cycloserine significantly augmented retention of gains achieved with CIMT. Greater distribution of practice and treatment with d-cycloserine do not appear to augment retention of gains achieved with CIMT. However, concentration of CIMT over 2 weeks ("massed practice") appears to confer no advantage either.
    Neurorehabilitation and neural repair 04/2014; DOI:10.1177/1545968314532032 · 4.62 Impact Factor
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    ABSTRACT: The Locomotor Experience Applied Post Stroke rehabilitation trial found equivalent walking outcomes for body weight-supported treadmill plus overground walking practice versus home-based exercise that did not emphasize walking. From this large database, we examined several clinically important questions that provide insights into recovery of walking that may affect future trial designs. Using logistic regression analyses, we examined predictors of response based on a variety of walking speed-related outcomes and measures that captured disability, physical impairment, and quality of life. The most robust predictor was being closer at baseline to the primary outcome measure, which was the functional walking speed thresholds of 0.4 m/s (household walking) and 0.8 m/s (community walking). Regardless of baseline walking speed, a younger age and higher Berg Balance Scale score were relative predictors of responding, whether operationally defined by transitioning beyond each speed boundary or by a continuous change or a greater than median increase in walking speed. Of note, the cutoff values of 0.4 and 0.8 m/s had no particular significance compared with other walking speed changes despite their general use as descriptors of functional levels of walking. No evidence was found for any difference in predictors based on treatment group.
    The Journal of Rehabilitation Research and Development 04/2014; 51(1):39-50. DOI:10.1682/JRRD.2013.04.0080 · 1.69 Impact Factor
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    ABSTRACT: The pain experience has multiple influences but little is known about how specific biological and psychological factors interact to influence pain responses. The current study investigated the combined influences of genetic (pro-inflammatory) and psychological factors on several pre-clinical shoulder pain phenotypes. An exercise-induced shoulder injury model was used, and a priori selected genetic (IL1B, TNF/LTA region, IL6 single nucleotide polymorphisms, SNPs) and psychological (anxiety, depressive symptoms, pain catastrophizing, fear of pain, kinesiophobia) factors were included as the predictors of interest. The phenotypes were pain intensity (5-day average and peak reported on numerical rating scale), upper-extremity disability (5-day average and peak reported on the QuickDASH instrument), and duration of shoulder pain (in days). After controlling for age, sex, and race, the genetic and psychological predictors were entered separately as main effects and interaction terms in regression models for each pain phenotype. Results from the recruited cohort (n = 190) indicated strong statistical evidence for the interactions between 1) TNF/LTA SNP rs2229094 and depressive symptoms for average pain intensity and duration and 2) IL1Β two-SNP diplotype and kinesiophobia for average shoulder pain intensity. Moderate statistical evidence for prediction of additional shoulder pain phenotypes included interactions of kinesiophobia, fear of pain, or depressive symptoms with TNF/LTA rs2229094 and IL1B. These findings support the combined predictive ability of specific genetic and psychological factors for shoulder pain phenotypes by revealing novel combinations that may merit further investigation in clinical cohorts, to determine their involvement in the transition from acute to chronic pain conditions.
    Medicine and science in sports and exercise 03/2014; 46(10). DOI:10.1249/MSS.0000000000000328 · 4.46 Impact Factor
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    ABSTRACT: Background Spinocerebellar ataxia type 10 (SCA10) is caused by an expansion of a normally polymorphic ATTCT repeat within intron 9 of the ATXN10 gene. Interrupting sequences in the expanded ATTCT repeat track are postulated to be a disease modifier, but are not fully characterized in SCA10 patients. AimAs the large size and the repetitive nature of the SCA10 expansion does not make it amenable for Sanger or next-generation sequencing, we need an alternative approach to determine whether there are interrupted repeat motifs within the SCA10 expansion. Method We developed a strategy that combines long-range PCR and shot-gun sequencing to characterize interruption sequences without full assembly of entire disease allele. We chose three SCA10-positive individuals with disparate clinical presentations and examined the resulting sequences for interrupting motifs. ResultsWith this strategy, we found both known heptanucleotide (ATTTTCT and ATATTCT) and pentanucleotide (ATCCC and ATCCT) interruption sequences in one allele. Additionally, we found novel pentanucleotide (ACTCT, ATTCA, ATTCC) and heptanucleotide (ATTCTCT) repeat interruption motifs in two additional samples. Conclusion Our results demonstrate the utility of this approach for determining the internal repeat structure of difficult to sequence repeat expansions. Furthermore, we find that the extent and type of interrupting sequences varies dramatically between these three SCA10-positive individuals.This article is protected by copyright. All rights reserved.
    02/2014; DOI:10.1111/ncn3.78
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    ABSTRACT: To describe changes in and predictors of comfortable gait speed (GS-C) in persons with stroke after 42 weeks (w) using a foot drop stimulator (FDS, Bioness L300™) DESIGN: Secondary analysis of prospective assessments SETTING: Multicenter clinical trial PARTICIPANTS: 99 subjects >3 months post-stroke with GS-C <0.8m/sec and drop foot with a mean age of 60.7y and time post-stroke of 4.8y. GS-C was assessed at baseline and 30w with and without FDS (therapeutic effect) and 6w, 12w, 30w, 36w and 42w with FDS (total effect.) After 8 physical therapy sessions, FDS was used for ambulation over 42w. Changes in mean GS-C over time, FDS "responder" status defined as either >0.1m/sec gain GS-C [the minimal clinically important difference (MCID)] or advancing by one Perry Ambulation Category (PAC), and adverse events (AE) RESULTS: 74 (75%) and 69 (70%) of 99 subjects completed assessments at 30w and 42w, respectively. Baseline GS-C was 0.42m/sec without and 0.49m/sec with FDS. GS-C improved to 0.54m/sec at 30w without FDS (effect size = 0.75) and .54, .55, .58, .60 and .61m/sec at 6w, 12w, 30w, 36w & 42w with FDS, respectively (effect size 0.84 at 42w.) Half achieved a maximum GS-C by 12w. About 18% were PAC and 29% MCID responders for 30w therapeutic effect and 55% were PAC and 67% MCID responders for 42w total effect. After logistic regression, younger age, faster baseline GS-C and Timed Up and Go and balance emerged as the strongest predictors of FDS responders. At 42w, 60% reported a device-related AE with 92% mild and 96% anticipated. GS-C with FDS improved progressively over 42w with >50% achieving a clinically meaningful 42w total effect and 50% achieving a maximum GS-C by 12w. Younger patients with higher mobility levels may benefit most. AE were frequent, mild and reversible.
    PM&R 01/2014; 6(7). DOI:10.1016/j.pmrj.2014.01.001 · 1.66 Impact Factor
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    ABSTRACT: Chronic pain is influenced by biological, psychological, social, and cultural factors. The current study investigated potential roles for combinations of genetic and psychological factors in the development and/or maintenance of chronic musculoskeletal pain. An exercise-induced shoulder injury model was used, and a priori selected genetic (ADRB2, COMT, OPRM1, AVPR1 A, GCH1, and KCNS1) and psychological (anxiety, depressive symptoms, pain catastrophizing, fear of pain, and kinesiophobia) factors were included as predictors. Pain phenotypes were shoulder pain intensity (5-day average and peak reported on numerical rating scale), upper extremity disability (5-day average and peak reported on the QuickDASH), and shoulder pain duration (in days). After controlling for age, sex, and race, the genetic and psychological predictors were entered as main effects and interaction terms in separate regression models for the different pain phenotypes. Results from the recruited cohort (N = 190) indicated strong statistical evidence for interactions between the COMT diplotype and 1) pain catastrophizing for 5-day average upper extremity disability and 2) depressive symptoms for pain duration. There was moderate statistical evidence for interactions for other shoulder pain phenotypes between additional genes (ADRB2, AVPR1 A, and KCNS1) and depressive symptoms, pain catastrophizing, or kinesiophobia. These findings confirm the importance of the combined predictive ability of COMT with psychological distress and reveal other novel combinations of genetic and psychological factors that may merit additional investigation in other pain cohorts. Interactions between genetic and psychological factors were investigated as predictors of different exercise-induced shoulder pain phenotypes. The strongest statistical evidence was for interactions between the COMT diplotype and pain catastrophizing (for upper extremity disability) or depressive symptoms (for pain duration). Other novel genetic and psychological combinations were identified that may merit further investigation.
    The journal of pain: official journal of the American Pain Society 01/2014; 15(1):68-80. DOI:10.1016/j.jpain.2013.09.012 · 4.22 Impact Factor
  • Journal of Neurosurgery 10/2013; 119(4):1075-1075. · 3.23 Impact Factor
  • Article: Response.
    Journal of Neurosurgery 10/2013; 119(4):1075. · 3.15 Impact Factor
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    ABSTRACT: Measures of central pain processing like conditioned pain modulation (CPM), and suprathreshold heat pain response (SHPR) have been described to assess different components of central pain modulatory mechanisms. Central pain processing potentially play a role in the development of postsurgical pain, however, the role of CPM and SHPR in explaining postoperative clinical pain and disability is still unclear. Seventy eight patients with clinical shoulder pain were included in this study. Patients were examined before shoulder surgery, at 3 months, and 6 months after surgery. The primary outcome measures were pain intensity and upper extremity disability. Analyses revealed that the change score (baseline - 3 months) of 5th pain rating of SHPR accounted for a significant amount of variance in 6 month postsurgical clinical pain intensity and disability after age, sex, preoperative pain intensity, and relevant psychological factors were considered. The present study suggests that baseline measures of central pain processing were not predictive of 6 month postoperative pain outcome. Instead, the 3 month change in SHPR might be a relevant factor in the transition to elevated 6-month postoperative pain and disability outcomes. In patients with shoulder pain, the 3 month change in a measure of central pain processing might be a relevant factor in the transition to elevated 6-month postoperative pain and disability scores.
    The Clinical journal of pain 09/2013; DOI:10.1097/AJP.0000000000000029 · 2.70 Impact Factor

Publication Stats

2k Citations
370.17 Total Impact Points

Institutions

  • 2001–2015
    • University of Florida
      • • Department of Biostatistics
      • • Department of Occupational Therapy
      • • College of Medicine
      • • Department of Statistics
      Gainesville, Florida, United States
  • 2012
    • Weill Cornell Medical College
      New York City, New York, United States
  • 2007–2011
    • Duke University
      Durham, North Carolina, United States
    • U.S. Department of Veterans Affairs
      Washington, Washington, D.C., United States
  • 2010
    • Florida Department of Health
      Tallahassee, Florida, United States
  • 2008–2009
    • University of North Carolina at Chapel Hill
      • Department of Medicine
      North Carolina, United States
  • 2002
    • University of North Texas
      • Department of Pharmacology & Neuroscience
      Denton, TX, United States