Samuel S Wu

University of Florida, Gainesville, Florida, United States

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Publications (99)306.8 Total impact

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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; · 3.71 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 02/2014; · 2.04 Impact Factor
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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; · 1.37 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. · 3.78 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 01/2014; · 3.34 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; · 3.01 Impact Factor
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    ABSTRACT: The step activity monitor (SAM) quantifies steps taken in the home and community by patient populations. While the SAM has been used to study individuals post-stroke, compliance with SAM has not been addressed. Participants' compliance in wearing the monitor is critical for obtaining accurate assessments. The purpose of this study was to determine the rate of and predictors for inferred compliance with the SAM post-stroke. Cross-sectional. 408 community-dwelling individuals two-months post-stroke with moderate-to-severe gait impairment (gait speed of ≤ 0.8 m/s). Step activity was assessed for two days with the SAM. Inferred compliance was established in three periods: 6:00AM-12:00PM, 12:01PM-6:00PM, and 6:01PM-12:00AM. Compliance was defined as activity recorded in all three periods. The percentage of participant compliance for the first day, second day, both days, and either day was calculated. Demographic and clinical characteristics of compliers and non-compliers were compared. Independent compliance predictors were identified using stepwise logistic regression. Inferred compliance rate in the first day, second day, both days, and either day was 68, 61, 53, and 76%, respectively. Upper and lower extremity impairment, balance control and endurance were significantly different between compliers and non-compliers. On the other hand, older age, greater balance self-efficacy, and better walking endurance were found to be significant predictors of compliance. Participants consisted of individuals with sub-acute stroke. Therefore, our findings may not be generalized to individuals during the acute and chronic phases of stroke recovery. Strategies to improve compliance are needed, when collecting data for more than one day, and in samples with younger individuals, and persons with low levels of balance self-efficacy and walking endurance.
    Physical Therapy 09/2013; · 2.78 Impact Factor
  • David H. Annis, Samuel S. Wu
    CHANCE 08/2013; 20(1):6-10.
  • Xiaomin Lu, Anqi Sun, Samuel S. Wu
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    ABSTRACT: Adaptive design is widely used in clinical trials. In this paper, we consider the problem of estimating the mean of the selected normal population in two-stage adaptive designs. Under the LINEX and L2 loss functions, admissibility and minimax results are derived for some location invariant estimators of the selected normal mean. The naive sample mean estimator is shown to be inadmissible under the LINEX loss function and to be not minimax under both loss functions.
    Journal of Statistical Planning and Inference 07/2013; 143(7):1215–1220. · 0.71 Impact Factor
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    ABSTRACT: BACKGROUND AND PURPOSE: Drop foot after stroke may be addressed using an ankle foot orthosis (AFO) or a foot drop stimulator (FDS). The Functional Ambulation: Standard Treatment versus Electric Stimulation Therapy (FASTEST) trial was a multicenter, randomized, single-blinded trial comparing FDS and AFO for drop foot among people ≥3 months after stroke with gait speed ≤0.8 m/s. METHODS: Participants (n=197; 79 females and 118 males; 61.14±11.61 years of age; time after stroke 4.55±4.72 years) were randomized to 30 weeks of either FDS or a standard AFO. Eight dose-matched physical therapy sessions were provided to both groups during the first 6 weeks of the trial. RESULTS: There was significant improvement within both groups from baseline to 30 weeks in comfortable gait speed (95% confidence interval for mean change, 0.11-0.17 m/s for FDS and 0.12-0.18 m/s for AFO) and fast gait speed. However, no significant differences in gait speed were found in the between-group comparisons. Secondary outcomes (standard measures of body structure and function, activity, and participation) improved significantly in both groups, whereas user satisfaction was significantly higher in the FDS group than in the control group. CONCLUSIONS: Using either an FDS or an AFO for 30 weeks yielded clinically and statistically significant improvements in gait speed and other functional outcomes. User satisfaction was higher in the FDS group. Although both groups did receive intervention, this large clinical trial provides evidence that FDS or AFO with initial physical therapy sessions can provide a significant and clinically meaningful benefit even years after stroke.Clinical Trial Registration Information-URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01138995.
    Stroke 05/2013; · 6.16 Impact Factor
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    ABSTRACT: BACKGROUND CONTEXT: Effective strategies for preventing low back pain (LBP) have remained elusive, despite annual direct health care costs exceeding $85 billion dollars annually. In our recently completed Prevention of Low Back Pain in the Military (POLM) trial, a brief psychosocial education program (PSEP) that reduced fear and threat of LBP reduced the incidence of health care-seeking for LBP. PURPOSE: The purpose of this cost analysis was to determine if soldiers who received psychosocial education experienced lower health care costs compared with soldiers who did not receive psychosocial education. STUDY DESIGN/SETTING: The POLM trial was a cluster randomized trial with four intervention arms and a 2-year follow-up. Consecutive subjects (n=4,295) entering a 16-week training program at Fort Sam Houston, TX, to become a combat medic in the U.S. Army were considered for participation. METHODS: In addition to an assigned exercise program, soldiers were cluster randomized to receive or not receive a brief psychosocial education program delivered in a group setting. The Military Health System Management Analysis and Reporting Tool was used to extract total and LBP-related health care costs associated with LBP incidence over a 2-year follow-up period. RESULTS: After adjusting for postrandomization differences between the groups, the median total LBP-related health care costs for soldiers who received PSEP and incurred LBP-related costs during the 2-year follow-up period were $26 per soldier lower than for those who did not receive PSEP ($60 vs. $86, respectively, p=.034). The adjusted median total health care costs for soldiers who received PSEP and incurred at least some health care costs during the 2-year follow-up period were estimated at $2 per soldier lower than for those who did not receive PSEP ($2,439 vs. $2,441, respectively, p=.242). The results from this analysis demonstrate that a brief psychosocial education program was only marginally effective in reducing LBP-related health care costs and was not effective in reducing total health care costs. Had the 1,995 soldiers in the PSEP group not received PSEP, we would estimate that 16.7% of them would incur an adjusted median LBP-related health care cost of $517 compared with the current 15.0% soldiers incurring an adjusted median cost of $399, which translates into an actual LBP-related health care cost savings of $52,846 during the POLM trial. However, it is likely that the unaccounted for direct and indirect costs might erase even these small cost savings. CONCLUSION: The results of this study will help to inform policy- and decision-making regarding the feasibility of implementing psychosocial education in military training environments across the services. It would be interesting to explore in future research whether cost savings from psychosocial education could be enhanced given a more individualized delivery method tailored to an individual's specific psychosocial risk factors.
    The spine journal: official journal of the North American Spine Society 04/2013; · 2.90 Impact Factor
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    ABSTRACT: OBJECTIVE: To assess the relationship between Exercise Tolerance Test (ETT) performance at 6-weeks post-stroke and subsequent performance in a treadmill and overground Locomotor Training Program (LTP). DESIGN: Prospective, cohort study. SETTING: Exercise testing laboratory in either a primary care hospital or outpatient clinic. PARTICIPANTS: Community-dwelling individuals (n= 469), 54.9±19.0 days post-stroke, enrolled in the Locomotor Experience Applied Post Stroke (LEAPS) randomized controlled trial. INTERVENTIONS: Not applicable MAIN OUTCOME MEASURES: For participants randomized to LTP, the number of sessions needed to attain the training goal of 20 minutes of treadmill stepping was determined. Regression analyses determined the contribution of ETT performance (cycling duration), age, and Six-Minute Walk Test (6MWT) distance to attainment of the stepping duration goal. RESULTS: Age, 6MWT and ETT performance individually accounted for 10.74%, 10.82% and 10.76%, respectively, of the variance in number of sessions needed to attain 20 minutes of stepping. When age and 6MWT were included in the model, the additional contribution of ETT performance was rendered non-significant (p=0.150). CONCLUSION: To the extent that ETT performance can be viewed as a measure of cardiovascular fitness rather than neurological impairment, cardiovascular fitness at the time of the ETT did not make a significant unique contribution to number of sessions needed to achieve 20 minutes stepping duration . The 6MWT, which involves less intensive exercise than the ETT and therefore likely to be predominantly affected by neurological impairment and muscular condition, appeared to account for as much variance as the ETT.
    Archives of physical medicine and rehabilitation 03/2013; · 2.18 Impact Factor
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    ABSTRACT: BACKGROUND: . After inpatient stroke rehabilitation, many people still cannot participate in community activities because of limited walking ability. OBJECTIVE: . To compare the effectiveness of 2 conceptually different, early physical therapy (PT) interventions to usual care (UC) in improving walking 6 months after stroke. METHODS: . The Locomotor Experience Applied Post-Stroke (LEAPS) study was a single-blind, randomized controlled trial conducted in 408 adults with disabling hemiparetic stroke. Participants were stratified at baseline (2 months) by impairment in walking speed: severe (<0.4 m/s) or moderate (0.4 to <0.8 m/s). Between 2 and 6 months, they received either only UC (n = 143) or UC plus 36 therapist-provided sessions of either (1) walking training on a treadmill using body-weight support and practice overground at clinics (locomotor training program [LTP], n = 139) or (2) impairment-based strength and balance exercise at home (home exercise program [HEP], n = 126). RESULTS: . LTP participants were 18% more likely to transition to a higher functional walking level: severe to >0.4 m/s and moderate to >0.8 m/s than UC participants (95% confidence interval [CI] = 7%-29%), and HEP participants were 17% more likely to transition (95% CI = 5%-29%). Mean gain in walking speed in LTP participants was 0.13 m/s greater (95% CI = 0.09-0.18) and in HEP participants, 0.10 m/s greater (95% CI = 0.05-0.14) than in UC participants. CONCLUSIONS: . Progressive PT, using either walking training on a treadmill and overground, conducted in a clinic, or strength and balance exercises conducted at home, was superior to UC in improving walking, regardless of severity of initial impairment.
    Neurorehabilitation and neural repair 03/2013; · 4.28 Impact Factor
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    ABSTRACT: BACKGROUND: Extensive data, primarily from animal studies, suggest that several classes of drugs may have antineuroplastic effects that could impede recovery from brain injury or reduce the efficacy of rehabilitation. AIMS: The Locomotor Experience Applied Post-Stroke trial, a randomized controlled study of 408 subjects that tested the relative efficacy of two rehabilitation techniques on functional walking level at one-year poststroke, provided us the opportunity to prospectively assess the potential antineuroplastic effects of several classes of drug. METHODS: Subjects were randomized to receive one of the two rehabilitation therapies at two-months poststroke. Drugs taken were recorded at time of randomization. Outcome was assessed at one-year poststroke. Regression models were used to determine the amount of variance in success in improving functional walking level, gains in walking speed, and declines in lower extremity, upper extremity, and cognitive impairment accounted for by α1 noradrenergic blockers + α2 noradrenergic agonists, benzodiazepines, voltage-sensitive sodium channel anticonvulsants, and α2δ voltage-sensitive calcium channel blockers. RESULTS: The maximum variance accounted for by any drug class was 1·66%. Drug effects were not statistically significant when using even our most lenient standard for correction for multiple comparisons. CONCLUSIONS: Drugs in the classes we were able to assess do not appear to exert a clinically important effect on outcome over the period between two- and 12 months poststroke. However, the potential antineuroplastic effects of certain drugs remain an incompletely settled scientific question.
    International Journal of Stroke 10/2012; · 2.75 Impact Factor
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    ABSTRACT: Background Limited evidence exists to inform how strength and endurance exercises commonly used to prevent low back pain affect muscle morphometry and endurance.Objective The purpose of this study was to analyze the effects of two exercise regimens on the morphometry and endurance of key trunk musculature in a healthy population.DesignRandomized Controlled Trial.SettingMilitary training setting.ParticipantsA random subsample (n=340, 72% male, 21.9±4.2 years, 24.8±2.8 kg/m(2)) from the larger Prevention of Low Back Pain in the Military trial (n = 4,325) were included.InterventionThe core stabilization exercise program (CSEP) included low load/low repetition motor control exercises while the traditional exercise program (TEP) included exercises conducted fast using a high load/high repetition trunk strengthening exercises.MeasurementsBaseline and follow-up examination included ultrasound imaging of the trunk muscles and endurance tests. Linear mixed models were fitted to study the group and time effect and their interactions, accounting for the clustering effect. RESULTS: /b>Symmetry generally improved in the rest and contracted states, but there were no differences suggestive of muscle hypertrophy or improved ability to contract the trunk muscles between Soldiers receiving CSEP or TEP. Total trunk endurance time decreased over the 12-week period; but endurance performance favored those Soldiers in the CSEP group (p≤0.05). Endurance time was not associated with future episodes of LBP.LimitationsThe lack of morphological changes may not be detectable in an already active cohort or a more intensive dose was needed. CONCLUSIONS:/b>Although improved symmetry was noted, neither the CSEP or TEP resulted in muscle hypertrophy. Longer endurance times were noted in individuals who completed CSEP but were not strongly predictive of future low back pain episodes.
    Physical Therapy 10/2012; · 2.78 Impact Factor
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    ABSTRACT: OBJECTIVE To collect the information necessary to design the methods and outcome variables for a larger trial of scheduled deep brain stimulation (DBS) for Tourette syndrome. DESIGN We performed a small National Institutes of Health-sponsored clinical trials planning study of the safety and preliminary efficacy of implanted DBS in the bilateral centromedian thalamic region. The study used a cranially contained constant-current device and a scheduled, rather than the classic continuous, DBS paradigm. Baseline vs 6-month outcomes were collected and analyzed. In addition, we compared acute scheduled vs acute continuous vs off DBS. SETTING A university movement disorders center. PATIENTS Five patients with implanted DBS. MAIN OUTCOME MEASURE A 50% improvement in the Yale Global Tic Severity Scale (YGTSS) total score. RESULTS Participating subjects had a mean age of 34.4 (range, 28-39) years and a mean disease duration of 28.8 years. No significant adverse events or hardware-related issues occurred. Baseline vs 6-month data revealed that reductions in the YGTSS total score did not achieve the prestudy criterion of a 50% improvement in the YGTSS total score on scheduled stimulation settings. However, statistically significant improvements were observed in the YGTSS total score (mean [SD] change, -17.8 [9.4]; P = .01), impairment score (-11.3 [5.0]; P = .007), and motor score (-2.8 [2.2]; P = .045); the Modified Rush Tic Rating Scale Score total score (-5.8 [2.9]; P = .01); and the phonic tic severity score (-2.2 [2.6]; P = .04). Continuous, off, and scheduled stimulation conditions were assessed blindly in an acute experiment at 6 months after implantation. The scores in all 3 conditions showed a trend for improvement. Trends for improvement also occurred with continuous and scheduled conditions performing better than the off condition. Tic suppression was commonly seen at ventral (deep) contacts, and programming settings resulting in tic suppression were commonly associated with a subjective feeling of calmness. CONCLUSIONS This study provides safety and proof of concept that a scheduled DBS approach could improve motor and vocal tics in Tourette syndrome. Refinements in neurostimulator battery life, outcome measure selection, and flexibility in programming settings can be used to enhance outcomes in a future larger study. Scheduled stimulation holds promise as a potential first step for shifting movement and neuropsychiatric disorders toward more responsive neuromodulation approaches. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01329198.
    Archives of neurology 10/2012; · 7.58 Impact Factor
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    ABSTRACT: BACKGROUND: Parkinson's disease (PD) is the second most common neurodegenerative syndrome, classically characterized by levodopa-responsive motor features accompanied by non-motor mood, cognitive, sensory and autonomic issues. Over time, disease burden slowly accumulates resulting in diminished health status. Many clinicians consider the 10 year disease duration mark as significant, however the clinical status and health-related quality of life of patients reaching this milestone have not been well documented. METHODS: A cross-sectional study was performed on PD patients with ≥10 years disease duration (PD-10) (n = 1835) included in the multicenter National Parkinson's Foundation Quality Improvement Initiative (NPF-QII). Demographic, clinical and health-related quality of life data was analyzed. RESULTS: PD-10 patients (62.2% male) had a mean age of 67.8 years (±9.5) with a mean age of PD onset of 52.7 years (±10.6), and median disease duration 14.3 years (interquartile range 11.5-18.1). Many were minimally disabled with Hoehn and Yahr stage 1 or 2 (44.0%) or experiencing postural instability (HY stage 3, 40.3%). Most (88.2%) were able to stand unaided, but falls were common (54.8%). Almost all were living at home (93.1%) with a family member as a regular caregiver (83.8%). PD-10 patients had an average of 1.9 (±1.4) co-morbidities, with arthritis (48.9%) and heart problems (31.7%) most commonly encountered. The majority (86.7%) took at least 2 medications: levodopa (95.7%), dopamine agonists (45.6%) and antidepressants (37.3%) were most commonly recorded. Most PD-10 patients were not currently utilizing physical, occupational or speech therapy, although two-thirds reported engaging in physical activity. Deep brain stimulation was documented in 22.4%. Overall the mean health-related quality of life and caregiver burden was impaired in all domains. CONCLUSIONS: Our data on PD patients with at least 10 years disease duration confirmed the younger age of onset of PD, but not the higher proportion of females or rest tremor, or the lower proportion of Caucasians seen in other aged PD cohorts. PD-10 patients had increased disease burden, increased caregiver burden, and impaired health-related quality of life. Although subjects mostly remained independently mobile, balance could be impaired with frequent falls identified. The prevalence of PD-10 patients living at home (93%) was very high in our sample which was drawn from specialty clinics, compared to prior studies reporting up to 27% PD patients institutionalized at 10 years duration. Thus policies to improve in-home support and caregiver support will be crucial in efforts aimed at maintaining patients in a home setting.
    Parkinsonism & Related Disorders 07/2012; · 3.27 Impact Factor
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    ABSTRACT: Objectives:  To screen for potentially underreported behavioral changes in patients with idiopathic Parkinson's disease (PD) pre- and post-deep brain stimulation (DBS), a retrospective data base review was performed. Methods:  In total, 113 patients who underwent unilateral or bilateral DBS at the University of Florida in either subthalamic nucleus or globus pallidus internus for PD were screened for behavioral issues by asking about the presence or absence of seven neuropsychiatric symptoms (panic, fear, paranoia, anger, suicidal flashes, crying, and laughing). Results:  There was a high prevalence of fear (16.3%), panic (14.0%), and anger (11.6%) at baseline in this cohort. In the first six months following DBS implantation, anger (32.6%), fear (26.7%), and uncontrollable crying (26.7%) were the most frequent symptoms reported. Those symptoms also were present following six months of DBS surgery (30.2%, 29.1%, and 19.8%, respectively). New uncontrollable crying occurred more in the acute postoperative stage (less than or equal to six months) (p= 0.033), while new anger occurred more in the chronic postoperative stage (greater than six months) (p= 0.017). The frequency of uncontrollable laughing significantly increased with bilateral DBS (p= 0.033). Conclusions:  Many of the neuropsychiatric issues were identified at preoperative baseline and their overall occurrence was more than expected. There was a potential for worsening of these issues post-DBS. There were subtle differences in time course, and in unilateral vs. bilateral implantations. Clinicians should be aware of these potential behavioral issues that may emerge following DBS therapy, and should consider including screening questions in preoperative and postoperative interviews. Standardized scales may miss the presence or absence of these clinically relevant issues.
    Neuromodulation 07/2012; · 1.19 Impact Factor
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    ABSTRACT: To compare subthalamic nucleus (STN) to globus pallidus internus (GPi) deep brain stimulation (DBS) for control of motor fluctuations and for potential dyskinesia-suppressing qualities. We conducted a retrospective database review of all patients who underwent GPi or STN DBS for idiopathic Parkinson's disease. Direct dyskinesia suppression (dDS) was defined as improvement in dyskinesia subscore of the unified Parkinson's disease rating scale (UPDRS) part IV (items 32-34), despite lack of reduction in dopaminergic medication dosage. We analyzed the data using methods appropriate for a case-control study. A total of 133 patients were evaluated. At the last evaluation Dyskinesia scores and motor fluctuations significantly improved in both the GPi (p < 0.0001) and STN groups (p < 0.0001). The GPi group was more likely than the STN group to experience dDS (odds ratio = 1.95, 95% CI = 0.556, 3.21). However, the association between DBS target and dDS was not statistically significant (Pearson chi-square = 2.286, p = 0.131). The overall clinical outcome of STN and GPi DBS for control of dyskinesia and motor fluctuations was similar. STN and GPi DBS both had some direct dyskinesia suppression effects.
    Parkinsonism & Related Disorders 04/2012; 18(7):814-8. · 3.27 Impact Factor

Publication Stats

793 Citations
306.80 Total Impact Points

Institutions

  • 2001–2014
    • University of Florida
      • • Department of Biostatistics
      • • Department of Physical Therapy
      • • College of Medicine
      • • Department of Statistics
      • • Department of Neurosurgery
      Gainesville, Florida, United States
  • 2013
    • Kaye Academic College of Education
      Be'er Sheva`, Southern District, Israel
  • 2012
    • Cardinal Hill Rehabilitation Hospital
      Lexington, Kentucky, United States
  • 2011–2012
    • University of Southern California
      • Division of Biokinesiology and Physical Therapy
      Los Angeles, CA, United States
    • Duke University
      Durham, North Carolina, United States
    • University of South Florida
      • College of Pharmacy
      Tampa, FL, United States
  • 2010
    • Wake Forest School of Medicine
      • Department of Neurology
      Winston-Salem, NC, United States
  • 2007–2008
    • U.S. Department of Veterans Affairs
      Washington, Washington, D.C., United States
    • Richard L. Roudebush VA Medical Center
      Indianapolis, Indiana, United States
  • 2004
    • University of North Texas HSC at Fort Worth
      • Department of Pharmacology and Neuroscience
      Fort Worth, TX, United States
  • 2002
    • University of North Texas
      • Department of Pharmacology & Neuroscience
      Denton, TX, United States