Christine Hunter

Baylor College of Medicine, Houston, Texas, United States

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Publications (56)280.99 Total impact

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    ABSTRACT: Importance Identifying measures that are associated with the cytosine-adenine-guanine (CAG) expansion in individuals before diagnosis of Huntington disease (HD) has implications for designing clinical trials.Objective To identify the earliest features associated with the motor diagnosis of HD in the Prospective Huntington at Risk Observational Study (PHAROS).Design, Setting, and Participants A prospective, multicenter, longitudinal cohort study was conducted at 43 US and Canadian Huntington Study Group research sites from July 9, 1999, through December 17, 2009. Participants included 983 unaffected adults at risk for HD who had chosen to remain unaware of their mutation status. Baseline comparability between CAG expansion (≥37 repeats) and nonexpansion (<37 repeats) groups was assessed. All participants and investigators were blinded to individual CAG analysis. A repeated-measures analysis adjusting for age and sex was used to assess the divergence of the linear trend between the expanded and nonexpanded groups. Data were analyzed from April 27, 2010, to September 3, 2013.Exposure Huntington disease mutation status in individuals with CAG expansion vs without CAG expansion.Main Outcomes and Measures Unified Huntington’s Disease Rating Scale motor (score range, 0-124; higher scores indicate greater impairment), cognitive (symbol digits modality is the total number of correct responses in 90 seconds; lower scores indicate greater impairment), behavioral (score range, 0-176; higher scores indicate greater behavioral symptoms), and functional (Total Functional Capacity score range, 0-13; lower scores indicate reduced functional ability) domains were assessed at baseline and every 9 months up to a maximum of 10 years.Results Among the 983 research participants at risk for HD in the longitudinal cohort, 345 (35.1%) carried the CAG expansion and 638 (64.9%) did not. The mean (SD) duration of follow-up was 5.8 (3.0) years. At baseline, participants with expansions had more impaired motor (3.0 [4.2] vs 1.9 [2.8]; P < .001), cognitive (P < .05 for all measures except Verbal Fluency, P = .52), and behavioral domain scores (9.4 [11.4] vs 6.5 [8.5]; P < .001) but not significantly different measures of functional capacity (12.9 [0.3] vs 13.0 [0.2]; P = .23). With findings reported as mean slope (95% CI), in the longitudinal analyses, participants with CAG expansions showed significant worsening in motor (0.84 [0.73 to 0.95] vs 0.03 [−0.05 to 0.11]), cognitive (−0.54 [−0.67 to −0.40] vs 0.22 [0.12 to 0.32]), and functional (−0.08 [−0.09 to −0.06] vs −0.01 [−0.02 to 0]) measures compared with those without expansion (P < .001 for all); behavioral domain scores did not diverge significantly between groups.Conclusions and Relevance Using these prospectively accrued clinical data, relatively large treatment effects would be required to mount a randomized, placebo-controlled clinical trial involving premanifest HD individuals who carry the CAG expansion.
    No preview · Article · Nov 2015
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    ABSTRACT: This study reports the baseline characteristics of diffusion tensor imaging data in Parkinson's disease (PD) patients and healthy control subjects from the Parkinson's Progression Markers Initiative. The main goals were to replicate previous findings of abnormal diffusion imaging values from the substantia nigra. in a large multicenter cohort and determine whether nigral diffusion alterations are associated with dopamine deficits. Two hundred twenty subjects (PD = 153; control = 67) from 10 imaging sites were included. All subjects had a full neurological exam, a ((123) I)ioflupane dopamine transporter (DAT) single-photon emission computer tomography scan, and diffusion tensor imaging. Fractional anisotropy as well as radial and axial diffusivity was computed within multiple regions across the substantia nigra. A repeated-measures analysis of variance found a marginally nonsignificant interaction between regional fractional anisotropy of the substantia nigra and disease status (P = 0.08), conflicting with an earlier study. However, a linear mixed model that included control regions in addition to the nigral regions revealed a significant interaction between regions and disease status (P = 0.002), implying a characteristic distribution of reduced fractional anisotropy across the substantia nigra in PD. Reduced fractional anisotropy in PD was also associated with diminished DAT binding ratios. Both axial and radial diffusivity were also abnormal in PD. Although routine nigral measurements of fractional anisotropy are clinically not helpful, the findings in this study suggest that more-sophisticated diffusion imaging protocols should be used when exploring the clinical utility of this imaging modality. © 2015 International Parkinson and Movement Disorder Society. © 2015 International Parkinson and Movement Disorder Society.
    Full-text · Article · Aug 2015 · Movement Disorders
  • Christopher Kenney · Christine Hunter · Nicte Mejia · Joseph Jankovic
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    ABSTRACT: We sought to evaluate the safety and efficacy of tetrabenazine (TBZ) in patients with moderate to severe Tourette syndrome (TS). TBZ, a monoamine-depleting drug, has been previously reported to be effective in the treatment of hyperkinetic movement disorders such as Huntington disease and tardive dyskinesia. TBZ has the distinct advantage over neuroleptics in that it does not cause tardive dyskinesia. We describe a retrospective, open-label study of 77 TS patients (75.3% male), and 14.8 ± 17.4 years of age, treated with TBZ for an average of 2.0 years. TBZ showed a moderate to marked improvement in TS-related symptoms and functional improvement in 83.1% of patients. Adverse events included drowsiness/fatigue (36.4%), nausea (10.4%), depression (9.1%), insomnia (7.8%), and parkinsonism (6.5%). In this retrospective, open-label study, TBZ was found to be generally safe and well-tolerated in patients with TS.
    No preview · Article · Jul 2015 · Journal of pediatric neurology: JPN
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    ABSTRACT: Importance Coenzyme Q10 (CoQ10), an antioxidant that supports mitochondrial function, has been shown in preclinical Parkinson disease (PD) models to reduce the loss of dopamine neurons, and was safe and well tolerated in early-phase human studies. A previous phase II study suggested possible clinical benefit.Objective To examine whether CoQ10 could slow disease progression in early PD.Design, Setting, and Participants A phase III randomized, placebo-controlled, double-blind clinical trial at 67 North American sites consisting of participants 30 years of age or older who received a diagnosis of PD within 5 years and who had the following inclusion criteria: the presence of a rest tremor, bradykinesia, and rigidity; a modified Hoehn and Yahr stage of 2.5 or less; and no anticipated need for dopaminergic therapy within 3 months. Exclusion criteria included the use of any PD medication within 60 days, the use of any symptomatic PD medication for more than 90 days, atypical or drug-induced parkinsonism, a Unified Parkinson’s Disease Rating Scale (UPDRS) rest tremor score of 3 or greater for any limb, a Mini-Mental State Examination score of 25 or less, a history of stroke, the use of certain supplements, and substantial recent exposure to CoQ10. Of 696 participants screened, 78 were found to be ineligible, and 18 declined participation.Interventions The remaining 600 participants were randomly assigned to receive placebo, 1200 mg/d of CoQ10, or 2400 mg/d of CoQ10; all participants received 1200 IU/d of vitamin E.Main Outcomes and Measures Participants were observed for 16 months or until a disability requiring dopaminergic treatment. The prospectively defined primary outcome measure was the change in total UPDRS score (Parts I-III) from baseline to final visit. The study was powered to detect a 3-point difference between an active treatment and placebo.Results The baseline characteristics of the participants were well balanced, the mean age was 62.5 years, 66% of participants were male, and the mean baseline total UPDRS score was 22.7. A total of 267 participants required treatment (94 received placebo, 87 received 1200 mg/d of CoQ10, and 86 received 2400 mg/d of CoQ10), and 65 participants (29 who received placebo, 19 who received 1200 mg/d of CoQ10, and 17 who received 2400 mg/d of CoQ10) withdrew prematurely. Treatments were well tolerated with no safety concerns. The study was terminated after a prespecified futility criterion was reached. At study termination, both active treatment groups showed slight adverse trends relative to placebo. Adjusted mean changes (worsening) in total UPDRS scores from baseline to final visit were 6.9 points (placebo), 7.5 points (1200 mg/d of CoQ10; P = .49 relative to placebo), and 8.0 points (2400 mg/d of CoQ10; P = .21 relative to placebo).Conclusions and Relevance Coenzyme Q10 was safe and well tolerated in this population, but showed no evidence of clinical benefit.Trial Registration clinicaltrials.gov Identifier: NCT00740714
    Full-text · Article · Mar 2014 · JAMA Neurology
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    ABSTRACT: Although tetrabenazine, a drug that depletes presynaptic dopamine by inhibiting vesicular monoamine transporter 2 (VMAT2), was approved by the U.S. Food and Drug Administration in 2008 for the treatment of chorea associated with Huntington's disease (HD), there is a paucity of data on its long-term efficacy and safety. Approximately 2,000 patients with a variety of hyperkinetic movement disorders had been treated with open-label tetrabenazine at the Movement Disorders Clinic, Baylor College of Medicine, since 1979. Tetrabenazine was usually started at 12.5 mg/day, and the dosage was gradually increased (up to 300 mg/day). Responses were rated by the investigator 1-5, with 1 = marked chorea reduction, excellent improvement in function; 2 = moderate chorea reduction, very good improvement in function; 3 = fair chorea improvement, only mild improvement in function; 4 = poor or no response for chorea and function; and 5 = worsening chorea, some functional deterioration. Efficacy and safety were analyzed retrospectively. By 2004, 98 HD chorea patients had received tetrabenazine for a mean of 3.1 years (range ≤1-11.4 years). Of those with valid ratings, 75% had either marked or very good responses (rating 1 or 2) at their optimal dosages. The most common adverse events occurring in ≥5% of the patients were somnolence (39%), insomnia (33%), depression (31%), accidental injury (26%), and dysphagia (19%). Efficacy and safety were comparable to results for non-HD chorea patients. Tetrabenazine treatment was associated with long-term improvement in chorea. Adverse event rates were comparable to those reported from controlled trials.
    Full-text · Article · Oct 2013
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    ABSTRACT: Essential tremor (ET) is typically measured in the clinic with subjective tremor rating scales which require the presence of a clinician for scoring and are not appropriate for measuring severity throughout the day. Motion sensors can accurately rate tremor severity during a set of predefined tasks in a laboratory. We evaluated the ability of motion sensors to quantify tremor during unconstrained activities at home. 20 ET subjects wore a wireless sensor continuously for up to 10 h daily on two days and completed hourly standardized tremor assessments involving pre-defined tasks. Mathematical models were used to predict tremor rating scores from the sensor data. At home tremor scores from hourly standardized assessments correlated with at home tremor scores estimated during unconstrained activities immediately following the standardized assessments. The hourly standardized assessments did not significantly fluctuate throughout the day, while fluctuations in the continuous assessments tended to follow changes in voluntary activity level. Both types of tremor ratings (standardized and continuous) showed high day-to-day test-retest reliability with intraclass correlation coefficients ranging from 0.67 to 0.90 for continuous ratings and 0.77 to 0.95 for standardized ratings. Results demonstrate the feasibility of continuous monitoring of tremor severity at home, which should provide clinicians with a measure of the temporal pattern of tremor in the context of daily life and serve as a useful tool for the evaluation of novel anti-tremor medications in clinical trials.
    No preview · Article · Sep 2013 · Parkinsonism & Related Disorders
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    ABSTRACT: Tetrabenazine is effective in the treatment of the chorea associated with Huntington disease and other hyperkinetic movement disorders. Following oral administration, tetrabenazine is hepatically transformed into 2 active metabolites that are CYP2D6 substrates. There are 4 CYP2D6 genotypes: poor metabolizers, intermediate metabolizers, extensive metabolizers, and ultrarapid metabolizers. CYP2D6 genotyping was performed on sequential subjects treated with tetrabenazine, but results were not known at the time of titration. Duration of titration to a stable dose, total daily dose, response rating scores, and adverse events were retrospectively collected and subsequently analyzed. Of 127 patients, the majority (n = 100) were categorized as extensive metabolizers, 14 as intermediate metabolizers, 11 as poor metabolizers, and 2 as ultrarapid metabolizers. Ultrarapid metabolizer patients needed a longer titration (8 vs 3.3, 4.4, and 3 weeks, respectively; P < .01) to achieve optimal benefit and required a higher average daily dose than the other patients, but this difference did not reach statistical significance. The treatment response was less robust in the intermediate metabolizer group when compared with the extensive metabolizer patients (P = .013), but there were no statistically significant differences between the various groups with regard to adverse effects. Our findings demonstrate that, aside from the need for a longer titration in the ultrarapid metabolizers, there are no distinguishing features of patients with various CYP2D6 genotypes, and therefore the current recommendation to systematically genotype all patients prescribed more than 50 mg/day of tetrabenazine should be reconsidered. © 2012 Movement Disorder Society.
    No preview · Article · Feb 2013 · Movement Disorders
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    ABSTRACT: Introduction Tetrabenazine (TBZ) reduces chorea related to Huntington disease (HD); however, it is uncertain whether this effect improves functionally relevant motor skills such as hand coordination and balance. The objective of this study was to provide pilot data regarding three motor function tests, which might be useful in monitoring symptom progression and therapeutic response, pending formal validation. Methods The authors assessed 11 ambulatory patients with HD-related chorea on two occasions: (1) while off TBZ (either prior to starting therapy or following a >24 h washout) and (2) when on a stable dose of TBZ, titrated to optimal effect. Study evaluations included the Jebsen-Taylor Hand Function Test (JTHFT) and Berg Balance Scale, a timed 25-foot walk, the Montreal Cognitive Assessment (MoCA) and the complete United Huntington Disease Rating Scale (UHDRS). Results Maximal chorea scores (UHDRS item 12) improved from 11.1 ± 2.9 to 8.5 ± 3.9 while on TBZ (P = 0.03), but we could not detect an improvement in functional measures while on TBZ in this small cohort. Scores of the JTHFT were globally slower than published normative data and correlated with MoCA summary scores, but not UHDRS chorea scores. Conclusions This pilot study did not detect significant functional gains with chorea suppression. The fact that performance on tests of hand function correlates with MoCA but not UHDRS chorea scores highlights the need for additional treatments targeted toward the cognitive aspects of HD.
    Full-text · Article · Dec 2012
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    ABSTRACT: To evaluate the efficacy and tolerability of lubiprostone (Amitiza) for constipation in Parkinson disease (PD) in a double-blind, randomized, controlled study. Patients with PD and clinically meaningful constipation (constipation rating scale score > 10 [range: 0-28]) were recruited from 2 academic movement disorder centers to participate in the study. After enrollment, patients were initially followed for 2 weeks and then were randomly assigned 1:1 to lubiprostone, and the dose was titrated up to 48 μg/day. They returned 4 weeks later for a final assessment. Data included stool diaries and global impressions (co-primary endpoints), demographics, Unified Parkinson's Disease Rating Scale scores, constipation scale scores, visual analog scale (VAS) scores, a stool diary, and adverse events. Fifty-four subjects (39 male, mean age 67.0 ± 10.1 years, and mean duration of PD 8.3 ± 5.4 years) were randomly assigned to lubiprostone or placebo. One patient in the drug group discontinued the study because of logistics, and one patient in the placebo group discontinued the study because of lack of efficacy. A marked or very marked clinical global improvement was reported by 16 of 25 (64.0%) subjects receiving drug vs 5 of 27 (18.5%) subjects receiving placebo (p = 0.001). The constipation rating scale (p < 0.05), VAS (p = 0.001), and stools per day in the diary (p < 0.001) all improved with drug compared with placebo. Adverse events with drug were mild, most commonly intermittent loose stools. In this randomized controlled trial, lubiprostone seemed to be well tolerated and effective for the short-term treatment of constipation in PD.
    No preview · Article · May 2012 · Neurology

  • No preview · Article · Apr 2012 · Neurology
  • W. Ondo · V. Hashem · C. Hunter · J. Simmons

    No preview · Article · Apr 2012 · Neurology

  • No preview · Article · Apr 2012 · Neurology

  • No preview · Article · Apr 2012 · Neurology

  • No preview · Article · Apr 2012 · Neurology
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    ABSTRACT: Apomorphine injections effectively abort "off" episodes in Parkinson's disease (PD). However, their use is limited by actual and perceived adverse events (AE). To our knowledge, no study has evaluated for predictors of these problems. To assess predictors of initial common AE and long-term tolerability of apomorphine injections in PD. We prospectively monitored for AE in 28 consecutive PD patients receiving initial apomorphine injections. Sequential visual analogue scale scores for nausea and in standing systolic blood pressure drops at baseline (mean of 2 assessments), 10, 20, and 40 min post-injection were acquired. Assessed historic variables included patient demographics and clinical data, treatment histories, previous AE to other dopaminergic treatments and whether patients received the recommended three day pre-treatment dose of trimethobenzamide. We also correlated the L-dopa equivalent doses with apomorphine dose needed to turn "on". No patient demographic or previous history of dopaminergic AE predicted nausea, except for baseline pre-injection nausea that day at baseline. Three days of trimethobenzamide, as recommended, was actually associated with more nausea than a single dose or no dose, even though a lack of association after matched analysis was found. A younger patient age was associated with hypotension. L-dopa equivalent dose modestly correlated with final apomorphine dose to turn "on". A previous history of nausea and hypotension, and older age should not dissuade a trial of apomorphine if clinically justified. A three day pre-treatment dose of trimethobenzamide, as recommended in the United States, does not reduce nausea.
    No preview · Article · Jan 2012 · Parkinsonism & Related Disorders
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    Full-text · Conference Paper · Jan 2012
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    ABSTRACT: The Parkinson Progression Marker Initiative (PPMI) is a comprehensive observational, international, multi-center study designed to identify PD progression biomarkers both to improve understanding of disease etiology and course and to provide crucial tools to enhance the likelihood of success of PD modifying therapeutic trials. The PPMI cohort will comprise 400 recently diagnosed PD and 200 healthy subjects followed longitudinally for clinical, imaging and biospecimen biomarker assessment using standardized data acquisition protocols at twenty-one clinical sites. All study data will be integrated in the PPMI study database and will be rapidly and publically available through the PPMI web site-www.ppmi-info.org. Biological samples including longitudinal collection of blood, cerebrospinal fluid (CSF) and urine will be available to scientists by application to an independent PPMI biospecimen review committee also through the PPMI web site. PPMI will rely on a partnership of government, PD foundations, industry and academics working cooperatively. This approach is crucial to enhance the potential for success of this ambitious strategy to develop PD progression biomarkers that will accelerate research in disease modifying therapeutics.
    No preview · Article · Dec 2011 · Progress in Neurobiology
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    ABSTRACT: Selegiline is a monoamine-B specific inhibitor used to treat Parkinson's disease. A Zydis sublingual preparation has more efficient absorption and less first pass amphetamine metabolites. We conducted an open label oral to Zydis switch study to evaluate tolerability of rapid switch, and relative efficacy, in 48 subjects from 5 sites. Overall patients preferred the Zydis preparation. Per clinician global impressions, fluctuations improved and the "on" UPDRS part II scores improved. Total UPDRS and measures of fatigue and sleep were unchanged. Adverse events were mild. Patients generally preferred the Zydis selegiline preparation but the modest difference is of unclear clinical significance given the open label nature of the trial.
    No preview · Article · Nov 2010 · Parkinsonism & Related Disorders
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    ABSTRACT: Advanced Parkinson's disease (PD) is associated with various motor and non-motor symptoms which adversely impact health-related quality of life (HRQoL). Subthalamic nucleus (STN) deep brain stimulation (DBS) has been reported to improve some dimensions of HRQoL in appropriately selected candidates. Prior studies of HRQoL following DBS have used instruments comprising a predetermined list of questions which assess issues that are generally relevant in PD, but that may not be of equal or consistent importance to all individuals. In this study, we evaluate the effect of STN DBS on quality of life using the QLS(M), a modular questionnaire in which satisfaction scores for each item are weighted in light of patient-rated importance. We prospectively analysed QLS(M) scores in 21 patients with PD (11 men, mean age 61.5+/-8.6 years) before STN DBS surgery and at a mean 7.4+/-1.5, and again at a mean 16.6+/-6.8 months postoperatively. Following STN DBS, patients experienced an improvement in HRQoL as measured by various items of the movement disorder and health modules of the QLS(M). Specifically, QLS(M) items pertaining to energy level/enjoyment of life, independence from help, controllability/fluidity of movement and steadiness when standing and walking showed significant improvements, although items concerning general life issues (eg, occupational function, interpersonal relationships, leisure activities) did not improve. Following STN DBS, symptomatic and functional improvements translate into higher HRQoL, with high satisfaction in domains related to movement disorders and general health.
    Full-text · Article · Oct 2009 · Journal of neurology, neurosurgery, and psychiatry
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    ABSTRACT: Objective: To determine whether ethyl-eicosapentaenoic acid (ethyl-EPA), an omega-3 fatty acid, improves the motor features of Huntington disease. Design: Six-monthmulticenter, randomized, double-blind, placebo-controlled trial followed by a 6-month open-label phase without disclosing initial treatment assignments. Setting: Forty-one research sites in the United States and Canada. Patients: Three hundred sixteen adults with Huntington disease, enriched for a population with shorter trinucleotide (cytosine-adenine-guanine) repeat length expansions. Interventions: Random assignment to placebo or ethyl-EPA, 1 g twice a day, followed by open-label treatment with ethyl-EPA. Main Outcome Measures: Six-month change in the Total Motor Score 4 component of the Unified Huntington's Disease Rating Scale analyzed for all research participants and those with shorter cytosine-adenine-guanine repeat length expansions (< 45). Results: At 6 months, the Total Motor Score 4 point change for patients receiving ethyl-EPA did not differ from that for those receiving placebo. No differences were found in measures of function, cognition, or global impression. Before public disclosure of the 6-month placebo-controlled results, 192 individuals completed the open-label phase. The Total Motor Score 4 change did not worsen for those who received active treatment for 12 continuous months compared with those who received active treatment for only 6 months (2.0-point worsening; P=.02). Conclusion: Ethyl-EPA was not beneficial in patients with Huntington disease during 6 months of placebo-controlled evaluation.
    No preview · Article · Dec 2008 · JAMA Neurology