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Frieri R, Rosenberger WF, Flournoy N, Lin Z. Design considerations for two-stage enrichment clinical trials. Biometrics 2023; 79:2565-2576. [PMID: 36435977 DOI: 10.1111/biom.13805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 09/09/2022] [Accepted: 11/18/2022] [Indexed: 11/28/2022]
Abstract
When there is a predictive biomarker, enrichment can focus the clinical trial on a benefiting subpopulation. We describe a two-stage enrichment design, in which the first stage is designed to efficiently estimate a threshold and the second stage is a "phase III-like" trial on the enriched population. The goal of this paper is to explore design issues: sample size in Stages 1 and 2, and re-estimation of the Stage 2 sample size following Stage 1. By treating these as separate trials, we can gain insight into how the predictive nature of the biomarker specifically impacts the sample size. We also show that failure to adequately estimate the threshold can have disastrous consequences in the second stage. While any bivariate model could be used, we assume a continuous outcome and continuous biomarker, described by a bivariate normal model. The correlation coefficient between the outcome and biomarker is the key to understanding the behavior of the design, both for predictive and prognostic biomarkers. Through a series of simulations we illustrate the impact of model misspecification, consequences of poor threshold estimation, and requisite sample sizes that depend on the predictive nature of the biomarker. Such insight should be helpful in understanding and designing enrichment trials.
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Affiliation(s)
- Rosamarie Frieri
- Department of Statistical Sciences, University of Bologna, Bologna, Italy
| | | | - Nancy Flournoy
- Department of Statistics, University of Missouri, Columbia, Missouri, USA
| | - Zhantao Lin
- Department of Statistics, Data and Analytics, Eli Lilly and Company, Indianapolis, Indiana, USA
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Thi Cam Ha V, Doan T, Holmes MJ, Tran TQ. Does Institutional Quality Matter for Foreign Direct Investment and Human Development? Eval Rev 2023:193841X231195798. [PMID: 37590912 DOI: 10.1177/0193841x231195798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
This study examines the relationship between foreign direct investment (FDI), institutional quality and human development) in host countries from 2002 to 2019, using the Human Development Index [HDI] as the measure of human development. This study utilized a panel dataset of 143 countries, including both developed and developing economies, over a 17-year period. Additionally, the study employed a GMM (generalized method of moments) estimator to address unobservable heterogeneity and simultaneity. This study reveals a significant positive relationship between FDI and human development, with a stronger effect observed in developing countries compared to in developed countries. Notably, the impact of FDI-HDI nexus is larger in countries with moderately high-quality institutions, irrespective of their income level. Furthermore, good governance plays a crucial role in enhancing human development, as developing economies with high governance quality experience a greater impact of FDI on HDI compared to other countries. The findings of this study suggest that attracting FDI can be beneficial for enhancing the HDI, especially in developing countries. Additionally, the study highlights governance as a moderating factor in the relationship between FDI and HDI. Improving governance quality can enhance the positive impact of FDI on human development in host countries, especially in developing countries.
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Affiliation(s)
- Van Thi Cam Ha
- School of Business and Management, RMIT International University, Vietnam
| | - Tinh Doan
- The Australian National University, Canberra, Australia
| | - Mark J Holmes
- Economics Department, School of Accounting, Finance and Economics, The University of Waikato, Waikato, New Zealand
| | - Tuyen Quang Tran
- International School, Vietnam National University Hanoi, Hanoi, Vietnam
- Thang Long Institute of mathematics and applied sciences, Thang Long University, Hanoi, Vietnam
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Mori S, Morimoto T, Murata Y, Okamoto Y, Kanzaki S. Tests of human auditory temporal resolution: preliminary investigation of ZEST parameters for amplitude modulation detection. Front Neurosci 2023; 17:1148476. [PMID: 37476830 PMCID: PMC10354262 DOI: 10.3389/fnins.2023.1148476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/10/2023] [Indexed: 07/22/2023] Open
Abstract
Auditory temporal resolution plays a critical role in the everyday experience of listening to complex acoustic patterns. Amplitude modulation detection thresholds are widely used to measure auditory temporal resolution. In an attempt to develop a standardized clinical test of auditory temporal resolution, we used ZEST (Zippy Estimation by Sequential Testing, a Bayesian threshold estimation procedure, to measure amplitude modulation detection thresholds. ZEST utilizes prior knowledge about a listener's thresholds, as represented by a probability density function of the thresholds, and psychometric functions of the listener's responses. This paper reports a preliminary study in which ZEST parameters that could be used for measurements of amplitude modulation detection thresholds were sought. For this purpose, we created histograms of the detection thresholds for a wide range of modulation frequencies, measured the psychometric functions of amplitude modulation detection, and performed computer simulations of ZEST threshold estimation. The results suggested that, with appropriately-set parameters, ZEST allows for the accurate estimation of amplitude modulation detection thresholds within 20 trials.
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Affiliation(s)
- Shuji Mori
- Department of Informatics, Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan
| | | | - Yuto Murata
- Department of Informatics, Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan
| | - Yasuhide Okamoto
- Department of Otorhinolaryngology, Tokyo Saiseikai Central Hospital, Tokyo, Japan
- Keio University School of Medicine, Tokyo, Japan
| | - Sho Kanzaki
- Keio University School of Medicine, Tokyo, Japan
- Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
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van der Laan L, Zhang W, Gilbert PB. Nonparametric estimation of the causal effect of a stochastic threshold-based intervention. Biometrics 2022:10.1111/biom.13690. [PMID: 35526218 PMCID: PMC10024462 DOI: 10.1111/biom.13690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 03/22/2022] [Indexed: 12/01/2022]
Abstract
Identifying a biomarker or treatment-dose threshold that marks a specified level of risk is an important problem, especially in clinical trials. In view of this goal, we consider a covariate-adjusted threshold-based interventional estimand, which happens to equal the binary treatment-specific mean estimand from the causal inference literature obtained by dichotomizing the continuous biomarker or treatment as above or below a threshold. The unadjusted version of this estimand was considered in Donovan et al.. Expanding upon Stitelman et al., we show that this estimand, under conditions, identifies the expected outcome of a stochastic intervention that sets the treatment dose of all participants above the threshold. We propose a novel nonparametric efficient estimator for the covariate-adjusted threshold-response function for the case of informative outcome missingness, which utilizes machine learning and targeted minimum-loss estimation (TMLE). We prove the estimator is efficient and characterize its asymptotic distribution and robustness properties. Construction of simultaneous 95% confidence bands for the threshold-specific estimand across a set of thresholds is discussed. In the Supporting Information, we discuss how to adjust our estimator when the biomarker is missing at random, as occurs in clinical trials with biased sampling designs, using inverse probability weighting. Efficiency and bias reduction of the proposed estimator are assessed in simulations. The methods are employed to estimate neutralizing antibody thresholds for virologically confirmed dengue risk in the CYD14 and CYD15 dengue vaccine trials.
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Affiliation(s)
- Lars van der Laan
- Department of Statistics, University of Washington, Seattle, Washington.,Vaccine and Infectious Disease and Public Health Sciences Divisions, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Wenbo Zhang
- Department of Biostatistics, University of Washington, Seattle, Washington
| | - Peter B Gilbert
- Vaccine and Infectious Disease and Public Health Sciences Divisions, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Department of Biostatistics, University of Washington, Seattle, Washington
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Saeedi A, Englert L, Hemmert W. eABR THR Estimation Using High-Rate Multi-Pulse Stimulation in Cochlear Implant Users. Front Neurosci 2021; 15:705189. [PMID: 34393715 PMCID: PMC8358126 DOI: 10.3389/fnins.2021.705189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/07/2021] [Indexed: 11/13/2022] Open
Abstract
We estimated the electrically-evoked auditory brainstem response thresholds (eABR THRs) in response to multi-pulses with high burst rate of 10,000 pulses-per-second (pps). Growth functions of wave eV amplitudes, root mean square (RMS) values, peak of phase-locking value (PLV), and the lowest valid data point (LVDP) were calculated in 1-, 2-, 4-, 8-, and 16-pulses conditions. The growth functions were then fitted and extrapolated with linear and exponential functions to find eABR THRs. The estimated THRs were compared to psychophysical THRs determined for multi-pulse conditions as well as to the clinical THRs measured behaviorally at the rate of 1,000 pps. The growth functions of features showed shallower growth slopes when the number of pulses increased. eABR THRs estimated in 4-, 8-, and 16-pulses conditions were closer to the clinical THRs, when compared to 1- and 2-pulses conditions. However, the smallest difference between estimated eABR THRs and clinical THRs was not always achieved from the same number of pulses. The smallest absolute difference of 30.3 μA was found for the linear fittings on growth functions of eABR RMS values in 4-pulses condition. Pearson's correlation coefficients (PCCs) between eABR THRs and psychophysical THRs were significant and relatively large in all but 16-pulses conditions. The PCCs between eABR THRs and clinical THRs, however, were smaller and in less cases significant. Results of this study showed that eABRs to multi-pulse stimulation could, to some extent, represent clinical stimulation paradigms, and thus in comparison to single pulses, could estimate clinical THRs with smaller errors.
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Affiliation(s)
- Ali Saeedi
- Department of Electrical and Computer Engineering, Technical University of Munich, Munich, Germany.,Munich School of Bioengineering, Technical University of Munich, Garching, Germany
| | - Ludwig Englert
- Department of Electrical and Computer Engineering, Technical University of Munich, Munich, Germany
| | - Werner Hemmert
- Department of Electrical and Computer Engineering, Technical University of Munich, Munich, Germany.,Munich School of Bioengineering, Technical University of Munich, Garching, Germany.,Munich School of Robotics and Machine Intelligence, Technical University of Munich, Munich, Germany
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Strohl MP, David AP, Dwyer CD, Rosen CA, Young VN, Chang JL, Cheung SW. Aesthesiometer-Based Testing for Laryngopharyngeal Hyposensitivity. Laryngoscope 2021; 132:163-168. [PMID: 34289117 DOI: 10.1002/lary.29761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 11/12/2022]
Abstract
OBJECTIVES/HYPOTHESIS To develop a method for threshold estimation of the laryngeal adductor reflex (LAR) response using Cheung-Bearelly monofilaments. STUDY DESIGN Cross-sectional. METHODS Twenty-two healthy adults (12 men, 10 women) were tested for LAR response outcome using 30 mm 5-0 and 4-0 nylon monofilaments. Tactile stimuli were delivered to the aryepiglottic (AE) fold and medial pyriform sinus (MPS). Dichotomous classifier features and performance (area under the curve (AUC)), the LAR response outcome agreement and disagreement matrix, and test-retest reliability were examined. From those data, a test protocol that would minimize patient burden to estimate the LAR triggering threshold was formulated. RESULTS Classifier performance of 5-0 monofilament stimulation of the AE fold (sensitivity = 0.63, specificity = 0.63, PPV = 0.74, NPV = 0.25) and MPS (sensitivity = 0.45, specificity = 0.77, PPV = 0.74, NPV = 0.23,) was slightly below that of 4-0 monofilament stimulation of the AE fold (sensitivity = 0.82, specificity = 0.50, PPV = 0.82, NPV = 0.50) and MPS (sensitivity = 0.84, specificity = 0.64, PPV = 0.90, NPV = 0.56), based on AUC. LAR response outcome agreement for 5-0 and 4-0 stimulations was high (93%) for 5-0 positive response, but low (29%) for 5-0 negative response. Aesthesiometer test-retest reliability for LAR response outcome was excellent (Cronbach's alpha = 0.97). CONCLUSIONS Threshold estimation of the LAR response may be operationalized by adopting a decision tree protocol. For negative LAR response to initial 5-0 monofilament stimulation and positive response to subsequent 4-0 monofilament stimulation, the higher threshold is confirmed. Positive LAR response to 5-0 or 4-0 monofilament stimulation is expected in over 90% of asymptomatic adults. Negative LAR response to 4-0 monofilament stimulation identifies patients at risk for laryngopharyngeal hyposensitivity. LEVEL OF EVIDENCE 3b Laryngoscope, 2021.
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Affiliation(s)
- Madeleine P Strohl
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California, U.S.A
| | - Abel P David
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California, U.S.A
| | - Christopher D Dwyer
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California, U.S.A
| | - Clark A Rosen
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California, U.S.A
| | - VyVy N Young
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California, U.S.A
| | - Jolie L Chang
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California, U.S.A
| | - Steven W Cheung
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, California, U.S.A
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