Statistical Analysis of Hippocampus Shape Using a Modified Mann-Whitney-Wilcoxon Test

The Mann-Whitney-Wilcoxon (MWW) test statistic, while distribution-free, suffers from a loss of efficacy for certain underlying distributions. In this manuscript, we instead use a data-adaptive weighted generalized Mann-Whitney-Wilcoxon (AWGMWW) test statistic, one that is optimal in the Pitman Asymptotic Efficacy (PAE) sense, to discern differences in hippocampus shape among twin populations with or without Major Depressive Disorder (MDD). We verify, based on a previous study using the MWW statistic, that a high-risk group is more similar to the control group than the depressed group in terms of hippocampus shape. In addition, we show that the control group is more similar to the high-risk group than the depressed group - a distinction that could not be made in the preceding study. Our results suggest that the AWGMWW statistic is more powerful for this application.

[1]  Carey E. Priebe,et al.  A data-adaptive methodology for finding an optimal weighted generalized Mann-Whitney-Wilcoxon statistic , 2007, Comput. Stat. Data Anal..

[2]  U. Grenander,et al.  Statistical methods in computational anatomy , 1997, Statistical methods in medical research.

[3]  U. Grenander,et al.  Hippocampal morphometry in schizophrenia by high dimensional brain mapping. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[4]  M. Miller,et al.  High-dimensional mapping of the hippocampus in depression. , 2003, The American journal of psychiatry.

[6]  F. Wilcoxon.  Individual Comparisons by Ranking Methods , 1945 .

[7]  Carey E. Priebe,et al.  Statistical Analysis of Twin Populations using Dissimilarity Measurements in Hippocampus Shape Space , 2008, Journal of biomedicine & biotechnology.

[8]  B. Silverman.  Density estimation for statistics and data analysis , 1986 .

[9]  Olga V. Demler,et al.  The epidemiology of major depressive disorder: results from the National Comorbidity Survey Replication (NCS-R). , 2003, JAMA.

[10]  C. Priebe,et al.  A weighted generalization of the Mann-Whitney-Wilcoxon statistic , 2002 .

[11]  H. B. Mann,et al.  On a Test of Whether one of Two Random Variables is Stochastically Larger than the Other , 1947 .

[12]  L. D. Goodstein,et al.  Abnormal Psychology: Current Perspectives , 1984 .

[13]  Carey E. Priebe,et al.  Collaborative computational anatomy: An MRI morphometry study of the human brain via diffeomorphic metric mapping , 2009, Human Brain Mapping.

[14]  C. D. Kemp,et al.  Density Estimation for Statistics and Data Analysis , 1987 .