title: A method for processing multivariate data in medical studies.
abstract: Traditional displays of principal component analyses lack readability to discriminate between putative clusters of variables or cases. Here, the author proposes a method that clusterizes and visualizes variables or cases through principal component analyses thus facilitating their analysis. The method displays pre-determined clusters of variables or cases as urchins that each has a soma (the average point) and spines (the individual variables or cases). Through three examples in the field of neuropsychology, the author illustrates how urchins help examine the modularity of cognitive tasks on the one hand and identify groups of healthy versus brain-damaged participants on the other hand. Some of the data used in this article were obtained from the Alzheimer's Disease Neuroimaging Initiative database. The urchin method was implemented in MATLAB, and the source code is available in the Supporting information. Urchins can be useful in biomedical studies to identify distinct phenomena at first glance, each having several measures (clusters of variables) or distinct groups of participants (clusters of cases).
authors.affiliation: The Neuropsychological Laboratory, CNS-Fed, 39 rue Meaux, 75019 Paris, France. olivier.coubard@cns-fed.com
authors.forename: Olivier A
authors.initials: OA
authors.lastname: Coubard
mesh_terms: D000544:Alzheimer Disease / Q000473:pathology; D016000:Cluster Analysis; D003627:Data Interpretation, Statistical; D015999:Multivariate Analysis; D059906:Neuroimaging / Q000379:methods / Q000592:standards; D025341:Principal Component Analysis; D012107:Research Design
keywords: multivariate analysis; neuropsychology; principal component analysis; statistics
references.citation: Heredity (Edinb). 2009 Apr;102(4):330-41
references.pmid: 19156164
references.citation: Methods Mol Biol. 2008;428:291-325
references.pmid: 18287780
references.citation: Trends Biotechnol. 2006 Sep;24(9):419-25
references.pmid: 16870286
references.citation: Neuropsychology. 2011 May;25(3):353-67
references.pmid: 21417533
references.citation: Neural Netw. 2006 Jul-Aug;19(6-7):847-54
references.pmid: 16777380
references.citation: J Plast Reconstr Aesthet Surg. 2010 Feb;63(2):218-26
references.pmid: 19059819
references.citation: Philos Trans R Soc Lond B Biol Sci. 2007 May 29;362(1481):901-15
references.pmid: 17412679
references.citation: BMC Bioinformatics. 2009 Oct 29;10:363
references.pmid: 19874601
references.citation: Ann N Y Acad Sci. 1995 Dec 15;769:191-211
references.pmid: 8595026
references.citation: Int J Food Microbiol. 2007 Nov 30;120(1-2):95-9
references.pmid: 17602772
references.citation: Biol Rev Camb Philos Soc. 2008 Feb;83(1):35-69
references.pmid: 18211281
references.citation: BMC Bioinformatics. 2012 Feb 03;13:24
references.pmid: 22305354
references.citation: Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2280-7
references.pmid: 15572782
references.citation: J Psychiatr Res. 1975 Nov;12(3):189-98
references.pmid: 1202204
references.citation: IEEE Trans Neural Netw. 2002;13(3):780-4
references.pmid: 18244475
references.citation: Res Nurs Health. 2009 Jun;32(3):345-60
references.pmid: 19274688
references.citation: J Neurosci Methods. 2009 Sep 30;183(1):86-94
references.pmid: 19607860
references.citation: BMC Bioinformatics. 2005 May 12;6:115
references.pmid: 15890080
references.citation: Methods Mol Biol. 2008;428:327-47
references.pmid: 18287781
references.citation: IEEE Trans Neural Netw. 2001;12(1):153-8
references.pmid: 18244371
references.citation: PLoS One. 2012;7(9):e43759
references.pmid: 22984441
references.citation: BMC Bioinformatics. 2005 Jun 23;6:158
references.pmid: 15975141
references.citation: BMC Bioinformatics. 2006 Feb 16;7:74
references.pmid: 16483359
references.citation: Chem Rev. 2007 Jul;107(7):3212-46
references.pmid: 17595149
references.citation: J Orofac Orthop. 2008 Nov;69(6):424-36
references.pmid: 19169639
references.citation: Bioinformatics. 2005 May 15;21(10):2548-9
references.pmid: 15734774
references.citation: Bioinformatics. 2005 May 15;21(10):2550-1
references.pmid: 15746290
references.citation: J Mol Graph Model. 2009 Jun-Jul;27(8):951-68
references.pmid: 19278879
references.citation: J Exp Psychol Learn Mem Cogn. 2007 Jul;33(4):645-62
references.pmid: 17576145