A maximum likelihood procedure for the analysis of group and individual data in aphasia research.
The limitations inherent in group versus case studies appear to lie in a complementary distribution, underscoring the importance of combining both strategies within a single research program. However, this compromise approach requires analytic tools that permit us to combine and evaluate individual and group data in a common format. Maximum likelihood estimation (MLE) belongs to a family of procedures for determining goodness of fit. MLE can be used in conjunction with a linear or nonlinear model of the way that sources of information combine to determine a given behavioral outcome; such models can be used to estimate the distance between two groups, the degree to which an individual case deviates from a given empirically or theoretically defined group profile, and the degree to which one individual case resembles another. We offer a demonstration of how MLE can be used to evaluate group and individual profiles, in a cross-linguistic study of sentence comprehension in nonfluent aphasic speakers of English, Italian, and German. This includes a demonstration in which the MLE models for each language are "lesioned" to simulate several competing accounts of receptive agrammatism.
Bates
E
E
Department of Psychology, University of California, San Diego, La Jolla 92093.
McDonald
J
J
MacWhinney
B
B
Appelbaum
M
M
D001037:Aphasia / Q000175:diagnosis* / Q000523:psychology; D001039:Aphasia, Broca / Q000175:diagnosis / Q000523:psychology; D003431:Cross-Cultural Comparison; D003627:Data Interpretation, Statistical; D006801:Humans; D007802:Language; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D015203:Reproducibility of Results