Two high resolution methods solving inverse problems potentially ill-posed, named 4-MUSIC and 4-RapMUSIC, are proposed. They allow for localization of brain current sources with unconstrained orientations from surface electro-or magneto-encephalographic data using spherical or realistic head geometries. The 4-MUSIC and 4-RapMUSIC methods are based on i) the separability of the data transfer matrix as a function of location and orientation parameters and ii) the fourth order (FO) virtual array theory. In addition, 4-RapMUSIC uses the deflation concept extended to FO statistics accounting for the presence of potentially but not totally coherent sources. Computer results display the superiority of the 4-RapMUSIC approach in different situations (two closed sources, additive Gaussian noise with unknown spatial covariance, ...) especially over classical algorithms.

Conf Proc IEEE Eng Med Biol Soc. 2006;1:4498-501. Albera L, Ferreol A, Cosandier-Rimele D, Merlet I, Wendling F. Lab. Traitement du Signal et de 1'Image, Rennes I Univ.

This study expanded the inference and story recognition literature by investigating differences within the older age range, differences as a result of cognitive impairment, no dementia (CIND), and applying signal detection procedures to the analysis of accuracy data. Old-old adults and those with more severe CIND showed poorer ability to accurately recognize inferences, and less sensitivity in discriminating between statement types. Results support the proposal that participants used two different recognition strategies. Old-old and CIND adults may be less able to recognize that something plausible with an event may not have actually occurred.

Exp Aging Res. 2007 Jul-Sep;33(3):295-322. Bielak AA, Hultsch DF, Kadlec H, Strauss E. Department of Psychology, University of Victoria, Victoria, British Columbia, Canada. abielak@uvic.ca