Statistical Modelling 6 (2006), 300–320
GLMM approach to study the spatial and temporal evolution of spikes in
the small intestine
Christel Faes
Center for Statistics
Hasselt University
Belgium
eMail:
christel.faes@uhasselt.be
Marc Aerts
Center for Statistics, Hasselt University, Belgium
Helena Geys
Center for Statistics, Hasselt University, Belgium
and
Janssen Pharmaceutica, Beerse, Belgium
Luc Bijnens
Janssen Pharmaceutica, Beerse, Belgium
Luc Ver Donck
Janssen Pharmaceutica, Beerse, Belgium
Wim J.E.P. Lammers
Department of Physiology, Faculty of Medicine and Health Sciences, UAE
Abstract:
Mixed models can be applied in a wide range of settings. Probably, they
are most commonly used to handle grouping in the data. In addition, mixed
models can be used for smoothing purposes as well. When dealing with
non-normal data, the use of smoothing methods within the generalized
linear mixed models (GLMM) framework is less familiar. We explore
the use of GLMM for smoothing purposes in both spatial and longitudinal
dimensions. The methodology is illustrated by analysis of spike
potentials in the small intestine of different cats. Spatio-temporal
models that use two-dimensional smoothing splines across the spatial
dimension and random effects to account for the correlations during
successive slow-waves are developed. A major advantage of the mixed-model
approach is that it can handle smoothing together with grouping (or
other types of correlations) in a unified model. In this way, areas
with high spike incidence compared with other areas can be detected.
Also, the temporal and spatial characteristics of spikes during
successive slow-waves can be identified.
Keywords:
gastroenterology; generalized linear mixed models; smoothing splines;
spatio-temporal model
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