Carolin Grünling | PubMed Health

PubMed2004

[First effects of training phonological awareness in two age cohorts of kindergarten children].

OBJECTIVE: This study investigated to what extent young kindergarten children already benefit from training phonological awareness. METHODS: The training program used here was the German "Würzburg training program of phonological awareness". The control group participated in the regular kindergarten program. A total of 80 children, one and two years before entering school, participated in the study. Tests of phonological awareness were assessed before and after the training as well as after six months. RESULTS: Young kindergarten children (two years before entering school) compared to preschoolers (one year before entering school) had significant lower phonological awareness skills. However both cohorts showed noticeable significant training effects, but preschoolers benefited significantly more from training phonological awareness. Long-term effects were obtained for both cohorts. CONCLUSIONS: Already young kindergarten children do benefit effectively from preschool phonological awareness training. Effects of this training on reading and spelling in school will be investigated further.

Age Factors↗

PubMed2002

How to avoid spurious cluster validation? A methodological investigation on simulated and fMRI data.

This paper presents an evaluation of a common approach that has been considered as a promising option for exploratory fMRI data analyses. The approach includes two stages: creating from the data a sequence of partitions with increasing number of subsets (clustering) and selecting the one partition in this sequence that exhibits the clearest indications of an existing structure (cluster validation). In order to achieve that the selected partition is actually the best characterization of the data structure, previous studies were directed to find the most appropriate validity function(s). In our analysis protocol, we first optimize the sequence of partitions according to the given objective function. Our study showed that an insufficient optimization of the partition, for one or more numbers of clusters, can easily yield a spurious validation result which, in turn, may lead the analyst to a misleading interpretation of the fMRI experiment. However, a sufficient optimization, for each included number of clusters, provided the basis for a reliable, adequate characterization of the data Furthermore, it enabled an adequate evaluation of the validity functions. These findings were obtained independently for three clustering algorithms (representing the hard and fuzzy clustering variant) and three up-to-date cluster validity functions. The findings were derived from analyses of Gaussian clusters, simulated data sets that mimic typical fMRI response signals, andreal fMRI data. Based on our results we propose a number of options of how to configure improved clustering tools.

Algorithms↗