Statistical analysisThe reliability of the SpNQ scales was evaluated with internal consistency coefficients (Cronbach´s alpha), which reflect the degree to which all items on a particular scale measure a single (uni-dimensional) concept. to combine several items with similar content, we relied on the technique of factor analysis (extraction of main components with eigenvalues > 1), which examines the correlations among a set of variables in order to achieve a set of more general `factors´. factor analyses were repeated rotating different numbers of items (Varimax rotation with Kaiser Normalization) in order to arrive at a solution embodying both the simplest structure and the most coherent one. Reliability and factor analyses, analyses of variance (aNoVa), correlation (Spearman rho) and stepwise regression analyses were performed with SPSS 15.0 for windows (SPSS GmbH Software, Munich). we considered a level of p < 0.05 as statistically significant.