The functional regression model (FRM) is one of the most studied topics in FDA over the last few years. A regression model is said to be “functional” if any of the variates involved (the predictors or the response) has a functional nature, i.e. it is a measure observed along a continuous interval. Cases with a scalar response and functional predictors have particularly attracted a lot of attention. For example, Sørensen et al.  gives a basic introduction for the analysis of functional data applied in datasets from medical science.