I am looking to build a mixed-effects location-scale model in brms, as implemented by Hedeker and Nordgren 2013 (https://www.ncbi.nlm.nih.gov/pubmed/23761062).

The parameterization is as such (taken from https://www.jstatsoft.org/article/view/v059c02):

Basically, this allows covariates for the mean value, the variance of the between-subject random effects, and the variance of the within-subject error terms. There is example code by Williams et al 2019 on how to do this with a non-linear version of this model (https://link.springer.com/article/10.3758/s13428-019-01255-9), but I cannot figure out how to implement the original linear version in brms. Is this even possible?

Please also provide the following information in addition to your question:

- Operating System: macOS Catalina 10.15.2
- brms Version: 2.10.0