Erratum to: Qual Life Res DOI 10.1007/s11136-010-9844-9

Please note that the following acknowledgements should be added to the Acknowledgements section in the original publication:

This work was funded in part by a NARCOMS visiting Scientist Fellowship to Dr. Schwartz, which was supported through a Foundation of the Consortium of Multiple Sclerosis Centers grant from EMD Serono, Inc. NARCOMS is supported by the Consortium of Multiple Sclerosis Centers and its Foundation.