The pace of basic science research defining the mechanisms of selective neuronal degeneration in Huntington disease (HD) has far exceeded the pace of translation of this information into clinically effective treatments for the disease. One reason for this bottleneck between bench and bedside is the paucity of available surrogate markers for HD. Identification of surrogate markers is critical for the design of future clinical trials. Such markers could provide a reliable signal of early brain dysfunction in HD and could be used as a biomarker in trials of agents that could prevent onset or delay progression of disease.