TABLE 2.

Outstanding research questions

Which dimensions of apathy and impulsivity overlap or are dissociable in HD?

What is the trajectory of co‐occurring apathy and impulsivity in HD?

What are the dissociable contributions of reward sensitivity and effort sensitivity in abnormal motivated behavior in HD?

Is background reward estimation altered in HD?

How is time perceived in persons with apathy and impulsivity in HD?

How does altered learning influence future valuation and subsequent behavior in HD in those with co‐occurring apathy and impulsivity?

Which neuromodulators and brain networks underlie apathy and impulsivity in HD, and how do these brain networks change over the disease course?

How can drug therapies be optimized to target specific components of apathy and impulsivity in HD, working toward personalized medicine?