Impact of Xenazine(Tetrabenazine)on Gait and Functional Activity in Individuals With Huntington's Disease

In individuals with Huntington's disease (HD), chorea may contribute to balance problems and difficulties with walking, sit to stand transfers and stair climbing that in turn may contribute to high fall rates. Xenazine (tetrabenazine) is a monoamine-depleting drug that is commonly used to reduce chorea.

The purpose of this study is to compare: 1) spatial and temporal gait measures, 2) performance on functional mobility measures, and 3) amount of daily walking activity before and after administration of Xenazine in individuals with HD. It is hypothesized that the use of Xenazine to decrease chorea will improve functions of 1) gait, 2) sit-to-stand transfers 3) stair climbing and 4) overall daily physical activity and function.

Individuals with HD who are ambulatory and are either already taking Xenazine or have been newly prescribed the medication will be recruited for this prospective open-label study. A variety of motor assessments will be preformed while subject are taking Xenazine or after a period off of the medications. These tests include: Unified Huntington's Disease Rating Scale (UHDRS) motor section, GAITRite forward walking, Tinetti Mobility Test, Timed Sit-to-Stand Test, Timed Stair Climb Test, Rhomberg test. A subset of subjects will wear an activity monitoring device on the wrist of the non-dominant hand for 5 consecutive days and nights.

Individuals with Huntington's disease who are already on Xenzaine (tetrabenazine) or who have recently been prescribed the medicaion.

Inclusion Criteria:

• Huntington's Disease
• Able to ambulate independently

Exclusion Criteria:

• Other orthopedic or neurological disorder that affects gait or balance
• Pregnancy
• Chorea score < 10 prior to initiation of medication.
• Inability to provide informed consent