Unified Huntington’s Disease Rating Scale (UHDRS®)

The UHDRS® is a research tool which has been developed by the HSG to provide a uniform assessment of the clinical features and course of HD. The UHDRS® has undergone extensive reliability and validity testing and has been used as a major outcome measure by the HSG in controlled clinical trials.

Components of the UHDRS®

  1. Motor Assessment
  2. Cognitive Assessment
  3. Behavioral Assessment
  4. Independence Scale
  5. Functional Assessment
  6. Total Functional Capacity (TFC)


UHDRS® ’99

UHDRS® ’99 represents an update and expansion of the UHDRS® to augment the utility and applicability of this research tool. In 1999 a team of HD researchers enhanced all of the components of the UHDRS®. In 2005 the Behavioral Assessment section was further clarified and refined based on research experience.

How to Obtain Permission to Use the UHDRS®

The Unified Huntington Disease Rating Scale and revised UHDRS® ’99 and accompanying manual created by the HSG members are the copyrighted intellectual property of the HSG (hereinafter collectively referred to as the, “UHDRS®”). The UHDRS®, case report forms, and other related materials are copyrighted by the HSG. Individuals, organizations, firms, or other entities seeking to use these tools and/or materials must obtain prior written permission from the HSG. License fees may apply.

Please complete the UHDRS® Request form to obtain permission and approval for use of the UHDRS® scales.

UHDRS® Request Form

Please note that there are certain non-HSG components incorporated within the UHDRS® that are not the intellectual property of the HSG, and therefore, you will be required to seek and obtain separate permissions from the owners of these scales.

These include the following:

  • Symbol Digit Modalities Test (SDMT) – Western Psychological Services owns this test. The testing form based on the original SDMT manuscript must be purchased for use. If an alternative version of the SDMT is used, permission must be obtained from WPS and a fee for use must be paid to WPS.
  • Stroop and Verbal Fluency – these tests are in the public domain, so you can create your own version, or there are several companies that sell their own version of the Stroop test, including WPS, PAR and Stoelting, among others, and it is also available for free online at psytoolkit.org.
  • Total Functional Capacity (TFC) – permission has been granted by the author, Ira Shoulson MD for the HSG to license the TFC.

If you have additional questions, contact:

Janine Mercandetti, Manager, Contracts & Projects
Huntington Study Group


UHDRS® Natural History Database

The UHDRS® Natural History Database is a compilation of more than 8,000 individuals. The database includes individuals affected by or immediately at risk for HD. HSG researchers have used this valuable cohort to investigate research questions. The following are two of many research publications using this cohort. Please click on HSG publications for additional manuscripts based on the UHDRS® Natural History Database.

Factors associated with the rate of functional decline were evaluated using the UHDRS® natural history database in a large HD cohort followed longitudinally for up to four years. A full report was published by The Huntington Study Group (Marder K, primary author). Rate of functional decline in Huntington’s disease. Neurology 54:452-458, 2000.

Early identification of clinical changes in HD may be of critical importance for the design and implementation of clinical trials to slow the progression of the disease. A full report of this paper was published by: The Huntington Study Group (Paulsen JS, primary author). Clinical markers of early disease in persons near onset of Huntington’s disease. Neurology 2001;57:658-662.

Full publication reference:

Huntington Study Group (Kieburtz K, primary author). The Unified Huntington’s Disease Rating Scale: Reliability and Consistency. Mov Dis 1996;11:136-142

The Motor Section of the UHDRS® is a supplement to the following Movement Disorders Journal publication:

Volume 11, Issues 1-3, The Unified Huntington’s Disease Rating Scale: Reliability and Consistency. Mov Dis 1996;11:136-142, Supplemental Tape

If you wish to obtain a copy of this article, contact the Movement Disorder Society, by phone or email: 414-276-2145, info@movementdisorders.org or see the Movement Disorder Society website.