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UHDRS® Licensing

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®


Motor Assessment


Cognitive Assessment


Behavioral Assessment


Independence Scale


Functional Assessment


Total Functional Capacity (TFC)*

*Please note: Permission has been granted by the author, Ira Shoulson MD for the HSG to license the TFC as part of UHDRS.

UHDRS® ’99

UHDRS® ’99 represents an update and expansion of the UHDRS® to augment the utility and applicability of this research tool. In 1999, components of the UHDRS® were enhanced and guidelines were provided for use of the scale. In 2005 the Behavioral Assessment section was further clarified and refined based on research experience.


The vUHDRS® (virtual Unified Huntington Disease Rating Scale) is a way to use the UHDRS® remotely with consistency and excellent reliability. This version of the tool breaks down accessibility barriers and allows for virtual assessments in HD trials as well as for virtual clinical assessment of patients with HD. Results of an observational study testing vUHDRS® can be seen here.

How to Obtain Permission to Use the UHDRS®

The Unified Huntington Disease Rating Scale, revised UHDRS® ’99, vUHDRS®, and accompanying manuals are the copyrighted intellectual property of the HSG (hereinafter collectively referred to as the “UHDRS®”). Individuals, organizations, firms, and entities seeking to use any part or version of the UHDRS® and/or its related materials must obtain a licensing agreement from the HSG. License fees may apply.

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

Licensure availability for the vUHDRS® will be available soon!

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.

If you have additional questions, contact:

Janine Mercandetti, Manager, Contracts & Projects
Huntington Study Group