HD-ISS Calculator for Clinical Research Purposes

This calculator should not be used independently of the paper Huntington's Disease Integrated Staging System (HD-ISS): A Novel Evidence-Based Classification System for Staging by Tabrizi et al.

Directions: Enter values for each variable (missing data is not allowed), then click "Calculate Stage" for results.

Age in Years

Round to nearest year
(≥18)
CAG Expansion


(≥40)
Putamen Volume

Must be proportion of
ICV ICV: intra-cranial volume

(0 to 1)
Caudate Volume

Must be proportion of
ICV ICV: intra-cranial volume

(0 to 1)
UHDRS UHDRS: Unified HD Rating Scale
Total Motor Score (TMS)


(0 to 124)
UHDRS UHDRS: Unified HD Rating Scale
Symbol Digit Modalities Test (SDMT)
(≥0)

Education: Required for SDMT interpretation
0 = high school or less,
1 = more than high school
(0 or 1)
UHDRS UHDRS: Unified HD Rating Scale
Total Functional Capacity (TFC)


(0 to 13)
UHDRS UHDRS: Unified HD Rating Scale
Independence Scale (IS)


(0 to 100, increments of 10)

Huntington's Disease Integrated Staging System Overview

stage