Table 1.

Enroll-HD assessments used in the analysis

Scale	Measurement capturing	Items used	Outcome measure
Unified Huntington’s disease rating scale-total motor score [24]	Motor features of HD	All	Total score: 0–124
Unified Huntington’s disease rating scale – total functional capacity	Daily functioning	Item 2: What is your level of functioning: finances	0 = unable, 1 = major assistance, 2 = slight assistance, 3 = normal
Unified Huntington’s disease rating scale – functional assessment	Daily functioning	Item 2: Could the participant manage his/her finances (monthly) without any help	1 = yes or 2 = no
Mini-mental state exam [26]	Global Cognition	All	Total score: 0 – 30  < 24 = dementia cut-off
Symbol digit modality (SDMT) [24]	Processing speed	All	Total number of symbols decoded in 90 s
Verbal fluency (VF) (Animal Naming) [24]	Language/executive function	All	Total animal words generated in 60 s (excluding repetitions or perseverations)
Stroop naming, word, interference [24]	Executive function	All	Total number of blocks verbalised in 45 s for each stage (colour naming, word reading, interference)
Trail-making A and B [27]	Executive function	All	Time take to complete task
Problem behaviour assessment (PBA) – short version	Psychiatric features of HD	Item for depression, irritability and apathy	Frequency: 0–4 0 = never/almost never 1 = seldom (less than once/week) 2 = sometimes (up to 4 times a week) 3 = frequently (most days/5,6 or 7 times a week) 4 = daily/almost daily for most (or all) of day Severity: 0–4 0 = absent 1 = slight, questionable 2 = mild (present, not a problem) 3 = moderate (symptom causing problem) 4 = severe (almost intolerable for carer)