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. 2022 Sep 8;37(12):2336–2341. doi: 10.1002/mds.29215

TABLE 1.

Identified limitations of the UMSARS related to different taxonomic properties

Property a Limitation
Content validity (including face validity)

  • MSA patients' and caregivers' input not considered

  • MSA disease‐specific features not considered (eg, depression, stridor)

  • Instrumental assessment of activities of daily living (other than chores) not considered

  • Lack of association with disease severity in some items (eg, UMSARS‐I item 11 on sexual function)

  • Some items are amenable to symptomatic treatment (eg, UMSARS‐I item 2 on swallowing; UMSARS‐1 item 12 on constipation; UMSARS‐I item 9 on orthostatic hypotension) b

Reliability

  • Moderate intrarater and interrater agreement in some items (eg, UMSARS‐II item 3 on oculomotor dysfunction)
Construct/Structural validity

  • Redundancy of some items (eg, UMSARS‐I item 7 and UMSARS‐II item 14 on gait are both the same)
Cross‐cultural validity

  • Cultural bias in some items (eg, UMSARS‐I item 4 on cutting food/handling utensils assumes that food is regularly cut for eating)
Criterion validity

  • Limitations to detect changes in advanced stages—possible ceiling effect
Responsiveness

  • Limitations to detect disease progression accurately in early stages—variable standard deviations in annual increase exceeding expected effect size of candidate disease‐modifying drugs
Interpretability

  • Although interrater reliability is good, anchoring descriptions in some items could be improved (eg, UMSARS‐I item 6 on difficulty with showering, unclear if this includes getting into the shower; UMSARS‐I item 2 on swallowing and UMSARS‐I item 8 on falling include “less than once a week” and “more than once a week” options, but it is unclear which would apply in a patient choking/falling once a week)
a

Taxonomy and definition of measurement properties according to Mokkink et al. 25

b

The impact of symptomatic therapies in some scale items is not limited to the UMSARS and affects other clinical outcome assessments used in the movement disorders field.

UMSARS, Unified Multiple System Atrophy Rating Scale; MSA, multiple system atrophy.