Objective:

To assess the interrater reliability of the Multidomain Impairment Rating (MIR) Scale for use in Frontotemporal Lobar Degeneration (FTLD)-related research and clinical trials.

Background:

The ARTFL LEFFTDS Longitudinal Frontotemporal Lobar Degeneration (ALLFTD) Consortium aims to characterize individuals with FTLD to prepare for clinical trials. The MIR was developed to be similar to the CDR® Dementia Staging Instrument (CDR®) scale and the CDR® plus NACC FTLD. The FTLD syndromes have a complex array of cognitive, behavioral/psychiatric and motor symptoms that can contribute to functional impairment, and one of the goals of the MIR is to capture the multidomain contributions to functional impairment.

Design/Methods:

Four additional domains were developed and added to the CDR® plus NACC FTLD; Concentration and Multitasking, Visuospatial Functioning, Psychiatric Features, and Motor. Each added domain is rated on a five‐point scale: 0 (normal), 0.5 (questionably or minimally impaired), 1 (mildly but definitely impaired), 2 (moderately impaired), and 3 (severely impaired) from information based on the interviews with the participant and the informant, and the neurological examination findings. An interrater reliability study was performed between four raters on 60 ALLFTD participants. Weighted cohen kappa and intraclass correlation coefficients (ICC) statistics measured interrater reliability.

Results:

Clinical diagnosis for the 60 participants were 11 behavioral variant frontotemporal dementia (bvFTD), 2 amyotrophic lateral sclerosis (ALS), 2 FTD/ALS, 5 corticobasal syndrome, 3 primary progressive aphasia, 3 progressive supranuclear palsy, 14 mild behavioral and/or cognitive impairment, and 20 normal. The global MIR score and the MIR sum of all subdomain scores (MIR-SS) both showed excellent interrater reliability for pairwise rater comparisons with weighted cohen kappa ranging from 0.88 to 0.94 for the global MIR score and with ICC ranging from 0.90 to 0.99 for the MIR-SS.

Conclusions:

The MIR scale may serve as a useful comprehensive clinical assessment tool in natural history studies and clinical trials in FTLD.