The Modified Rivermead Mobility Index: reliability and convergent validity in a mixed neurological population.
OBJECTIVE
To assess the inter-rater reliability, internal consistency and convergent validity of the Modified Rivermead Mobility Index (MRMI) in a mixed neurological population.


METHODS
The MRMI was scored for 30 consecutive patients (mean age 54.5+/-15.6 years) by two individual testers. Reliability was examined using intraclass correlation coefficients (ICC3,1) and Bland and Altman plots; internal consistency reliability using Cronbach's alpha (alpha) and convergent validity using Spearman's correlation coefficient (rho) test to compare the MRMI to the 10-m walk test as a gold standard of mobility. As the majority of patients had bilateral deficits, the MRMI was measured and added independently for both sides.


RESULTS
The inter-rater reliability was excellent: ICC (95% CI)=0.93(0.86, 0.96). The Bland and Altman plots contained most data points and there was perfect agreement between raters bilaterally in 27% of cases, with a difference of one point in 60% of cases on the left and 63% of cases on the right. Internal consistency was good at alpha=0.72 (Rater 1) and 0.80 (Rater 2). The Spearman rho between MRMI and the 10-m walk test was high at 0.86.


CONCLUSIONS
The MRMI was shown to have high levels of reliability in a mixed neurological population but we recommend that its psychometric properties are further investigated to establish the true clinical utility of this measure.
Department of Physiotherapy, Royal College of Surgeons in Ireland, and Beaumont Hospital, Dublin, Ireland. walshj7@tcd.ie
Julie M
JM
Walsh
Aileen
A
Barrett
Deirdre
D
Murray
Joseph
J
Ryan
Joan
J
Moroney
Michelle
M
Shannon
D000328:Adult; D000368:Aged; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009468:Neuromuscular Diseases / Q000150:complications* / Q000534:rehabilitation; D015588:Observer Variation; D015203:Reproducibility of Results