Validity of the Mini‐BESTest in adults with myotonic dystrophy type 1

Abstract

Introduction Myotonic dystrophy type 1 (DM1) is a multisystemic neuromuscular disease that causes balance problems. The objective of this study was to assess the construct validity of the Mini‐BESTest among adults with DM1. Methods Fifty‐nine individuals with late‐onset or adult phenotypes of DM1 were recruited. Participants performed the Mini‐BESTest, 10‐Meter Walk Test (10mWT), 6‐Minute Walk Test (6MWT), and Timed Up & Go (TUG) and were questioned on their tendency to lose balance and whether they fell in the past month. Results Scores on the Mini‐BESTest were significantly different between phenotypes and CTG repeat numbers (P < .02). Significant correlations were found with the 10mWT, 6MWT, and the TUG (r = 0.77–0.84; P < .001). A cutoff score of 21.5 was found to identify fallers with 90% posttest accuracy. Discussion The Mini‐BESTest demonstrates evidence of construct validity when assessing balance in the DM1 population.

Explanatory factors of dynamic balance impairment in myotonic dystrophy type 1

“…Although correlations between CTG repeat length and the severity of symptoms are not highly robust, 29 it is well‐recognized that the number of CTG repeats decreases from the congenital to the late‐onset form of the disease 30 . The contribution of CTG repeat length in balance impairment found in this study reflects the previously published significant difference observed between adult and late‐onset phenotypes in Mini‐BESTest score 7 . Finally, the presence of self‐reported fatigue is contributing to lower balance score.…”

“…However, this scale demonstrated a ceiling effect in our population, and other tests are now recommended by the International Outcome Measures in Myotonic Dystrophy type 1 (OMMYD) group including the Mini Balance Evaluation System Test (Mini‐BESTest) 6 . This test has shown evidence of validity in this population, especially in individuals with the adult phenotype, in which strong associations with walking capacity were found 7 . The influence on dynamic balance impairment of muscle strength and other factors that have a large impact on daily life such as fatigue, daytime sleepiness and other central nervous system manifestations 8‐14 remains unknown.…”

“…30 The contribution of CTG repeat length in balance impairment found in this study reflects the previously published significant difference observed between adult and late-onset phenotypes in Mini-BESTest score. 7 Finally, the presence of self-reported fatigue is contributing to lower balance score. Similar results were found in our previous study on self-reported restriction in mobility-related participation in daily life.…”

“…6 This test has shown evidence of validity in this population, especially in individuals with the adult phenotype, in which strong associations with walking capacity were found. 7 The influence on dynamic balance impairment of muscle strength and other factors that have a large impact on daily life such as fatigue, daytime sleepiness and other central nervous system manifestations [8][9][10][11][12][13][14] remains unknown. By identifying the main contributors of balance impairment, specific rehabilitation programs could be developed.…”