Balance impairment in myotonic dystrophy type 1: Dynamic posturography suggests the coexistence of a proprioceptive and vestibular deficit

Abstract

Falls are frequent in Myotonic Dystrophy type 1 (DM1), but the pathophysiology of the balance impairment needs further exploration in this disease. The current work aims to provide a richer understanding of DM1 imbalance. Standing balance in 16 patients and 40 controls was tested in two posturographic tests (EquiTest™). In the Sensory Organization Test (SOT), standstill balance was challenged by combining visual (eyes open vs. closed) and environmental conditions (fixed vs. sway-tuned platform and/or visual surround). In the “react” test, reflexes induced by sudden shifts in the support base were studied. Oscillations of the body centre of mass (COM) were measured. In the SOT, COM sway was larger in patients than controls in any condition, including firm support with eyes open (quiet standing). On sway-tuned support, COM oscillations when standing with closed eyes were larger in patients than controls even after taking into account the oscillations with eyes open. In the “react” paradigm, balance reflexes were delayed in patients. Results in both experimental paradigms (i.e., SOT and react test) are consistent with leg muscle weakness. This, however, is not a sufficient explanation. The SOT test highlighted that patients rely on vision more than controls to maintain static balance. Consistently enough, evidence is provided that an impairment of proprioceptive and vestibular systems contributes to falls in DM1. Rehabilitation programs targeted at reweighting sensory systems may be designed to improve safe mobility in DM1.

Differential Item Functioning of the Mini-BESTest Balance Measure: A Rasch Analysis Study

“…In addition, removing these three items would likely resolve multidimensionality, but this would affect the content validity of the Mini-BESTest. Testing the ability to recover balance is fundamental in balance assessment of neurological patients [ 8 ].…”

“…However, regarding the future developments of this line of research, other Mini-BESTest features such as its ability to predict future falls should be investigated further. Furthermore, it also seems natural to compare the functioning of this clinical balance measure with other balance measures, such as instrumental ones [ 7 , 8 , 9 , 10 , 11 , 12 ].…”

“…Many balance measures are available, both instrumental and from clinical tests. As instrumental balance measures, it is worth mentioning those from posturography [ 7 , 8 , 9 ], measures from the Timed Up and Go test [ 10 , 11 ], and measures of walking stability [ 12 ]. Among the balance scales, the Mini Balance Evaluation Systems Test (Mini-BESTest) [ 13 ] is likely one of the most used [ 14 ].…”

Fatigue may improve equally after balance and endurance training in multiple sclerosis: a randomised, crossover clinical trial

“… MS diagnosis according to the revised McDonald criteria ( 20 ); relapsing–remitting, and primary and secondary progressive MS forms were allowed; Expanded Disability Status Scale (EDSS) ( 21 ) between 2 and 6; Fatigue as indicated by a total score of the Modified Fatigue Impact Scale (MFIS) ( 22 ) ≥20 of 84; A performance on dynamic posturography [Equitest Sensory Organisation Test, SOT ( 14 , 23 , 24 )] below age-matched normal values (95th percentile of control values). …”

Pay attention: you can fall! The Mini-BESTest scale and the turning duration of the TUG test provide valid balance measures in neurological patients: a prospective study with falls as the balance criterion

“…The study only included stroke, peripheral neuropathies, and parkinsonism [and excluded rarer diseases also known to cause a balance and gait impairment, such as neuromuscular disorders (22)] since they represent three widespread and prototypical motor syndromes affecting gait and gross motor functions. In plain words, these three motor syndromes are common causes of increased risk of falling.…”