Balance control impairments in Fabry disease

Abstract

Background: Fabry disease (FD) is a rare inherited lysosomal storage disorder caused by the deficiency of the enzyme alpha-galactosidase A. This deficiency leads to an accumulation of glycosphingolipids leading to progressive and multisystemic disease, including renal, cardiac, and neurological damages. FD may also have neuro-otological and visual impairments, which can generate postural control alterations, inner ear, and vision being involved in this function. This study aimed to evaluate the impact of FD on postural control.

Methods: In total, fourteen adult patients (8 men/6 women, mean age = 37.6 ± 11.4 years) and two children (mean age = 11 years) with FD and 19 healthy adults (12 men/7 women, mean age = 36.5 ± 16.9 years) and two healthy children (mean age = 10.5 years) took part in this study. Postural control was evaluated by a sensory organization test combining three visual situations (eyes open, eyes closed, and sway referenced visual surround motion) with two platform situations (stable platform and sway referenced platform motion), aiming to calculate a composite equilibrium score (CES), a high score being representative of good postural control. Somatosensory (R^SOM), visual (R^VIS), and vestibular (R^VEST) contributions to postural control were calculated, a low score reflecting a poor use of the indicated sensory input.

Results: The CES was lower in adult patients with FD compared with the healthy subjects (p < 0.001). R^VIS (p = 0.001) and R^VEST (p = 0.003) were lower in patients with FD compared with the control group, whereas no difference in R^SOM was observed.

Conclusion: Inner ear and visual pathologies associated with the central nervous system impairments are factors of postural control impairments. Physical activities, which can also be rehabilitative, by maintaining or increasing the weight of proprioception, may help diminish dependency on altered sensorial inputs.

Keywords: Fabry disease; cochleo-vestibular disorders; postural control; posturography; rehabilitation.

Figure 1

The six conditions of the SOT (EquiTest, NeuroCom International Inc., Clackamas, OR, USA). Conditions 1–3 were performed on a fixed platform with eyes open, eyes closed and vision sway-referenced. Conditions 4–6 were performed on a sway-referenced platform (somatosensory input inaccurate) with eyes open, eyes closed and vision sway-referenced (visual input inaccurate).

Figure 2

Sensory organization test. On the left: normal values of the Composite score (82) and of R^SOM, R^VIS, R^VEST. Strategy analysis: ankle dominant, Center of gravity (COG) alignment: normal. On the right: Fabry disease patient (patient No 14): low Composite score (51), low values of R^SOM and R^VEST. Strategy: ankle and hip dominant strategies and falls according to the condition. Center of gravity shifted to the backward position.