Relations Between Standing Stability and Body Posture Parameters in Adolescent Idiopathic Scoliosis

Nault, Marie-Lyne; Allard, Paul; Hinse, Sébastien; Blanc, Richard Le; Caron, Olivier; Labelle, Hubert; Sadeghi, Heydar

doi:10.1097/00007632-200209010-00018

Cited by 227 publications

(181 citation statements)

References 34 publications

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“…These sensory issues can be explained by static or dynamic adaptive strategies. The static upright posture results from an increase of both the oscillation range [23] and the centre of pressure displacement [8,22]. Spinal deformity has no effect on trunk motion but influences movement between body segments (spine and limbs) [22].…”

Section: Introductionmentioning

confidence: 99%

Dynamical asymmetries in idiopathic scoliosis during forward and lateral initiation step

et al. 2009

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Adolescent idiopathic scoliosis (AIS) is characterized by morphological trunk modifications acting on body mass distribution. Some specific biomechanical strategies during postural regulation have been reported. Given that spinal deformity is three-dimensional, some strategy analysis resulting from different stepping directions should lead to a better understanding of the dynamic adaptation of behaviour. The aim of this study is to identify dynamic strategies of AIS patients stepping in lateral and forward directions. Ten AIS patients with a right thoracic curve and 15 controlled volunteers have been tested. Ground reaction forces (GRF) have been recorded for rightlimb stepping and for left-limb stepping associated to forward and lateral directions. Force amplitudes, corresponding occurrences, impulses of stepping phases and an asymmetry index have been computed. Asymmetry and variability increased in the AIS group, compared to the control group, whatever the stepping direction is. Asymmetry for AIS patients systematically provides an increased left initiation GRF compared to a right initiation. Nevertheless, for both groups, lateral initiation shows the largest asymmetry index reported for a forward initiation. More precisely, adaptive dynamic strategies for the AIS group have been characterized by an asymmetry between right and left limbs for lateral and forward initiation. These results can be explained by the influence of scoliosis pathology on dynamic movements due to spinal deformity. A right thoracic curve leads to an extra weight on the limb, which needs to be moved; consequently, stepping initiation with the right limb was more challenging for patients than stepping with the left limb. For the AIS group, the observed variability can also depend on the ontogenesis of adaptive strategies. Lateral step initiation has to be considered as the most relevant paradigm to study scoliosis and may also serve as a clinical basis for treatment to analyse the dynamic postural control and asymmetry strategies of the scoliosis patient.

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Section: Introductionmentioning

confidence: 99%

Dynamical asymmetries in idiopathic scoliosis during forward and lateral initiation step

et al. 2009

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“…In addition to a motor deficit problem, the spinal deformity is also responsible for posture or body misalignment in the horizontal plane [13,27,29]. Both the type of curve [18] and body posture attitude [32] was associated with standing imbalance in scoliotic girls. In standing, it is argued that, postural sway control can be achieved by the whole body moving in a single block [17] or through individual body segment movements to stabilize the joints [1,40].…”

Section: Introductionmentioning

confidence: 99%

Free moment contribution to quiet standing in able-bodied and scoliotic girls

et al. 2007

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Adolescent idiopathic scoliosis girls are known to display standing imbalance. In addition to a motor deficit problem, the axial torsion of the spine and trunk torsion could reflect an imbalance around the vertical axis. Unlike the excursion of the center of pressure (COP), the forces and moments were rarely addressed to characterize the quiet standing balance. Nonetheless, one dynamical parameter, called free moment (T V ), representing the vertical torque on the feet can reflect the oscillation around the vertical axis associated to the standing imbalance. The objectives of this study were to test if the free moment variability can be utilized to characterize standing balance in a group of able-bodied and non-treated scoliotic girls and to determine if it was associated with that of the COP among each group of subjects tested. Forty-six adolescent girls with half of them presenting an adolescent idiopathic scoliosis were tested during quiet standing balance.Standing balance was assessed with the subjects standing upright and bare feet on a force plate. RMS and range of COP excursions and free moment were calculated.The scoliotic group displayed higher variability in COP excursion by about 24% than the able-bodied girls. Similarly, the T V RMS (P = 0.00136) and range (P = 0.00197) were statistically higher by about 42% in the scoliotic group. The variability of T V was associated with that of the COP in both groups. In the medio-lateral direction, the significant correlations between the RMS and range of the free moment and those of the COP were about 0.7 for the able-bodied group and 0.5 for the medio-lateral COP range for the scoliotic group girls. Along the antero-posterior axis, the only statistically significant correlations were observed for the scoliotic group. The free moment variability about the COP measured during quiet standing can be suggestive of an asymmetry control of the trunk around the vertical axis during standing balance. Its variability was more pronounced in scoliotic girls and was associated with the antero-posterior COP variability reflecting both biomechanical and motor control deficits. Free moment calculation could be a supplement insight into the standing balance of scoliotic subjects. Keywords Scoliosis Á Standing balance Á Free moment Abbreviations APAntero-posterior direction COM The center of mass is a point equivalent of the total body mass resulting from the location of each body segment COP The center of pressure is the location of the net ground reaction force. ML Medio-lateral direction x where X m is the arithmetic mean of the variable X. X i is the ith value of the variable X measured at the instant i, and N is the number of X i values

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“…Even if such discrepancy may be due to the chosen parameters, the position itself seemed to be more relevant. The standing posture reflected, through the modification of GRF, the global segmental organisation of the body [25,29]. Contrary to standing, seated posture enlightened the specific postural control of the trunk that allowed the assessment of specific balance strategies [28,32].…”

Section: Discussionmentioning

confidence: 99%

“…The specific postural strategies occurring in AIS have been previously studied during upright stance [8], stepping initiation [4], walking [10] and side-stepping initiation [4]. Scoliotic patients show an increase of the amplitude of the postural oscillations [27] associated with instability [8,25] and an increased asymmetry of the dynamics of the lower limbs [5,18,29]. The variability of the parameters analysed was greater for scoliotic patients than for control subjects [4], especially in the mediolateral (ML) and anteroposterior (AP) directions [16,30].…”

Section: Introductionmentioning

confidence: 99%

Idiopathic scoliosis: relations between the Cobb angle and the dynamical strategies when sitting on a seesaw

Bruyneel¹,

Chavet²,

Ebermeyer³

et al. 2010

Eur Spine J

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The aim of this study was to determine the influence of the severity of the spinal curve on the postural regulation when self-imposed disturbances occur in a seated position in anteroposterior (AP) and mediolateral (ML) orientations. Twelve female adolescents with a right thoracic scoliosis (Cobb = 30.4°± 9.7) were included in this study. The ground reaction forces (GRF) were studied while the subjects were maintaining their sitting on a seesaw (ML or AP destabilisation). Five conditions were tested: eyes open; with additional loads placed onto the subject's right or left shoulder; or onto the subject's right or left pelvis. We tested the correlation between the Cobb angle and the postural parameters (index of performance and GRF variability) for each condition. When the destabilisation was AP, the Cobb angle was significantly correlated with GRF variability and anterior and concavity index of performance. Two conditions showed higher correlations: stabilisation with the concavity pelvis load (GRF variability) and the open eyes (index of performance). In contrast, whatever the condition tested was, no link was found when the destabilisations were applied in ML direction. The destabilisation in a seated position highlights the influence of the curve severity on the postural organisation. In seated position, the postural control strategies specific to the scoliotic patients were always correlated by severity of curve, especially when the destabilisation is applied in AP directions. This study showed that the unstable seating position can be considered as a pertinent paradigm to help finding a postural clinical index for adolescent idiopathic scoliosis.

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Relations Between Standing Stability and Body Posture Parameters in Adolescent Idiopathic Scoliosis

Cited by 227 publications

References 34 publications

Dynamical asymmetries in idiopathic scoliosis during forward and lateral initiation step

Dynamical asymmetries in idiopathic scoliosis during forward and lateral initiation step

Free moment contribution to quiet standing in able-bodied and scoliotic girls

Idiopathic scoliosis: relations between the Cobb angle and the dynamical strategies when sitting on a seesaw

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