Abstract：
The objective of this study is to compare shear modulus of lower limb muscles between children with hypotonia versus typical development (TD) or developmental disorders associated with altered tone. Nineteen children with mild hypotonia (mean age 9.4 ± 2.3y, 13 male) completed assessment of resting shear modulus of rectus femoris, biceps femoris (BF), tibialis anterior (TA) and gastrocnemius lateralis (GL) at short and long lengths using shear wave elastography. Data was compared with previous data from TD children and a scoping review for children with developmental disorders. Data were collated according to Net-Longitudinal Tension Angle (Net-LTA), which is the muscle length expressed as the net proximal and distal joint angles. Effects of Net-LTA (e.g., short, neutral, long) were examined according to sex, age and body mass index (BMI). In children with hypotonia, shear modulus was: higher at longer versus shorter lengths for four muscles (p < 0.01); correlated with age for BF-short (r = 0.60, p < 0.03) and GL-short (r = -0.54, p < 0.03), with BMI for BF-short (r = 0.71, p < 0.05); and not different between sexes (p > 0.05). The shear modulus values for lower limb muscles for children with mild hypotonia were lower than those for children with Duchenne Muscular Dystrophy (TA-neutral), or Cerebral Palsy (GL-neutral), but not TD children (all four muscles). In conclusion, shear modulus increases with longer muscle length (i.e. higher Net-LTA) in mildly hypotonic children. Children with mild hypotonia have lower shear modulus than children with cerebral palsy and Duchenne muscular dystrophy.
摘要：
这项研究的目的是比较张力减退儿童与典型发育（TD）或与张力改变相关的发育障碍之间下肢肌肉的剪切模量。19例轻度张力减退儿童（平均年龄9.4±2.3岁，13男性)完成股直肌静息剪切模量评估，股二头肌（BF），使用剪切波弹性成像在短和长长度的胫骨前肌（TA）和腓肠肌外侧肌（GL）。将数据与TD儿童的先前数据进行了比较，并对患有发育障碍的儿童进行了范围审查。根据净纵向张力角(Net-LTA)整理数据，即以净近端和远端关节角度表示的肌肉长度。净LTA的影响(例如，短,中性,长)根据性别进行检查，年龄和体重指数（BMI）。在张力减退的儿童中，剪切模量是：在较长与较短长度的四块肌肉（P<0.01）;与年龄相关的BF-short（r=0.60，P<0.03）和GL-short（r=-0.54，P<0.03），BMI为BF-short（r=0.71，p<0.05）；性别之间没有差异（p>0.05）。轻度张力减退儿童的下肢肌肉剪切模量值低于Duchenne肌营养不良（TA中性）儿童的剪切模量值，或脑瘫（GL中性），但不是TD儿童（所有四块肌肉）。总之,在轻度低渗儿童中，剪切模量随着肌肉长度的延长（即较高的Net-LTA）而增加。轻度肌张力减退儿童的剪切模量低于脑瘫和Duchenne型肌营养不良儿童。
