The effect of low magnitude mechanical stimulation (LMMS) on bone density in patients with Rett syndrome: a pilot and feasibility study.

PURPOSE: Low magnitude mechanical stimulation (LMMS) has been used successfully to promote bone formation in certain patient populations. This study evaluated the feasibility and effectiveness of LMMS on improving bone mineral density (BMD) in patients with Rett syndrome.

METHODS

A 12-month crossover pilot study design of 6 months of intervention with LMMS and 6 months without was studied in 14 subjects divided in two subgroups. BMD was assessed using Dual Energy X-ray Absorptiometry (DXA). The levels of 25-hydroxy vitamin D (25OHD), Parathyroid Hormone (PTH), Insulin-Like Growth Factor 1 (IGF-1), and circulating markers of bone resorption (NTx) were analyzed in blood samples. Health questionnaires and diet logs were obtained at 0, 6, and 12 months.

RESULTS

Of the 11 subjects who completed the protocol, 9 had an adherence of > 65% and showed an increase in spine BMD Z-scores from the intervention (Z: -2.51) compared to non-intervention period (Z: -2.27) of 0.23 SD (p=0.048). Following intervention, favorable trends were also observed for IGF-1 (p=0.06) and right distal femur BMD Z-scores (p=0.07).

CONCLUSIONS

These preliminary results are promising for a larger, placebo-controlled randomized study of subjects with Rett syndrome.