Vibration therapy in young children with mild to moderate cerebral palsy: does frequency and treatment duration matter? A randomised-controlled study.

BACKGROUND: Vibration therapy (VT) has been increasingly studied in children with cerebral palsy (CP) over the last years, however, optimal therapeutic VT protocols are yet to be determined. The present study compared the effects of side-alternating VT protocols varying in frequency and treatment duration on the health of young children with mild-to-moderate CP. METHODS: Thirty-four participants aged 6.0 to 12.6 years with CP acted as their own controls and underwent two consecutive study periods: a 12-week lead-in (control) period prior to the intervention period of 20-week side-alternating VT (9 min/session, 4 days/week), with the frequency either 20 Hz or 25 Hz, determined by randomisation. Participants had 4 assessment visits: baseline, after the control period, after 12-week VT (12VT), and after further 8 weeks of VT (20VT). Assessments included 6-minute walk test (6MWT); dual-energy x-ray absorptiometry; gross motor function; muscle function testing on the Leonardo mechanography plate and by hand-held dynamometry, and a quality-of-life questionnaire (CP QOL). Analysis was carried out using linear mixed models based on repeated measures. RESULTS: Side-alternating VT was well-tolerated, with occasional mild itchiness reported. The median compliance level was 99%. VT led to improvements in 6MWT (+ 23 m; p = 0.007 after 20VT), gross motor function in standing skills (+ 0.8 points; p = 0.008 after 12VT; and + 1.3 points; p = 0.001 after 20VT) and in walking, running and jumping skills (+ 2.5 points; p < 0.0001 after 12VT; and + 3.7 points; p < 0.0001 after 20VT), spine bone mineral density z-score (+ 0.14; p = 0.015 after 20VT), velocity rise maximum of the chair rising test (+ 0.14 m/s; p = 0.021 after 20VT), force maximum of the single two-leg jump test (+ 0.30 N/kg; p = 0.0005 after 12VT; and + 0.46 N/kg; p = 0.022 after 20VT) and in the health module of CP QOL (+ 7 points; p = 0.0095 after 20VT). There were no observed differences between the two VT frequencies (i.e., 20 Hz vs 25 Hz) on study outcomes. CONCLUSIONS: The study confirms that side-alternating VT has positive effects on mobility, gross motor function, body composition, muscle function, and quality of life, independent of VT frequencies tested. Long-term, 20VT appears to be a more efficient treatment duration than a short-term, 12VT. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12618002026202 ; 18/12/2018.