AIMS: To evaluate the use of Manual Muscle Strength Tests (MMST), Timed Functional Tests (TFT) and Respiratory Function Tests (RFT) as measures of muscle strength in young boys with Duchenne Muscular Dystrophy (DMD) and specifically to evaluate the use of Peak Expiratory Flow (PEF). BACKGROUND: There is a need to measure the effect of treatments that potentially increase muscle strength in DMD. PEF may have advantages over Vital Capacity (VC) as a measure of respiratory function in young boys with DMD. METHODS: 17 boys with DMD (aged 5-10 years) were assessed regularly over one year. Assessment involved Respiratory Function Testing (PEF, VC, Forced Expiratory Volume in one second [FEV1]), Timed Functional Testing (walking 9 metres, climbing four stairs, arising from supine) and MMST. A single investigator performed MMST and TFTs. A separate investigator performed RFTs. For RFTs a percentage of predicted was calculated [PEF(%), FEV1(%), VC(%)].11/17 boys were treated with prednisolone which increases strength in DMD. RESULTS: At baseline, all boys had significant weakness. Mean (+/- SD) PEF(%) 69 +/- 13% and VC(%) 77 +/- 18% were abnormal. Baseline PEF(%) predicted correlated with MMST (P=0.003) and time to walk 9 metres (P=0.022). Baseline VC(%) correlated with MMST (P=0.049). There was a consistent statistically significant correlation between MMST and all TFTs. PEF was performed well on 80% of occasions, spirometry on 65%. Changes in PEF(%) showed statistically significant correlation with changes in all TFTs. The correlation was not statistically significant for VC(%) or FEV1(%). Prednisolone treated boys did better than those not treated. PEF, time to walk 9 metres and time to climb 4 stairs showed statistically significant improvement. The mean improvement from baseline in PEF(%) was 19 +/-14% in treated and 2 +/- 7% in untreated boys (P=0.012). CONCLUSIONS: MMST, TFTs and RFTs are valid measures of muscle strength in young boys with DMD. PEF is abnormal in young boys with DMD; correlates with other measures of strength and is sensitive to changes in strength. PEF is more easily performed than spirometry and has a role in monitoring muscle strength in young boys with DMD.
| Identifer | oai:union.ndltd.org:ADTP/187010 |
| Date | January 2003 |
| Creators | Webster, Richard Ian, School of Women & Children's Health, UNSW |
| Publisher | Awarded by:University of New South Wales. School of Women and Children's Health |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Richard Ian Webster, http://unsworks.unsw.edu.au/copyright |
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