Background

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disorder where later disease progress is difficult to objectively measure. This study compared the Egen Klassification (EK) scale with grip strength testing in non-ambulant DMD patients.

Methods

This was a retrospective review of patients seen in the neuromuscular clinic at the National University Hospital from March 2011 to June 2013. EK scale was applied by trained physiotherapists. Strength testing with hand grip and pinch was performed with hand grip dynamometer in the dominant hand. EK scores and grip strength were correlated with age, functional stage, and lung function parameters.

Results

19 non-ambulant DMD males aged 11 – 25 years (mean 17.4 years) were recruited. The mean EK score was 13.47 (range 4-27). EK score showed significant positive correlation with functional stage [r = 0.92 (p<0.001)] and age [r = 0.746 (p<0.001)]. EK showed significant negative correlation with FEV1 [r of -0.619 (p<0.05)] and FVC [r -0.497 (p<0.05)]. Mean grip strength was 3.92 kg (range of 1-19 kg). Hand grip showed negative correlation with patient’s functional stage [r -0.456 (p<0.05)]. EK did not show any significant correlation with hand grip strength.

Conclusion:

The EK scale was an easily used scale for the outpatient clinic setting with good correlation with lung function parameters as well as functional stage of the disease. Paradoxically this scale outperformed objective grip strength testing. Periodic assessment of non-ambulant patients should ideally comprise a combination of functional and objective strength testing especially in patients with limited motor abilities.

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