Muscular Impairment Rating Scale (MIRS) for Myotonic Dystrophy

Mathieu et al developed a rating scale to describe the extent of muscular impairment in a patient with myotonic dystrophy.

Distal Muscle Weakness	Proximal Muscle Weakness	Other Signs	Grade
none	none	none	1
none or only digit flexors	none	myotonia, jaw and temporal wasting, ptosis, neck flexor weakness, nasal speech	2
present	with or without weakness of the elbow extensors		3
present	mild to moderate		4
present	severe		5

where:

• Severe weakness corresponds to MRC scale <= 3 (see above)

To read more or access our algorithms and calculators, please log in or register.

Myotonic Dystrophy Muscular Impairment Rating Scale (MIRS)