| Type of DM | Muscle groups commonly affected | Clinical myotonia (grip and percussion)* | Muscle pain¶ | Respiratory muscle involvementΔ | Dysphagia and dysarthriaΔ |
| DM I (Steinert's disease) | Facial, neck, forearm, hand intrinsic, foot dorsiflexor | Common and often pronounced | Yes (Rarely a presenting complaint) | Yes | Yes |
| DM II (Proximal myotonic myopathy) | Neck flexor, elbow extensor, finger flexor, hip flexor | Mild or inobvious | Yes (Often a presenting complaint) | Uncommon | Uncommon |
