Electrodiagnostic and nerve ultrasonographic features in upper limb spasticity: an observational study.

To better understand the effects of spasticity on peripheral nerves, we evaluated the electrodiagnostic and nerve ultrasonographic features of the median and ulnar nerves in adults with upper limb spasticity. Twenty chronic stroke patients with spastic hemiparesis underwent nerve conduction study and nerve ultrasonography of the median and ulnar nerves at both upper limbs. Affected versus unaffected upper limb comparisons showed significant differences in the median and ulnar nerve distal motor latencies, compound muscle action potentials and F-wave minimal latencies. Furthermore, we observed a significantly greater median nerve crosssectional area at the elbow of the affected upper limb compared with the unaffected one. Our findings confirmed electrodiagnostic asymmetries and nerve ultrasonographic abnormalities in the affected versus the unaffected upper limb after stroke. Slight changes in lower motor neuron activity and spasticity might contribute to these alterations.