Nerve ultrasound detects abnormally small nerves in patients with spinal and bulbar muscular atrophy.

These ultrasound changes are similar to those reported in other inherited sensory neuronopathies and clearly different from the ultrasound findings in axonal neuropathy. Smaller nerves are possibly a distinctive finding in SBMA that may distinguish it from other motor neuron syndromes. Further studies are warranted to confirm this and determine the optimal sonographic protocol.