Expert consensus on the combined investigation of polyneuropathies with electrodiagnostic tests and neuromuscular ultrasound.

Consensus was sought from 17 nominated global expert leaders to provide guidance on the combined use of neuromuscular ultrasound (NMUS) and electrodiagnostic tests (EDX) in the investigation of peripheral neuropathy (PN) in clinical practice. Consensus was based on an initial systematic review of the literature by the experts themselves, followed by three anonymised surveys, using the Delphi method. No consensus was defined as < 60 % rating frequency. The panel agreed that NMUS should be used if EDX cannot differentiate an axonal from a demyelinating process or an acquired from a hereditary process, and in the investigation of vasculitic neuropathy; NMUS of the brachial plexus should be used in Guillain-Barre' syndrome if EDX is negative; when NMUS is used, at least two nerves of the upper limbs should be scanned; NMUS should be used for screening or repeat testing for carpal tunnel syndrome in children with mucopolysaccharidoses. Areas of disagreement exposed gaps in current knowledge and informed the direction of future research, which should aim to identify situations in which NMUS can stand alone as a diagnostic test, particularly for screening or repeat testing and especially in vulnerable individuals and paediatric populations.