Electrodiagnostic Characterization of Hereditary Neuropathy With Liability to Pressure Palsies.

OBJECTIVES: The study objective was electrodiagnostic characterization of a large cohort of patients with genetically confirmed hereditary neuropathy with liability to pressure palsies (HNPP).

METHODS: A retrospective review was conducted on all patients with HNPP seen at the neuromuscular clinic (London, Canada) from 1977 to 2015. Clinical data obtained included patient characteristics, examination findings, and nerve conduction study results.

RESULTS: A total of 46 patients were analyzed. The mean age and median disease duration were 42.6 and 5.0 years, respectively. Most patients had abnormalities on sural nerve conduction studies. The most common focal neuropathies at compressive sites were ulnar nerve at the elbow (85.7%), distal median nerve at the wrist (84.4%), and fibular nerve at the fibular head (36.7%). Distal median neuropathy was associated with a mean terminal latency of 6.64 milliseconds.

CONCLUSIONS: The presence of polyneuropathy, median terminal motor latency prolongation, and multiple compressive neuropathies are the most common findings associated with HNPP.