How long can demyelinating findings persist on nerve conduction studies (NCS) after AIDP illness?

This question was studied in a retrospective review in Muscle and Nerve (Guémy et al., PMID 36814082) in a group of patients with AIDP. At least one feature of demyelination was present in 23% of the cohort (14 out of 61) up to 2 years after the onset of the AIDP-like illness. Using the EFNS-PNS criteria for "definite CIDP," 9.8% still had nerve conduction testing results compatible with "definite CIDP" without a clinical syndrome consistent with CIDP. Prolonged distal latency, slowed conduction velocity, temporal dispersion, conduction block, and F wave abnormalities were observed (to varying proportions) up to 2 years, with F wave abnormalities remaining the most frequent (up to 52% at 1 year). However, it is important to observe that amo...