Pain‐Related Evoked Potentials in Hereditary Transthyretin Amyloidosis With Polyneuropathy

INTRODUCTION/AIMS: Pain-related evoked potentials with concentric electrodes (PrEP-CE) provide a method for screening for small fiber neuropathy, which is usually the first manifestation of hereditary transthyretin amyloid polyneuropathy (ATTR v-PN). Despite that, this technique has not yet been fully explored in this condition. The current study aimed to compare PrEP-CE responses among patients with ATTRv-PN, presymptomatic carriers of TTR mutations, and healthy controls. METHODS: We recruited 17 patients with ATTRv-PN, 12 presymptomatic TTR mutation carriers (pre-ATTRv-PN), and 13 healthy controls. PrEP-CE were obtained by separately stimulating the hands and feet. We analyzed the latencies of negative (N1) and positive (P1) peaks and peak-to-peak amplitudes between groups using nonparametric tests. RESULTS: Median ages were 45 years for both ATTRv-PN and pre-ATTRv-PN groups, and 32 years for controls. In the arms, N1 and P1 latencies were significantly longer in the ATTRv-PN group compared to controls (p < 0.05). In the legs, P1 latency was significantly longer in the ATTRv-PN (p = 0.005) and the pre-ATTRv-PN (p = 0.001) groups vs. controls. PrEP-CE amplitudes were reduced in both the ATTRv-PN (p = 0.015) and the pre-ATTRv-PN (p = 0.021) compared to the control group. DISCUSSION: PrEP-CE facilitates recognition of ATTRv-PN, with lower limb P1 latency and amplitude indicating small fiber involvement. It is a rapid, well-tolerated technique that may support the assessment of small-fiber impairment in ATTRv-PN.