Pain-Related Evoked Potentials in Hereditary Transthyretin Amyloidosis With Polyneuropathy
Renan Flávio de França Nunes1, Maria Paula Carvalho Azevedo1, Alberto Rolim Muro Martinez1
1Department of Neurology, School of Medical Sciences, University of Campinas, Campinas, Brazil.
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.
