Neurology
The Role of Vemp as a Marker in the Progression of HTLV-1- Associated Myelopathy Tiago Almeida de Oliveira* Tiago Oliveira Juliana Augusta Nunes da Cruz Denise Utsch Gonçalves Júlia Fonseca de Morais Caporali Nathália de Castro Botini Rausse Tatiana Rocha Silva Ana Lúcia Borges Starling César Daniel Alves Caldeira Tiago Almeida de Oliveira Ludimila Labanca
Myelopathy (HAM) associated with human T-cell lymphotropic virus type 1 (HTLV-1) is a chronic inflammation of the spinal cord that leads to impairment of posture and gait. The diagnosis of HAM is usually delayed. To evaluate the role of galvanic vestibular evoked myogenic potential (G-VEMP) as a marker of progression to HAM in individuals followed for 10 years. This longitudinal study was carried out between 2012 and 2022 and was approved by the Research Ethics Committee (number: 2898825). All 21 HTLV-1-infected participants were submitted to a clinical, neurological and G-VEMP examination in 2012(T1), 2017(T2), and 2022(T3). Galvanic stimuli were applied bilaterally to the mastoid processes and VEMP was recorded from the gastrocnemius muscle. The latency and amplitude of the short-latency (SL) and medium-latency (ML) responses and the progression of individuals from asymptomatic carrier to possible-HAM and HAM were investigated. Data were compared using the Friedman and multiple linear regression. It was considered significant p<0.05. Twenty-one individuals were included, with a mean age of 61 years at T1 and 13 (62%) women. There was an increase in the latency of the SL and ML response over the 10-year follow-up (p<0.001). The SL and ML wave amplitude decreased (p<0,001). The percentage of altered VEMP at T1 was 33%, T2 was 43% and T3 was 52%. All individuals with altered VEMP at T1 developed possible-HAM or HAM during follow-up. The diagnostic accuracy of G-VEMP was 90,48%, sensitivity 78%, and specificity 100%. Using multiple linear regression analysis, the effect of CL is statistically significant and positive (beta = 1.02, 95% CI (0.23, 1.81), t(28) = 2.66, p = 0.013; standard beta = 0.52, 95% CI (0.12, 0.92)). The Friedman test followed by Dunn showed that the VEMP signal is significantly different between T1 and T3.