S70. Correlation of functional scales in patients with myelopathy associated with HTLV1 and its relationship with neurofisiological tests

Abstract

Introduction HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic inflammatory disease of the CNS characterized by progressive spastic paraparesis, bowel/bladder dysfunction and lower limb sensory changes. We investigate the degree of correlation between the Osame scale and SPRS (Spastic Paraplegia Rating Scale) as well as the degree of correlation between these scales and the amplitudes and latencies of the H reflex in patients with HAM/TSP. Methods We studied subjects of both genders, aged 18 yo or older, with a proven diagnosis of HAM/TSP. The sample size calculation was estimated in 16 subjects based on a correlation coefficient of 0.7 according to a study by Rocha et al., a 95% confidence level and a 90% power. Osame and SPRS scales were applied to all patients. The H-reflex was performed in the manner recommended by the IFCN. The correlation between the Osame and SPRS scales and of the scales with the amplitudes and latencies of the H reflex were evaluated with the Kendall tau a coefficient. To evaluate the effect on these correlations of the variables such as age, sex, time of evolution and presence or absence of treatment, it was stratified by each of these variables. A p value Results n16, median age 58.5 yo. F:15 M:1. A good correlation was found between the Osame and SPRS scales (0.6 p = 0.0012). Between these scales and the amplitude of the H reflex, a weak negative correlation was found (−0.22 p = 0.23 and −0.14 p = 0.47, respectively), while the correlation between the scales and the latency of the H reflex was positive (0.26 p = 0.15 and 0.24 p = 0.20, respectively). The negative correlation between the scales and the amplitude of the H reflex, is contrary to that expected considering that the patients had spasticity in which an increase in amplitude and decrease in H reflex latency has been described. This phenomenon could be related with the involvement of the anterior horn motoneurons. The time of evolution of the disease greater than 5 years (0.5 p = 0.016), age over 60 years (1, p = 0.02) and not receiving specific treatment for HAM/TSP (0.66 p = 0.04) increased the positive correlation between the Osame and SPRS scales. This increase in correlation probably indicates worsening of the disease, which causes the two scales that differ in some items tend to converge. An important finding in this study was that receiving treatment decreased this correlation, (0.47 p = 0.08) indicating probable improvement. Conclusion The good correlation between the Osame and SPRS scales makes the Osame scale advantageous in clinical practice, given its simplicity and short execution time. The factors that decrease the positive correlation between the Osame and SPRS scales and those that decrease the magnitude of the negativity between the scales and the amplitude of the H reflex, may be related to improvement of the disease and could be evaluated as indicators of therapeutic efficacy in future studies.