Neurological disability in HTLV-1 infected individuals according to the initial clinical presentation: cohort study by Dellavechia Taís, Luna Tânia, Gusmão Valéria, Viana Katia, Dantas Lorena, Souza Anselmo, Braga Silvany, dos Santos André Muniz, Sundberg Michael, Tannus Matheus, Castro Néviton, Costa Davi, Orge Glória, Carvalho Edgar