Jr. Zunt et al., Quantitative assessment of subclinical spasticity in human T-cell lymphotropic virus type I infection, NEUROLOGY, 53(2), 1999, pp. 386-390
Objective: To compare human T-cell lymphotrophic virus type I(HTLV-I) serop
ositive and seronegative women for symptoms and signs of spasticity. Backgr
ound: Infection with HTLV-I causes tropical spastic paraparesis/HTLV-I-asso
ciated myelopathy (TSP/HAM). Certain populations, including female commerci
al sex workers (FSW), are at increased risk of developing this infection. F
ewer than 5% of HTLV-I-seropositive persons develop TSP/HAM, which is typic
ally associated with spasticity. Methods: Cross-sectional study of 255 regi
stered FSW in Callao, Peru, involving a questionnaire detailing demographic
s and neurologic symptoms, standard neurologic examination, quantitative as
sessment of spasticity (QSA) of muscle tone, and serologic testing for HTLV
-I. Participants and examiners were blinded to serology results. Results: O
n the questionnaire and neurologic examination, none of the 32 HTLV-I-serop
ositive or 223 seronegative women had signs or symptoms of spasticity. Howe
ver, mean values on QSA were significantly higher among seropositive women
(27.1 Newton-meters/radian [N-m/r]) than among seronegative women (21.6 N-m
/r, p = 0.01), indicating a subclinical increase in lower extremity tone. W
ith values of QSA divided into tertiles, and the first tertile serving as t
he comparison group, the odds ratio for seropositivity was 1.4 (95% confide
nce interval [CI] 1.0 to 2.0) in the second and 3.1 (95% CI 2.2 to 4.3) in
the third tertile, after adjusting for age and place of birth. Conclusions:
Although a standard neurologic evaluation could not distinguish beta een w
omen with and without HTLV-I infection, QSA indicated significantly increas
ed lower extremity tone in those with infection. Long-term follow-up will d
etermine whether these subclinical findings in asymptomatic women progress
to overt TSP/HAM.