Relationship of CD4 counts to neurophysiological function in HIV-1--infected homosexual men
A. A. Boccellari, J. W. Dilley, C. D. Yingling, D. B. Chambers, M. A. Tauber, A. R. Moss and D. H. Osmond
Department of Psychiatry, San Francisco General Hospital, CA 94110.
OBJECTIVE--To explore the relationship of immune dysfunction to
neurophysiological measures of brain-stem conduction time.
DESIGN--Three-year longitudinal prospective cohort study; results of time 1
analyses reported. SETTING--San Francisco (California) General Hospital,
Departments of Psychiatry and Epidemiology. PATIENTS--Volunteer sample of
55 human immunodeficiency virus (HIV)-positive and 37 HIV-negative
homosexual men recruited from a larger cohort of homosexual men followed up
since 1983 at San Francisco General Hospital as part of an ongoing study of
the natural history and course of HIV type 1 infection. INTERVENTION--None.
MAIN OUTCOME MEASURES--Auditory brain-stem responses and somatosensory
evoked potentials for subjects stratified separately on HIV serostatus,
Centers for Disease Control and Prevention symptom groupings, and absolute
CD4 counts. RESULTS--The HIV-positive subjects had an increased wave III-V
interpeak latency of the right ear auditory brain-stem response compared
with the HIV-negative subjects (t test, P < .05). There were no
significant differences among the three Centers for Disease Control and
Prevention groupings on any evoked potential measure. When HIV-positive
subjects were stratified on a measure of immune functioning, ie, CD4
counts, individuals with greater immune suppression were more impaired on
speed of auditory brain-stem conduction time (Mann-Whitney U test, P <
.05). Furthermore, 85% of subjects impaired on this evoked potential
measure had CD4 counts of less than 0.40 x 10(9)/L (400/microL), whereas
only 15% of those impaired on this measure had CD4 counts of greater than
0.40 x 10(9)/L. CONCLUSIONS--Asymptomatic HIV-positive subjects who do not
have evidence of immune suppression do not appear to be at greater risk for
neurophysiological impairment than HIV-negative subjects. The HIV-positive
individuals who are immune suppressed (even while asymptomatic) appear to
have an increased likelihood of central conduction time slowing as measured
by evoked potential procedures.
