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May 1993

Relationship of CD4 Counts to Neurophysiological Function in HIV-1-Infected Homosexual Men

Author Affiliations

From the Departments of Psychiatry (Drs Boccellari, Dilley, Chambers, and Tauber), Neurological Surgery and Otolaryngology (Dr Yingling), and Epidemiology (Drs Moss and Osmond), San Francisco General Hospital, University of California, San Francisco School of Medicine.

Arch Neurol. 1993;50(5):517-521. doi:10.1001/archneur.1993.00540050067018

• 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 0.40×109/L (400/μL), whereas only 15% of those impaired on this measure had CD4 counts of greater than 0.40×109/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.

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