Neurophysiological abnormalities in HIV-infected long term survivors

HIV is a neurotropic virus causing neuronal damage independent of opportunistic infections. A subgroup of patients suffer from long-term infection without developing significant disease symptoms requiring antiretroviral therapy (long-term survivors, LTS). We investigated the prevalence and severity of neurophysiological abnormalities in LTS.

The outpatient database of the Dept. of Neurology, University of Münster, was searched for HIV-infection LTS (infection for more than 9 years, no antiretroviral therapy since infection, stable CD4-positive lymphocyte count of more than 400/ul). Their neurophysiological test results (nerve conduction studies, event-related potentials, EEG) were compared to a control group of patients with similar disease duration not fulfilling the criteria for LTS.

Sixteen LTS patients and 22 control patients were investigated. Median age at examination was 35 years. There were no significant differences between the groups regarding age, sex, duration of the disease and way of infection. By definition, CD4+-lymphocyte counts differed between LTS and both control groups. Standard nerve conduction studies of the peroneal or the sural nerve were abnormal in 1 LTS patient and 3 control patients. Sural nerve paired stimulation amplitude showed abnormal findings in 4 LTS patients and 4 control patients. P300 latency was prolonged in 4 LTS patients and 4 control patients. EEG background frequency was normal in all but one patient (LTS). There were no differences between groups regarding any of the parameters.

Sensitive methods showed subtle affection of the nervous system in HIV-infected outpatients infected for more than 9 years. However, there was no difference between patients fulfilling accepted criteria of LTS, and those who did not. LTS most likely form the extreme end of a continuum of disease severity.