Neurophysiological evaluation of zidovudine in asymptomatic HIV-1 infection: a longitudinal placebo-controlled study

Brain and cognitive functions in two groups of naïve HIV patients selected for a different plan of antiretroviral therapy: A qEEG study

OBJECTIVE

Cortical sources of electroencephalographic (EEG) rhythms were investigated in two sub-populations of naïve HIV subjects, grouped based on clinical criteria to receive different combination anti-retroviral therapies (cARTs). These EEG sources were hypothesized to reflect beneficial effects of both regimes.

METHODS

Eyes-closed resting state EEG data were collected in 19 (Group A) and 39 (Group B) naïve HIV subjects at baseline (i.e. pre-treatment; T0) and after 5months of cART (T5). Compared with the Group A, the Group B was characterized by slightly worse serological parameters and higher cardiovascular risk. At T0, mean viral load (VL) and CD4 count were 87,694copies/ml and 435cells/μl in the Group A and 187,370copies/ml and 331cells/μl in the Group B. The EEG data were also collected in 50 matched control HIV-negative subjects. Cortical EEG sources were assessed by LORETA software.

RESULTS

Compared to the Control Group, the HIV Groups showed lower alpha (8-12Hz) source activity at T0 while the Group B also exhibited higher delta source activity. The treatment partially normalized alpha and delta source activity in the Group A and B, respectively, in association with improved VL, CD4, and cognitive functions.

CONCLUSIONS

Different cART regimens induced diverse beneficial effects in delta or alpha source activity in the two naïve HIV Groups.

SIGNIFICANCE

These sources might unveil different neurophysiological effects of diverse cART on brain function in naïve HIV Groups as a function of clinical status and/or therapeutic compounds.

Prevention of AIDS dementia by HAART does not depend on cerebrospinal fluid drug penetrance

The impact of the cerebrospinal fluid (CSF) penetrance properties of different highly active antiretroviral therapy (HAART) regimes on cognitive processing in AIDS dementia is still undetermined. We therefore designed a retrospective cross-sectional and prospective longitudinal analysis of event-related potentials in HIV-infected patients with different combinations of HAART or without antiretroviral treatment. A total of 353 consecutive patients without secondary CNS manifestation of HIV infection were enrolled in the cross-sectional study and 135 consecutive patients without secondary CNS manifestations of HIV infection were enrolled in the longitudinal study. HAART in different combinations (n = 306) or no antiretroviral treatment (n = 47) was given for at least 6 months in the retrospective cross-sectional study. HAART in different combinations (n = 110) or no antiretroviral treatment (n = 25) was given for 1 year in the prospective longitudinal study. We evaluated the latency and amplitude of the P3 component of visually evoked event-related potentials and mean choice reaction time as measures of cognitive processing. Patients receiving HAART had decreased P3 latencies as compared to those patients not receiving HAART but P3 latency and P3 amplitude were not correlated with the amount of CSF penetrance of the different HAART combinations in either statistical analysis. However, mean choice reaction time was significantly correlated with the amount of CSF penetrance. In HIV-infected patients, the CSF penetrance properties of HAART do not have any significant influence on cognitive processing as measured by event-related potentials.

Impact of highly active antiretroviral therapy on cognitive processing in HIV infection: cross-sectional and longitudinal studies of event-related potentials

Patients with HIV infection often complain of cognitive disturbances, which can be related to AIDS dementia or HIV-associated encephalopathy (HIVE). We investigated the impact of highly active antiretroviral therapy (HAART) in comparison with other therapeutic regimens on the progression of these cognitive disturbances as measured by visual event-related potentials (ERP). In a cross-sectional study, 214 patients without secondary neuromanifestation of their infection were divided into four groups with respect to their treatment status for 1 year before examination: (1) without antiretroviral treatment, (2) zidovudine monotherapy, (3) zidovudine in combination with didanosine, zalcitabine, or lamivudine, and (4) HAART. In a prospective longitudinal study, we divided 54 patients into three groups: (1) without antiretroviral treatment, (2) zidovudine monotherapy, and (3) HAART. Latencies of the P2, N2, and P3 components and the amplitude of the P3 component were evaluated. A significant negative correlation between CD4(+) lymphocyte cell count and P3 latency was found in all patients (p < 0.004). In the cross-sectional study, P3 latency was significantly decreased in the HAART group as compared with patients with no antiretroviral treatment (p < 0.01). During the 1-year period of the prospective longitudinal study, the P3 latency significantly increased in patients with no antiretroviral treatment (p < 0.05) and significantly decreased in patients with HAART (p < 0.05). In summary, these results suggest that HAART has an improving therapeutic effect on cognitive processing in HIV-infected patients and is superior to zidovudine monotherapy or dual antiretroviral treatment. Because prolongation of ERP might in part reflect HIVE, we conclude that this condition represents an indication for HAART.

Risk of HIV dementia and opportunistic brain disease in AIDS and zidovudine therapy

OBJECTIVE

To determine the incidence of HIV dementia and opportunistic brain disease in AIDS relative to the use of licensed antiretoviral medication (zidovudine, zalcitabine, didanosine, and stavudine).

METHOD

Medical records were evaluated retrospectively in a longitudinal cohort of 1109 patients with AIDS during the period 1991-4. Treatment groups were defined by start and duration of zidovudine treatment, the drugs used most often during this period were: (a) no zidovudine, (b) zidovudine before AIDS, (c) zidovudine before and after AIDS, and (d) zidovudine used in AIDS. Main outcome measures were cumulative incidence and survival from AIDS to onset of HIV dementia, progressive multifocal leukoencephalopathy (PML), cerebral toxoplasmosis, and primary CNS lymphoma.

RESULTS

Risk of brain disease including HIV dementia and opportunistic brain disease was reduced in patients who started zidovudine before AIDS and continued in AIDS (relative risk (RR) 0.55, 95% confidence interval (95% CI) 0.36-0.84) as well as zidovudine initiated in AIDS (RR 0.27, 95% CI 0.17-0.45) compared with untreated subjects. Treatment effects were not constant over time, decreasing by 14%-32% for each six months of follow up. This was supported by unadjusted incidences across groups stratified by duration of zidovudine use, indicating reduced risk with treatment for up to 18 months but not with longer duration of use of zidovudine. Other antiretroviral drugs had no significant effect, although these were used by only 14% of patients in this cohort.

CONCLUSION

The time limited but effective neuroprotection offered by zidovudine monotherapy for <18 months suggests that non-specific mechanisms of cerebral immunological defence may benefit from antiretroviral treatment. Due to the limitations of a retrospective study these findings require confirmation and further investigation in the context of current combination drug treatments.

Impact of antiretroviral treatment on AIDS dementia: a longitudinal prospective event-related potential study

We investigated the impact of antiretroviral treatment on event-related potentials (ERP) as a possible marker of AIDS dementia. A total of 154 HIV-infected patients without central nervous system (CNS) neoplasm or opportunistic infection were examined and randomized to receive either zidovudine 500 mg/day or no antiretroviral treatment. The participants were prospectively examined by visually evoked ERP in a longitudinal design. Latencies and amplitudes of ERP were evaluated at the beginning of the study, after 1 year, and after 2 years. After 1 year, 98 patients could be analyzed, 47 of whom were taking zidovudine. In the treatment group, P3 latency was 419 +/- 55 msec at baseline and 424 +/- 52 msec at follow-up (not significant). In the patients without treatment, P3 latency was 437 +/- 42 msec at baseline and 462 +/- 53 msec at follow-up (p < .0001, Wilcoxon test). A significant inverse correlation existed between P3 latency and CD4 cell count in both groups. The increase of P3 latency in untreated patients and a stable P3 latency in treated patients could be confirmed in a subgroup analysis of 21 patients with a follow-up of three examinations in a 2-year period. Our data suggest that zidovudine has a positive impact on AIDS dementia as measured by ERP. This finding was observed in patients in different stages of HIV infection, thus suggesting that zidovudine is indicated in all stages of HIV infection to treat encephalopathy.

Neurophysiological changes associated with psychiatric symptoms in HIV-infected individuals without AIDS

HIV-1 infection may be complicated by a number of psychopathological conditions. While organic mental disorders, such as HIV-related psychosis and dementia, are late manifestations, mood disorders may occur during both asymptomatic and symptomatic stages of infection. The possible impact of brain involvement due to neurotropism of HIV-1 has not been investigated systematically in these latter conditions. The psychiatric caseness of HIV-seropositive individuals without AIDS and seronegative controls was assessed using a standardized clinical interview (Present State Examination). A comparison was made between individuals with and without psychiatric caseness using clinical, neuropsychological, and neurophysiological assessments. An increased prevalence of current psychiatric illness was found in subjects with early symptomatic HIV infection compared to those with asymptomatic infection and controls. This could not be attributed to psychiatric history, as well as to clinical and immunological markers of HIV infection, however, psychiatric caseness in early symptomatic infection was associated with marked neurophysiological changes, detectable by quantitative electroencephalography. Altogether, this study provided preliminary evidence that psychiatric symptoms in symptomatic but not asymptomatic HIV infection may be associated with subtle brain involvement preceding the immunological and neurocognitive impairment characteristic for AIDS.

Prospective associations between lateralised brain function and immune status in HIV infection: analysis of EEG, cognition and mood over 30 months

Prospective relations between individual differences in both lateralised neuro-psychophysiological functions and mood ratings with immune status (CD4 and CD8 counts) were examined in asymptomatic HIV-positive men (n = 27) over thirty months. They participated in a controlled study of zidovudine versus placebo (results published elsewhere). Measures included EEG spectra, neuropsychological tests and mood ratings. A model of reciprocal lateralised influences on the immune system was tested whereby patients with left superior to right hemispheric functions were predicted to show a less deleterious outcome than those with the opposite asymmetry pattern. Prospective relations with immune status were found in the EEG with lateralised theta, alpha and beta activity; among cognitive measures with word fluency, semantic processing, and lateralised motor and recognition memory (word/face) processes; with mood ratings including depression, confusion and the total mood score. The nature of the effects supported the laterality predictions. These unique data, showing that neuro-psychophysiological factors in HIV+ but otherwise healthy subjects predict immune competence and compromise present 2-3 years later, warrant replication in a larger cohort.