Neurological and neuropsychological performance in HIV seropositive men without symptoms

Emotional deficit: an adaptative and evolutive process in HIV infection

The objective of the present study was to evaluate emotional disturbances and psychopathological symptoms in early stages of human immunodeficiency virus (HIV) infection. Seventy-one homosexual subjects, positive to HIV and two groups of HIV-negative subjects (32 homosexuals and 26 heterosexuals) were evaluated in a semi-structured interview by two trained raters. The results showed the presence of emotional perturbations already in asymptomatic HIV-positive individuals even in the absence of caracterized depression and/or anxiety. This emotional deficit seemed to be more important in more advanced stages of the disease. Depressive and anxious symptoms appeared to be slightly but significantly present in both groups of homosexual men. This emotional deficit could be the reflect of an adaptative process to the threatening consequences of HIV-infection. Emotional perturbations, even mild should not be neglected, because their reduction contributes to the psychological well being of HIV-positive subjects.

Neuropsychological performance in patients with asymptomatic HIV-1 infection

Human immunodeficiency virus (HIV-1) infection and acquired immunodeficiency syndrome (AIDS) lead to neurocognitive disorders; however, there is still much knowledge to be gained regarding HIV-associated neurocognitive disorders. The purpose of this study was to assess the cognitive performance, instrumental activities of daily living, depression, and anxiety in patients with asymptomatic HIV-1 infections compared with seronegative participants without neurocognitive impairment. We studied a sample consisted of 60 patients with asymptomatic HIV-1 infections and 60 seronegative participants without neurocognitive impairment from the city of Barranquilla, Colombia, with a mean age of 36.07 years. A protocol of neuropsychological and psychopathological tests was applied to the participants. The group of patients with asymptomatic HIV infections significantly underperformed on tasks that assessed global cognitive screening, attention span, learning, phonemic verbal fluency, auditory-verbal comprehension, information processing speed, cognitive flexibility, and motor skills compared to the group of seronegative participants. No significant differences were found in memory, visual confrontation naming, vocabulary, inhibition, and instrumental activities of daily living. Additionally, the patients with asymptomatic HIV-1 infection had a higher anxiety index than the seronegative participants, but no significant difference was found in depression. A correlation was found between depression and anxiety. In conclusion, the patients with asymptomatic HIV-1 infection had lower cognitive performances than the seronegative participants in the cognitive functions mentioned above and more anxiety but still performed the instrumental activities of daily living.

Do Patients With HIV-Associated Minor Cognitive/Motor Disorder Exhibit a “Subcortical” Memory Profile? Evidence Using the California Verbal Learning Test

A new diagnostic category for HIV seropositive patients–Minor Cognitive/Motor Disorder (MCMD)—was recently proposed by an AIDS task force sponsored by the American Academy of Neurology. Based on past memory research with HIV+ patients who were diagnosed according to the Center for Disease Control (CDC) definition of AIDS, we predicted that HIV+ patients who met the new criteria for MCMD would exhibit a “subcortical” memory profile (i.e., they would display primarily a retrieval deficit). This hypothesis was generally supported, but with some exceptions. The HIV+ patients with MCMD were found to have a mild encoding deficit (suggestive of some cortical involvement) superimposed on a pronounced retrieval deficit (suggestive of more extensive subcortical involvement). These findings are consonant with those from a recent neuropathological study indicating an increase in cortical involvement, in addition to predominately subcortical involvement, in more advance stages of the HIV disease process.

Neuropsychological Dysfunction in HIV Infection:A Review

FIfty-six studies which used neuropsychological tests to investigate areas of function affected by central nervous system dysfunction in HIV were reviewed. Only studies which compared the performance of HIV + subjects to HIV - controls using analysis of variance techniques were included. The results are examined in terms of broad neuropsychological function domains, and are examined separately for asymptomatic and symptomatic subjects. Studies which did and did not find significant differences between HIV + and HIV - subjects were compared in terms of various confounding factors such as risk groups, number of tests, sample size and subject characteristics. There was evidence for some dysfunction among subjects who are otherwise asymptomatic in the areas of verbal memory (27% of studies), executive function (43%), motor performance (20%) and information processing (44%). Studies of subjects with more advanced HIV infection showed consistent evidence of abnormal functioning in the areas of verbal (48% of studies) and visual memory (43%), executive functioning (71%), complex attention (62%), motor performance (37%) and information processing (69%). These deficits occurred prior to the onset of clinically apparent dementia. There were no consistent significant differences between studies which did and did not find significant differences between HIV + and HIV - subjects in terms of most of the confounding variables investigated, although studies of ASX subjects were more likely to find differences between HIV + subjects and controls with larger neuropsychological test battereies. However, much of the variation in results due to the neuropsychological tests used. In many cases, tests which relied on functions with a frontal lobe component were more likely to find significant results.

HIV, dementia and antiretroviral drugs: 30 years of an epidemic

Neurological complications due to the HIV itself became apparent early on in the course of the AIDS epidemic. The most feared were the cognitive and motor complications termed AIDS dementia complex or HIV-associated dementia. With the introduction of combination antiretroviral therapy, the incidence of HIV-associated dementia has been dramatically reduced. However, the prevalence of less severe forms of the disorder remains around 20%. There is controversy about whether some patients may continue with progressive cognitive decline despite adequate suppression of the HIV. The salient issues are those of cerebrospinal fluid (CSF) drug penetration, drug neurotoxicity and persistent immune activation and inflammation. This review will also discuss other newly encountered complications, including the compartmentalisation (or CSF escape) and immune reconstitution inflammatory syndromes.

The motor evoked potential in aids and HAM/TSP State of the evidence

OBJECTIVE: We aimed to better understand the involvement of the corticospinal tract, assessed by non-invasive transcranial stimulation, in order to determine the actual involvement of the motor system in patients with HAM/TSP and AIDS. METHOD: An exhaustive MEDLINE search for the period of 1985 to 2008 for all articles cross-referenced for "HTLV-I, HTLV-II, HTLV-III and HIV, HIV1, HIV2, evoked potential, motor evoked potential, high voltage electrical stimulation, transcranial magnetic stimulation, magnetic stimulation, corticomotor physiology, motor pathways, acquired immunodeficiency syndrome, AIDS, SIDA, tropical spastic paraparesis, HTLV-I-associated myelopathy, HAM, TSP, and HAM/TSP" were selected and analysed. RESULTS: Eighteen papers published in English, Spanish, Portuguese, French and Japanese were identified. Only the central motor conduction time has been analyzed in seropositive patients to human retroviruses. The investigations done on HAM/TSP support the involvement of the pyramidal tract mainly at lower levels, following a centripetal pattern; in AIDS, such an involvement seems to be more prominent at brain levels following a centrifugal pattern. CONCLUSION: The central motor conduction time abnormalities and involvement differences of the corticospinal tract of patients with AIDS and HAM/TSP dissected here would allow to re-orient early neurorehabilitation measures in these retroviruses-associated neurodegenerative disorders. Besides this, more sophisticated and sensitive non-invasive corticospinal stimulation measures that detect early changes in thalamocortical-basal ganglia circuitry will be needed in both clinically established as well as asymptomatic patients at times when the fastest corticospinal fibers remain uninvolved.

Motor skill impairment in SIV-infected rhesus macaques with rapidly and slowly progressing disease

A number of studies have shown that simian immunodeficiency virus (SIV) infection in rhesus macaques parallels many aspects of HIV disease in humans. The purpose of this study was to further characterize the rhesus macaque infected with neurovirulent SIV as a model of neuroAIDS. Using a motor skill task, our objective was to detect SIV-related movement impairments in behaviorally trained macaques. The motor skill task required retrieval of a food pellet from a cup in a rotating turntable across a range of speeds. Nine monkeys were infected with neurovirulent strains of SIVmac (R71/17E): four monkeys served initially as controls pre-inoculation. Seven monkeys developed simian AIDS within 4 months of inoculation (rapid progressors), and two survived more than 18 months post-inoculation (slow progressors). Of the rapid progressors, five exhibited significant deficits in this task, most showing a gradual decline in performance terminating in a sharp drop to severely impaired levels of performance. One slow progressor (AQ15) showed no performance declines. The other slow progressor (AQ94) showed a significant decrease in maximum speed that was concurrent with the onset of clinical signs. For AQ94, the role of sickness behavior related to late stage simian AIDS could not be ruled out. These results demonstrate that motor system impairment can be detected early in the course of SIV infection in rhesus macaques, further establishing the SIVmac-infected macaque monkey as a viable model of neuroAIDS.

Evidence of CNS impairment in HIV infection: clinical, neuropsychological, EEG, and MRI/MRS study

OBJECTIVES

To identify by clinical examination, EEG, MRI, and proton spectroscopy, and neuropsychological assessment the prevalence of signs of CNS involvement in patients infected with HIV, and to relate such findings to the evidence of immunosuppression.

METHODS

The design was a cross sectional analysis of a cohort of male patients with infected HIV with an AIDS defining diagnosis or low CD4 count (<350), and seropositive asymptomatic subjects, both groups being followed up in a longitudinal study. Control groups consisted of seronegative subjects from the same genitourinary medicine clinics.

RESULTS

This report sets out the cross sectional findings at the seventh visit in the longitudinal study. Patients with AIDS had more signs of neurological dysfunction, poorer performance on a neuropsychological test battery, were more likely to have an abnormal EEG, and to have abnormalities on MRI. They more often had cerebral atrophy, abnormal appearing white matter, and abnormal relaxometry and spectroscopy. There was little evidence of abnormality in seropositive people who had a CD4 count >350 compared with seronegative people from a similar background.

CONCLUSIONS

Detailed testing failed to disclose significant CNS impairment without immunosuppression in men infected with HIV. Findings from MRI and magnetic resonance spectroscopy (MRS) correlated with those of the neurological examination and neuropsychological assessment. A combination of such assessments offers a simple surrogate for studies of CNS involvement in HIV disease.

Discriminant validity of the Medical Outcomes Study cognitive function scale in HIV disease patients

Human immunodeficiency virus (HIV) infection results in a chronic course of disease progression and eventual death. With this disease progression comes decreases in health-related quality of life and cognitive function in many patients. We evaluated the construct and discriminant validity of the Medical Outcomes Study four-item and six-item cognitive function scale in a sample of 162 patients with HIV disease. The patients were assessed at baseline and after 4 months with the cognitive function scale, a cognitive functioning transition item, the Reitan trail making test (TMT) and the Centers for Epidemiologic Studies Depression (CES-D) scale. The results found that the four- and six-item cognitive function scales varied by HIV disease stage, CD4 count, self-reported change in cognitive function, TMT-based cognitive impairment and depression. The differences in the cognitive function scores were attenuated, but still remained statistically significant even after controlling for depression. The cognitive function scales predict cognitive impairment based on the TMT. The results support the construct validity of these self-report cognitive function scales.

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.

Biochemical changes in the frontal lobe of HIV-infected individuals detected by magnetic resonance spectroscopy

We have developed a proton magnetic resonance spectroscopy method that selectively can sample cortical gray matter and adjacent white matter in the frontal lobe. We have used this approach to study a group of patients (n = 7) infected with HIV and clinical manifestations of the AIDS dementia complex (ADC), a group of patients (n = 8) infected with HIV without any indications of ADC, and seven controls. The patients without ADC had a statistically significant increase in the ratio of myo-inositol to creatine in white matter compared with normal controls. In contrast, the group of patients with ADC had almost normal levels of myo-inositol to creatine in both gray matter and white matter and showed a statistically significant decrease in the N-acetylaspartate to creatine ratio in gray matter compared with either the normal controls or the patients without ADC. Patterns of spectral abnormalities correlated with neuropsychological measures of frontal lobe dysfunction, suggesting that the evaluation of frontal lobe metabolism by magnetic resonance spectroscopy can play a role in the early detection of ADC, in determining its progression, and in assessing responses to therapeutic interventions.

Cognitive and emotional deficits in early stages of HIV infection: an event-related potentials study

1. In order to inventory different Event-Related Potentials (ERP) modifications in HIV-infection the authors have evaluated 23 HIV-positive subjects and 12 HIV-negative subjects. ERP were recorded during an auditory oddball task. 2. Electrophysiological results showed that the latency of the N100 component of the ERP was significantly increased in HIV-positive subjects compared to the HIV-negative subjects. The latency of the N200 component of the ERP showed a similar tendency which just failed to reach significance when considering HIV-positive subjects vs HIV negative subjects. This result was in agreement with the literature which reported increased latencies in HIV infection. 3. Considering all subjects the authors have observed a correlation between the amplitude of the P300 and the emotional deficit. This correlation was stronger in subjects who presented an emotional deficit and was independent of any other psychopathological symptom. 4. The use of ERP appeared to be a sensitive technique to detect subclinical manifestations in HIV asymptomatic subjects and therefore would help to identify subjects at higher risk for developing cognitive impairments.

Imaging in acquired immune deficiency syndrome dementia complex (AIDS dementia complex): a review

1. Since 1986, the AIDS dementia complex has been recognized increasingly as a significant sequela of HIV infection. Though the pathogenesis remains poorly characterized and the diagnosis is one of exclusion, research utilizing various imaging techniques has resulted in greater understanding of the progressive character of ADC. 2. CT and MR studies have revealed general atrophy, atrophy of the basal ganglia, and white matter lesions that appear to increase in severity with progression of HIV infection. 3. CT and MR are relatively insensitive to the presence of clinical dementia, neurological signs, or positive findings on neuropsychological tests. In addition, they show poor correlation with histopathologic findings. 4. PET, SPECT, and MRS show the greatest sensitivity to changes wrought by primary HIV infection of the CNS and thus the greatest potential for early diagnosis of ADC. 5. PET, SPECT, and MRS show involvement of the basal ganglia, bloodflow abnormalities, and metabolite disturbances in HIV-seropositive subjects without findings on examination or neuropsychological tests.

Longitudinal neuropsychological evaluation of HIV-infected intravenous drug users

The present study aimed to describe the cognitive status of a group of HIV-positive asymptomatic intravenous drug users (IVDU) and changes which occurred over a 12-month follow-up period. Forty-two HIV positive IVDU were selected and matched for age, sex, educational level and pattern of drug abuse with 39 seronegative IVDU controls. Baseline and follow-up evaluation included neuropsychological tests exploring attention, language, memory, logic and visuomotor abilities, biological markers and clinical parameters. About one-third of both seropositive and seronegative subjects showed at baseline slight cognitive deficits, which did not change during the follow-up period.

Hippocampal neuronal atrophy occurs in rhesus macaques following infection with simian immunodeficiency virus

There is strong evidence that patients with AIDS have loss of cortical neurons. In this study we have examined the hippocampus of rhesus monkeys infected with simian immunodeficiency virus (SIV) to determine whether neuronal damage occurs in this model of human AIDS and to investigate its time course. Twenty-eight infected monkeys (23 young [< 9 years] and five elderly [> 16 years]) were compared with 11 controls (six young and five elderly). Numbers of nucleolated neurons per unit area of section and mean pyramidal cell diameters were measured in each CA sub-field of each animal. There was neuronal atrophy in all regions examined, as early as 3 months following inoculation. An initial apparent increase in neuronal density at 3 months did not reach statistical significance. In younger animals, however, there was a later, significant association between the reduction in neuronal density and duration of infection. Elderly animals were only examined at a single, early time point. These results show that there is neuronal pathology following infection with SIV and that there is probably subsequent neuronal death.

Neuropsychological deficits in tests of executive function in asymptomatic and symptomatic HIV-1 seropositive men

There has been much debate about the exact nature and time of onset of the cognitive impairments associated with infection by the human immunodeficiency virus type 1 (HIV-1). Studies to date have not reached consistent conclusions. The present study comprised 22 asymptomatic and 18 symptomatic HIV-1 seropositive men, whose only risk factor for contraction of the virus was sexual intercourse, and 18 seronegative controls matched for age and IQ. Subjects were given computerized neuropsychological tests from the CANTAB battery, which assessed visuospatial memory, attention and executive function. Both the asymptomatic and the symptomatic HIV-1 seropositive subjects showed a selective pattern of deficits relative to the controls. In addition, the seropositive subjects were subtly but significantly impaired on tests of executive function but unimpaired on certain tests of visual memory. This finding supports an hypothesis that frontostriatal dysfunction occurs in HIV-1 infected individuals prior even to the expression of clinical symptoms.

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

The effect of early antiretroviral medication with zidovudine on neurophysiological functions was evaluated in subjects with asymptomatic HIV-1 infection. Patients were recruited participants of a larger double-blind randomised placebo-controlled treatment trial with zidovudine (Concorde). The main outcome measures included: quantitative electroencephalography (QEEG), auditory event-related potentials (AEP) and pattern-reversal visual evoked potentials (PRVEP), as well as standard clinical, virological and immunological markers. No significant impairment and no difference between treatment groups was found in visual P100 latency and auditory long-latency P3 responses which is in agreement with the absence of neurological and neuropsychological impairment over the study period. Significant treatment effects were revealed by quantitative electroencephalography (QEEG). While the placebo group showed a significant increase in delta and theta slow frequency QEEG activity over the study period, slow wave amplitude remained unchanged in the zidovudine group after a mean follow-up period of 28 months. In summary, the data provide evidence for a low level neuropathological process in asymptomatic HIV-1 infection which can be effectively suppressed by antiretroviral medication.

Neurophysiological assessment of peripheral nerve and spinal cord function in asymptomatic HIV-1 infection: results from the UCMSM/Medical Research Council neurology cohort

As part of the Medical Research Council prospective study of the neurological complications of HIV infection, neurophysiological tests of spinal cord and peripheral nerve function were recorded in a cohort of homosexual or bisexual men. The studies included motor and sensory nerve conduction studies, vibration perception thresholds, somatosensory evoked potentials and motor evoked potentials elicited by magnetic stimulation. The results were compared with markers of immune function. The findings from 114 volunteers were analysed in a cross-sectional study. Fifty-nine were HIV-seropositive but asymptomatic, 26 had progressed to the symptomatic stages of HIV disease and 29 were persistently HIV-seronegative. There was some evidence of a mild sensory axonopathy in the symptomatic HIV-seropositive group. No differences were detected between the asymptomatic HIV-seropositive group and the HIV-seronegative comparison group. There were no consistently significant correlations between the neurophysiological measurements and CD4 counts and beta 2-microglobulin levels. On repeated testing, there was no evidence of a trend towards deterioration over a mean period of approximately 3 years in 36 HIV-seropositive subjects who remained asymptomatic compared with 22 HIV-seronegatives. These findings have failed to demonstrate neurophysiological evidence of spinal cord or peripheral nerve dysfunction in the asymptomatic stages of HIV infection.

The snout and palmomental reflexes in HIV disease in Tanzania

Following earlier observations on the snout (SR) and palmomental(PMR) reflexes in AIDS in Tanzania, a series of 1127 adults, 649 HIV-positive and 478 HIV-negative, from 4 groups at different risk of HIV infection were examined neurologically between 1987 and 1992. The prevalence of SR and PMR was calculated according to HIV status, HIV stage, demographic factors and neurologic findings. In the total series of HIV positives the prevalence ranged from SR 39.3% and PMR 22.6% in asymptomatic HIV disease to SR 87% and PMR 69% in terminal AIDS. In HIV negatives the prevalence of SR was 19.2% and PMR 15.3%, and increased with age. There was no relationship with age in the HIV positives and no gender differences. SR and PMR were also associated with neuropathy, myelopathy and AIDS dementia complex independent of HIV stage. This study shows a strong association between SR and PMR and HIV disease in Africa. The prevalence increased with HIV stage and related neurological disorders.

The HNRC 500--neuropsychology of HIV infection at different disease stages. HIV Neurobehavioral Research Center

The present study examined neuropsychological (NP) functioning and associated medical, neurological, brain magnetic resonance imaging (MRI), and psychiatric findings in 389 nondemented males infected with Human Immunodeficiency Virus-Type 1 (HIV-1), and in 111 uninfected controls. Using a comprehensive NP test battery, we found increased rates of impairment at each successive stage of HIV infection. HIV-related NP impairment was generally mild, especially in the medically asymptomatic stage of infection, and most often affected attention, speed of information processing, and learning efficiency; this pattern is consistent with earliest involvement of subcortical or frontostriatal brain systems. NP impairment could not be explained on the bases of mood disturbance, recreational drug or alcohol use, or constitutional symptoms; by contrast, impairment in HIV-infected subjects was related to central brain atrophy on MRI, as well as to evidence of cellular immune activation and neurological abnormalities linked to the central nervous system.

Neuropsychological studies of asymptomatic human immunodeficiency virus-type-1 infected individuals. The HNRC Group. HIV Neurobehavioral Research Center

The current review was conducted to address the ongoing debate regarding the presence or absence of neuropsychological impairment in asymptomatic HIV-Type 1 (HIV-1) seropositive individuals. Results were summarized from 57 studies that compared the performances of seropositive asymptomatic and seronegative individuals. Overall, the differences observed between median rates of impairment for asymptomatic (35%) and seronegative (12%) groups provided the clearest indication of deficits in asymptomatics. In addition, five variables were examined as possible contributors to inconsistencies found in the literature: mode of infection, test battery type, test battery size, sample size, and method of data analysis. Of these variables, only mode of infection and test battery size appeared to substantially influence the outcome of the studies reviewed with regard to identifying neuropsychological impairment in asymptomatics.

Sensorimotor neuropathy and abnormal vitamin B12 metabolism in early HIV infection

Distal sensory peripheral neuropathy (DSPN) has been reported in 5 to 75% of patients with human immunodeficiency virus (HIV) infection, particularly in advanced stages of the disease. Twenty HIV seropositive patients were studied prospectively to determine the frequency of DSPN in clinical stage II and III of the HIV infection, and to investigate the role of vitamin B12 deficiency on the frequency of DSPN in HIV patients. All patients had complete blood count, serum vitamin B12 level, anti-intrinsic factor antibody, Schilling test, and electrodiagnostic studies including nerve conduction studies and concentric needle examination in the lower extremities, and sympathetic skin responses. Only 1 patient (5%) had clinical and electrophysiological evidence of possible DSPN. Of the 6 patients with abnormal Schilling test, only one had DSPN based on distal sensory symptoms, abnormal neurological examination and electrodiagnostic studies. Evidence for possible DSPN was present in 5% of patients with early HIV infection and did not appear to be more frequent in patients with concurrent vitamin B12 deficiency.

Feline immunodeficiency virus as a model for study of lentivirus infection of the central nervous system

Feline immunodeficiency virus infects the CNS and results in predictable pathophysiology strikingly similar to that seen with HIV-1 infection of humans. The observed pathophysiology is mimicked in several physiologically assessed modalities, further supporting the validity of the feline model. Peripheral and control evoked potential findings and the occurrence of the sleep architecture changes in both cat and human disease provide an intriguing focus for further investigation. Although structurally diverse in an absolute sense, FIV and HIV-1 share basic structural features and commonalities of their life cycle. It is likely that by understanding the common mechanisms by which these lentiviruses influence CNS function, a more complete understanding of the neurological deficits seen in HIV-1 infected patients will be obtained. The cat model is particularly valuable for study of CNS disease, since it allows detailed analyses of events during the acute phase of infection, under circumstances in which the nature and timing of the infection are carefully controlled. The availability of molecular clones for mutational analysis will facilitate mapping of genomic regions critical to the perturbation of CNS function. It is suggested that development of intervention strategies in the cat model will yield treatment modalities directly applicable to HIV-1 infection of humans.

Neuropsychological function in asymptomatic HIV-1 infection: methodological issues

There have been conflicting reports as to whether significant neuropsychological deterioration occurs in asymptomatic HIV-1 infection. Comparisons among studies have been hindered by substantial variations in sample size, statistical methods, definitions of neuropsychological abnormality, and attention to potential confounding factors. In this study, the neuropsychological performance of 44 subjects with asymptomatic HIV-1 infection and 41 seronegative (SN) controls was compared using analysis of variance models. Rates of abnormality were also determined using commonly employed impairment criteria. The seropositive (SP) subjects performed comparably to SN controls once differences in full scale IQ were taken into account. Rates of abnormality for HIV-1 SP subjects were estimated at 10%, 17.5%, and 67.5% by three different criteria, and were not significantly different from the rates of the control group. The findings indicated that both premorbid characteristics, and the validity and biases of definitions of impairment should be examined and incorporated into the interpretation of study findings.

Verbal memory performance of patients with human immunodeficiency virus infection: evidence of subcortical dysfunction. The HNRC Group

In the present study, the California Verbal Learning Test (CVLT) was administered to symptomatic HIV+ (n = 31), asymptomatic HIV+ (n = 94), and HIV-normal control (HIV-NC) (n = 40) subjects to assess the prevalence and nature of their verbal memory deficits. Symptomatic HIV+ subjects were significantly impaired relative to HIV-control subjects on CVLT measures of acquisition and retention, and were significantly less likely than control subjects to use a semantic clustering strategy to support recall. The performance of the asymptomatic HIV+ subjects fell between those of the symptomatic HIV+ subjects and HIV-controls on almost every CVLT measure. A linear discriminant function analysis (DFA) was used to compare the performances of these three groups to Alzheimer's disease (AD). Huntington's disease (HD), and normal control (NC) subjects on three CVLT measures, including total recall over five learning trials, intrusion errors, and a derived score of delayed recognition discriminability minus the final learning trial. Significant differences were found between the number of symptomatic HIV+ subjects classified as HD (32%), AD (3%), and normal (65%), the number of asymptomatic HIV+ subjects classified as HD (16%), AD (1%), and normal (83%), and the number of HIV-NC subjects classified as HD (2%), AD (0%), and normal (98%). The profile of verbal memory deficits exhibited by the subgroup of impaired HIV+ subjects was similar to that of patients with HD, a prototypical subcortical dementia, and different from that of patients with AD, a prototypical cortical dementia. This finding is consistent with reports of the predominance of subcortical neuropathological changes associated with HIV infection.

Serial MRI of the brain in asymptomatic patients infected with HIV: results from the UCMSM/Medical Research Council neurology cohort

Seventy-six homosexual or bisexual men underwent two cranial MRI studies at a mean interval of 13 months; 23 were HIV seronegative, 41 seropositive but asymptomatic (Center for Disease Control (CDC) groups II/III), and 12 had AIDS related complex (ARC)/AIDS (CDC group IV). Agreement between two neuroradiologists was rated as very good for assessment of enlargement of ventricles and good for widening of cerebral sulci and the presence of focal lesions. For assessment of serial studies, the agreement was moderate. The prevalence of cerebral atrophy and focal white matter lesions was no higher in the asymptomatic patients (CDC group II/III) than in appropriate seronegative controls. Some patients with ARC/AIDS showed evidence of developing cerebral atrophy during the study period when serial scans were compared. The imaging evidence supports the other data obtained from this cohort, which suggest that no significant CNS involvement occurs in HIV infection before the development of ARC/AIDS.

Long-latency event-related potentials in asymptomatic human immunodeficiency virus type 1 infection

As part of the Medical Research Council prospective study of the neurological and neuropsychological complications of human immunodeficiency virus (HIV) infection, long-latency event-related potentials were recorded in a cohort of homosexual and bisexual men. The latencies and amplitudes of the potentials, recorded from three scalp sites, were compared with the scores from neuropsychological tests of memory, attention, and concentration and with markers of immune function. The findings from 94 men were analyzed in the cross-sectional study of whom 47 were HIV seropositive without symptoms or signs of HIV type 1 (HIV-1) infection, 24 had progressed to the symptomatic stages of the disease, and 23 were persistently HIV seronegative. There were no consistently significant differences between the three subject groups in mean latencies and amplitudes of the P300 and N200 or in the numbers of abnormal P300 latencies. There were no significant correlations between either the neuropsychological tests scores or the immune measures (CD4 lymphocyte count and beta 2 microglobulin level) and the neurophysiological parameters. On repeated testing an average of 2 years later, there was no evidence of a significant trend towards deterioration in 30 HIV-seropositive subjects who remained asymptomatic compared with 22 HIV seronegatives. These findings indicate that there is no neurophysiological evidence of cognitive dysfunction in the asymptomatic stages of HIV-1 infection.

Neuropsychiatric aspects of HIV-1 infection in gay men: controlled investigation of psychiatric, neuropsychological and neurological status

The aim of this study was to determine whether HIV infection is associated with psychiatric morbidity or neuropsychological impairment in asymptomatic and early symptomatic stages of disease in gay men. The subjects were 100 gay men (68 HIV-ve, 32 HIV+ve, 6 being CDC IV). All subjects were recruited at the time of requesting their first HIV test and the assessment was double-blind to HIV serostatus. There were no differences in psychiatric status or neuropsychological performance between the HIV-ve and HIV+ve groups. Multiple regression analysis and logistic regression were used to identify factors associated with psychiatric morbidity, neuropsychological impairment and subjective reporting of memory problems and physical symptoms for all 100 subjects. Previous psychiatric history and current illegal (non-dependent) drug use were associated with psychiatric morbidity, poor education was associated with neuropsychological impairment and psychiatric status (score on HAD and PSE) was associated with subjective reporting of memory problems and physical symptoms.

Detection of subclinical motor dysfunctions in early symptomatic HIV infection with topographical EEG

Motor dysfunctions are amongst the earliest and most common signs of brain impairment caused by human immunodeficiency virus (HIV) infection. Topographical EEG was recorded in patients both with asymptomatic and early symptomatic infection (without acquired immunodeficiency syndrome (AIDS) defining illness), as well as in seronegative controls under resting and motor activation conditions. While patients' motor performance did not differ from control values, the EEG showed a consistent increase in rhythmic activity in Theta, Alpha and Beta frequency bands in Symptomatics. This amplitude increase was evident in different topographical regions during resting states as compared with motor activation, findings which suggest concurrent involvement of several motor areas possibly due to a functional impairment in subcortical integratory mechanisms. Comparing motor task and baseline both patient groups showed less consistent patterns of task-related EEG amplitude reduction than found in the control group. Here topographical EEG in connection with motor activation procedures was found to be more sensitive than behavioral measures of motor performance and offers a technique to assess treatment effects before the development of motor abnormalities in patients with HIV infection.

Total reaction time: a new approach in early HIV encephalopathy?

In an attempt to develop better methods for diagnosis, screening and serial assessment of HIV-1-associated cognitive/motor complex, we have added a motor component to tests of reaction time, defining the new parameter as total reaction time. Thirty-four non-drug-using, HIV-positive men underwent four different tests of total reaction time. All four tests reached a level of statistical significance, both for a group of patients with early disease and for a group of patients with symptoms, compared with a control group. Total reaction time had a better discriminatory ability than standard reaction time, particularly for patients with early disease. It is suggested that neuropsychological studies of HIV-1-associated cognitive/motor complex should include tests of total reaction time.

Zidovudine. An update of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy

Zidovudine remains the mainstay in the treatment of patients infected with human immunodeficiency virus (HIV). The drug delays disease progression to acquired immunodeficiency syndrome (AIDS) and to AIDS-related complex (ARC), reduces opportunistic infections, and increases survival in patients with advanced HIV infection. There is evidence to suggest that zidovudine also delays disease progression in patients with mild symptomatic disease. Although one study has shown zidovudine to have no significant beneficial effects on survival or disease progression in patients with asymptomatic HIV infection, several other studies have shown zidovudine to delay disease progression in this patient group. Results from related ongoing studies are awaited with interest. Zidovudine reduces the incidence of AIDS dementia complex (ADC) and appears to prolong survival in these patients, and improves other neurological complications of HIV infection. The drug also appears to enhance the efficacy of interferon-alpha in patients with Kaposi's sarcoma. Although zidovudine is widely used as postexposure prophylaxis following accidental exposure to HIV, its efficacy in preventing seroconversion is unclear. Whether zidovudine prevents vertical transmission also remains to be determined. The overall efficacy of zidovudine in the treatment of children with HIV infection appears similar to that in adults despite more rapid disease progression in younger patients. Zidovudine-resistant isolates can emerge as early as after 2 months' therapy, and primary infection with zidovudine-resistant strains has been documented. Both zidovudine resistance and the syncytium-inducing HIV phenotype appear to be associated with poor clinical outcome. However, zidovudine resistance may revert on drug withdrawal or switching to an alternative therapy. Zidovudine-associated haematotoxicity may be dose-limiting. Nonhaematological adverse events associated with zidovudine therapy are generally mild and usually resolve spontaneously. Dosages of approximately 500 to 600 mg/day appear to be at least as effective as dosages of 1200 to 1500 mg/day and are better tolerated in patients with less advanced disease. However, optimal dosage are unclear. Despite beneficial effects, zidovudine monotherapy is not curative. There is evidence to suggest that the concomitant administration of zidovudine with didanosine or zalcitabine is effective in patients with HIV disease progression despite receiving zidovudine monotherapy, and there is some evidence that concomitant zidovudine plus didanosine therapy is more effective than alternating monotherapy. However, results from studies of combination therapy in asymptomatic patients, and from comparative combination therapy studies are awaited. Cotherapy with agents that augment haematopoiesis allows the continuation of therapeutic zidovudine dosages.(ABSTRACT TRUNCATED AT 400 WORDS)

Auditory and visual event-related potentials in a controlled investigation of HIV infection

Auditory and visual event-related brain potentials (ERPs) were used to complement neuropsychological and medical assessment in neurologically healthy subjects with asymptomatic and symptomatic human immunodeficiency virus type 1 (HIV-1) infection. Auditory and visual ERPs, recorded using standard oddball paradigms, disclosed delays in late waves (N2 and P3) in symptomatic subjects (CDC stage IV) when compared with matched controls. Abnormally delayed P3 waves in at least one modality were recorded in 41% of symptomatics and this was associated with deficits in neuropsychological performance, particularly psychomotor slowing. However, no differences in late wave latencies between asymptomatic and control subjects were found, though asymptomatics showed delays in auditory N1 and P2 latencies. The number of morphological abnormalities, such as indiscernible late waves as well as topographical variability of the P3 wave, was increased in both HIV seropositive groups and possibly indicates a distinct mechanism of impairment, different from latency delay. Whilst P3 delay in symptomatics was not associated with changes in immune function (T4 cells) there was, however, a link with anaemia and subclinical hepatic dysfunction.

Electrophysiological study of neurologically asymptomatic HIV1 seropositive patients

EEGs, brainstem auditory evoked potentials (BAEPs) and auditory event-related potentials (ERPs) were recorded from 33 individuals infected with the human immunodeficiency virus, type 1 (HIV1+ patients: 13 CDC Class II or III; 20 Class IV). All were neurologically asymptomatic, non-demented, and had a past history of intravenous drug abuse. Sixteen age- and sex-matched normals and 10 HIV1- former drug addicts served as controls. Half of the HIV1+ and HIV1- subjects displayed mild EEG anomalies and, except for one HIV1+ patient, BAEPs were normal in both groups. ERPs were normal in all HIV1- subjects but anomalous (longer latencies of components P2, N2, P3; reduced amplitude of P3) in 9 HIV1+ patients (27%), the incidence of such anomalies being higher for Class IV than Class II/III patients. Auditory ERPs proved the most sensitive and specific of these electrophysiological procedures in detecting subclinical central nervous system involvement in HIV1 infection.