Heterogeneity of Neuropsychological Impairment in HIV Infection: Contributions from Mild Cognitive Impairment

Despite longstanding acknowledgement of the heterogeneity of HIV-associated neurocognitive disorders (HAND), existing HAND diagnostic methods classify according to the degree of impairment, without regard to the pattern of neuropsychological strengths and weaknesses. Research in mild cognitive impairment (MCI) has demonstrated that classifying individuals into subtypes by both their level and pattern of impairment, using either conventional or statistical methods, has etiologic and prognostic utility. Methods for characterizing the heterogeneity of MCI provide a framework that can be applied to other disorders and may be useful in clarifying some of the current challenges in the study of HAND. A small number of studies have applied these methods to examine the heterogeneity of neurocognitive function among individuals with HIV. Most have supported the existence of multiple subtypes of neurocognitive impairment, with some evidence for distinct clinicodemographic features of these subtypes, but a number of gaps exist. Following a review of diagnostic methods and challenges in the study of HAND, we summarize the literature regarding conventional and empirical subtypes of MCI and HAND and identify directions for future research regarding neurocognitive heterogeneity in HIV infection.

HIV-associated neurocognitive disorder in Australia: a case of a high-functioning and optimally treated cohort and implications for international neuroHIV research

The Australian HIV-infected (HIV+) population is largely comprised of high-functioning men who have sex with men (MSM). Like other English-speaking countries, Australia mostly relies on US neuropsychological normative standards to detect and determine the prevalence of neurological disorders. Whether the US neuropsychological (NP) normative standards are appropriate in Australian HIV+ MSM has not been established. Ninety virally suppressed HIV+ and 49 HIV-uninfected (HIV-) men (respectively 86 and 85 % self-reported MSM; mean age 54 and 56 years, mean premorbid verbal IQ estimate 110 and 111) undertook standard NP testing. The raw neuropsychological data were transformed using the following: (1) US standards as uncorrected scaled scores and demographically corrected T scores (US norms); and (2) z scores (without demographic corrections) derived from Australian comparison group scaled scores (local norms). To determine HIV-associated neurocognitive disorder prevalence, we used a standard definition of impairment based upon a battery-wide summary score: the global deficit score (GDS). Impairment classification (GDS ≥ 0.5) based on the local norms was best at discriminating between the two groups (HIV- = 14.3 % vs. HIV+ = 53.3 %; p < 0.0001). This definition was significantly associated with age. Impairment classification based on the US norms yielded much lower impairment rate regardless of the HIV status (HIV- = 4.1 % vs. HIV+ = 14.7 %; p = 0.05), but was associated with historical AIDS, and not age. Both types of summary scores were associated with reduced independence in activities of daily living (p ≤ 0.03). Accurate neuropsychological classifications of high (or low) functioning individuals may need country-specific norms that correct for performance-based (e.g., reading) estimates of premorbid cognition in addition to the traditional demographic factors.

HIV-associated cognitive impairment in sub-Saharan Africa--the potential effect of clade diversity

In the US, HIV dementia occurs in 10-15% of HIV-positive individuals with advanced infection. The prevalence of HIV dementia in sub-Saharan countries, where the vast majority of individuals with HIV reside, is largely unknown. This Review will summarize our current understanding of HIV-associated cognitive impairment in resource-limited settings, focusing specifically on the countries of sub-Saharan Africa. We will describe the frequency of HIV dementia and HIV-associated cognitive impairment from several case series in the sub-Saharan region. We will then summarize recent studies from Uganda and Ethiopia that included detailed neuropsychological assessments. The potential influence of clade diversity on HIV-associated cognitive impairment will be discussed. Differences between the results of the studies in Uganda and in Ethiopia raise the possibility that HIV subtypes might have different biological properties with respect to their capacity to cause HIV-associated cognitive impairment. Further studies are needed to determine the true prevalence of HIV dementia in sub-Saharan Africa and to establish whether specific clade subtypes might influence the presentation of neurological complications.

Klinik, Diagnostik und Therapie HIV-induzierter neuropsychiatrischer Störungen

Since the acquired immune deficiency syndrome (AIDS) was first recognized in 1981, more than 25 million individuals have died from complications of the human immunodeficiency virus (HIV) infection. The introduction of highly active antiretroviral therapy (HAART) in 1995 has resulted in a significantly decreased incidence rate of AIDS in the developed world. As HAART led to considerable improvements in survival for patients with HIV infection, HIV-neurotropically associated neuropsychiatric disorders have become an increasingly important challenge for clinical medicine. This article gives an overview of epidemiology, clinical features, diagnosis, and therapy of HIV-induced cognitive-motor impairments including HIV-associated dementia complex, organic mood disorders and psychosis.

Ezrin Immunoreactivity Reveals Specific Astrocyte Activation in Cerebral HIV

The actin-binding protein ezrin is associated with cellular shape changes, motility, tumor invasion, and lymphocyte activation. We have earlier shown that ezrin immunoreactivity (IR) is faintly present in normal astrocytes but increased in malignant human astrogliomas. We studied the role of ezrin in astrocyte activation, applying immunostaining on serial paraffin sections from human autopsied brain tissues (51 cases). Cerebral HIV infection was chosen as a model displaying consistent exemplary astrocyte activation. Semiquantitative ezrin-IR was compared with the common glial markers GFAP, ferritin, and HLA-DR in relation to clinical and morphologic criteria of HIV encephalopathy. In all cases with HIV infection, GFAP-, HLA-DR-, and ferritin-IR were elevated in comparison to normal brain tissues. In contrast, high ezrin-IR in HIV infection strictly correlated with additional HIV encephalopathy. HIV encephalopathy with particularly high ezrin-IR was correlated with neuronal apoptosis (TUNEL). Combined ezrin-IR and GFAP-IR thus reveals 2 distinct states of astrocytic activation. Normal ezrin-IR, when paralleled by upregulated GFAP, reflects astroglial activation not associated with neuronal apoptosis. High ezrin-IR indicates specific astrocyte stressors related to cellular damage within the central nervous system. Ezrin-IR might also provide a diagnostic tool for the classification of HIV encephalopathy.

Recommendations for the classification of HIV associated neuromanifestations in the German DRG system

HIV associated neuromanifestations are of growing importance in the in-patient treatment of HIV infected patients. In Germany, all in-patients have to be coded according to the ICD-10 classification and the German DRG-system. We present recommendations how to code the different primary and secondary neuromanifestations of HIV infection. These recommendations are based on the commentary of the German DRG procedures and are aimed to establish uniform coding of neuromanifestations.

Neurological manifestations of HIV infection in Kwazulu-Natal South Africa

South Africa has one of the fastest growing HIV epidemics in the world and KwaZulu-Natal, one of its nine provinces, is the epicentre of the epidemic. Of the estimated 5.3 million people infected with HIV in South Africa, 1.2 million reside in KwaZulu-Natal. Transmission of HIV is almost exclusively heterosexual, intravenous drug misuse does not occur and the patients attending state hospitals are antiretroviral drug naive. The neurological complications of HIV infection include bacterial and fungal meningitis, intracranial mass lesions, acute disseminated encephalomyelitis, a variety of spinal cord disorders, and peripheral nerve dysfunction. Tuberculous meningitis, especially that due to multidrug resistant organisms has a high mortality rate. Toxoplasmosis is the most frequent cause of intracranial mass lesions. These cases are successfully treated with cotrimoxazole alone. Multiple bacterial abscesses and tuberculomata are other important causes whilst primary central nervous system lymphoma is rare. The spinal cord disorders include co-infection with HTLV-I, tuberculosis and syphilis. Intramedullary tuberculomata, often multiple, and spinal epidural tuberculous abscess without bony disease are seen more commonly than in the pre HIV era. Peripheral nerve dysfunction include Gillian Barre Syndrome, chronic inflammatory demyelinating polyneuropathy and mononeuritis multiplex. Until the antiretroviral therapy roll out programme is well established the above HIV related neurological complications will continue to be seen for several years.

Evidence for a change in AIDS dementia complex in the era of highly active antiretroviral therapy and the possibility of new forms of AIDS dementia complex

This review will discuss emerging evidence for the possibility that AIDS dementia complex (ADC) has changed in the era of highly active antiretroviral therapy (HAART). The consequences of not considering these possibilities at the patient level and at the level of research are considerable. Data will be discussed that are derived from epidemiological studies, neuropsychological and positron emission tomography studies, as well as analyses from the abacavir ADC trial. These will then be assessed to develop the concept that there are now different forms of ADC: an inactive form, a chronic variety and a 'transformed' variant. Whereas the latter relates to the compounding influence of a number of other processes on ADC, such as hepatitis C, particular discussion will focus upon Alzheimer's disease and whether HIV may lead to Alzheimer-like changes. It is certainly recognized that some of the concepts discussed here are highly speculative.

Effect of combination antiretroviral therapy on cerebrospinal fluid HIV RNA, HIV resistance, and clinical manifestations of encephalopathy

OBJECTIVES

This study evaluated the effect of treatment with abacavir/lamivudine/zidovudine versus lamivudine/zidovudine on cerebrospinal fluid (CSF) human immunodeficiency virus (HIV) RNA and clinical manifestations of HIV encephalopathy in children.

STUDY DESIGN

HIV-infected children 7 months to 10 years of age (n = 23) were studied. CSF and plasma were obtained at baseline and weeks 8, 16, and 48. Genotype analysis of HIV was attempted at baseline and week 48. Neurologic evaluations were performed at baseline and weeks 16, 32, and 48.

RESULTS

At baseline, 83% of children had >2.00 log(10) copies/mL HIV RNA in CSF, but only 10% had HIV RNA measurable at week 48. Among children in whom paired genotyping of HIV was possible, 8 of 11 had identical patterns in both CSF and plasma at baseline, whereas at week 48, only 1 of 9 children had similar patterns. Neurologic abnormalities were observed in 83% of children at baseline but only 35% of children at week 48 (P =.004), suggesting a benefit of treatment.

CONCLUSIONS

Antiretroviral therapy was associated with a decline in CSF HIV RNA and an improvement in neurologic status. The development of genotypic mutations was different in CSF and plasma, suggesting discordant viral evolution. These results suggest that antiretroviral treatment in children should include agents with activity in the CNS.

Analyses of nursing home residents with HIV and dementia using the minimum data set

OBJECTIVE

The objective of this paper is to profile nursing home residents with HIV who also have dementia at the time of admission, using the Minimum Data Set (MDS). In addition, this paper compares HIV residents with dementia with other residents with HIV. These resident profiles contain sociodemographic characteristics, health status measures, treatments, and procedures.

STUDY SUBJECTS

There are 1,074 admission assessments for HIV residents with dementia and 4,040 admission assessments for other residents with HIV in the MDS between June 22, 1998 and January 17, 2000; these were analyzed for this study.

RESULTS

Other residents with HIV were twice as likely to be physically independent as HIV residents with dementia. Only 1 of 5 HIV residents with dementia was independent in cognitive skills for daily decision making compared with 3 of 5 other residents with HIV who were independent in these skills. Significantly greater percentages of HIV residents with dementia also had anemia, depression, schizophrenia, cognitive and memory problems, hepatitis, renal failure, and cancer than other residents with HIV.

CONCLUSIONS

These analyses demonstrate that HIV residents with dementia were significantly more likely to have other diseases, infections, and health care conditions than other residents with HIV.

HIV-related brain impairment from palliative care to rehabilitation

Brain impairment is a distressing manifestation of human immunodeficiency virus (HIV) disease characterized by progressive cognitive impairment leading eventually to dementia and death. Patients with advanced brain impairment are clinically difficult to manage and usually require residential care. In 1997, a brain impairment unit opened at the Mildmay Hospital UK in London to meet the needs of this patient group. It began as a nurse-led unit, has adopted an interdisciplinary approach to care and aims to maximize the quality of life until death. In a study of patients admitted during its first year, it emerged that while the condition of many patients declined resulting in death, some patients improved sufficiently with rehabilitation and ongoing medical treatment to return to independent living. The possible reasons for this are discussed in this article. Study findings have not only affected the approach to care but have also highlighted some unexpected problems; the importance of adopting an interdisciplinary approach in caring for the group of patients becomes evident.

Neurodevelopmental outcomes of Ugandan infants with HIV infection: an application of growth curve analysis

Neurodevelopmental outcomes of human immunodeficiency virus Type 1 (HIV-1)-infected infants of non-drug-using mothers were assessed in a controlled, prospective study from birth to 24 months with 3 groups: 61 infants of HIV-infected mothers, 234 uninfected infants of HIV-infected mothers (seroreverters), and 115 uninfected infants of uninfected mothers. Compared with seroreverters and uninfected infants, HIV-infected infants demonstrated lower mental and motor development on the Bayley Scales and greater deceleration in their rate of motor development. HIV-infected infants with abnormal neurologic exams had lower motor and mental test scores and lower rates of motor Bayley Scales scores than their HIV-infected counterparts with normal neurologic exams. Contrary to prediction, no group differences in mean performance or growth rates were found on visual information processing on the Fagan Test of Infant Intelligence.

[Routine electroencephalogram in follow-up of patients with HIV infections of different stages. A long-term study]

Electroencephalography (EEG) is a well-tolerated non-invasive method and is therefore well suited for repetitive examinations. We performed serial EEG's on 117 HIV patients without any clinical signs of secondary neuromanifestation in order to document electroencephalographic changes in the course of HIV infection. Clinical signs of HIV-associated encephalopathy presented 18 patients at the first examination and 23 at reexamination. EEGs were analyzed visually; there was a mean interval of 20.3 +/- 13.7 months between the first and the second examination. Significant slowing of background activity occurred in the course of the disease; the alpha rhythm decreased from 10.7 +/- 2.3 Hz to 10.0 +/- 2.4 Hz (P < 0.05) with an increase in amplitudes from 60.9 +/- 24.6 microV to 69.5 +/- 33.7 microV (p < 0.05). The percentage of spontaneous dysrhythmias also increased from 30.7% to 41.8% (P < 0.05); pathological findings provoked by hyperventilation increased from 13.6% to 18.2%. Foci occurred rarely and did not increase in frequency with time. CD4 cell counts decreased from 294.2 +/- 209.5/microliter to 188.7 +/- 208.3/microliter (P < 0.01). The results of this study indicate progressive CNS dysfunction with worsening of the immunostatus.

Variable progression of HIV-associated dementia

A consecutive series of 71 patients diagnosed with HIV-associated dementia (HAD) (1984-1994) were studied to characterize the clinical course of HAD, and to identify predictive markers of rapid neurologic progression. Neurologic progression rate was determined from the change in the Memorial Sloan Kettering (MSK) dementia severity score from diagnosis to death. Those with the most rapid progression in neurologic disability were compared with those with slow or no progression. Autopsy material was immunostained for macrophage activation markers and gp41 in 30 individuals. Median survival was 3.3 months and 6.1 months for rapid-progression and no-progression patients, respectively. Rapid progression was associated with injection drug use but not with race, gender, or age. CD4+ cell counts were lower at diagnosis among rapid-progression than no-progression patients but no differences in AIDS-defining illnesses or patterns of antiretroviral therapy were found. At presentation, rapid-progression patients had more prominent symptoms of mental slowing than those with no progression; however, no other clinical features, CSF, or imaging features distinguished the groups. Less abundant macrophage activation in both basal ganglia and midfrontal gyrus regions, as judged by HAM56 immunostaining, was noted in 9 no-progression patients, compared with 12 rapid-progression patients. Neurologic progression and survival with HAD is highly variable. A significant proportion of individuals with dementia have prolonged survival of more than 12 months and remain cognitively stable. A history of injection drug use and presentation with prominent psychomotor slowing is associated with more rapid neurologic progression, and these patients tend to show more abundant macrophage activation within the CNS.

Spontaneous eye blinking, a measure of dopaminergic function, in children with acquired immunodeficiency syndrome

OBJECTIVE

To investigate possible alterations in dopaminergic function in children with acquired immunodeficiency syndrome by evaluating spontaneous eye blink rate, a putative measure of central dopaminergic function.

DESIGN

Evaluation of previously videotaped test sessions of a consecutive case series of 50 children (mean age, 5.2 years; range, 2-12 years) with acquired immunodeficiency syndrome.

SETTING

Government medical research center.

RESULTS

Intrarater reliability was high, expected co-variation of blink rate with age and concurrent mental activity were confirmed, and obtained rates were similar to published data. Higher blink rates, suggestive of increased dopaminergic function, were associated with more severe cortical atrophy (P < .05) and white matter abnormality (P < .05) on computed tomographic brain scans. The presence or severity of basal ganglia calcifications did not seem to influence blink rate. In addition, higher blink rates were associated with higher ratings of depressed affect (P < .05) and lower ratings of hyperactive behaviors (P < .05) during other test activities.

CONCLUSIONS

The higher blink rates in human immunodeficiency virus-infected children with more severe cortical abnormalities suggest increased central dopamine activity compared with that in children without cortical computed tomographic brain scan abnormalities. Thus, as a result of structural brain abnormalities, neurotransmitter levels in children with acquired immunodeficiency syndrome may vary and this may be reflected in their socioemotional functioning.

[HIV-1 cognitive and motor syndrome]

The central nervous system (CNS) is often affected by HIV-1 infection. Over 40% of AIDS cases present with neurological symptoms and CNS lesion are detected by anatomical and pathological studies in 80 to 90% of AIDS cases. There may be infections and tumors secondary to the immunodeficiency and pathologies may occur directly due to the neurotropism of the virus. Neurological problems associated with HIV-infection include encephalopathies, myelopathies, neuropathies and myopathies. HIV-1-induced encephalopathy may develop at any stages of HIV-1 infection and affects all risk groups equally. Its frequency worldwide is between 4 and 65% among individuals seropositive for HIV-1. The frequencies reported differ between studies due to differences in sampling methods, geographical factors, diagnostic criteria and investigative methods used. The pathogenesis of HIV-1-associated encephalopathy is not understood, but there are several hypotheses. The involvement of HIV-1 infected macrophages and microglial cells has been demonstrated. Indirect mechanisms such as release of lymphokines (tumor necrosis factor-TNF alpha- and interleukin-1) and neurotoxicity of the HIV envelope protein, gp 120, have also been suggested. This disorder is known as HIV-1-associated cognitive and motor syndrome. It presents clinically as a form of sub-cortical dementia with cognitive problems, motor deficits and behavioral disorders depending on the type and stage of HIV infection. The diagnosis can only be made after all other infections and tumors common in HIV-1 patients have been ruled out by appropriate investigations such as cerebrospinal fluid analysis, cerebral scan and magnetic resonance imaging. Electrophysiological studies, such as evoked responses and electroencephalograms, are particularly useful in its diagnosis. Anatomical examination shows diffuse paleness of the white matter, multi-nucleated giant cells and microglial nodes. Neuropsychological studies could be of value in diagnosis and in assessing the response to anti-retroviral treatment. There is currently no specific therapy for HIV-1-associated cognitive and motor syndrome. The use of new nucleoside analogue drugs in combination with existing drugs may provide new approaches to managing these patients.

Brain atrophy in HIV infection is more strongly associated with CDC clinical stage than with cognitive impairment

HIV infection often results in MRI-detectable brain atrophy and white matter signal hyperintensities (WMSHs). Magnetic resonance images were obtained from 31 HIV+ male patients and 10 high-risk controls. Variation within the HIV+ group on neuropsychological (NP) impairment and stage of systemic disease were relatively independent, allowing examination of the relative association of MRI measures with NP impairment versus with systemic stage of disease. HIV+ patients compared to high-risk controls evidenced global atrophy, reduced caudate nuclei volume, and a trend to gray matter volume loss but no difference in white matter volume or in WMSHs. These effects were progressive with CDC clinical stage such that patients at CDC stage A had values very close to those of controls, while patients at CDC stage C had the most abnormal values. In contrast, the relationship between these MRI variables and severity of NP impairment was much less dramatic, with the mildly to moderately impaired HIV+ subjects showing MRI volume effects greater than or equal to those of the severely impaired HIV+ subjects. These results suggest that MRI-detectable brain atrophy secondary to HIV infection is not the primary substrate underlying the progressive NP impairment in HIV disease.

Neurological complications of HIV infection

Neurological complications of HIV infection cause considerable morbidity and are often associated with high mortality. These complications include not only the more common opportunistic diseases affecting the brain (cerebral toxoplasmosis, primary central nervous system lymphoma, progressive multifocal leucoencephalopathy, and cryptococcal meningitis) but also the AIDS dementia complex, with its characteristic cognitive and motor dysfunction, which is caused by HIV itself. Additionally, the peripheral nervous system is the target of several disorders, including a common painful neuropathy. Because these and other, less common, central and peripheral nervous system complications of HIV can often be specifically treated or effectively palliated, their accurate and timely diagnosis is important.

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.

Differential receptive and expressive language functioning of children with symptomatic HIV disease and relation to CT scan brain abnormalities

OBJECTIVES

To investigate the effect of HIV disease on the receptive and expressive language of children and the relationship between CT scan brain abnormalities and language functioning.

METHODS

Thirty-six children (mean age, 5.5 years; range, 1 through 10 years; 75% vertical transmission; 58% classified as encephalopathic) with symptomatic HIV infection and 20 uninfected siblings (mean age, 7.8 years; range, 3 through 15 years) were administered an age-appropriate comprehensive language test assessing both receptive and expressive language (Reynell Developmental Language Scales or Clinical Evaluation of Language Fundamentals--Revised). Each HIV-infected child had a CT scan of the brain as part of the baseline evaluation, which was rated independently and blindly by two neurologists, for presence and severity of brain abnormalities using a semiquantitative rating system.

RESULTS

Expressive language was significantly more impaired than receptive language in the overall sample of HIV-infected children. The encephalopathic children scored significantly lower than the non-encephalopathic children, however, the degree of discrepancy between mean receptive and expressive language scores was not significantly different between these two groups. The uninfected sibling control group did not have a significant discrepancy between receptive and expressive language, and they scored significantly higher than the infected patient group. Greater severity of CT scan abnormalities was significantly correlated with poorer receptive and expressive language functioning in the overall HIV-infected sample and a higher discrepancy between receptive and expressive language in the encephalopathic group.

CONCLUSION

Pediatric HIV disease is associated with differential receptive and expressive language functioning in which expressive language is significantly more impaired than receptive language. The sibling data and CT scan correlations suggest that the observed language impairments are associated with the direct effects of HIV-related central nervous system disease.

Assessment of 'subcortical dementia' in patients with Huntington's disease, Parkinson's disease, multiple sclerosis and AIDS by a neuropsychological screening battery

Four diagnostic groups categorized as 'subcortical dementia' were studied using a neuropsychological screening battery. The specificity of the battery in disclosing characteristic patterns of impairment in subgroups within the category, and the correspondence between natural subgroups generated by an unsupervised statistical classification technique and the diagnostic labels were investigated. All cognitive affected subgroups demonstrated impairment on tests of sensomotor function, cognitive efficiency and/or memory, and were characterized in terms of severity of impairment as well as a progressive involvement of functional areas. The diagnostic groups were not evenly represented in all natural subgroups. Affected AIDS-patients seemed to resemble patients with Huntington's disease more than the other diagnostic groups. The screening battery could give a general characterization of the pattern of 'subcortical dementia' and different levels of impairment, but more specific process-oriented tasks are needed to contrast diagnostic groups within the concept of 'subcortical dementia'.

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.

Cerebral pathology in AIDS: a new nomenclature and pathogenetic concepts

Complementary to a clinical classification of human immunodeficiency virus (HIV)-associated nervous system syndromes, a neuropathology-based terminology defines entities at tissue level, including the new HIV-specific diseases, HIV encephalitis and HIV leukoencephalopathy. Poor clinico-neuropathological correlation may be explained by complex pathogenetic mechanisms in which several factors, including virus load, neurotoxicity, vascular changes, and metabolic abnormalities, may act together to damage both white and gray matter of the brain.

[Stage-independence and individual outcome of neuro-cognitive deficits in HIV. A follow-up study of 62 HIV-positive hemophilic patients]

62 of a series of 188 HIV-positive hemophiliacs, who had been neuropsychologically evaluated already in 1988 (T1), were re-examined 1 1/2 years later (T2). The aims of the study were to confirm the cross-sectional results of the 1988 study and to compare cross-sectional and longitudinal aspects of HIV infection and associated neurocognitive deficits. Patients were staged at T1 and T2 according to CDC classification criteria and retested using parallel tests of attention, verbal/nonverbal memory performance and depression. The following results were observed: (i) Data at T2 paralleled the findings from 1988, indicating increased deficits in attention and verbal learning and memory at an advanced stage of the disease. No association with the T4/T8 ratio was found. (ii) Between T1 and T2, 65% of the patients showed no change in stage, 27% changed one stage and only 8% showed a rapid progression through two stages. (iii) Only this latter group showed a significant cognitive deterioration over time. The remaining groups exhibited inconsistent performance changes which did not correlate with depression of changes of the T4/T8 ratio. Conclusively, the longitudinal data support the assumption of stage independent and individual different courses of the neurocognitive manifestations of HIV. A small minority of patients, however, manifested a rapid progression of the disease during the T1-T2 interval.

Ventricle brain ratio in the clinical course of HIV infection

As part of the computerized tomographic assessment of an unselected group of 47 patients in different stages of HIV infection we determined the ventricle brain ratio (VBR) and the width of several cortical sulci. We compared the findings for subgroups of patients defined by their stage in the Walter Reed Staging Classification. There was a significant increase in VBR only in the subgroup of patients with manifest acquired immune deficiency syndrome (AIDS) (WR 6). The findings are discussed in connection with the question of the likelihood that dementia will develop even in stages of HIV-infection preceding AIDS.

Effect of the revised AIDS case definition on AIDS reporting in San Francisco: evidence of increased reporting in intravenous drug users

To examine the effect of the revision of the US national AIDS case definition in September 1987, we compared demographic and clinical information for AIDS patients diagnosed and reported to the San Francisco Department of Public Health between 1 September 1987 and 31 October 1989. Of the 3167 patients diagnosed and reported during the study period, 584 (18%) met the revised case definition only, increasing AIDS case reporting in San Francisco by 23%. One hundred and thirty-four of these 584 patients (23%) subsequently developed diagnoses meeting the old definition. After adjusting for this proportion, the revised case definition increased reporting by 17%. The mean time between initial diagnosis with a disease meeting the revised definition and subsequent development of a disease meeting the old definition was 18.5 months. Patients who met the revised case definition only were slightly older and more likely to be Black, female, and intravenous drug users (IVDUs) than those meeting the old case definition. The majority of patients who met the revised case definition only had initial diagnoses of HIV wasting syndrome (26%), HIV encephalopathy (21%), and presumptive Pneumocystis carinii pneumonia (19%). The revised AIDS case definition has significantly increased the reporting of severe morbidity associated with HIV infection, particularly among IVDUs.