Electroencephalography in AIDS and AIDS-related complex

Cortical sources of resting state electroencephalographic rhythms probe brain function in naïve HIV individuals

OBJECTIVE

Here we evaluated the hypothesis that resting state electroencephalographic (EEG) cortical sources correlated with cognitive functions and discriminated asymptomatic treatment-naïve HIV subjects (no AIDS).

METHODS

EEG, clinical, and neuropsychological data were collected in 103 treatment-naïve HIV subjects (88 males; mean age 39.8 years ± 1.1 standard error of the mean, SE). An age-matched group of 70 cognitively normal and HIV-negative (Healthy; 56 males; 39.0 years ± 2.0 SE) subjects, selected from a local university archive, was used for control purposes. LORETA freeware was used for EEG source estimation in fronto-central, temporal, and parieto-occipital regions of interest.

RESULTS

Widespread sources of delta (<4 Hz) and alpha (8-12 Hz) rhythms were abnormal in the treatment-naïve HIV group. Fronto-central delta source activity showed a slight but significant (p < 0.05, corrected) negative correlation with verbal and semantic test scores. So did parieto-occipital delta/alpha source ratio with memory and composite cognitive scores. These sources allowed a moderate classification accuracy between HIV and control individuals (area under the ROC curves of 70-75%).

CONCLUSIONS

Regional EEG abnormalities in quiet wakefulness characterized treatment-naïve HIV subjects at the individual level.

SIGNIFICANCE

This EEG approach may contribute to the management of treatment-naïve HIV subjects at risk of cognitive deficits.

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.

Epilepsia Partialis Continua as Presenting Manifestation of AIDS: A Rarity

Seizures, most commonly generalized tonic-clonic, are common in known human immune deficiency virus (HIV) sero-positive patients, and they usually have a focal lesion on brain imaging. However, it is very unusual to see a patient with no premorbid illness presenting with epilepsia partialis continua (EPC) and then being detected HIV seropositive with an Acquired Immune Deficiency Syndrome (AIDS)-defining illness. We report the case of a teenaged boy with no past significant history or known high-risk behavior who presented with recurrent focal seizures of 5 days' duration, EPC, and encephalopathy. His electroencephalogram showed periodic lateralized epileptiform discharges (PLEDS), and magnetic resonance imaging (MRI) of the brain showed abnormal signal changes in the right parieto-occipital cortex and thalamus, both as yet unreported in cytomegalovirus (CMV) encephalitis, which was diagnosed by the cerebrospinal fluid (CSF) analysis.

Host response and dysfunction in the CNS during chronic simian immunodeficiency virus infection

CNS abnormalities can be detected during chronic human immunodeficiency virus (HIV) infection, before the development of opportunistic infections or other sequelae of immunodeficiency. However, although end-stage dementia caused by HIV has been linked to the presence of infected and activated macrophages and microglia in the brain, the nature of the changes resulting in the motor and cognitive disorders in the chronic stage is unknown. Using simian immunodeficiency virus-infected rhesus monkeys, we sought the molecular basis for CNS dysfunction. In the chronic stable stage, nearly 2 years after infection, all animals had verified CNS functional abnormalities. Both virus and infiltrating lymphocytes (CD8+ T-cells) were found in the brain. Molecular analysis revealed that the expression of several immune response genes was increased, including CCL5, which has pleiotropic effects on neurons as well as immune cells. CCL5 was significantly upregulated throughout the course of infection, and in the chronic phase was present in the infiltrating lymphocytes. We have identified an altered state of the CNS at an important stage of the viral-host interaction, likely arising to protect against the virus but in the long term leading to damaging processes.

Electroencephalogram in the dementia workup

Dementia is affecting an increasing proportion of the population in the developed world. It is important to reach a correct diagnosis of dementia, because this has implications on the treatment. The electroencephalogram (EEG) is, in general, not a sensitive test for detecting dementia and is not recommended in the standard workup of dementia. In spite of this, however, EEG is useful in patients with deteriorating mental status in whom dementia is suspected mainly to rule out delirium, depression, atypical complex partial seizures, and prion disease. An EEG also provides insight into the physiology of different dementia types. The EEG is most useful when interpreted within a well-defined clinical context, such as knowing the patient's degree of cognitive impairment. It is a noninvasive and inexpensive test, and the threshold should be low for ordering it. This article summarizes EEG findings with aging, different dementia types, and conditions masked as dementia.

Insomnia in HIV infection: a systematic review of prevalence, correlates, and management

OBJECTIVE

Insomnia in people with HIV and AIDS has been widely but inconsistently reported. We present the results of a systematic review of the subject.

METHODS

MEDLINE, EMBASE, PSYCHLIT, and CINAHL databases were searched, and inclusion criteria were applied. The study results were then collated and described.

RESULTS

Twenty-nine studies were identified, and there was wide variation in both method and quality. Insomnia was reported frequently and at all stages of HIV infection. Early reports of sleep-specific electroencephalographic changes were not confirmed. The role of immune dysregulation, virus progression, and adverse drug effects in contributing to insomnia is unclear. The presence of cognitive impairment, an AIDS-defining illness, and treatment with efavirenz were found to be significant risk factors, but the most notable association was with psychologic morbidity. There was limited evidence for the effect of specific treatments for insomnia in HIV infection.

CONCLUSIONS

This review found that psychologic morbidity was a major determinant of insomnia in HIV infection. Further study would be of value in clarifying the role of other factors, as well as measuring the impact of insomnia on functioning and quality of life in this population.

Asymptomatic HIV-infected women: preliminary study of quantitative EEG activity and performance on a continuous performance test

Several studies have examined the electrophysiological correlates of human immunodeficiency virus (HIV) infection in medically asymptomatic men. Although the rates of HIV infection are increasing at a greater rate in women than men, there have been no publications to date of electrophysiological functioning in HIV-infected women. In the present study, quantitative electroencephalographic (qEEG) activity was measured in 22 women (11 asymptomatic HIV-seropositive and 11 HIV-seronegative) utilizing a procedure comprised of three auditory continuous performance tests and a set of qEEG components derived from principal components analysis. No significant group differences were found in qEEG or in performance on the continuous performance tests; however, task-related differences were detected across groups between simple and complex language tasks in EEG fast beta power, delta power, and a left-hemisphere principal components analysis-derived EEG component. In examining the electrophysiological correlates of HIV infection, researchers might employ a similar methodology while increasing the sample size and varying the task modality or difficulty.

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.

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.

Magnetic resonance spectroscopy in childhood AIDS encephalopathy

Twenty-five children with acquired immunodeficiency syndrome (AIDS) underwent cranial magnetic resonance imaging and proton magnetic resonance spectroscopy. Patients were divided into 2 groups based on clinical parameters: encephalopathy and nonencephalopathy. N-acetyl aspartate/creatine ratios were compared between the 2 groups and to control data. Spectra were obtained for 2 volumes of interest: the basal ganglia region and the white matter. The mean basal ganglia region ratio for the AIDS encephalopathy patients (n = 8) was 1.12 and the ratio for the AIDS nonencephalopathy patients (n = 17) was 1.48. The ratio for the 9 controls was 1.57. The encephalopathy group had a significantly lower ratio than both the control (P < .001) and the AIDS nonencephalopathy group (P < .002). The mean white matter ratio for the encephalopathy group (n = 8) was 1.47 and for the AIDS nonencephalopathy group (n = 13) was 1.82 with a control (n = 6) ratio of 1.82. The encephalopathy patients had a lower white matter ratio than the nonencephalopathy (P < .05) patients but the ratio was not different than controls (P < .11). It is concluded that N-acetyl aspartate/creatine ratios are reduced in childhood AIDS encephalopathy and proton magnetic resonance spectroscopy may be helpful in defining brain human immunodeficiency virus-1 infection. However, further longitudinal studies are necessary to determine the sensitivity and specificity of this technique.

QEEG in hemophiliacs with HIV infection

Conventional visual analysis of the EEG was performed on 320 hemophiliacs infected with HIV, who spanned the range of the Walter Reed (WR) system for classifying clinical stage of HIV infection, and on 50 HIV seronegative hemophiliac controls. Intermittent or paroxysmal slowing was the conventional EEG abnormality most commonly seen in early stages of HIV infection (stages WR1 and 2), with increased focal epileptiform activity and generalized slowing appearing in patients with the full clinical syndrome of AIDS (WR6). Slowing of the manually measured alpha rhythm was noted in stages WR2 and above. Quantitative EEG (qEEG) was obtained in a subset of 103 male HIV seropositive male hemophiliacs and 35 male HIV seronegative hemophiliac controls. The principal findings were a progressive relative increase in theta power with a tendency towards an anterior topographic distribution, and a progressive decline of spectral power in fast alpha relative to slow alpha with increasing severity of HIV disease. Significant qEEG differences from controls were apparent in WR2 subjects (seropositive with lymphadenopathy and without other constitutional symptoms), and were relatively greater in WR3-6 subjects. These results suggest sensitivity of qEEG to early CNS involvement with HIV infection.

Parasitic diseases and psychiatric illness

Distinguishing parasitic diseases from other infections and tropical medical disorders based on microbiological classification is a matter of convenience. Organic brain syndromes are associated with both protozoan and helminthic infections; side-effects of drugs commonly used to treat parasitoses may impair mood and cause anxiety, agitation or psychosis. Emotional states may in turn affect the experience of medical illness. Psychiatrically significant features of medical illness are determined both by pathophysiology and by the personal and social context in which they occur. Many factors affect mental health in the tropics where the synergy of infection, emotional strengths, vulnerabilities, social supports and stressors is critical. This review discusses parasitic diseases of psychiatric interest by virtue of their effects on thinking, mood and behaviour; and it distinguishes issues that apply mainly to indigenous populations and visitors to endemic areas. In some paradoxical instances the psychiatric influence of parasitic diseases does not require infection; the review concludes by considering the prime example, delusions of parasitosis, which is a primary psychiatric disorder.

EEG diagnostic and predictive value on HIV infection in childhood

This prospective study evaluated the electroencephalographic (EEG) diagnostic and prognostic value in childhood HIV infection. It was carried out on 125 subjects and included all Piemonte's seropositive children. The EEG was repeated every three months during the first 15 months of life, and then, at least, annually in the P1 and P2 group. Data of group P2 was compared blindly to that of the seroconverted control group of the same age and risk. EEG results were normal in P0, P1 and control patients. In group P2, EEG was abnormal in 35.5% of subjects, of these 54.6% developed an encephalopathy with a delay of 2.5 months to 2 years 11 months. EEG is therefore useful to evaluate early CNS damage and to identify onset features and evolution of encephalopathy in P2 patients.

Electroencephalography

Notwithstanding recent advances in neuroimaging, EEG remains a major technique for investigation of the brain. Its main applications are in assessment of cerebral function rather than for detecting structural abnormalities. The principal clinical applications are in epilepsy, states of altered consciousness including postanoxic and traumatic coma, the parasomnias, dementias, toxic confusional states, cerebral infections, and various other encephalopathies. Abnormalities in EEG reflect general pathophysiological processes, raised intracranial pressure, cerebral anoxia, or oedema, epileptogenesis etc, and show little specificity for a particular disease. Consequently, they need to be interpreted in a particular clinical context; the use of routine EEG examination for screening purposes is rarely of value. Conversely, the investigation becomes most cost effective when applied to specific problems--for instance, monitoring serial changes in postanoxic coma or during open heart surgery, differential diagnosis (by telemetric ictal recordings) of epileptic and non-epileptic attacks, and providing early prediction of outcome after stroke. High technological standards and an individualised problem solving approach are prerequisites of a cost effective, reliable clinical EEG service. These are most likely to be achieved by a considered, selective referral policy, the use where necessary of prolonged complex procedures such as telemetry, and the avoidance of routine examinations of dubious clinical relevance.

Electroencephalographic coherence in acquired immune deficiency syndrome

We studied a quantitative electroencephalographic (EEG) measure, coherence, in 28 patients with acquired immune deficiency syndrome (AIDS) and 56 uninfected volunteers. Compared with uninfected subjects, AIDS patients had increased coherence in the 6- to 10-Hz band. The largest increases in coherence were between frontal and occipital regions and between temporal and frontal regions. Coherence within contiguous regions was less affected. Eight of the 28 AIDS patients (29%) had clinically abnormal EEG findings, compared with four of the 56 uninfected control subjects (7%). Among the AIDS patients, 12 had normal neuropsychological performance, nine had mild impairment, and six had moderate impairment. Coherence was increased in each subgroup of AIDS patients, including those with normal neuropsychologic performance and/or normal clinical EEG results. AIDS patients were then classified by quantitative EEG power in frontal head regions as "abnormal" (the upper third of patients) or "normal" (the remainder). Increased coherence was found among both groups. Because the development of abnormal neuropsychological performance or a clinically abnormal EEG examination indicates relatively advanced central nervous system disease, alterations in specific coherence measures may detect subclinical effects of the human immunodeficiency virus on brain function before other changes are evident.

EEG and dementia indicators in AIDS patients' Rorschach test

We studied the EEG and Rorschach test (RT) of nineteen AIDS patients and eight normal people in the same age group. Eight patients presented slow alpha rhythms (8 to 9 Hz); three, not-slow alpha rhythms (> 9 to 13 Hz); and eight, beta rhythms in background activity. Paroxystic activity, characterized by diffuse theta or delta waves, was present in eleven patients. We observed Oberholzer syndrome (organic dementia diagnosed by RT) in ten patients and Piotrowski syndrome (organic dementia diagnosed by RT) in eleven patients; six presented both. When considering only the group of AIDS patients, we did not observe a significant relation among slow alpha rhythm, not-slow alpha rhythm and the presence of paroxystic activity with the above-mentioned syndromes. AIDS patients with slow alpha rhythms showed a significantly greater number of Piotrowski syndrome dementia indicators when compared to normal individuals or those with slow alpha rhythms. We did not observe the same with Oberholzer syndrome.

Reversible myoclonic encephalopathy revealing the AIDS-dementia complex

A 40-year-old HIV-positive right handed homosexual man was admitted for progressive mental deterioration coexisting with permanent segmental middle-amplitude arrhythmic, asynchronous and asymmetrical myoclonic jerks. EEG showed fronto-central bursts of rhythmic triphasic 1.5-2 Hz sharp waves similar to the characteristic periodic pattern of Jakob-Creutzfeldt disease. Biological procedures were negative, thus eliminating a metabolic encephalopathy. Dramatic neurological improvement occurred shortly after initiation of i.v. and then oral zidovudine which produced perfect EEG normalisation. This unusual electroclinical presentation of the AIDS-dementia complex underlines the fact that this affection may present a diagnostic challenge, particularly in individuals in whom HIV infection is unknown.

Quantitative EEG in patients with AIDS and asymptomatic HIV infection

Although neuropsychiatric abnormalities are common in subjects with the acquired immunodeficiency syndrome (AIDS), they are less frequent in asymptomatic human immunodeficiency virus (HIV) seropositive subjects. In contrast, others have reported high rates of electroencephalographic (EEG) abnormality among asymptomatic subjects. Here we report clinical and quantitative EEG findings across all stages of the disease in order to define when during the course of illness abnormalities are detectable. We studied 28 men with AIDS, 32 men with asymptomatic HIV infection, and 56 uninfected controls using clinical and quantitative EEG, measures of immunosuppression, and tests of neuropsychological performance. All were gay or bisexual without other significant risk factors for encephalopathy. We found very low rates of clinical EEG abnormality (less than 7%) among the asymptomatic HIV-infected group, a rate comparable to those of the uninfected group (7.1%). There were no differences between asymptomatic HIV-seropositive subjects and uninfected controls on quantitative EEG measures. Among AIDS patients 28.6% had abnormal clinical electroencephalograms. On quantitative measures, the greatest differences were found in the 6-10 Hz band, where AIDS patients had consistently increased absolute power, relative power, and coherence compared to the uninfected and asymptomatic seropositive groups. A subgroup (n = 9) of asymptomatic HIV-seropositive subjects had worsening performance on Trailmaking test, part B, at or after the time of recording. This subgroup had quantitative electroencephalographic measures similar to those of the AIDS patients and different from the remainder of the asymptomatic HIV-seropositive group.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Human immunodeficiency virus type 1 infection of the brain

Direct infection of the central nervous system by human immunodeficiency virus type 1 (HIV-1), the causative agent of AIDS, was not appreciated in the early years of the AIDS epidemic. Neurological complications associated with AIDS were largely attributed to opportunistic infections that arose as a result of the immunocompromised state of the patient and to depression. In 1985, several groups succeeded in isolating HIV-1 directly from brain tissue. Also that year, the viral genome was completely sequenced, and HIV-1 was found to belong to a neurotropic subfamily of retrovirus known as the Lentivirinae. These findings clearly indicated that direct HIV-1 infection of the central nervous system played a role in the development of AIDS-related neurological disease. This review summarizes the clinical manifestations of HIV-1 infection of the central nervous system and the related neuropathology, the tropism of HIV-1 for specific cell types both within and outside of the nervous system, the possible mechanisms by which HIV-1 damages the nervous system, and the current strategies for diagnosis and treatment of HIV-1-associated neuropathology.

Low amplitude EEGs in demented AIDS patients

We have observed an unusual low amplitude, slow and featureless electroencephalogram (EEG) pattern in some human immunodeficiency virus (HIV) infected patients without focal lesions on computerized tomography (CT scan) of the head. Out of 17 cases, 13 with AIDS and 4 with HIV positive status, 6 had low amplitude EEGs with slowing, all in the AIDS group. Nine of the 13 AIDS patients were demented, and 4 of these demented patients had slow verbal responses and mutism, indicating advanced HIV-related dementia. All 4 had low amplitude, slow EEGs. The patients with low amplitude, slow EEGs also had atrophy on CT scan by visual assessment and by measurement of ventricular indices. Of 17 age-matched controls referred for non-specific complaints such as headache and dizziness or for psychiatric disorders, 3 had EEGs read as low amplitude with slowing; two had normal mental status and one was psychotic. Although this EEG pattern is not etiologically specific, it may correlate with advanced dementia and atrophy on CT scan in AIDS patients.

Electroencephalogram base rhythm in AIDS patients

We studied the EEG of 73 patients diagnosed with HIV infection, with or without secondary complications. Sixty-eight belonged to CDC (Center for Disease Control) group IV and 38 presented signs or symptoms of encephalic neurological impairment. Rhythms constituting base activity were alpha (65.75%), beta (13.70%), theta (12.33%), and delta (8.22%). The alpha rhythm presented two modes: slow (8 to 9 Hz) in 25/48 or 52.08% of the cases and not-slow (> 9 to 13 Hz) in 23/48 or 47.92% of the cases. The alpha slow-mode has been observed in about 10 to 15% of the normal population, with the 8 Hz frequency being found in only 1% of the normal adult population, which suggests that in some manner HIV is implicated in the slowing-down of the EEG base rhythm in AIDS patients. The patients from CDC group IV with encephalic neurological involvement presented a base rhythm significantly lower than those with non-encephalic involvement or the absence of neurological impairment.

Longitudinal study of EEG and evoked potentials in neurologically asymptomatic HIV infected subjects

Serial electroencephalograms (EEGs) and multimodality evoked potentials (EPs) were performed along with neurological and neuropsychological evaluation, cerebrospinal fluid assessment and magnetic resonance imaging at 6 month intervals in 73 neurologically asymptomatic HIV infected subjects. The results were compared with 50 age- and sex-matched controls. EEG was abnormal in 2 subjects (3%) initially and was abnormal in 7 (9%) subjects by the last examination. EEG abnormality (diffuse slowing) correlated significantly with slowed reaction time in neuropsychological testing (P < 0.05). VEP and BAEP provided low yields of 1.3% and 4% respectively. SEP was abnormal in 7 (9%) of the subjects initially and in 10 (13%) subjects by the last testing, with 80% of the abnormalities seen on the posterior tibial study. In 3 subjects, initial SEP abnormalities predicted later development of myelopathy and peripheral neuropathy. Event-related auditory evoked potentials were performed in 39 subjects. They were abnormal in 5 subjects initially (12%) and in 6 subjects (15%) by the last examination and more commonly in advanced stages of the illness with lower T4 counts. This data shows the evolution and association of electrophysiological abnormalities in early HIV infection and suggests a predictive value for SEP in HIV infected asymptomatic individuals.

[EEG in HIV infection]

Since 1985, early changes in the EES have been demonstrated in the course of HIV infection. This method can be considered one of the accurate tests for the assessment of evolution of the disease. Abnormal anterior changes are present in about 30% of HIV+subjects with at least stage II disease. EEG abnormalities during the disease form a spectrum ranging from minor changes to slow diffuse activity, usually found in cortical lesions. These are associated in some cases with a periodic or pseudo-periodic activity as often found in white matter lesions.

EEG and evoked potentials in HIV-infected children

Forty-seven HIV-seropositive children were investigated by EEG and evoked potentials (BAEP, SEP). Twenty-three children were symptomatic (P2), 8 seropositive without symptoms (P1), and 16 children were less than 15 months of age (P0). Some of them were investigated at different stages of HIV infection. During the neonatal period, 7 newborns of drug-addicted mothers had seizures and frequent spikes and sharp waves in their EEGs. Among (P2) children 6/23 showed background slowing and 1 had rhythmic theta activity (6 with and 1 without neurological symptoms). In BAEP, bilateral prolonged interpeak latencies (IPL) were found in 1 child with severe AIDS encephalopathy. Side differences greater than or equal to 0.4 ms in IPL were seen in 2 (P2), 1 without and 1 with neurological symptoms. A late onset was seen in 2 (P1) and 4 (P2) children. Median SEPs were normal in 24/26 patients; N20/N13 amplitude ratio was reduced in 2 (P1) patients. EEG and BAEP revealed nonspecific abnormal features in HIV encephalopathy. The the progression of the disease. However, also in the symptomatic group, normal results of EEG and BAEP dominated. SEP in the symptomatic group revealed only normal values. For monitoring the effectiveness of AZT treatment in HIV encephalopathy, EEG seems to be a relevant investigation; for evoked potentials more data and experience are needed.

EEG in early HIV-1 infection is characterized by anterior dysrhythmicity of low maximal amplitude

We analyzed the EEGs of 67 HIV-1-infected patients at various stages of the disease and of 35 HIV-1-seronegative controls. The most common EEG abnormality in HIV-1 infection was an increased amount of generalized episodic or persistent, predominantly anterior slow activity, associated with a low level of maximal amplitude. When compared to the controls, a lower maximal amplitude of dominant background activity (p less than 0.001), and more marked generalized (p less than 0.01) and anterior (p less than 0.001) disturbances were already seen in early stages of HIV-1 infection. EEG abnormalities were more severe in patients with advanced HIV-1 infection than in those at early infection (p less than 0.001 to p less than 0.05). The presence of a more marked, posteriorly (p less than 0.01) accentuated, generalized slow activity (p = 0.02) was found more often in patients with T-helper cell counts lower than 0.4 x 10(9) (p = 0.05) than in those with higher numbers of T-helper cells. No clear associations were found between the severity of EEG abnormalities and the duration of HIV-1 infection. Our results suggest that EEG is a sensitive method in detecting subclinical functional cerebral disturbances caused by HIV-1.

Nocturnal sleep EEG in patients with HIV infection

Nocturnal sleep was studied in 14 human immunodeficiency virus (HIV)-positive patients without opportunistic infections of the central nervous system. Seven patients had no bodily complaints at the time of the investigation. Patients exhibited an impaired nocturnal sleep with longer sleep onset latency, reduced total sleep time, reduced sleep efficiency, and more time spent awake and in stage 1. Stage 2 sleep was significantly decreased; in 2 cases, sleep spindle density was extremely low. REM latency was reduced and correlated negatively with depressive symptomatology, while the percentages of REM and slow wave sleep were normal. No significant differences in sleep parameters were present among patients in different stages of the illness, or between patients with and without bodily complaints. Ventricular size and sulcal width on computed tomography scans correlated with sleep variables indicating reduced sleep quality, and with REM density. Decreased tryptophan plasma levels were associated with shorter and less efficient sleep, and with reduced stage 2 sleep. The findings demonstrate that sleep EEG investigations can be valuable for detecting and monitoring central nervous system affection in HIV-positive individuals.

HIV-related encephalitis presenting as convulsant disease

Because of the growing incidence of neurological disorders in HIV-infected patients, an early detection of the disease seems to be of paramount importance, especially in asymptomatic subjects. By using electroencephalography coupled with computerized spectral analysis and "mapping" (EEG-CSA), paroxysmal sharp activity was detected in 26 patients belonging to different stages of HIV infection. Seven of them (27%) were also symptomatic, (table; see text) showing signs of convulsant disease. The presence of focal or generalized paroxysmal activity, often associated with seizures, might suggest an early localization of HIV in cortical structures.

A controlled study of early neurologic abnormalities in men with asymptomatic human immunodeficiency virus infection

BACKGROUND

Although neurologic complications are frequent in the acquired immunodeficiency syndrome, their incidence and progression in early human immunodeficiency virus (HIV) infection remain controversial. The goal of this study was to assess neurologic manifestations in asymptomatic carriers of HIV.

METHODS

We studied 29 HIV-seropositive homosexual men and 33 seronegative homosexual controls by means of neurologic and neuropsychological examinations, magnetic resonance imaging (MRI), and electrophysiologic tests (electroencephalography, multimodal evoked-potential tests, and otoneurologic tests). After six to nine months, the tests were repeated in 27 seropositive men and 30 controls. The investigators were blind to the serologic status of the subjects.

RESULTS

The seropositive subjects had a mean CD4+ lymphocyte count of 635 X 10(6) per liter. Neurologic and neuropsychological examination, MRI, and measurements of pattern visual evoked potentials did not show significant differences between the two groups. The latencies of the median-nerve somatosensory evoked potentials were slightly prolonged in the seropositive men. The initial electroencephalogram was judged abnormal in 8 of 27 of the seropositive subjects (30 percent) as compared with none of the controls, with a slowing of fundamental activity, anterior spread [corrected] of alpha rhythm, subnormal reactivity, and unusual anterior theta activities. These findings were confirmed by computerized spectral analysis. The second electroencephalogram was abnormal in 10 of 25 of the seropositive men (40 percent). The otoneurologic evaluation identified abnormalities in the central auditory or vestibulo-ocular pathways in 34 percent of the seropositive men (10 of 29), as compared with 6 percent of the controls (2 of 33), on the first examination and in 44 percent (12 of 27) and 7 percent (2 of 30), respectively, on the second examination. Altogether, electrophysiologic abnormalities were found in 67 percent of the seropositive men (18 of 27) and 10 percent of the controls (3 of 30) (P less than 0.00005).

CONCLUSIONS

In persons with asymptomatic HIV infection, electrophysiologic tests may be the most sensitive indicators of subclinical neurologic impairment. Electrophysiologic abnormalities are far more common in asymptomatic carriers of HIV than in controls and tend to progress over time.

Computer-analyzed EEG (CEEG) and dynamic brain mapping in AIDS and HIV related syndrome: a pilot study

In a group of HIV positive young male patients without any significant neuropsychiatric signs, computer-analyzed EEG (CEEG) and Dynamic Brain Mapping evaluations were conducted. These patients, who only had micro-neuropsychiatric symptoms, demonstrated CEEG profiles that more closely resemble those of patients diagnosed as suffering from mild dementia than age-related normals from our CEEG data base. The CEEGs of patients diagnosed as having Acquired Immune Deficiency Syndrome (AIDS), compared to patients with HIV positive, showed greater similarity in CEEG patterns to severely demented patients than to normal control groups. The findings of this pilot study suggest that CEEG may be useful for early determination of the Central Nervous System's (CNS) involvement with the AIDS virus and monitoring the progress of the illness.

Electroencephalogram and HIV infection: a prospective study in 100 patients

In order to study the correlation between central nervous system (CNS) involvement and EEG abnormalities in HIV infection we studied 100 consecutive HIV patients. Patients were divided into 4 groups; Group I: 42 neurologically asymptomatic subjects; Group II: 6 patients with peripheral neuropathies; Group III: 28 patients with AIDS Dementia Complex; Group IV: 24 patients with secondary CNS involvement. The results of this study emphasize that abnormal EEGs are correlated with CNS involvement. Neurologically asymptomatic patients showed no abnormal tracings, but the presence of borderline EEGs (33%) in asymptomatic patients should be evaluated prospectively.

Multimodal evoked potentials in HIV infected patients

We studied 126 HIV seropositive patients (106 men, 20 women; mean age: 32 years): 45 had neurological signs, 81 had none. Multimodal evoked potential (MEP) assessment included: visual EPs by flash and reversal checkerboard; brain-stem auditory EPs; somatosensory EPs by stimulation of the median nerve. Evaluation also included: electroencephalography, electromyography with measurement of conduction velocities, neuroimaging (CT scan and MRI). We found abnormal MEPs for all modalities. The prevalence of abnormal results was high in neurologically symptomatic patients; in non-neurological subjects, the changes were more dramatic as HIV infection progressed. Whatever the stage of the disease, the modalities were equally affected. MEPs were abnormal in 54.7% of patients: in 41.8% of those without neurological signs vs. 85.7% of those with these signs. Comparison of MEPs and other electrophysiological procedures and neuroimaging techniques showed the high sensitivity of MEPs at all stages of the disease. EMG was sensitive and complementary to MEPs. EEG and neuroimaging showed abnormalities principally at the neurological symptomatic stage. Our results agree with those found in the literature. Abnormal MEPs may: (1) indicate latent neurological involvement of the visual, auditory and somatosensory pathways, (2) help diagnose an encephalitis suspected on neuropsychological, non-quantifiable testing.

Electroencephalography in the early diagnosis of HIV-related subacute encephalitis: analysis of 185 patients

Of subjects with asymptomatic HIV infection or Lymphoadenopathy Syndrome, 185 were studied by means of electroencephalography coupled with computerized spectral analysis and mapping (EEG-CSA). Abnormal EEGs were found in 30 of 118 (25.4%) patients with asymptomatic infection (CDC Group II) and in 20 of 67 (29.9%) patients with Lymphoadenopathy Syndrome (CDC Group III). The most common EEG abnormalities were represented by theta slowing on the frontal and fronto-temporal lobes and, in some cases, by delta slowing and paroxysmal sharp activity on the forebrain. Among 50 patients with abnormal EEGs, 16 showed some abnormalities on neuropsychological testing, whereas mild signs of cerebral atrophy were evident on CT scan in only 12 patients. These findings suggest that EEG-CSA could be a useful and sensitive method in the early detection and monitoring of HIV-related subacute encephalitis.