Speed of memory scanning is not affected in early HIV-1 infection

Cognitive functions in newly diagnosed patients with HIV infection in a tertiary health facility: Assessment using community screening interview for dementia

INTRODUCTION

Neurocognitive dysfunction is a detrimental complication of HIV infection. In this study we attempt to characterize the pattern of cognitive dysfunction in a sample of Nigerian patients with newly diagnosed HIV infection.

METHODS

We conducted a prospective study in which 50 patients with newly diagnosed HIV infection were studied along with 50 normal control subjects. The participants were evaluated with the medical history, general, physical and neurological examination. Laboratory evaluation and chest X-Ray were done for all patients. The Community Screening Interview for Dementia (CSID) questionnaire was administered to all the study participants.

RESULTS

About 70% of the patients were in advanced disease stage. The mean age (SD) of the patients and controls in years were 36.44 ± 8.22 and 35.40 ± 11.53 respectively. More than half (56%) of the patients had secondary level of education (12 years of education). About 20% of the patients had severe neurocognitive impairment while 48% had minor neurocognitive disorder. The patients with HIV infection performed poorly in the domains of language, memory, orientation, attention/calculation and praxis relative to controls (p < 0.05).There were no significant effect of gender, age, sex and level of education on cognitive functions in the patients (p > 0.05) but the presence of opportunistic infections had negative impact on the performances on orientation and total CSID scores in the patients with HIV infection (p < 0.05).

CONCLUSION

Patients with newly diagnosed HIV infection have poor cognitive functions when compared to normal controls and some presence of opportunistic infections in the patient is a significant risk factor for cognitive impairment.

Cognitive function in patients with newly diagnosed HIV infection in a tertiary health facility in south - west Nigeria: Assessment using computer-assisted neuropsychological test battery

INTRODUCTION

Cognitive dysfunction is common among patients with human immunodeficiency virus (HIV) infection however there are few reports from sub-Saharan Africa.

METHODS

We studied fifty seropositive patients with human immunodeficiency virus (HIV) infection along with fifty matched seronegative control. Medical history taking and general physical and neurological examinations were done for all study participants. Laboratory evaluations and chest X-ray were done for all the patients. The cognitive function was done with the aid of 'Fepsy' automated test battery for all the study participants. The data was analyzed with statistical package for social sciences software version 21.0 (SPSS Chicago IL).

RESULT

About 70% of the HIV patients were in advanced disease stage. The auditory and visual reaction times, binary choice reaction times, and computerized visual scanning task time were more prolonged in the HIV group (p < 0.05). There were also increased memory accuracy and binary choice task accuracy in the HIV group (p < 0.05). However the vigilance task performance was similar between the two groups (p > 0.05). Among the patients with HIV infection, the presence of anemia and central nervous system toxoplasmosis infection was associated with prolonged auditory and visual reaction times.

CONCLUSION

There was a high rate of cognitive dysfunction in patients with HIV infection in this study.

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.

Differential effect of alcoholism and HIV infection on visuomotor procedural learning and retention

BACKGROUND

Selective declarative memory processes are differentially compromised in chronic alcoholism (ALC) and HIV infection (HIV) and likely reflect neuropathology associated with each condition: frontocerebellar dysfunction in ALC and frontostriatal dysfunction in HIV infection. Evidence for disease overlap derives from observed exacerbated impairments in these declarative memory processes in ALC-HIV comorbidity. Less is known about nondeclarative memory processes in these disease conditions. Examination of visuomotor learning in chronic ALC and HIV infection could provide insight into the differential and combined contribution of selective disease-related injury to visuomotor procedural memory processes.

METHODS

We examined component processes of visuomotor learning and retention on the rotary pursuit task in 29 ALC, 23 HIV, 28 ALC + HIV, and 20 control subjects. Participants were given 4 rotary pursuit learning sessions over 2 testing days, typically separated by 1 week, to assess visuomotor learning and retention patterns. Ancillary measures of simple motor, psychomotor, explicit memory, and balance abilities were administered to test which component processes independently predicted visuomotor learning.

RESULTS

All clinical groups showed visuomotor learning across rotary pursuit testing sessions, despite impairment in visuomotor speed in the HIV groups and impairment in explicit memory and psychomotor speed in the alcohol groups. The 2 alcoholic groups showed retention and consolidation over time (i.e., improved performance without further training), whereas the HIV-infected group showed learning and retention but no consolidation effect. The comorbid group shared impairments associated with the ALC-only group (explicit memory and psychomotor speed) and the HIV-only group (visuomotor speed), although there was no clear compounded effect of alcohol and HIV infection on visuomotor learning performance.

CONCLUSIONS

This study supports the hypothesis that ALC and HIV infection exert differential effects on components of visuomotor procedural learning. Further, the results provide behavioral evidence for dissociable influences of frontocerebellar and frontostriatal disruption to visuomotor procedural learning and retention.

Neuropsychological consequences of HIV and substance abuse: a literature review and implications for treatment and future research

Neuropsychological dysfunction, ranging from mild cognitive symptoms to dementia has been a consistent part of the clinical picture of HIV/AIDS. However, advances in clinical management, particularly antiretroviral (ARV) treatment, have mitigated the neuropsychological effects of HIV and revised the pattern and nature of cognitive deficits, which are observed in HIV-infected individuals. The attendant improvements in mortality and morbidity have led to a need for programs and interventions that sustain healthy behavior and prevent a resurgence of HIV transmission risk. Psychiatric risk factors, particularly substance use, which often contribute to initial acquisition of HIV, still require attention. These risk factors may also exacerbate neuropsychological dysfunction and compromise adherence to prevention recommendations and treatment. Specifically, a more complete understanding of the effects of substance abuse on the progression of HIV related cognitive decline can inform evaluation and management of HIV seropositives with concurrent substance use disorders. This review provides an overview of the neuropsychology of HIV and substance abuse and the extant research that has examined the effects of both HIV disease and substance use on neuropsychological functioning and implications for treatment and future research.

A family history of psychopathology modifies the decrement in cognitive control among patients with HIV/AIDS

The present study was designed to evaluate the effect of HIV/AIDS on cognitive control and to determine if the effect is modified by familial risk for either alcohol or mood disorders. Sixty HIV-1 seropositive and 75 seronegative volunteers were assigned to four subgroups defined by the crossing of a diagnosis of alcohol dependence in the biological father with diagnoses of either major depressive disorder or bipolar disorder in the biological mother. Cognitive control was evaluated during a task in which subjects were asked, on occasion, to inhibit the impulse to respond in the same physical direction as the stimulus and instead respond in the opposite direction. Event related brain potentials and measures of task performance were recorded. The task evoked a negative shift in a late slow potential (SP) as well as an increment in reaction time when cognitive control was challenged. An important finding was an interaction between trial type, HIV/AIDS, and family history: HIV/AIDS and family history each attenuated the negative shift in the SP to such a degree that no further attenuation could be accomplished by the other. The effects of familial risk for alcohol versus mood disorders were equivalent. In conclusion, the absence of change in a late slow potential following a challenge to cognitive control may represent a marker of familial risk for both externalizing and internalizing disorders. The effects of familial risk on this slow potential are sufficiently robust as to attenuate the effects of HIV/AIDS on the probable generators of the response: the anterior cingulate and prefrontal cortex.

Reaction time slowing in adults with HIV: results of a meta-analysis using brinley plots

A meta-analysis in the form of Brinley plots was conducted on the mean reaction times of HIV+ and HIV- groups. HIV+ reaction times were regressed on HIV- reaction times across 122 task conditions from 29 studies, producing a highly linear function (r(2) = .94), with a slope b = 1.039, which was not significantly different than b = 1.00. Asymptomatic and symptomatic HIV+ reaction times were also separately regressed on HIV- reaction times across 67 task conditions from 13 studies. Both functions were highly linear (r(2) = .97 and.90 respectively), with slopes of 1.034 and 1.117 respectively. Only the slope for symptomatic HIV+ groups was significantly larger than b = 1.00, suggesting a modest generalized slowing of cognition in these adults.

Neurobehavioural consequences of substance abuse and HIV infection

Although our understanding of how human immunodeficiency virus (HIV)-related neurobehavioural deficits develop is nascent and preliminary, some clues have emerged which may clarify lingering uncertainties. In particular, HIV seems to yield brain dysfunction by mediating pathological changes upon neuronal function. HIV also compromises immunological integrity, thereby resulting in secondary infections that may further increase brain dysfunction. Notably, many individuals with HIV tend to be current or past abusers of drugs, and, in some cases, their drug use may have actually presented a pathway for initial HIV infection. Similar to HIV, many drugs tend to yield pathological changes upon neuronal function. Further paralleling HIV, some drugs seem to compromise immune function, which in turn may yield secondary detrimental effects upon the brain. Yet, despite the relatively high comorbidity rates of HIV infection and substance abuse, few investigations have addressed the potential interaction between these two factors upon neurobehavioural status. Towards this end, the present paper reviews the existing literature concerning neuropsychological effects of HIV and substance use, and suggests potential mechanisms whereby substance use may potentiate and exacerbate the onset and severity of neurobehavioural abnormalities in HIV infection.

Cognitive Effects of HIV-1 Infection

The major neurological complication of human immunodeficiency virus type 1 (HIV-1) infection is cognitive impairment, which can range in severity from a mild subclinical cognitive inefficiency to a severe dementing illness. Mild to moderate cognitive impairment is identified primarily by neuropsychological tests. The prevalence and severity of cognitive impairment associated with HIV-1 infection increases as the disease progresses. Deficits in attention, information processing speed, memory, and motor abilities can occur early in the course of HIV-1 infection, with deficits in abstraction and executive functions observed in later stages of infection. The nature of the cognitive impairment observed is thought to reflect the effects of HIV-1 infection on the integrity of subcortical or frontostriatal brain systems. Issues related to the detection of subclinical to severe cognitive impairment are discussed, along with the clinical significance of mild cognitive impairment as a significant risk factor for mortality in HIV-1 infection. The need to control for possible confounding factors that can influence test performance is also reviewed.

Decline in working memory associated with HIV infection. HNRC Group

HIV infection has been associated with decline in a number of cognitive functions that are components of 'working memory'. Thus, tests of working memory that require the interaction of these components may be particularly sensitive to cognitive dysfunction that arises from HIV infection. To assess this possibility, working memory was examined in 147 HIV-seropositive (HIV+) and 38 HIV-seronegative (HIV-) males using the Reading Span Test and the Digit Span subtest from the Wechsler Memory Scale-Revised (WMS-R). Speed of information processing, a component of some working memory tasks, was assessed with a version of the Sternberg Memory Scanning task. Results indicated that symptomatic HIV+ subjects were impaired relative to HIV- control subjects on the Reading Span and Digit Span tests. Asymptomatic and mildly symptomatic HIV+ groups exhibited a trend toward impairment on these tests, and on the whole, a greater proportion of HIV+ subjects than HIV- subjects were impaired. The groups did not differ significantly in information processing speed. These results indicate that deficits in working memory are apparent in at least a subset of HIV-infected individuals. These deficits are most apparent in symptomatic HIV+ individuals, but the decline may begin during the asymptomatic phase of infection.

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.

Methodological considerations in estimating speed of cognitive operations

Individuals infected with Human Immunodeficiency Virus (HIV) and having cognitive impairment have been described as having slow mentation. Data supporting this proposition come from a variety of sources, including Sternberg's (1966) item recognition memory task. The procedure nominally provides an index of speed of mental operations, independent from input/output demands. However, since the original use of this procedure in the 1960s, advances in cognitive psychology have revealed many of its limitations. The purpose of the present study was to examine the psychometric characteristics of this task. Each participant performed the Sternberg item recognition task twice, 6 mo apart. The stability of the estimate of the slope of regression equations and for zero intercept ranged from excellent (r = .87) to poor (r = .30), and the data from many individual subjects could not be reliably modelled using multiple linear regression techniques. These data, as well as those from previous research, demonstrate the limited practical use of this task in clinical samples. Furthermore, as cognitive psychological theory has advanced in the past 30 yr, the conceptual underpinnings of the procedure have essentially evaporated.