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The aim of this study was to assess the prevalence pattern of mixed-Plasmodium falciparum malaria infections in Brazil by molecular diagnosis and to address its clinically important features. DNA was extracted from 115 thick blood film P. falciparum human blood positive samples using the phenol-chloroform method, followed by a semi-nested PCR protocol with species-specific primers. Seventy-three percent of P. falciparum single infections and 26.95% of mixed infections were found. Amongst mixed infections, the majority was double infection (96.77%). Our results suggest that the prevalence of one species over the other can be important on weakening P. falciparum malaria clinical symptoms. We confirm that P. falciparum co-infections frequently occur in Brazilian malaria endemic areas, with underestimated diagnosis. The results point to the need of improving microscopy or changing for another accurate diagnosis technique to differentiate among human malaria species, as this is essential to choose the best treatment and control measure for malaria. More investigations are necessary in order to clarify the role of mixed-infections in the severity of P. falciparum disease.

Optimal adherence to antiretroviral medications is critical to the effective long-term management of HIV infection. Although prospective memory (ProM; i.e., "remembering to remember") has long been theorized to play an important role in medication adherence, no prior studies have evaluated whether HIV-associated ProM impairment possesses unique predictive value in this regard. Results from this study demonstrate a robust association between ProM impairment and self-reported medication management in 87 HIV-infected persons currently prescribed antiretroviral medications. Specifically, more frequent ProM complaints and performance deficits on both laboratory and semi-naturalistic ProM tasks were all independently related to poorer self-reported medication management. A series of hierarchical regression analyses revealed that HIV-associated ProM impairment accounted for a significant amount of variance in self-reported medication management beyond that which was explained by other factors known to predict nonadherence, including mood disorders, psychosocial variables, environmental structure, and deficits on a traditional battery of neuropsychological tests. Overall, these findings support the hypothesis that ProM captures a unique and largely untapped aspect of cognition that is germane to optimal medication adherence. The potential benefits of individualized remediation strategies that are informed by conceptual models of ProM and specifically target medication adherence warrant further exploration.

HIV infection is associated with impairments in prospective memory (ProM), an aspect of episodic memory that refers to the ability to execute a future intention, such as remembering to take a medication at a specific time. The current study sought to examine the relationship between HIV-associated ProM impairment and the successful management of instrumental activities of daily living (IADLs). In a cohort of 66 HIV-infected individuals, ProM accounted for a significant proportion of variance in self-reported IADL dependence, over and above that which was explained by retrospective memory and by current affective distress. Analysis of component cognitive processes revealed that the relationship between HIV-associated ProM deficits and IADL dependence was driven by impaired cue detection and by deficits in self-initiated intention retrieval. Results were not better explained by demographic factors, HIV disease severity, psychiatric comorbidity, or substance use. Collectively, these data support the potential incremental ecological validity of ProM as a predictor of dependence in IADLs among persons living with HIV infection.

The abuse of methamphetamine (MA) has increased in the United States over the past 15 years and is associated with considerable negative social, psychological, and health effects, including symptoms of depression. Infection with the hepatitis C virus (HCV), which is independently associated with increased risk of depression, is common among MA users, possibly due to high rates of transmission risk behaviors in this cohort (eg, injection drug use). Given the prevalence of depression among HCV-infected individuals and MA users separately, the current study aimed to determine whether HCV infection and MA dependence are associated with additive effects on depression. Focused psychiatric evaluations were conducted on 39 individuals with both MA dependence and HCV infection (MA + HCV +), 57 persons with only MA dependence (MA + HCV -), and a comparison sample of 46 participants with neither risk factor (MA - HCV -). Consistent with prior research, greater self-reported symptoms of depression were observed in the MA + groups relative to MA - HCV - participants; however, there was no evidence to suggest an additive effect of HCV infection. Surprisingly, the prevalence of current and lifetime diagnoses of Major Depressive Disorder (MDD) did not differ across the study groups. Results from this study suggest that HCV infection does not confer an additive effect on the severity of depressive symptoms or the prevalence of major depression in persons with MA dependence.

Failures of episodic retrospective memory (RetM) are among the most frequently reported cognitive complaints endorsed by individuals living with HIV infection. The present study sought to examine the nature, frequency, and determinants of self-reported complaints of prospective memory (ProM) in HIV, which is a singly dissociable and ecologically relevant aspect of episodic memory involving the execution of future intentions. Seventy-five HIV seropositive individuals and 60 seronegative volunteers were administered the Prospective and Retrospective Memory Questionnaire (PMRQ) as part of extensive neuropsychological, psychiatric, and medical research assessments. The HIV sample endorsed more frequent ProM complaints in daily life than the seronegative group, particularly on items requiring self-initiated cue detection and retrieval. Within both study groups, ProM complaints were significantly more frequent than RetM complaints. Although the HIV sample was impaired relative to the seronegative group on an objective, performance-based ProM test, self-reported ProM complaints did not correspond to actual ProM abilities. However, greater frequency of self-reported ProM complaints was moderately associated with increased fatigue, as well as with symptoms of anxiety and depression. Consistent with prior research on RetM in HIV, results indicate that affective distress contributes to a metamemory deficit for HIV-associated ProM impairment, which highlights the potential importance of assessing both self-reported and performance-based ProM in clinical and research neuroAIDS evaluations.

Given the largely prefrontostriatal neuropathogenesis of HIV-associated neurobehavioral deficits, it is often presumed that HIV infection leads to greater impairment on letter versus category fluency. A meta-analysis of the HIV verbal fluency literature was conducted (k = 37, n = 7110) to assess this hypothesis and revealed generally small effect sizes for both letter and category fluency, which increased in magnitude with advancing HIV disease severity. Across all studies, the mean effect size of category fluency was slightly larger than that of letter fluency. However, the discrepancy between category and letter fluency dissipated in a more conservative analysis of only those studies that included both tests. Thus, HIV-associated impairments in letter and category fluency are of similar magnitude, suggesting that mild word generation deficits are evident in HIV, regardless of whether traditional letter or semantic cues are used to guide the word search and retrieval process.

Auditory steady-state responses to amplitude-modulated tones with modulation frequencies between 80 and 105 Hz can be recorded when multiple stimuli are presented simultaneously through a soundfield speaker and amplified using a hearing aid. Responses were recorded at carrier frequencies of 500, 1000, 2000, and 4000 Hz in a group of 35 hearing-impaired children using hearing aids. The physiologic responses were recorded at intensities close to the behavioral thresholds for sounds in the aided condition, with average differences between the physiologic and behavioral thresholds of 17, 13, 13, and 16 dB for carrier frequencies 500, 1000, 2000, and 4000 Hz. The technique shows great promise as a way to assess aided thresholds objectively in subjects who cannot reliably respond on behavioral testing.

Auditory brainstem responses (ABRs) can be reliably recorded from infants in the first few months of life. Since they are normally recognizable down to intensities that are 30 dB above normal hearing thresholds, ABRs elicited by clicks are useful in screening for hearing-impairment in infancy. The ABRs can also provide further diagnostic information about the hearing losses that are detected by screening: the threshold for the response represents a reasonable estimate of the severity of the hearing loss; bone-conduction studies can assess the extent of a conductive loss; and frequency-specific techniques can evaluate hearing thresholds at different frequencies. At present, ABRs are mainly used for screening infants who have been treated in neonatal intensive care units. Because the majority of infants with hearing impairment are not seen in these units, it might be worthwhile to use ABRs in a more widespread screening program.

The thresholds for the short-latency auditory evoked potentials (SLAEPs) to short-duration tones presented in notched-noise masking were evaluated in 20 normal-hearing and 20 hearing-impaired subjects. The differences (dB) between these thresholds (dB nHL) and the pure-tone behavioral thresholds (dB HL) across all 40 subjects were 11.6, 6.1, 6.3 and 0.8 dB for 500, 1,000, 2,000 and 4,000 Hz, respectively. These differences were significantly smaller for the hearing-impaired subjects than for the normal-hearing subjects. Ninety-eight percent of the SLAEP threshold estimations were within 30 dB of the subjects' pure-tone behavioral thresholds and 91% were within 20 dB.