Steady-state evoked potentials can be recorded from the human scalp in response to auditory stimuli presented at rates between 1 and 200 Hz or by periodic modulations of the amplitude and/or frequency of a continuous tone. Responses can be objectively detected using frequency-based analyses. In waking subjects, the responses are particularly prominent at rates near 40 Hz. Responses evoked by more rapidly presented stimuli are less affected by changes in arousal and can be evoked by multiple simultaneous stimuli without significant loss of amplitude. Response amplitude increases as the depth of modulation or the intensity increases. The phase delay of the response increases as the intensity or the carrier frequency decreases. Auditory steady-state responses are generated throughout the auditory nervous system, with cortical regions contributing more than brainstem generators to responses at lower modulation frequencies. These responses are useful for objectively evaluating auditory thresholds, assessing suprathreshold hearing, and monitoring the state of arousal during anesthesia.

Interventions targeting PWLH are efficacious in reducing unprotected sex and acquisition of sexually transmitted diseases. Efficacious strategies identified in this review should be incorporated into community HIV prevention efforts and further evaluated for effectiveness.

Pediatric adherence to daily drug regimens has not been widely assessed in Africa where majority of HIV infected children live. Using in-depth interviews of 42 HIV-infected children taking ART and/or cotrimoxazole prophylaxis, and 42 primary caregivers, at a comprehensive HIV/AIDS clinic in Uganda, we evaluated their adherence experiences for purposes of program improvement. Daily drug regimens provided by the pediatric clinic included cotrimoxazole prophylaxis as well as ART and cotrimoxazole combined. Complete disclosure of HIV status by caregivers to children and strong parental relationships were related to good adherence. Structural factors including poverty and stigma were barriers to adherence even for children who had had complete disclosure and a supportive relationship with a parent. To ensure adherence to life-extending medications, our findings underscore the need for providers to support caregivers to disclose, provide on-going support and maintain open communication with HIV-infected children taking cotrimoxazole prophylaxis and ART.

Background:CDC has not previously calculated disease rates for men who have sex with men (MSM) because there is no single comprehensive source of data on population size. To inform prevention planning, CDC developed a national population size estimate for MSM to calculate disease metrics for HIV and syphilis.Methods:We conducted a systematic literature search and identified seven surveys that provided data on same-sex behavior in nationally representative samples. Data were pooled by three recall periods and combined using meta-analytic procedures. We applied the proportion of men reporting same-sex behavior in the past 5 years to U.S. census data to produce a population size estimate. We then calculated three disease metrics using CDC HIV and STD surveillance data and rate ratios comparing MSM to other men and to women.Results:Estimates of the proportion of men who engaged in same-sex behavior differed by recall period: past year = 2.9% (95%CI, 2.6–3.2); past five years = 3.9% (3.5–4.4); ever = 6.9% (5.1–8.6). Rates on all 3 disease metrics were much higher among MSM than among either other men or women (38 to 109 times as high).Conclusions:Estimating the population size for MSM allowed us to calculate rates for disease metrics and to develop rate ratios showing dramatically higher rates among MSM than among other men or women. These data greatly improve our understanding of the disproportionate impact of these diseases among MSM in the U.S. and help with prevention planning.

Auditory feedback during speech production is known to play a role in speech sound acquisition and is also important for the maintenance of accurate articulation. In two studies the first formant (F1) of monosyllabic consonant-vowel-consonant words (CVCs) was shifted electronically and fed back to the participant very quickly so that participants perceived the modified speech as their own productions. When feedback was shifted up (experiment 1 and 2) or down (experiment 1) participants compensated by producing F1 in the opposite frequency direction from baseline. The threshold size of manipulation that initiated a compensation in F1 was usually greater than 60 Hz. When normal feedback was returned, F1 did not return immediately to baseline but showed an exponential deadaptation pattern. Experiment 1 showed that this effect was not influenced by the direction of the F1 shift, with both raising and lowering of F1 exhibiting the same effects. Experiment 2 showed that manipulating the number of trials that F1 was held at the maximum shift in frequency (0, 15, 45 trials) did not influence the recovery from adaptation. There was a correlation between the lag-one autocorrelation of trial-to-trial changes in F1 in the baseline recordings and the magnitude of compensation. Some participants therefore appeared to more actively stabilize their productions from trial-to-trial. The results provide insight into the perceptual control of speech and the representations that govern sensorimotor coordination.

In the United States, there continues to be high incidence of HIV infection among men who have sex with men (MSM), who represent 57% of new infections in 2009. While many studies report associations between non-injection substance use and sexual risk behavior among MSM, overall results are mixed. Summarizing these studies is difficult because researchers have used a variety of assessment periods for substance use and sexual behavior. We review the scientific literature on event-level measures, which assess substance use and sexual risk behavior immediately before or during a sexual encounter and provide the most precise link between these two behaviors. From January 2009 through March 2010, we searched four databases: Ovid (MEDLINE and PsycINFO), Web of Knowledge, and Sociofile. Across studies, results varied by substance with little within substance consistency or a lack of research except for two notable exceptions: methamphetamine and binge alcohol use. The findings underscore the importance of providing HIV risk-reduction interventions for substance-using MSM.

Temporal auditory acuity, the ability to discriminate rapid changes in the envelope of a sound, is essential for speech comprehension. Human envelope following responses (EFRs) recorded from scalp electrodes were evaluated as an objective measurement of temporal processing in the auditory nervous system. The temporal auditory acuity of older and younger participants was measured behaviorally using both gap and modulation detection tasks. These findings were then related to EFRs evoked by white noise that was amplitude modulated (25% modulation depth) with a sweep of modulation frequencies from 20 to 600 Hz. The frequency at which the EFR was no longer detectable was significantly correlated with behavioral measurements of gap detection (r = -0.43), and with the maximum perceptible modulation frequency (r = 0.72). The EFR techniques investigated here might be developed into a clinically useful objective estimate of temporal auditory acuity for subjects who cannot provide reliable behavioral responses.

Overall, evidence for harm reduction was identified; however, significant differences across the two cities were found. The complicated nature of the sexual practices of gay and bisexual men are discussed, and the findings have important implications for prevention efforts and future research studies.