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Brain-computer interfaces (BCIs) employ various paradigms which afford intuitive, augmented control for users to navigate digital technologies. In this study we explore the application of these BCI concepts to predictive text systems: commonplace interactive and assistive tools with variable usage contexts and user behaviors. We conducted an experiment to analyze user neurophysiological responses under these different usage scenarios and evaluate the feasibility of a closed-loop, adaptive BCI for use with such technologies. We recorded electroencephalogram (EEG) and eye tracking (ET) data from participants while they completed a self-paced typing task in a simulated predictive text environment. Participants completed the task with different degrees of reliance on the predictive text system (completely dependent, completely independent, or their choice) and encountered both correct and incorrect text generations. Data suggest that erroneous text generations may evoke neurophysiological responses that can be measured with both EEG and pupillometry. Moreover, these responses appear to change according to users' reliance on the predictive text system. Results show promise for use in a passive, hybrid, BCI with a closed-loop, adaptive framework, and support a neurophysiological approach to the challenge of real-time human feedback on system performance.

Background: Surgical outcomes for intramedullary spinal cord tumors are affected by many variables including tumor histology and preoperative neurological function., Objective: To analyze the impact of tumor histology on neurological outcome in primary intramedullary spinal cord tumors., Methods: A retrospective review of 102 consecutive patients with intramedullary spinal cord tumors treated at a single institution between January 1998 and March 2009., Results: Ependymomas were the most common tumors with 55 (53.9%), followed by 21 astrocytomas (20.6%), 12 hemangioblastomas (11.8%), and 14 miscellaneous tumors (13.7%). Gross total resection was achieved in 50 ependymomas (90.9%), 3 astrocytomas (14.3%), 11 hemangioblastomas (91.7%), and 12 miscellaneous tumors (85.7%). At a mean follow-up of 41.8 months (range, 1-132 months), we observed recurrences in 4 ependymoma cases (7.3%), 10 astrocytoma cases (47.6%), 1 miscellaneous tumor case (7.1%), and no recurrence in hemangioblastoma cases. When analyzed by tumor location, there was no difference in neurological outcomes (P = .66). At the time of their last follow-up visit, 11 patients (20%) with an ependymoma improved, 38 (69%) remained the same, and 6 (10.9%) worsened. In patients with an astrocytoma, 1 (4.8%) improved, 10 (47.6%) remained the same, and 10 (47.6%) worsened. One patient (8.3%) with a hemangioblastoma improved and 11 (91.7%) remained the same. No patient with a hemangioblastoma worsened. In the miscellaneous tumor group, 2 (14.3%) improved, 10 (71.4%) remained the same, and 2 (14.3%) worsened. Preoperative neurological status (P = .02), tumor histology (P = .005), and extent of resection (P < .0001) were all predictive of functional neurological outcomes., Conclusion: Tumor histology is the most important predictor of neurological outcome after surgical resection because it predicts resectability and recurrence.

We present results from a mixed methods study of screen reader use and switching behavior among people with vision impairments in India. We examine loyalty and experimentation with screen readers and find that the main drivers of adoption for early users differ significantly from the factors that drive continued use by advanced users. We discuss the factor that emerges as one of the strongest stated drivers of early adoption, text-to-speech "voice" quality, particularly a "human-sounding voice" as one of the key features differentiating free/open source products from more expensive proprietary products. While the initial preferences are driven by voice quality, application support becomes more important over time as users speed up their sound settings and become more comfortable with the resultant non-human-sounding speech. We discuss these findings from two theoretical perspectives--first, through the application of the economics of behavior switching, and second, vis-à-vis novice and expert approaches toward new product adoption. We argue that these findings further our understanding of initial user comfort related to assistive technology adoption, and the impact of early technology choices on long-term technology switching behavior.

Background: Surgical outcomes for intramedullary spinal cord tumors are affected by many variables including tumor histology and preoperative neurological function., Objective: To analyze the impact of tumor histology on neurological outcome in primary intramedullary spinal cord tumors., Methods: A retrospective review of 102 consecutive patients with intramedullary spinal cord tumors treated at a single institution between January 1998 and March 2009., Results: Ependymomas were the most common tumors with 55 (53.9%), followed by 21 astrocytomas (20.6%), 12 hemangioblastomas (11.8%), and 14 miscellaneous tumors (13.7%). Gross total resection was achieved in 50 ependymomas (90.9%), 3 astrocytomas (14.3%), 11 hemangioblastomas (91.7%), and 12 miscellaneous tumors (85.7%). At a mean follow-up of 41.8 months (range, 1-132 months), we observed recurrences in 4 ependymoma cases (7.3%), 10 astrocytoma cases (47.6%), 1 miscellaneous tumor case (7.1%), and no recurrence in hemangioblastoma cases. When analyzed by tumor location, there was no difference in neurological outcomes (P = .66). At the time of their last follow-up visit, 11 patients (20%) with an ependymoma improved, 38 (69%) remained the same, and 6 (10.9%) worsened. In patients with an astrocytoma, 1 (4.8%) improved, 10 (47.6%) remained the same, and 10 (47.6%) worsened. One patient (8.3%) with a hemangioblastoma improved and 11 (91.7%) remained the same. No patient with a hemangioblastoma worsened. In the miscellaneous tumor group, 2 (14.3%) improved, 10 (71.4%) remained the same, and 2 (14.3%) worsened. Preoperative neurological status (P = .02), tumor histology (P = .005), and extent of resection (P < .0001) were all predictive of functional neurological outcomes., Conclusion: Tumor histology is the most important predictor of neurological outcome after surgical resection because it predicts resectability and recurrence.

Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA-viral peptide interaction as the major factor modulating durable control of HIV infection.

Background: Human immunodeficiency virus type 1 (HIV-1) elite controllers are able to control virus replication to levels below the limits of detection by commercial assays, but the actual level of viremia in these individuals is not well defined. Here, we quantify plasma HIV-1 RNA in elite controllers and correlate this with specific immunologic parameters., Methods: Plasma HIV-1 RNA levels were quantified in 90 elite controllers with use of a real time reverse-transcriptase polymerase chain reaction assay with a sensitivity of 0.2 copies/mL. HIV-1-specific immune responses and longitudinal CD4(+) T cell counts were examined., Results: The median plasma HIV-1 RNA level was 2 copies/mL (interquartile range, 0.2-14 copies/mL). A longitudinal analysis of 31 elite controllers demonstrated 2-5-fold fluctuations in viremia in the majority of individuals; 6 had persistent levels below 1 copy/mL. Viremia correlated directly with HIV-1-specific neutralizing antibodies and Western blot reactivity but not with CD8(+) T cell responses. Absolute CD4(+) T cell decrease was more common among individuals with detectable viremia (P = .04)., Conclusions: Low-level viremia is present in the majority of elite controllers and is associated with higher HIV-1-specific antibody responses. Absolute CD4(+) T cell loss is more common among viremic individuals, suggesting that even very low-level viremia has negative consequences over time.

Antibodies to HIV are potentially important reagents for basic and clinical studies. Historically, these reagents have been produced by random cloning of heavy and light chains in phage display libraries [Burton, D.R., Barbas, C.F. III, Persson, M.A.A., Koenig, S., Chanock, R.M., and Lerner, R.A., (1991), A large array of human monoclonal antibodies to type 1 immunodeficiency virus from combinatorial libraries of asymptomatic seropositive individuals. Proc. Natl. Acad. Sci. U. S. A. 88, 10134-10137.] and electrofusion techniques [Buchacher, A., Predl, R., Tauer, C., Purtscher, M., Gruber, G., Heider, R., Steindl, F., Trkola, A., Jungbauer, A., and Katinger, H., (1992), Human monoclonal antibodies against gp41 and gp120 as potential agent for passive immunization. Vaccines 92, 191-195]. Here we describe a method to identify and potentially enrich human memory B cells from HIV infected patients that show serum titers of neutralizing antibodies. When biotinylated gp140 is used to stain peripheral blood mononuclear cells it identifies a distinct population of gp140 binding B cells by flow cytometry.

Human immunodeficiency virus type 1 (HIV-1) elite controllers (EC) maintain viremia below the limit of commercial assay detection (<50 RNA copies/ml) in the absence of antiviral therapy, but the mechanisms of control remain unclear. HLA-B57 and the closely related allele B*5801 are particularly associated with enhanced control and recognize the same Gag(240-249) TW10 epitope. The typical escape mutation (T242N) within this epitope diminishes viral replication capacity in chronically infected persons; however, little is known about TW10 epitope sequences in residual replicating viruses in B57/B*5801 EC and the extent to which mutations within this epitope may influence steady-state viremia. Here we analyzed TW10 in a total of 50 B57/B*5801-positive subjects (23 EC and 27 viremic subjects). Autologous plasma viral sequences from both EC and viremic subjects frequently harbored the typical cytotoxic T-lymphocyte (CTL)-selected mutation T242N (15/23 sequences [65.2%] versus 23/27 sequences [85.1%], respectively; P = 0.18). However, other unique mutants were identified in HIV controllers, both within and flanking TW10, that were associated with an even greater reduction in viral replication capacity in vitro. In addition, strong CTL responses to many of these unique TW10 variants were detected by gamma interferon-specific enzyme-linked immunospot assay. These data suggest a dual mechanism for durable control of HIV replication, consisting of viral fitness loss resulting from CTL escape mutations together with strong CD8 T-cell immune responses to the arising variant epitopes.

Responses of rhesus monkeys were reinforced by delivery of either a pentobarbital (4.0 mg/ml) solution or a vehicle (water) or saccharin solution under a concurrent signaled differential reinforcement of low rates 30-s schedule. After 30 s of no responding, the first response on the pentobarbital or saccharin spout resulted in the delivery of the appropriate solution and reset the timing on both spouts (i.e. a mutually exclusive choice). In the first experiment, the concentration of saccharin was gradually increased across sessions. As saccharin concentration increased, pentobarbital deliveries decreased and saccharin as well as total session deliveries increased. In a second experiment, pentobarbital and 0.24 (mg/ml) saccharin were made available under concurrent signaled differential reinforcement of low rates 30-s schedules which operated independently. Under these conditions responding on one spout had no consequences with respect to the other spout. The reduction of pentobarbital deliveries was substantially attenuated when the choice was not mutually exclusive.

During daily 3-h sessions two separate pentobarbital solutions were concurrently available to rhesus monkeys under signalled differential-reinforcement-of-low-rates (signalled DRL) schedules of mouth contacts with spouts. The schedules were synchronized so that each time the 30-s DRL interval expired, lights above both spouts were illuminated and a liquid delivery could be obtained either from the left or right spout, but not both. First water and then each of four 'comparison-concentration' pentobarbital solutions (0.0625, 0.25, 1 and 4 mg/ml) were successively available under one schedule for a block of sessions. Concurrently, deliveries of a 'standard concentration' solution were available from the second spout under an identical DRL schedule; the concentration of this standard solution remained constant throughout the testing of the series of comparison solutions. Three pentobarbital concentrations (4, 1 and 0.25 mg/ml) in turn served as the standard concentration. Relative reinforcing effects were directly related to pentobarbital concentration: in general, within pairs of concurrently available pentobarbital solutions more behavior was maintained by the higher of the two drug concentrations. These findings are discussed in the context of previous studies using ratio and interval schedules which have found relative reinforcing effects to be directly related to reinforcer magnitude.