Evaluating brain-computer interface performance using color in the P300 checkerboard speller.

OBJECTIVE: Current Brain-Computer Interface (BCI) systems typically flash an array of items from grey to white (GW). The objective of this study was to evaluate BCI performance using uniquely colored stimuli. METHODS: In addition to the GW stimuli, the current study tested two types of color stimuli (grey to color [GC] and color intensification [CI]). The main hypotheses were that in a checkboard paradigm, unique color stimuli will: (1) increase BCI performance over the standard GW paradigm; (2) elicit larger event-related potentials (ERPs); and, (3) improve offline performance with an electrode selection algorithm (i.e., Jumpwise). RESULTS: Online results (n=36) showed that GC provides higher accuracy and information transfer rate than the CI and GW conditions. Waveform analysis showed that GC produced higher amplitude ERPs than CI and GW. Information transfer rate was improved by the Jumpwise-selected channel locations in all conditions. CONCLUSIONS: Unique color stimuli (GC) improved BCI performance and enhanced ERPs. Jumpwise-selected electrode locations improved offline performance. SIGNIFICANCE: These results show that in a checkerboard paradigm, unique color stimuli increase BCI performance, are preferred by participants, and are important to the design of end-user applications; thus, could lead to an increase in end-user performance and acceptance of BCI technology.

Midlife managerial experience is linked to late life hippocampal morphology and function.

An active cognitive lifestyle has been suggested to have a protective role in the long-term maintenance of cognition. Amongst healthy older adults, more managerial or supervisory experiences in midlife are linked to a slower hippocampal atrophy rate in late life. Yet whether similar links exist in individuals with Mild Cognitive Impairment (MCI) is not known, nor whether these differences have any functional implications. 68 volunteers from the Sydney SMART Trial, diagnosed with non-amnestic MCI, were divided into high and low managerial experience (HME/LME) during their working life. All participants underwent neuropsychological testing, structural and resting-state functional MRI. Group comparisons were performed on hippocampal volume, morphology, hippocampal seed-based functional connectivity, memory and executive function and self-ratings of memory proficiency. HME was linked to better memory function (p = 0.024), mediated by larger hippocampal volume (p = 0.025). More specifically, deformation analysis found HME had relatively more volume in the CA1 sub-region of the hippocampus (p < 0.05). Paradoxically, this group rated their memory proficiency worse (p = 0.004), a result correlated with diminished functional connectivity between the right hippocampus and right prefrontal cortex (p < 0.001). Finally, hierarchical regression modelling substantiated this double dissociation.

Therapeutically relevant structural and functional mechanisms triggered by physical and cognitive exercise.

Physical and cognitive exercise may prevent or delay dementia in later life but the neural mechanisms underlying these therapeutic benefits are largely unknown. We examined structural and functional magnetic resonance imaging (MRI) brain changes after 6 months of progressive resistance training (PRT), computerized cognitive training (CCT) or combined intervention. A total of 100 older individuals (68 females, average age=70.1, s.d.±6.7, 55-87 years) with dementia prodrome mild cognitive impairment were recruited in the SMART (Study of Mental Activity and Resistance Training) Trial. Participants were randomly assigned into four intervention groups: PRT+CCT, PRT+SHAM CCT, CCT+SHAM PRT and double SHAM. Multimodal MRI was conducted at baseline and at 6 months of follow-up (immediately after training) to measure structural and spontaneous functional changes in the brain, with a focus on the hippocampus and posterior cingulate regions. Participants' cognitive changes were also assessed before and after training. We found that PRT but not CCT significantly improved global cognition (F(90)=4.1, P<0.05) as well as expanded gray matter in the posterior cingulate (Pcorrected <0.05), and these changes were related to each other (r=0.25, P=0.03). PRT also reversed progression of white matter hyperintensities, a biomarker of cerebrovascular disease, in several brain areas. In contrast, CCT but not PRT attenuated decline in overall memory performance (F(90)=5.7, P<0.02), mediated by enhanced functional connectivity between the hippocampus and superior frontal cortex. Our findings indicate that physical and cognitive training depend on discrete neuronal mechanisms for their therapeutic efficacy, information that may help develop targeted lifestyle-based preventative strategies.

Predictive spelling with a P300-based brain-computer interface: Increasing the rate of communication.

This study compared a conventional P300 speller brain-computer interface (BCI) to one used in conjunction with a predictive spelling program. Performance differences in accuracy, bit rate, selections per minute, and output characters per minute (OCM) were examined. An 8×9 matrix of letters, numbers, and other keyboard commands was used. Participants (n = 24) were required to correctly complete the same 58 character sentence (i.e., correcting for errors) using the predictive speller (PS) and the non-predictive speller (NS), counterbalanced. The PS produced significantly higher OCMs than the NS. Time to complete the task in the PS condition was 12min 43sec as compared to 20min 20sec in the NS condition. Despite the marked improvement in overall output, accuracy was significantly higher in the NS paradigm. P300 amplitudes were significantly larger in the NS than in the PS paradigm; which is attributed to increased workload and task demands. These results demonstrate the potential efficacy of predictive spelling in the context of BCI.

Rapid KABP survey for evaluation of NGO HIV/AIDS prevention projects.

The Johns Hopkins University HAPA Support Program (HSP) provided technical assistance to Save the Children (SC), a U.S.-based nongovernmental organization, to conduct a survey of knowledge, attitudes, beliefs, and practices (KABP) related to AIDS among rural Zimbabweans. The objectives of the HSP technical assistance were to field test a rapid KABP survey methodology and to assist SC to provide data that would contribute to their final project evaluation. The entire process of planning, implementation, preliminary data analysis, and preparation of a draft report of survey results was completed in a four-week period. A total of 660 respondents, aged 18-45 years, selected by a modified 30-cluster sampling method, were interviewed in two SC project areas. Although knowledge about HIV/AIDS was high, a number of misconceptions about HIV transmission and unfavorable attitudes to people with AIDS were noted. Of five knowledge and attitude variables that could be compared with the baseline survey results, 4 showed favorable changes and 1 showed an unfavorable trend. Comparing responses from those who were educated by SC with those who had other sources of information about HIV/AIDS, higher levels of knowledge were seen in the SC-educated group and, in one area, somewhat greater willingness to care for family members with AIDS. However, there were no differences seen in other attitudes, beliefs, or in practices regarding condom use. The rapid KABP survey approach was successful in providing, with a relatively modest investment of resources, quantitative data useful for project evaluation, and for developing HIV/AIDS-intervention strategies.

Tension band arthrodesis of small joints in the hand.

Two-hundred three patients underwent 290 tension band arthrodeses of the metacarpophalangeal and proximal interphalangeal joints of the hand. Nine patients (3%) failed to achieve bony union, four had painless pseudarthroses, and one patient had a small finger amputation. Twenty-five fusions (9%) required hardware removal. There were 10 superficial infections (all responded to oral antibiotic therapy), and three fusions were malrotated. Tension band arthrodesis is our choice for fusion of the metacarpophalangeal and proximal interphalangeal joints. It is reliable and provides stable fixation, pins do not protrude, and external splinting is unnecessary in the cooperative patient.

Prevalence and effect of subclinical ovine progressive pneumonia virus infection on ewe wool and lamb production.

The prevalence of infection with ovine progressive pneumonia (OPP) virus and its effects on ewe wool and lamb production were investigated in a flock of 2,976 ewes of 6 breed types (Rambouillet, Targhee, Columbia, Polypay, 1/4 cross Finnsheep, and 1/2 cross Finnsheep). Prevalence of seropositivity was significantly (P less than or equal to 0.01) lower among Rambouillet and Targhee breeds (44 and 42%, respectively), intermediate in Polypay, Columbia, and 1/4 cross Finnsheep (approximately 53%), and higher among 1/2 cross Finnsheep (62%). Seropositivity increased with age in all breed types from 11% at 1 year of age to 93% at greater than or equal to 7 years of age. Lateral disease transmission is indicated by linear increase of seropositivity prevalence with increasing age, including that in sheep greater than 6 years old. Subclinical infection with OPP virus had no apparent detrimental effect on number of lambs born, lamb viability, birth weight, number of lambs weaned, or growth rate of single and twin lambs, compared with findings for noninfected sheep in the same flock. Mature ewe body weight and grease fleece weight did not differ between subclinically infected seropositive and seronegative ewes. Subclinical infection with OPP virus does not appear to have an adverse economic effect on ewe wool and lamb production. Culling rate attributable to clinical manifestation of infection with OPP virus must be accurately determined before the true effects of virus infection on production can be determined and an eradication program can be recommended.

Primary isolation and serial passage of hepatitis A virus strains in primate cell cultures.

Although several primate cell types have been reported to support replication of hepatitis A virus, optimal conditions for the isolation and production of quantities of virus have not been defined. We therefore examined seven different primate cell types for their ability to support replication of primate-passaged and wild-type virus as reflected by intracytoplasmic accumulation of viral antigen (direct immunofluorescence and radioimmunoassay) and propagation of cell culture-adapted virus. Of the cells tested, low-passage African green monkey kidney (AGMK) cells were most sensitive for initial isolation. Viral replication was documented after inoculation of AGMK cells with seven of nine hepatitis A virus antigen-positive fecal specimens (from seven epidemiologically distinct sources). With six inocula, virus was successfully passed in serial cultures. AGMK-adapted virus was readily propagated in continuous AGMK (BS-C-1) cells. The optimal temperature for the growth of virus in BS-C-1 cells was 35 degrees C. Viral release into supernatant fluids was documented in the absence of any cytopathic effect, and infectivity titers in supernatant fluids 21 days after inoculation (50% tissue culture infective does [TCID50], 10(6.0)/ml) equalled or exceeded those in the cell fraction (TCID50, 10(5.5)/ml). Cells maintained in serum-free media readily supported viral growth, with yields of virus (TCID50, 10(6.5)/ml) equal to or greater than those obtained with cells maintained in 2% fetal bovine serum.

Failure in passive transfer of immunoglobulin G1 to lambs: measurement of immunoglobulin G1 in ewe colostrums.

Concentrations of immunoglobulin (Ig) G1 were measured in 590 sera from 24- to 36-hour-old lambs, and failure in passive transfer (FPT), less than 6 mg/ml, occurred in 20 lambs. Of the 20 FPT lambs, 45% died before 3 weeks of age, whereas only 5% of the 570 lambs with adequate passive transfer died before 3 weeks of age. The low percentage of FPT was attributed to management practices ensuring suckling by the lambs and possibly to influences from several years of selecting ewes on the basis of weaned lamb production. The correlation between the concentration of IgG1 in 257 postpartum, presuckle ewe colostrum samples and the IgG1 concentrations in 362 lamb sera from those ewes was low (r = 0.32). However, the mean serum IgG1 concentration in 20 lambs from ewes with the lowest postpartum, presuckle colostrum IgG1 concentrations (less than 30 mg/ml) was significantly lower (P less than 0.001) than mean serum IgG1 concentration in 24 lambs from ewes with the highest postpartum, presuckle colostrum IgG1 concentrations (greater than 110 mg/ml). Postpartum, presuckle colostrum IgG1 was measured in 7 ewes whose lambs had FPT, and the IgG1 values varied throughout the colostrum IgG1 range. Colostrum IgG1 concentrations could not be used to explain FPT or to identify ewes likely to have lambs with FPT.

IgM antibody to hepatitis B core antigen as a diagnostic parameter of acute infection with hepatitis B virus.

Because many patients with acute hepatitis B lack detectable hepatitis B surface antigen (HBsAg), a radioimmunoassay for IgM antibody to hepatitis B core antigen (anti-HBc) was developed and evaluated as a diagnostic test. IgM anti-HBc was detected in each of 47 patients with acute hepatitis and transient HBsAg (geometric mean titer, greater than or equal to 1:191,000), but also in five of 12 HBsAg carriers (geometric mean titer, 1:459) and one of 46 healthy individuals positive for anti-HBc. However, it was not present in one patient during the first six months of a persistent infection. Of 255 patients with acute hepatitis and HBsAg and/or anti-HBc, 210 were HBsAg-positive whereas 230 had IgM anti-HBc. The latter was the only specific marker in 12.3% of all cases of acute hepatitis B. Thus, IgM anti-HBc is a valuable marker for the diagnosis of acute infection with hepatitis B virus.

Role of Salmonella arizonae and other infective agents in enteric disease of lambs.

Fecal samples from 545 diarrheic lambs on 12 ranches in southern Idaho and western Montana were examined for potential enteric pathogens. On 3 of the 12 ranches, enterotoxigenic Escherichia coli, Salmonella typhimurium, or S dublin was implicated as the etiologic agent. Rotavirus and coronavirus were identified on 1 ranch and rotavirus alone on another. Salmonella arizonae serotype 26:30 was isolated from the feces of diarrheic lambs on 6 of the 12 ranches in this study. Pregnant ewes from 1 of the 6 ranches in which S arizonae was enzootic were transported to the Montana Veterinary Research Laboratory and studies on S arizonae were conducted in lambs from these ewes. Salmonella arizonae was shown to elaborate an enterotoxin, the activity of which was reduced when assayed in the gut loop test, using lambs from ewes vaccinated with an S arizonae 26:30 bacterin. Oral challenge inoculation of 22 young colostrum-fed lambs with S arizonae 26:30 failed to produce any significant enteric disease, in contrast to oral challenge inoculation with S. oranienburg which resulted in death, with severe diarrhea and dehydration, in 4 of 6 lambs tested. Salmonella arizonae serotype 26:30 appears to be well adapted to the ovine host and may not be a significant cause of diarrheal disease on ranches where it is enzootic.

Evaluation of lasalocid in salt against ovine Coccidia.

Lasalocid at a level of 0.75% in free-choice granulated salt was highly efficacious against naturally acquired coccidia infections in lambs maintained in semiconfinement. Treated lambs consumed 18 g of medicated salt/day, reflecting an average daily lasalocid dosage of 4.3 mg/kg of body weight. Treated lambs gained 5.7 kg more than did untreated lambs (P less than 0.01) during the 84-day experiment. Clinical signs of coccidiosis were not observed in treated or untreated lambs.

Epizootic streptococcal pneumonia in captive coyotes.

Severe death loss was observed in captive coyotes, Canis latrans. Of 48 coyotes in one kennel, 22 (46%) died within a 7 day period. Cause of death was determined to be acute fibrinopurulent (bacterial) broncho-pneumonia and pleuritis. Streptococcus equisimilis was isolated from the lungs of two coyotes examined.

Visceral caseous lymphadenitis in thin ewe syndrome: isolation of Corynebacterium, Staphylococcus, and Moraxella spp from internal abscesses in emaciated ewes.

The relationship between the visceral form of caseous lymphadenitis and a chronic debilitating condition of mature sheep designated as the thin ewe syndrome was investigated. Internal abscesses were found during necropsy in 81% of animals with thin ewe syndrome and Corynebacterium pseudotuberculosis (C ovis) was recovered from 86% of the animals with internal abscesses. Other pyogenic bacteria, including C pyogenes, C equi, Staphylococcus epidermis, S aureus, and Pseudomonas aeruginosa were often recovered in association with C pseudotuberculosis. Moraxella sp was recovered in 41% of the animals with internal abscesses. In some abscesses, Moraxella sp was the dominant microorganism isolated and in others, they were outnumbered only by C pseudotuberculosis. Species isolated included M bovis, M osloensis, and M nonliquefaciens. The potential importance of Moraxella sp to the cause and pathogenesis of the thin ewe syndrome is not known. The results of the present study indicate that visceral caseous lymphadenitis is either an important contributing factor to the development of thin ewe syndrome or that the presence of thin ewe syndrome may predispose affected sheep to the development of visceral caseous lymphadenitis. A skin test reagent prepared by sonicating C pseudotuberculosis was of limited value in detecting animals with visceral caseous lymphadenitis. Only 56% of the animals with abscesses caused by C pseudotuberculosis gave positive delayed-type hypersensitivity skin test responses.

Coyote laparotomy: in vivo determination of reproductive success.

Reproductive tracts of 24 female coyotes hand-reared for behavioral research were examined by laparotomy following the 1977-78 breeding season. Litter counts revealed 51 whelps with 10 of the 24 females while examination by laparotomy indicated 83 uterine swellings in 18 of the same 24 females. The laparotomy proved to be an effective, relatively precise procedure and gave a 39% increase in data acquisition.

Hematologic and serum chemistry values of pen-raised coyotes.

Blood samples obtained from 48, eighteen-month-old pen-raised coyotes (Canis latrans) were analyzed for 32 hematologic and serum chemistry parameters. Mean, standard deviation, and range were established for each parameter. No differences attributable to sex were observed for any parameter. The reported hematologic and serum chemistry values establish non-fasting baseline values for pen-raised coyotes.