[Diagnosis of intestinal amebiasis using coproscopic and immunological methods in a population sample in greater metropolitan Belém, Pará, Brazil]. / Diagnóstico de amebíase intestinal utilizando métodos coproscópicos e imunológicos em amostra da população da área metropolitana de Belém, Pará, Brasil.

We compare diagnostic methods for Entamoeba histolytica in fecal samples from the city of Belém, Pará, Brazil. We analyze stool samples from children and adults (Group I); stool and serum samples from adults (Group II); and stool samples from children (Group III). In groups I and III, we used direct examination with lugol (DM), Faust et al (FM), and ELISA (detection of E. histolytica anti-GIAP coproantigen) and in group II, DM, iron hematoxylin staining (IHS), FM, ELISA, and the indirect immunofluorescence test (IFAT) for detection of IgG antibodies. Positivity was 10.50% by DM plus FM and 28.99% by ELISA. There was no correlation between positivity and age group. In Group II (n = 87), the positive rate was 4.59% by DM plus FM, 8.04% by IHS, 4.59% by IFAT, and 21.83% by ELISA. The ELISA test was the most sensitive for all groups. IFAT alone is still not a useful tool for diagnosis of E. histolytica infection. The ELISA test is simple, performed in one-third of cases used for IHS and IFAT, and greatly improves quality of diagnosis. We recommend this as the method of choice for diagnosis of suspected E. histolytica infection.

Effects of aerobic exercise and gender on visual and auditory P300, reaction time, and accuracy.

Visual and auditory reaction times (RTs) have been reported to decrease during moderate aerobic exercise, and this has been interpreted as reflecting an exercise-induced activation (EIA) of cognitive information processing. In the present study we examined changes in several independent measures of information processing (RT, accuracy, P300 latency and amplitude) during exercise, and their relationship to visual or auditory modalities and to gender. P300 latencies offer independent measures of cognitive speed that are unrelated to motor output, and P300 amplitudes have been used as measures of attentional allocation. Twenty-four healthy college students [mean (SD) age 20 (2) years] performed auditory and visual "oddball" tasks during resting baseline, aerobic exercise, and recovery periods. Consistent with previous studies, both visual and auditory RTs during exercise were significantly shortened compared to control and recovery periods (which did not differ from each other). We now report that, paralleling the RT changes, auditory and visual P300 latencies decreased during exercise, indicating the occurrence of faster cognitive information processing in both sensory modalities. However, both auditory and visual P300 amplitudes decreased during exercise, suggesting diminished attentional resource allocation. In addition, error rates increased during exercise. Taken together, these results suggest that the enhancement of cognitive information processing speed during moderate aerobic exercise, although operating across genders and sensory modalities, is not a global facilitation of cognition, but is accompanied by decreased attention and increased errors.

Measurement of mood states in stroke patients: validation of the visual analog mood scales.

OBJECTIVE: The Visual Analog Mood Scales (VAMS) were recently developed by Stern and colleagues to assess mood state in neurologically impaired patients. These brief scales require that a patient place a single pen mark along a 100mm vertical line to indicate how he or she presently feels. Although previous studies have garnered evidence in support of the validity of these brief scales when administered to psychiatric patients and healthy young adult and geriatric control subjects, it is presently unknown whether the VAMS are valid measures of internal mood state in neurologically impaired stroke patients. The purpose of the present investigation was to assess reliability and validity of the VAMS in a stroke-patient population. PARTICIPANTS: Participants were 41 (21 men and 20 women) inpatients admitted for either acute stroke or rehabilitation following stroke. DESIGN: Participants completed both the VAMS and a modified version of the Profile of Mood States (POMS). Nonparametric multitrait-multimethod analyses were performed using the Pearson correlations among and between the six subscales of the VAMS and the POMS. CONCLUSION: The VAMS possess good convergent and discriminant validity when administered to stroke inpatients, providing further support for the utility of these brief, easily administered scales.

Validation of a right hemisphere vigilance system as measured by principal component and factor analyzed quantitative electroencephalogram.

Arruda and colleagues [Arruda, J.E., Weiler, M.D., Valentino, D.A. et al., 1996. A guide for applying principal-component analysis and confirmatory factor analysis to qEEG data. Int. J. Psychophysiol. 23, 63-81.] recently described seven neurophysiological measures that were previously derived and confirmed using factor analytic procedures and the quantitative electroencephalogram (EEG) sampled from 208 normal controls during an auditory continuous performance test (CPT). The purpose of the present investigation was to further test the validity of these empirically derived measures by examining each measure's relationship with CPT-related declines in performance. Participants were 48 right-handed men (n = 13) and women (n = 35) who reported being free of any neurological condition, birthing complications, or loss of consciousness greater than 2 min. After completing an eyes-closed resting condition, participants performed a 23-min CPT while both quantitative EEG and behavioral performance were measured at 45, 405, 765 and 1125 s into the CPT. Bipolar recordings were gathered using the International 10-20 system, from eight sites: frontal, fronto-temporal, temporal and temporal-occipital. Multivariate and follow-up univariate tests suggest the existence of a neurophysiological system located within the right temporal region that appears essential for the maintenance of a sustained attentional state. If confirmed, the further quantification of this neurocognitive system may prove useful as part of a clinical diagnostic workup.

Concurrent visual task effects on evoked and emitted auditory p300 in adolescents.

Using an oddball stimulus presentation paradigm, the effects of divided attention on auditory P300s were studied. Auditory attention was either divided or focused, depending on the demands placed on subjects during the performance of a concomitantly presented visual task. Two types of auditory tasks were performed under each of the two auditory attention conditions. In one, subjects responded to infrequently presented high pitched tones (oddball stimuli). In the other they responded to the occasional omission of a stimulus in an otherwise rhythmically presented chain of stimuli. P300s and reaction times were recorded to both the rare tones and the omissions. The Sternberg visual memory task was used to manipulate the subject's auditory attention state. Subjects actively performed the Sternberg task during the divided auditory attention condition, whereas during the focused attention condition they were not required to respond to the visual stimuli. During focused auditory attention, evoked auditory P300s were both larger and faster than their emitted counterparts. During divided attention, auditory P300s were reduced in amplitude but latency was unaffected. Evoked auditory P300s showed evidence of containing P300a as well as P300b components, particularly when attention was shared with the visual task.

Neurobehavioral functioning in asymptomatic HIV-1 infected women.

Numerous reports have assessed the neuropsychological functioning of medically asymptomatic HIV-1 infected men. However, to date there have been no published studies of the neuropsychological functioning of asymptomatic HIV-1 infected women, even though women represent the fastest-growing demographic group of HIV-1 infected individuals. In this investigation, 31 women (17 asymptomatic HIV-1 seropositive, 14 seronegative) were administered a battery of neurocognitive and neuropsychiatric instruments. Participants in both groups were matched for age, education, months since injection drug use, and substance use. Group comparisons revealed no significant differences in any of the neurocognitive or neuropsychiatric measures. The results of this preliminary study suggest that clinically significant differences in neurobehavioral function are unlikely in medically asymptomatic HIV-1 infected women compared to seronegative controls. However, additional studies are needed with larger sample sizes and with careful attention to possible confounding or masking variables.

Asymptomatic HIV-infected women: preliminary study of quantitative EEG activity and performance on a continuous performance test.

Several studies have examined the electrophysiological correlates of human immunodeficiency virus (HIV) infection in medically asymptomatic men. Although the rates of HIV infection are increasing at a greater rate in women than men, there have been no publications to date of electrophysiological functioning in HIV-infected women. In the present study, quantitative electroencephalographic (qEEG) activity was measured in 22 women (11 asymptomatic HIV-seropositive and 11 HIV-seronegative) utilizing a procedure comprised of three auditory continuous performance tests and a set of qEEG components derived from principal components analysis. No significant group differences were found in qEEG or in performance on the continuous performance tests; however, task-related differences were detected across groups between simple and complex language tasks in EEG fast beta power, delta power, and a left-hemisphere principal components analysis-derived EEG component. In examining the electrophysiological correlates of HIV infection, researchers might employ a similar methodology while increasing the sample size and varying the task modality or difficulty.

Assessment of mood state in patients undergoing electroconvulsive therapy: the utility of visual analog mood scales developed for cognitively impaired patients.

Reliable, valid, and brief measures of mood state are essential to the evaluation of electroconvulsive therapy (ECT) efficacy. However, existing measures of mood state may be inappropriate for patients with transient cognitive impairment. Stern and colleagues have recently developed a set of Visual Analog Mood Scales (VAMS) for use in neurologically impaired patients. These brief scales (including measures of sad, confused, afraid, happy, tired, angry, and energetic states) are easily administered and have documented reliability and validity in neurologically impaired patients and in healthy adult and geriatric samples. In the present study, we assessed the validity and sensitivity of the VAMS to detect ECT-related mood change. Twenty-five inpatients who were diagnosed with major depressive episode and referred for ECT were administered the VAMS and the Hamilton Depression Rating Scale (HDRS) both pre- and post-ECT. Results indicate that the VAMS are as sensitive to the therapeutic effects of ECT as is the more lengthy and verbally demanding HDRS. In addition, the VAMS were highly correlated with the clinician's Clinical Global Improvement rating and the patient's self-report using a modified Center for Epidemiological Studies-Depression scale. The VAMS are brief, reliable scales that are sensitive to the treatment effects of ECT and that are appropriate for patients with transient cognitive impairment.

A guide for applying principal-components analysis and confirmatory factor analysis to quantitative electroencephalogram data.

Principal-components analysis (PCA) has been used in quantitative electroencephalogram (qEEG) research to statistically reduce the dimensionality of the original qEEG measures to a smaller set of theoretically meaningful component variables. However, PCAs involving qEEG have frequently been performed with small sample sizes, producing solutions that are highly unstable. Moreover, solutions have not been independently confirmed using an independent sample and the more rigorous confirmatory factor analysis (CFA) procedure. This paper was intended to illustrate, by way of example, the process of applying PCA and CFA to qEEG data. Explicit decision rules pertaining to the application of PCA and CFA to qEEG are discussed. In the first of two experiments, PCAs were performed on qEEG measures collected from 102 healthy individuals as they performed an auditory continuous performance task. Component solutions were then validated in an independent sample of 106 healthy individuals using the CFA procedure. The results of this experiment confirmed the validity of an oblique, seven component solution. Measures of internal consistency and test-retest reliability for the seven component solution were high. These results support the use of qEEG data as a stable and valid measure of neurophysiological functioning. As measures of these neurophysiological processes are easily derived, they may prove useful in discriminating between and among clinical (neurological) and control populations. Future research directions are highlighted.

A survey study of neuropsychiatric complaints in patients with Graves' disease.

One hundred thirty-seven patients with treated Graves' disease completed a questionnaire pertaining to neuropsychiatric complaints. Psychiatric symptoms, especially anxiety and irritability, were common prior to treatment of hyperthyroidism. These complaints appeared to result in delays in seeking treatment as well as delays in receiving appropriate diagnosis. Subjects reported significantly worse memory, attention, planning, and productivity while hyperthyroid than prior to becoming hyperthyroid, and, although somewhat improved once euthyroid, they reported residual cognitive deficits. These results suggest that neuropsychiatric impairments are highly prevalent in Graves' disease, may lead to initial misdiagnosis or delays in diagnosis of the endocrine disorder, and may continue even once patients are believed to be euthyroid.

Comparison of QEEG and response accuracy in good vs poorer performers during a vigilance task.

Subjects performed an auditory continuous performance test requiring them to detect targets in a series of letters presented at a rate of 2/s. 2-min samples of EEG were obtained from eight bipolar sites during a resting condition and during early and late (7-10 min) test performance. EEG power spectra from 27 subjects whose performance accuracy decreased between these latter periods (LoVig group) were compared with those from 27 subjects who maintained a constant level of performance (HiVig group). In both groups EEG power changed significantly between resting and test conditions for all frequency bands: beta power increased, especially in fronto-temporal and temporal left-hemisphere sites; alpha and posterior theta decreased; anterior theta and delta increased. Significant changes also were found between early and late test performance: anterior theta and delta power decreased in both groups; temporal beta power decreased in the LoVig group only, and is thus considered the best indicator of performance changes. Other differences found between groups were across conditions. The HiVig group had more anterior beta and less posterior alpha and theta than the LoVig group. EEG results are discussed in relation to an explanation of vigilance errors based on signal detection theory.