Analysis of descriptive electrophysiological parameters in contralateral interlimb reflexes on tetraplegic patients.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: The present study aims to analyze and correlate the interlimb reflexes (ILRs), through a standard methodology, in tetraplegic and healthy subjects. The study of the connectivity between the injured spinal cord and the ILR transmission empowers new rehabilitation pathways for tetraplegic patients. SETTING: University Hospital-UNICAMP, Campinas, Brazil. METHODS: A total of 15 chronic tetraplegic patients and 10 healthy subjects were analyzed with the same methodology. Two tests were performed: (i) In test 1, the stimulus was applied to the right-arm radial nerve and the electromyography (EMG) signal collected in contralateral left tibial muscle. (ii) In test 2, the stimulus was applied to the left-leg fibular nerve and EMG collected in contralateral limb biceps, exploring the opposite direction of the pathway. In both tests, the subjects were stimulated with intensities from 5 to 30 mA (5 mA step) and 40 × 500 µs current modulated pulses. Reflexes were detected from the averaging of the 40 EMG sweeps. RESULTS: Each group was analyzed with regard to the reflexes' incidence, amplitude and latency. ILRs were found with similar prominence in both groups. A correlation between the ILR amplitude and the subject injury level was verified. Significant differences were found in the correlation of ILR latency with stimulation charge between healthy and tetraplegic subjects. CONCLUSION: The ILR transmission parameters of healthy and tetraplegic subjects were studied. The results obtained strongly suggest a different ILR transmission between healthy and tetraplegic subjects, reinforcing the hypothesis of nerve regeneration after injury.

Fatigue Evaluation through Machine Learning and a Global Fatigue Descriptor.

Research in physiology and sports science has shown that fatigue, a complex psychophysiological phenomenon, has a relevant impact in performance and in the correct functioning of our motricity system, potentially being a cause of damage to the human organism. Fatigue can be seen as a subjective or objective phenomenon. Subjective fatigue corresponds to a mental and cognitive event, while fatigue referred as objective is a physical phenomenon. Despite the fact that subjective fatigue is often undervalued, only a physically and mentally healthy athlete is able to achieve top performance in a discipline. Therefore, we argue that physical training programs should address the preventive assessment of both subjective and objective fatigue mechanisms in order to minimize the risk of injuries. In this context, our paper presents a machine-learning system capable of extracting individual fatigue descriptors (IFDs) from electromyographic (EMG) and heart rate variability (HRV) measurements. Our novel approach, using two types of biosignals so that a global (mental and physical) fatigue assessment is taken into account, reflects the onset of fatigue by implementing a combination of a dimensionless (0-1) global fatigue descriptor (GFD) and a support vector machine (SVM) classifier. The system, based on 9 main combined features, achieves fatigue regime classification performances of 0.82 ± 0.24, ensuring a successful preventive assessment when dangerous fatigue levels are reached. Training data were acquired in a constant work rate test (executed by 14 subjects using a cycloergometry device), where the variable under study (fatigue) gradually increased until the volunteer reached an objective exhaustion state.

Prevalence of epilepsy in rural Bolivia: a door-to-door survey.

OBJECTIVE: To carry out a door-to-door survey in rural areas of the Cordillera Province, Santa Cruz Department, Bolivia, to determine the prevalence of neurologic diseases (epilepsy, stroke, parkinsonism, and peripheral neuropathy) in a sample of approximately 10,000 inhabitants. METHODS: A team of nondoctor health workers administered a standard screening instrument for neurologic diseases-a slightly modified version of the World Health Organization protocol. All subjects found positive during the screening underwent a neurologic examination. RESULTS: On screening, the authors found 1,130 positive subjects, of whom 1,027 were then investigated by neurologists. On the basis of the definition proposed by the International League Against Epilepsy, we detected 124 epileptic patients (prevalence, 12.3/1,000), 112 of whom had active epilepsy (prevalence, 11.1/1,000) on the prevalence day (November 1, 1994). Peak age-specific prevalence occurred in the 15 to 24-year age group (20.4/1,000). Sex-specific prevalence was higher in women (13.1/1,000) than men (11.4/1,000). Eighty-nine patients (71.8%) underwent a standard EEG recording. Considering both EEG and clinical data, partial seizures were the most common type (53.2%) based on the classification of the International League Against Epilepsy. The mean age at onset was 20.7 years for partial seizures and 13.6 years for generalized seizures. Only 10.5% of patients had received specific treatment for more than 2 months of their life. CONCLUSION: This report on epilepsy prevalence in Bolivia confirms that epilepsy is a major health problem in rural areas of developing countries.

Seroprevalence of Toxocara canis-IgG antibodies in two rural Bolivian communities.

A survey on toxocara canis-IgG seroprevalence was carried out in two Bolivian communities (Mora and Zanja Honda) living in the Cordillera Province, Department of Santa Cruz. Two hundred and sixteen people, both males and females, 2 to 85 years old were sampled. Altogether, 73 people were positive (34%). The seroprevalence was 27% in Mora and 42% in Zanja Honda (p = 0.022). No statistical correlations were found with sex and age. High prevalences were also found for intestinal helminths (hookworms, Trichuris trichiura, Ascaris lumbricoides, Hymenolepis nana and Strongyloides stercoralis). Positive association between T. canis seropositivity and presence of T. trichiura and between T. trichiura and hookworms were found. T. canis egg prevalence in dog population was found consistently higher in Zanja Honda than in Mora (40% vs 27%).

In vitro antimicrobial sensitivity of staphylococci isolated in the Santa Cruz region of Bolivia.

The in vitro antimicrobial susceptibility of staphylococci isolated in two different communities, Camiri and Javillo, of the Santa Cruz region in south-eastern Bolivia was tested by the agar diffusion technique and by a micro dilution susceptibility test to determine the Minimum Inhibitory Concentrations. Staphylococcal strains isolated from hospital staff of the Camiri Hospital were compared to that isolated from healthy people of Javillo, a very small community isolated in the jungle. In the Camiri Hospital, staphylococci showed a high prevalence of penicillin resistance, 100% for S. aureus strains and 73.5% for coagulase-negative staphylococci. Among coagulase-negative strains we found a high rate of multiresistant strains, mainly to ampicillin, tetracycline and chloramphenicol. In the rural population of Javillo we found staphylococcal strains highly susceptible to all the antibiotics tested.

Comparative efficacy of a single 400 mg dose of albendazole or mebendazole in the treatment of nematode infections in children.

The relative efficacy of a single 400 mg dose of albendazole or mebendazole in the treatment of nematode infections was assessed in 2- to 9-year-old children living in two different Bolivian rural communities. Both agents were equally very effective (100% cure rate) in treating ascariasis. Albendazole was clearly more active than mebendazole against hookworm infections, both in terms of egg reduction rate (92.8% vs. 62.4%) and cure rate (81.8% vs. 17.2%). As far as trichuriasis is concerned, albendazole produced a higher egg reduction rate than mebendazole (45.7% vs 15%), but a lower cure rate (33.3% vs 60%). Both drugs were well tolerated.

Spectral analysis of cervical cells using the discrete Fourier transform.

This paper contains results from a preliminary study of spectral analysis techniques applied to the classification of cervical cells from routinely prepared Papanicolaou cervical smears. Experiments were conducted using a subset of 110 normals and 110 dyskaryotic single cell images randomly selected from a larger cell image data base. An assessment was made of the contribution of different regions within a cell image to the frequency spectrum. Three image sets were used, the original image itself plus two derived from it. In the first derived set, only nuclear size and shape were used. In the second set nuclear morphology and texture were included. Nuclear masking was performed using an interactive segmentation procedure. The discrete Fourier transform was applied to each image in the three image sets and classification experiments were performed using 80 features derived from the frequency spectra. An optimum set of features was selected for each experiment by canonical analysis. Good classification results were obtained when features extracted solely from nuclear shape were used. The inclusion of information relating to nuclear texture improved the results. However, inclusion of the extra nuclear region degraded the classifier's ability to discriminate between cell groups.

Antimicrobial agent susceptibility patterns of staphylococci isolated in urban and rural areas of Bolivia.

Staphylococcal strains obtained from cutaneous swabs of hospital staff and school students of Camiri and Boyuibe and healthy people living in Javillo, Bolivia, were tested for their in-vitro antimicrobial susceptibility. The highest percentages of resistance to the antibiotics tested were found in staphylococcal strains isolated from hospital personnel. All the S. aureus strains from these subjects were resistant to penicillin. Coagulase-negative staphylococci from hospital personnel evidenced a high rate of multiresistant strains, mainly to penicillin, ampicillin, tetracycline, and chloramphenicol. The staphylococcal strains isolated in the rural population of Javillo were highly susceptible to all the antibiotics tested.

Prevalence of measles antibodies before and after vaccination in previously unvaccinated children of the Cordillera Province (Santa Cruz Department, Bolivia).

A study was carried out in the Cordillera Health District (Santa Cruz Department, Bolivia) from October 1988 to April 1989 to determine the seroprevalence of measles antibodies and the seroconversion rates among a group of previously unvaccinated children (9-36 months of age) from the urban and rural area of the province, before and after immunization with a standard dose of Schwarz measles vaccine. Among 265 previously unvaccinated children, 77 (29%) had measles IgG antibodies prior to immunization; 141 out of 147 (96%) seronegative children at the time of vaccination seroconverted. No difference in seroprevalence and in seroconversion rates was found between the urban and rural groups.

A neuroepidemiological survey in rural Bolivia: background and methods.

A door-to-door survey was carried out in rural areas of the Cordillera province, Santa Cruz Department, Bolivia. A cluster sample of 10,124 inhabitants was selected. The aim was to determine the prevalence of the most common neurological diseases (epilepsy, stroke, parkinsonism and peripheral neuropathy) in this population using a modification of the World Health Organization screening instrument. 1,130 subjects screened positive and were then investigated by neurologists. In this paper we describe the background and methods of the survey and the characteristics of the population.

Prevalence of stroke : a door-to-door survey in rural Bolivia.

BACKGROUND AND PURPOSE: We carried out a door-to-door survey in rural areas of the Cordillera Province, Santa Cruz Department, Bolivia. A cluster sample of 10 124 inhabitants was selected, and 9955 subjects were screened. The aim was to determine the prevalence of the most common neurological diseases (epilepsy, stroke, parkinsonism, and peripheral neuropathy) in this population. METHODS: We used a modified version of the World Health Organization screening instrument. On screening we found that 1130 subjects tested positive, and 1027 underwent a complete neurological examination. According to the World Health Organization guidelines, we defined stroke as "rapidly developing clinical signs of focal (or global) disturbance of cerebral functions, lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin." We considered only first stroke and excluded a possible stroke. RESULTS: We found 16 subjects (cases) who had experienced 1 complete stroke on prevalent day (November 1, 1994). The crude prevalence of stroke was 174/100 000 (322/100 000 age-adjusted to the world standard population) and 663/100 000 in subjects aged >/=35 years. Prevalence was >2-fold higher in men than in women (247/100 000 and 99/100 000, respectively) and increased rapidly with age. Seven cases were hospitalized and received specific treatment. CONCLUSIONS: Our crude prevalence is lower compared with rates from developed countries, probably because of a high case fatality rate. Our findings are comparable with those reported from other surveys carried out in rural developing countries.

Automation in cervical cytology: an overview.

Cancer of the uterine cervix is one of the more common female cancers and a major source of premature female mortality. UK deaths in 1987 exceeded 2000. To reduce these rates, national screening programmes have been introduced using the Papanicolaou method. In screening for cancer, the examination of specimens is an intensive and expensive task. Its high cost has led to a number of attempts to automate the process, either fully or partially. Over the last 30 years, various experimental prescreening systems have been developed for the diagnosis of cytological samples including the use of image processing techniques. This paper presents a historical overview of automation in cervical cytology and the status of current developments for automated cytological diagnosis.

Frequency of atlantoaxial subluxation and neurologic involvement in patients with ankylosing spondylitis.

OBJECTIVE: To determine the prevalence of anterior and vertical atlantoaxial subluxation (AAS) and its neurological effect in a consecutive sample of Mexican patients with ankylosing spondylitis (AS). METHODS: Consecutive patients with a diagnosis of AS who attended 2 secondary care outpatient rheumatology clinic in the city of Guadalajara within a period of 6 mo were included in the study. Patients had prospective rheumatologic and neurologic assessments using structured questionnaires and examinations. Recorded variables included demographic data, disease characteristics, neurologic symptoms and signs, and axial mobility measurements. Somatosensory evoked potentials (SSEP) were performed in all patients. Patients also underwent standard cervical spine radiography with anteroposterior open mouth, and neutral, full flexion and extension lateral views. RESULTS: We studied 103 patients. Mean age was 35 yrs, 74% were male, and mean disease duration was 10 yrs (S/- SD 7.9). Anterior AAS was observed in 22 patients (21%, 95% CI 13-29%) and vertical AAS in 2 cases (2%, 95% CI 0-7%). Ossification of the posterior longitudinal ligament (OPLL) was present in 16 patients. Statistically significant associations were observed between anterior AAS and SSEP (p < 0.0001) and OPLL (p = 0.04). The degree of radiologic sacroiliitis was also associated with anterior AAS. After completion of the study, 2 patients required surgical fusion due to severe cervical cord compression. CONCLUSION: The prevalence of AAS and OPLL in this population was higher than previously reported in other settings. The association of anterior AAS with OPLL and radiological sacroiliitis could identify a subgroup of patients with more severe axial enthesopathy. Although clinically significant neurologic complications are not frequent in these patients, AAS may cause severe spinal cord compression requiring surgical fusion.