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INTRODUCTION: Semantic verbal fluency (SVF) is the most commonly used test in the evaluation of normal and pathological functioning, whether it be clinically or experimentally. Several studies have suggested that the age, schooling and culture of the subject all affect performance in this test. To date no research has been conducted that proves whether there are differences between subjects who speak the same language but who come from different countries. PATIENTS AND METHODS: Data from the 'animals' category of the SVF in adult Spanish-speaking subjects and also the influence exerted by culture, age and schooling on the outcomes in this test were both submitted to analysis. The aforementioned variables were compared with the data reported by five research groups. RESULTS: The SVF test yields similar data from one Spanish-speaking country to another, provided that the subjects' age and schooling are taken into account. The differences found in this study may be due to variations in the way the tests are administered and scored rather than any cultural effect. We propose a standardised method of applying the test, so as to allow these variables to be unified in the future. CONCLUSION: Age and schooling are factors that determine performance in the SVF, although this is not true of culture.

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INTRODUCTION AND AIMS: In this work we review some of the options available in rehabilitation technology that are used to aid people with severe neuromuscular disorders, and which take electrophysiological activity as a source of biological signals with which to design interfaces. DEVELOPMENT: A number of different researchers have generated a novel communication and control system that utilises the electrical activity of the brain as a signal that represents the messages or commands an individual sends to the outside world, without using the normal output pathways of the brain, such as peripheral nerves and muscles; instead, this is achieved through an artificial system that extracts, encodes and applies them, called a brain-computer interface (BCI). The electrophysiological activity for a BCI can be obtained by means of superficial or implanted electrodes, and may therefore be classified as invasive or non-invasive. Five types of brain signals have been explored for use with a BCI: visual evoked potentials, slow cortical potentials, cortical neuronal activity, beta and mu rhythms, and event-related potentials. CONCLUSIONS: Thanks to recent improvements and developments in prototypes, this technology is sure to open up new possibilities of communication and control for the affected population; it also represents a valuable field of multidisciplinary research with numerous interesting applications in areas beyond the sphere of health care.

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We analyzed the influence of education and of culture on the neuropsychological profile of an indigenous and a nonindigenous population. The sample included 27 individuals divided into four groups: (a) seven illiterate Maya indigenous participants, (b) six illiterate Pame indigenous participants, (c) seven nonindigenous participants with no education, and (d) seven Maya indigenous participants with 1 to 4 years of education . A brief neuropsychological test battery developed and standardized in Mexico was individually administered. Results demonstrated differential effects for both variables. Both groups of indigenous participants (Maya and Pame) obtained higher scores in visuospatial tasks, and the level of education had significant effects on working and verbal memory. Our data suggested that culture dictates what it is important for survival and that education could be considered as a type of subculture that facilitates the development of certain skills.

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Departing from the observation that illiterates significantly underscore in some neuropsychological tests, a learning-to-read method named NEUROALFA was developed. NEUROALFA is directed to reinforce these underscored abilities during the learning-to-read process. It was administered to a sample of 21 adult illiterates in Colima (Mexico). Results were compared with 2 control groups using more traditional procedures in learning to read. The NEUROPSI neuropsychological test battery was administered to all the participants before and after completing the learning-to-read training program. All 3 groups presented some improvement in the test scores. Gains, however, were significantly higher in the experimental group in Orientation in Time, Digits Backward, Visual Detection, Verbal Memory, Copy of a Semi-Complex Figure, Language Comprehension, Phonological Verbal Fluency, Similarities, Calculation Abilities, Sequences, and all the recall subtests, excluding Recognition. Performance in standard reading tests was also significantly higher in the experimental group. Correlations between pretest NEUROPSI scores and reading ability were low. However, correlations between posttest NEUROPSI scores and reading scores were higher and significant for several subtests. Results are interpreting as supporting the assumption that reinforcement of those abilities in which illiterates significantly underscore results in a significant improvement in neuropsychological test scores and strongly facilitates the learning-to-read process. The NEUROALFA method of teaching reading to adult illiterates is beginning to be used extensively in Mexico. To our knowledge, this is the first attempt to apply neuropsychological principles to social problems.

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The purpose of this research was to develop, standardize, and test the reliability of a short neuropsychological test battery in the Spanish language. This neuropsychological battery was named "NEUROPSI," and was developed to assess briefly a wide spectrum of cognitive functions, including orientation, attention, memory, language, visuoperceptual abilities, and executive functions. The NEUROPSI includes items that are relevant for Spanish-speaking communities. It can be applied to illiterates and low educational groups. Administration time is 25 to 30 min. Normative data were collected from 800 monolingual Spanish-speaking individuals, ages 16 to 85 years. Four age groups were used: (1) 16 to 30 years, (2) 31 to 50 years, (3) 51 to 65 years, and (4) 66 to 85 years. Data also are analyzed and presented within 4 different educational levels that were represented in this sample; (1) illiterates (zero years of school); (2) 1 to 4 years of school; (2) 5 to 9 years of school; and (3) 10 or more years of formal education. The effects of age and education, as well as the factor structure of the NEUROPSI are analyzed. The NEUROPSI may fulfill the need for brief, reliable, and objective evaluation of a broad range of cognitive functions in Spanish-speaking populations.

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Most of the tests, questionnaires, and neuropsychological batteries for the assessment of dementia have been translated and adapted for use in the Hispanic population without having normative data, which results in a high number of false positives when age and educational level are not considered. The Short Cognitive Performance Test (SKT) is a psychometric instrument evaluating memory and attention deficits that has been developed and standardized in Germany (Erzigkeit, 1989a, 1989b). The objective of this study was to adapt the SKT, to establish normative criteria that take into consideration age and educational level, and to establish its concurrent validity in comparison to other neuropsychological tests: Brief Neuropsychological Evaluation for Spanish-Speaking Subjects (Ostrosky-Solis et al., 1994), the Mini-Mental State Examination (Folstein et al., 1975), and the Blessed Functional Scale (Blessed et al., 1968) in 238 neurologically intact subjects and 97 subjects with mild to moderate dementia. The SKT showed adequate sensitivity (80.5%) and specificity (80.3%) in subjects with medium and high educational level; however, the sensitivity and specificity diminished (75% and 56.7%) in subjects with no education or low educational level. The adapted and validated version of the SKT in the Mexican population has been shown to be a psychometric instrument that in subjects with medium educational level can detect cognitive alterations and is able to determine the severity of deterioration; however, in subjects with low educational level and severe dementia, the SKT cannot be usefully administered.

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One hundred and five normal subjects from 20 to 89 years old, and with a minimum of six years of formal education were selected. Subjects were divided into seven age ranges, with 15 subjects in each group. The following tests were individually administered: (1) Wechsler Memory Scale (WMS) (Wechsler, 1945); (2) Serial Verbal Learning (Ardila, Rosselli & Puente, 1994; Ardila & Ostrosky, 1991); (3) The Rey-Osterrieth Complex Figure (ROCF) (Osterrieth, 1944) (copy, immediate, and delayed reproduction); (4) Corsi's blocks (Milner, 1971) (forwards and backwards); and (5) Rivermead Behavioural Memory Test (Wilson, Cockburn, & Baddeley, 1985). This last test may be considered as a functional or ecological memory test. All test scores declined across ages between 4.1% and 76.6%. In all the tests, excepting Digits, standard deviations increased with age. It was observed that the youngest subjects could retain about three-fourths of the information presented, whereas the oldest retained around one-third of this information. About half of the test significantly correlated with the Rivermead Behavioral Memory Test. A factor analysis revealed four different factors accounting for 63.3% of the variance. A single nonverbal memory factor accounted for over 40% of the variance.

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The purpose of this study was to further analyze the effects of education across different age ranges on neuropsychological test performance. Two different analyses were performed. The first analysis was conducted in order to pinpoint the impact of school attendance on neuropsychological testing. A group of 64 illiterate normal subjects was selected in the Mexican Republic. Their performance was compared with two barely schooled control groups (1-2 and 3-4 years of schooling). The subjects' ages ranged from 16 to 85 years. In the second analysis, the illiterate subjects were further matched by age and sex with individuals with 1 to 4, 5 to 9, and 10 to 19 years of formal education. The Spanish version of the NEUROPSI neuropsychological test battery (Ostrosky, Ardila, & Rosselli, 1997) was used. Results indicated a significant educational effect on most of the tests. Largest educational effect was noted in constructional abilities (copying of a figure), language (comprehension), phonological verbal fluency, and conceptual functions (similarities, calculation abilities, and sequences). Aging effect was noted in visuoperceptual (visual detection) and memory scores. In the first subject sample, it was evident that, despite using such limited educational range (from 0-4 years of formal education), and such a wide age range (from 16-85 years), schooling represented a stronger variable than age. It is proposed that education effect on neuropsychological test performance represents a negatively accelerated curve, tending to a plateau.

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Subjects from four Mexican families at risk of inheriting Alzheimer's disease (AD) were studied using a complete neuropsychological battery. These tests were repeated and compared 1 year later. Some of the experimental subjects belong to an international protocol on molecular chromosomal study. A control group matched in age and schooling was included. The subjects at risk underwent a complete physical, neurological and neuropsychological assessment. A neuropsychological battery of cognitive domains designed for the the study of dementia syndromes was administered to all subjects. Six of the subjects showed abnormal performance in cognitive functions, memory, visuospatial functions or language which persisted 1 year later. The present work describes the initial findings of a long-term prospective study aimed at delineating the neuropsychological profile of subjects at risk and to validate subtle abnormalities which in some cases could be the incipient changes of AD.

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Research on aging processes have involved the study of evoked potentials. The last decades have witnessed increases in the study of the relationship between event related potentials and the brain's information processes. P300 has been widely studied to assess the neurophysiologic bases that underlie changes which take place during normal and physiologic aging settings. This study was aimed to establish normative data on the P300 component (latency and amplitude) in a Mexican population. One hundred and six (106) neurologically intact subjects, with ages ranging from 20 to 100 years were divided into seven groups. An electrophysiologic assessment using the classical paradigm to generate P300 was used. Monopolar registries referring to the auricular lobules and short circuiting in the Fz, Cz y Pz derivations while monitoring eye movements were used. ANOVA was used for analyzing the effects of age in the latency and the amplitude of both the N100 and P300 components for each one of the derivations. This analysis revealed statistically significant differences (p < 0.05) among the seven groups. The linear regression analysis showed an increase for each aging year in the 0.38 ms latency (r = 0.3804, p < 0.001) and a decrease in the 0.20 mV amplitude (r = 0.2036, p < 0.03). The normative data of the P300 component in the Mexican population studied yielded an objective reference for differential diagnosis and early detection of dementia disorders in patients belonging to a normal aging population.

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