Alfredo Ardila

Age-related cognitive decline during normal aging: the complex effect of education.

The purpose of this study was to further analyze the effects of education on cognitive decline during normal aging. An 806-subject sample was taken from five different Mexican regions. Participants ranged in age from 16 to 85 years. Subjects were grouped into four educational levels: illiterate, 1-4, 5-9, and 10 or more years of education, and four age ranges: 16-30, 31-50, 51-65, and 66-85 years. A brief neuropsychological test battery (NEUROPSI), standardized and normalized in Spanish, was administered. The NEUROPSI test battery includes assessment of orientation, attention, memory, language, visuoperceptual abilities, motor skills, and executive functions. In general, test scores were strongly associated with level of educational, and differences among age groups were smaller than differences among education groups. However, there was an interaction between age and education such as that among illiterate individuals scores of participants 31-50 years old were higher than scores of participants 16-30 years old for over 50% of the tests. Different patterns of interaction among educational groups were distinguished. It was concluded that: (a) The course of life-span changes in cognition are affected by education. Among individuals with a low level of education, best neuropsychological test performance is observed at an older age than among higher-educated subjects; and (b) there is not a single relationship between age-related cognitive decline and education, but different patterns may be found, depending upon the specific cognitive domain.

The impact of culture and education on non-verbal neuropsychological measurements: A critical review

Clinical neuropsychology has frequently considered visuospatial and non-verbal tests to be culturally and educationally fair or at least fairer than verbal tests. This paper reviews the cross-cultural differences in performance on visuoperceptual and visuoconstructional ability tasks and analyzes the impact of education and culture on non-verbal neuropsychological measurements. This paper compares: (1) non-verbal test performance among groups with different educational levels, and the same cultural background (inter-education intra-culture comparison); (2) the test performance among groups with the same educational level and different cultural backgrounds (intra-education inter-culture comparisons). Several studies have demonstrated a strong association between educational level and performance on common non-verbal neuropsychological tests. When neuropsychological test performance in different cultural groups is compared, significant differences are evident. Performance on non-verbal tests such as copying figures, drawing maps or listening to tones can be significantly influenced by the individuals culture. Arguments against the use of some current neuropsychological non-verbal instruments, procedures, and norms in the assessment of diverse educational and cultural groups are discussed and possible solutions to this problem are presented.

Neuropsychological assessment in illiterates: Visuospatial and memory abilities

A basic neuropsychological battery of visuospatial and memory abilities was administered to extreme educational groups (illiterates and professionals). Subjects were matched according to sex and age. The following visuospatial tasks were included: figure copy (cube, house, and Rey-Osterrieth complex figure), telling time, recognition of superimposed figures, recognition of a map, and drawing of the plan of the room. The following memory tasks were used: basic information, digit retention (forward and backward), memory curve, delayed verbal recall, sentence repetition, logical memory, delayed logical memory, immediate recall of the Rey-Osterrieth complex figure, immediate reproduction of a cube, visuospatial memory, and sequential memory. In visuospatial tasks all differences between the two groups were statistically significant. Five of the seven visuospatial tasks (all but telling time and recognition of superimposed figures) showed differences between age groups with a better performance found in the younger groups and four of the tasks (cube, house, Rey-Osterrith complex figure copying, and telling time) were significant between sexes with a better performance in men. In memory tasks, with the exception of the immediate memory of sentences, all tasks showed statistically significant differences between educational groups. Eight of the 13 memory tasks (digits forward and backward, delayed memory of words, immediate and delayed logical memory, Rey-Osterrieth immediate memory, cube immediate memory, and sequential memory) showed significant differences for age while 4 of the tasks (digits backward, memory curve, Rey-Osterrieth immediate memory, and cube immediate memory) were significant for sex. Results are analyzed with regard to current theories in cognitive psychology and anthropology. Emphasis is placed on the finding that cognitive skills usually examined by neuropsychological tests represent learned and highly trained abilities.

Directions of research in cross-cultural neuropsychology

Comparable cognitive disturbances associated with brain pathology have similar manifestations across members of the human species. However, cognitive abilities measured by neuropsychological tests represent, at least in their contents, culturally learned abilities. Performance is under the influence of a vast array of moderating variables, including: culture, ecological demands, primary language, and educational level. Test scores are associated therefore, not only with the subjects learning opportunities, but also with those variables which a culture dictates are worthy of cognitive amplification. Different cultural environmental contexts will result in the development of different patterns of abilities. The evaluation of an alien cultural group using our current neuropsychological instruments, procedures and norms, results in conceptual errors in assessment. Cross-cultural neuropsychology is in need of addressing several key focal points of neglected research: (1) the normalization of current basic neuropsychological instruments, in different cultural contexts, (2) the development of new neuropsychological instruments, appropriate for different cultural contexts, (3) the analysis of educational factors and subcultural variations in relation to test performance, (4) the analysis of cognitive disturbances in cases of brain pathology in different cultural and educational contexts, (5) the search for commonality in neuropsychological performance among existing human groups, and (6) the analysis of the origins of cognitive activity.

Neuropsychological assessment in illiterates. II, Language and praxic abilities

A basic neuropsychological examination of language and praxic abilities was administered to extreme educational groups (100 illiterates and 100 professionals). Subjects were matched according to sex and age (16-25, 26-35, 36-45, 46-55, and 56-65). The following tasks were included: language comprehension, phonological discrimination, naming (objects, figures, and body parts), repetition of words, verbal fluency, calculation, buccofacial and ideomotor praxis, finger alternating movements, meaningless movements, cancellation task, coordinated movements with both hands, and motor impersistence tasks. All the differences between the two educational groups were statistically significant. Two of the eight language tests (phonological discrimination and naming figures) and three of the seven praxic tests (buccofacial praxis, coordinated movements, and cancellation task) showed differences between age groups with a better performance in the younger groups. Calculation tasks and ideomotor praxis showed differences between sexes with a better performance in males. Influence of educational factors in performing routine neuropsychological tests is analyzed.

Prevalence of Attention-Deficit/Hyperactivity Disorder Symptoms in 4- to 17-Year-Old Children in the General Population

The purposes of this study were (a) to estimate the prevalence of Attention-Deficit/Hyperactivity Disorder (AD/HD) symptoms in the general preschool and school population; and (b) to analyze the influence of gender, age, and socioeconomic status (SES) variables on AD/HD symptoms. Out of the 80,000 preschool and schoolchildren living in Manizales, Colombia, a random sample of 540 children was selected. Two gender, three age (4- to 5-year olds, 6- to 11 -year olds, and 12- to 17-year olds), and three SES (low, middle, and high) groups were used. The 18 DSM-IV symptoms corresponding to AD/HD Criterion A were assessed on a scale of 0 (never) to 3 (almost always). All three demographic variables established statistically significant differences: AD/HD symptoms were more frequent in 6-to 11-year-old, low-SES, male participants. DSM-IV Criterion A for AD/HD was fulfilled by 19.8% of the boys and 12.3% of the girls. However, this difference was marginally significant only in the AD/HD Subtype I: Combined. It was concluded that demographic variables are significant correlates of the AD/HD diagnosis. The prevalence found in this study was higher than usually reported, even though only the symptomatic DSM-IV AD/HD criterion was analyzed. We failed to confirm the assumed AD/HD gender ratio.

The role of the arcuate fasciculus in conduction aphasia

In aphasia literature, it has been considered that a speech repetition defect represents the main constituent of conduction aphasia. Conduction aphasia has frequently been interpreted as a language impairment due to lesions of the arcuate fasciculus (AF) that disconnect receptive language areas from expressive ones. Modern neuroradiological studies suggest that the AF connects posterior receptive areas with premotor/motor areas, and not with Brocas area. Some clinical and neurophysiological findings challenge the role of the AF in language transferring. Unusual cases of inter-hemispheric dissociation of language lateralization (e.g. Brocas area in the left, and Wernickes area in the right hemisphere) have been reported without evident repetition defects; electrocortical studies have found that the AF not only transmits information from temporal to frontal areas, but also in the opposite direction; transferring of speech information from the temporal to the frontal lobe utilizes two different streams and conduction aphasia can be found in cases of cortical damage without subcortical extension. Taken altogether, these findings may suggest that the AF is not required for repetition although could have a subsidiary role in it. A new language network model is proposed, emphasizing that the AF connects posterior brain areas with Brocas area via a relay station in the premotor/motor areas.

Cultural values underlying psychometric cognitive testing.

It is proposed that culture (values, beliefs, styles of behavior) can affect neuropsychological testing.Cognitive testing represents a social situation that-as any social situation, it is one governed by implicit cultural rules. At least eight different culture-dependent values underlie cognitive testing: (1)One-to-one relationship, (2) Background authority, (3) Best performance, (4)Isolated environment (5) Special type of communication, (6) Speed, (7) Internal or subjective issues, and (8) The use of specific testing elements and strategies. In addition, it is proposed that“the distance” (e.g., gender, age, ethnicity) between the examiner and the examinee may potentiallyimpact the testing situation. A special analysis regarding the function of instruction in cognitive tests is also presented emphasizing that test instruction interpretation is also culture-dependent. Some potential avenues of research are finally proposed.

Cognitive Effects of Cocaine and Polydrug Abuse

One hundred and eighty-three participants were divided into three groups containing: 61 cocaine-dependent; 59 polydrug-dependent; and 63 normal subjects. All were evaluated using a basic neuropsychological assessment battery. The dependent groups exhibited significantly lower scores on short-term memory, attention, and concept formation tests. Performance on some subtests correlated negatively with the length of dependency and frequency of substance use. As compared with the control group, the dependent groups exhibited significant differences in the following personal and family areas: (a) depression and anxiety traits; (b) self-aggression and lack of fear in childhood; (c) family history of substance dependency; and (d) difficulties with interpersonal relationships. The operation of predisposing developmental factors for substance dependence is suggested.

Neuropsychological characteristics of normal aging

A basic neuropsychological battery was given to 346 normal adults. Participant characteristics were balanced according to: (a) age (55 to 60, 61 to 65, 66 to 70, 71 to 75, 76 or older), (b) sex, and (c) educational level (0 to 5 years, 6 to 12 years, more than 12 years of schooling). The items of the neuropsychological battery assessed language, memory, attention, abstraction, and constructional abilities, and also included a behavioral scale. Differences based on educational level were found for 28 of the 29 tests used, and age differences were found for 23, with better performance among younger and more highly educated participants. Sex differences were found for 10 tests, with better performance among males in 9 of these tasks. Few interactions were significant. A factor analysis was performed in which 43 factors were found to explain the total variance. However, a single factor explained 35.9% of the variance; this factor was related to visuospatial and visuomotor abilities. A second factor (6% of the...