Biomedical subjects

A Ardila

Publications and source records attributed to A Ardila.

At least 73 records · Page 4Linked to original sources

PubMed1989

Effects of cultural background and education on handedness.

A 5-item handedness questionnaire was given to 317 subjects in four different groups: (1) 51 Tucano (Amazonian jungle) adolescents (36 male, 15 female); (2) 66 Spanish-speaking adolescents (43 male, 23 female) with similar age and educational background to the Tucano group; (3) 100 urban subjects (50 male, 50 female) with a low educational level; and (4) 100 urban subjects (50 male, 50 female) with a high level of education. Hand preference scores were not affected by sex or educational level. The incidence of left-handedness was lower in the Tucano group than in the other groups, despite the fact that the Tucano culture is a highly permissive one. The two rural groups showed less extreme hand preferences than the urban groups, and the Tucano in particular were less likely to indicate extreme hand preferences on any of the items. These results indicate significant effects of culture and environment on declared hand preference, and may be pertinent to recent discussions of cerebral organization in illiterates.

Adolescent↗

PubMed1989

Calculation deficits in patients with right and left hemisphere damage.

Calculation abilities were studied in 41 left and 21 right hemisphere damaged patients. Their results were compared with a normal group matched by age, sex and educational level. Left hemisphere patients were grouped according to the type of accompanying aphasia. All patient groups presented at least a certain degree of acalculia. However, maximum difficulties were found in retrorolandic left hemisphere patients. Right hemisphere patients, especially retrorolandic patients, also presented impairments in calculation abilities, resulting mainly from spatial defects. Different types of errors were analyzed. Observed errors may be similar, but due to highly different neuropsychological dysfunctioning. Primary and secondary observed defects may be attributed to a diverse array of underlying deficits.

Adolescent↗

PubMed1989

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.

Adolescent↗

PubMed1989

Detection of brain damage: neuropsychological assessment in a Spanish speaking population.

We developed a neuropsychological battery for assessment of cognitive processes that was standardized in 150 neurologically intact subjects from different socioeducational levels in Mexico City (Ostrosky et al., 1985, 1986). The present study was designed to explore the capacity of this neuropsychological battery to discriminate a brain-injured population from a normal one. Thirty-four patients attending the neurological service of two hospitals institutions in Mexico City were studied. The reasons for going to the hospital included both neurological and neuropsychological symptoms. The group was divided into two subgroups: twenty-four patients who showed brain damage confirmed by brain scans, and ten patients with a normal brain scan. A control group of 19 normal subjects was also studied and paired with the other groups by sex, age and sociocultural level. The results show that the neuropsychological battery was able to recognize 83.3% of the patients with scanographically confirmed brain damage: the total percentage of successful diagnosis was 88.2% and there were no false positives. These results indicate that neuropsychological assessment is a powerful diagnostic procedure that also evaluates the patient's cognitive-behavioral activity and can help to predict the possibilities for rehabilitation and return to work.

Adult↗

PubMed1988

Neuropsychologic symptoms in the migraine syndrome.

Twenty patients with complex neuropsychologic symptoms associated with classic migraine were selected from a group of 200 patients with vascular headache. Twenty types of symptoms were found and grouped into six categories (language, visual symptoms, cognitive-dysmnesic symptoms, olfactory-gustatory hallucinations, automatisms, and somatosensory symptoms). Some of the symptoms found have apparently not been reported previously. The importance of the analysis of this complex neuropsychologic set of symptoms and of the possible consequences of complicated, frequent vascular headache is emphasized.

Adult↗

PubMed1988

Complex partial status and schizophrenia.

Three cases of complex partial status which were diagnosed as psychotic episodes are presented. The scans of two of these cases show structural abnormalities in the left temporal lobe. It is proposed that there are similar neurophysiological mechanisms in primary schizophrenia and in the perceptual, affective and cognitive phenomena apparent is some complex and psychic partial seizures. The hippocampal-amygdaline system plays a central role in both cases.

Adult↗

PubMed1988

Severe dementia associated with neurocysticercosis.

A severe case of dementia associated with a parenchymous miliar neurocysticercosis in a 15-year-old girl is described. Although there was general cerebral involvement, EEG, neurological and neuropsychological examinations showed a marked decrease in right hemisphere activity. Treatment with Praziquantel reduced the patient's intellectual deterioration, but hydrocephalus developed.

Adolescent↗

PubMed1988

Temporal lobe involvement in Capgras syndrome.

A Capgras syndrome case is presented. The clinical profile appeared at the onset of treatment with Praziquantel for neurocysticerosis. A left-temporal cysticercum was shown by means of a CT scan. Delusion, accompanied by some neurological symptoms diminished but did not disappear after treatment. The hypotheses for Capgras syndrome are reviewed and it is concluded that it constitutes a cognitive-dysmnesic phenomenon (feeling of unreality, impossibility to integrate recently acquired information with old memory traces) and, as such, its origin is likely temporal.

Adult↗

PubMed1988

Partial cognitive-dysmnesic seizures as a model for studying psychosis.

Nineteen patients were analyzed who exhibited cognitive-dysmnesic psychic partial seizures and structural damage shown by means of CT scans. It was observed that these seizures originated in the amygdala-hippocampal system, coinciding with the effects found when using electrical stimulation of the brain. An attempt is made to relate these findings to the present biochemical hypotheses of schizophrenia, the kindling effect and the genetico-maturational hypotheses. All these data seem to agree and point in the direction of the possible neurophysiological mechanisms of psychosis and of schizophrenia in particular.

Adolescent↗

PubMed1987

Linguistic abilities in patients with prefrontal damage.

The language abilities of 21 patients with prefrontal lesions (11 right and 10 left) and 15 matched normal subjects were analyzed, using a linguistic ability test designed to evaluate performance in six areas: automatic language, language production, verbal memory, syntax, derivative words, and comprehension of logical grammatical structures. Significant differences in the obtained scores of all groups were found. In spite of formal conservation of language in patients with frontal damage, their complex and conceptual verbal abilities were severely compromised.

Adolescent↗

PubMed1987

Aphasia for Morse code: a comment on Wyler and Ray (1986).

A. R. Wyler and R. W. Ray (1986, Brain and Language, 27, 195-199), present a case of aphasia for Morse code; they relate the deficit to the inability to detect high-speed auditory temporal sequences. Based on a personal observation of transient aphasia for Morse code, we proposed that at least three different abilities participate in recognizing and producing Morse code messages: (1) a specific linguistic ability, (2) a praxic skill, and (3) an auditory discrimination skill. Our patient presents difficulties in the first and second abilities, Wyler and Ray's in the third ability.

Aphasia↗

PubMed1987

Neuroelectric correlates of a neuropsychological model of word decoding and semantic processing in normal children.

The use of event-related potentials (ERPS) as a technique in the study of word decoding and semantic processing in the cerebral cortex was investigated. Ten right-handed boys, aged between nine and eleven, with adequate school performance were studied. Visual ERPS were obtained using four derivations: occipital (O1-O2) and parietal (P3-P4). Four stimuli were presented: a frequently used noun written in capitals; the same noun in handwriting; the pictorial representation of this noun (drawing); and a pattern consisting of a checkerboard (25 squares). The data were analyzed using multivariate procedures. A Principal Component Analysis with varimax rotation of the solution was applied. Concepts about reading contributed by cognitive psychology, neuropsychology and neurophysiological research are reviewed, and a hypothetical model of the neuronal bases underlying the act of reading is presented. This model emphasizes the complex, dynamic interplay of the neural structures involved and points to the differences which probably exist between beginning and fluent readers. The results are discussed in accordance with the proposed model.

Brain↗

PubMed1987

Neuroelectric correlates of a neuropsychological model of word decoding and semantic processing in reading disabled children.

The purpose of this study was to distinguish the characteristics and components of event related potentials (ERPs) correlated with word decoding and semantic processing in a subgroup of children with specific reading disabilities related to visual processing deficiencies. The results were compared with those obtained from a group of normal readers previously studied (Ostrosky et al. in press). Visual ERPs were recorded to four stimuli: three physically different but with the same semantic content: a frequently used noun written in capitals (COCHE), the same noun in handwriting, the pictorial representation of the noun (drawing), and a neutral stimulus consisting of a checkerboard. Four derivations were used: occipital (O1-O2) and parietal (P3-P4) with reference to linked mastoids. Data were analyzed using multivariate procedures. A Principal Component Analysis with Varimax rotation of the solution was applied. In the normal readers, we found some components in the occipital derivations which identified the words presented in different styles of handwriting and others which seemed to identify these words with the pictorial representation (and not with the neutral stimuli). The first "verbal" components were situated around the 156-256 ms latency range and the second "semantic" components were observed at over 380 ms. In the disabled readers, there was no "verbal" or "semantic" recognition grouping of these physically different stimuli. As opposed to the normal readers, interhemispheric responses were symmetrical. At the left parietal leads in the normal readers, the morphology of the verbal stimuli (capitals and handwriting) were very similar throughout the sweep and both were very different from the nonverbal stimuli. At 376 ms the four stimuli elicited a prominent negative peak in which the verbal stimuli elicited significantly higher amplitude than the nonverbal stimuli. In the disabled group, the morphologies of the four stimuli were very similar and no significant differences were observed. The results are discussed in accordance with a hypothetical model of the neural bases underlying reading. The model takes into account the complexity of the reading process and the various cognitive skills required for its adequate performance, and emphasizes a complex, dynamic interplay between occipital, parietal and temporal areas.

Cerebral Cortex↗

PubMed1987

Handedness and psychophysics: weight and roughness.

A sample of 20 men (10 right-handed, 10 left-handed) was selected. Using the method of constant stimuli, the number of correct responses and the differential threshold for weight and roughness for both hands, were studied. The findings were: (1) In the weight test, the number of correct responses was greater and the differential threshold lower in the right-handed than in the left-handed subjects, and the preferred hand was superior to the nonpreferred hand for both groups; (2) In the roughness test, the number of correct responses was greater and the differential threshold lower for the nonpreferred hand. Implications of these findings with regard to our present knowledge of handedness organization are analyzed.

Adult↗

PubMed1987

Palinopsia and visual allesthesia.

Two cases of palinopsia are reported. The first patient had palinopsia and visual allesthesia secondary to an occipital calcified cysticercus. Symptoms were more prominent during treatment for his parasitic infection. The second case was a patient with long standing vascular headaches associated for many years with episodes of visual persistence; he had a right occipital lobe infarct; he reported deformation of images, illusion of movement and macropsia in his left homonymous hemianoptic visual field. Different hypotheses for explaining palinopsia have been proposed. An analysis of our cases does not prove or disprove any of the current hypotheses. However, the current hypotheses do not necessarily contradict each other. Implications of the two cases reported are analyzed.

Adult↗

PubMed1987

Huntington's disease in Colombia: a neuropsychological analysis.

This is the first publication of the presence of Huntington's disease (HD) in Colombia. We studied four families comprising nine adult HD patients and 45 high risk adult offspring; all received complete physical, neurological and neuropsychological examinations. Among affected individuals, intensity of mental involvement varied in direct proportion with duration of the symptoms. The HD patients and some of the asymptomatic offspring displayed similar low scores on standardized tests of memory, language and constructive abilities. Prolonged follow-up of the latter group will allow assessment of the potential value of such tests for early diagnosis. The sequence followed by mental deterioration is discussed.

Adolescent↗

PubMed1986

Severe stuttering associated with right hemisphere lesion.

Following a right hemisphere stroke, a right-handed, 50-year-old male experienced a permanent dysfluency characterized by phoneme and syllable reiterations and, to a lesser extent, word and phrase reiterations. The reiterations occurred in initial, medial, and final positions and for all sentence elements (e.g., subject nouns, object nouns, verbs, modifiers). There was a notable loss of verbal automatisms (poems, songs, etc.). The patient's symptoms conform to the acquired stuttering syndrome described by A. Helm, R. Butler, and D.F. Benson (1978, Neurology, 28, 1159-1165).

Cerebrovascular Disorders↗

PubMed1986

Echoic memory and language perception.

The purpose of this study was to analyze asymmetry in echoic memory as a relevant factor in language perception. Two experimental procedures were used: the presentation of temporally segmented words in fragments of 40, 80, 120 and 240 msec, separated by intervals of 40, 80, 120 and 240 msec, similar to the procedures used by A. W. F. Huggins (1975, Perception & Psychophysics, 18, 149-157); the presentation of two tones of short duration, "high" and "low," followed by an interference tone equivalent to the mean frequency of the two tones, closely following the procedure used by D. W. Massaro (1975, in D.W. Massaro (Ed.), Understanding language, New York: Academic Press). A stereophonic tape recorder was used as follows: one channel was employed for the presentation of the words or tones while, through the other channel, the subject received a white noise equivalent in intensity. All subjects carried out the task twice (right ear, left ear) and the order of presentation was counterbalanced. Only the first task showed differences between ears. Implications of the results are analyzed.

Adolescent↗