Felipe García-Pedroza

Motor Control Alteration in Posturography in Learning-Disabled Children

BACKGROUND Some authors have mentioned that intersensory integration is damaged in children with learning disabilities (LDs), and other investigators point to motor control alterations in the same patients. Thus, we decided to study these hypotheses by means of posturographic recordings. METHODS A highly selected group of 27 children with LDs was compared with 27 children of control group without LDs. Patients and controls were placed on the Equitest equipment platform. Sensory organization tests evaluated different test conditions that systematically vary visual, vestibular, and foot somatosensory cues available to subjects while they attempt to maintain a stable, quiet stance. Movement coordination test involved sudden posterior and anterior translations of the patient support surface. RESULTS No significant correlations between scholastics and posturographic performance were observed. No difference in the six conditions and in sensory organization ratios or in visual preference between both groups was disclosed. Motor control test on children with LDs showed significant higher values in latencies in averages of large translations. CONCLUSIONS Our data suggest that vestibular-visual-somatosensory organization for posture control are not abnormal in children with LDs; instead, motor controls show higher latencies with large translation movements, which suggest abnormal rate and timing precision motor coordination.

Phonological and Visuo-Spatial Working Memory Alterations in Dyslexic Children

BACKGROUND Working memory allows the retention of a limited amount of information for a brief period of time and the manipulation of that information. This study was undertaken to compare possible differences in working memory between dyslexic and control children. METHODS To test the executive central process that controls attention, subjects were requested to assemble a 100-piece puzzle. To test the phonological loop, subjects were requested to repeat orally a 10-item list with the following characteristics: digits spanning two numbers; phonologically similar words, and unfamiliar pseudowords. The visuo-spatial sketchpad was tested by means of assembling a 25-piece puzzle. RESULTS Forty dyslexic and and forty control children were studied. Dyslexic children recall a lesser number of similar words in the phonological loop and spend a longer time in puzzle assembly in the visuo-spatial sketchpad. No statistical difference in the central executive process was found. CONCLUSIONS Present results suggest the importance of visuo-spatial and phonological loop alterations in dyslexic children that may result in difficulties with similar words and spatial information.

Characteristics of specific reading disability in children from a neuropsychological clinic in Mexico City

OBJECTIVE This report describes the main clinical features associated with specific reading disability (RD) in a group of 778 school-age children studied in a Neuropsychological Clinic in Mexico City. MATERIAL AND METHODS The study was performed retrospectively, using data abstracted from clinical records of subjects seen in 1995-1996. Children were mainly from low and middle economic strata and aged between 6 to 12 years. The following data were collected: age, gender, diagnosis, school grade, food intake, maternal complications during pregnancy, perinatal and postnatal neurological risk factors, and neurological signs and handedness. RESULTS Subjects with RD had a mean age of 102.9 months, were predominantly male (male female ratio, 2:1). Among the study group, 49.1% of the children were diagnosed with RD of a visuo-sensory-motor type, and 75.1% were from early school years (1st to 3rd grades); 27.6% showed evidence of malnutrition. A previous history of language disorders (49.2%), and a high frequency of perinatal risk factors and neurological soft signs were also found. CONCLUSIONS This study shows that variables such as gender, food intake, and genetic and neurological risk factors, were associated with reading disabilities in school children. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Right cerebral hemisphere and central auditory processing in children with developmental dyslexia

OBJECTIVE We hypothesized that if the right hemisphere auditory processing abilities can be altered in children with developmental dyslexia (DD), we can detect dysfunction using specific tests. METHOD We performed an analytical comparative cross-sectional study. We studied 20 right-handed children with DD and 20 healthy right-handed control subjects (CS). Children in both groups were age, gender, and school-grade matched. Focusing on the right hemispheres contribution, we utilized tests to measure alterations in central auditory processing (CAP), such as determination of frequency patterns; sound duration; music pitch recognition; and identification of environmental sounds. We compared results among the two groups. RESULTS Children with DD showed lower performance than CS in all CAP subtests, including those that preferentially engaged the cerebral right hemisphere. CONCLUSION Our data suggests a significant contribution of the right hemisphere in alterations of CAP in children with DD. Thus, right hemisphere CAP must be considered for examination and rehabilitation of children with DD.

Evaluación de procesos centrales de la audición con pruebas psicoacústicas en niños normales

OBJECTIVE To identify the natural tendencies of hits and calculate the cutoff for a test group of central auditory processes (CAP): binaural fusion, filtered words, dichotic digits, frequency patterns and duration patterns and ambient sounds in normal 5-, 7-, 9- and 11-year-old children. MATERIAL AND METHODS We studied 369 children (738 ears) who attend public schools in Puebla City, administering 6 CAP tests (two binaural and four monaural); we used an audiometer at 50dB SL re-threshold at 1 kHz, from a CD recorded at the CCECADET-UNAM-INR (Centre for Applied Science and Technological Development at the National Autonomous University of Mexico and the National Institute for Rehabilitation). RESULTS We determined the cutoff points for the six tests. CONCLUSION This information represents an advance in the normative standards in the field of psychoacoustic tests for CAP in Spanish and in the socio-educational context prevalent in Mexico. It is important to evaluate these results against CAP disorders.

Los objetos de aprendizaje reutilizables como recurso para la docencia en Medicina Familiar

Educational and operational strategies of distance education –including computer systems, internet and its applications– allow reducing costs associated with professional training and favor the creation of programs to address similar needs of groups whose geographical dispersion would be difficult and expensive to the educational process. The Sub-division of Family Medicine of the Division of Post-graduate Studies of the Faculty of Medicine at the National Autonomous University of Mexico (unam) is expecting to incorporate the Reusable Learning Objects –made by their personal academic– in national and international repositories. Therefore both teachers and students –of the Course of Specialization in Family Medicine– can strengthen their academic and clinical performance.