Neurociencia y Educación: ¿podemos ir de la investigación básica a su aplicación? Un posible marco de referencia desde la investigación en dislexia1 / Neurociencia y Educación: ¿podemos ir de la investigación básica a su aplicación? Un posible marco de referencia desde la investigación en dislexia

La neurociencia podría transformar la educación, pues proporciona nuevos métodos para comprender el aprendizaje y el desarrollo cognitivo, sus mecanismos causales y una forma empírica de evaluar la eficacia de diferentes pedagogías. No obstante, éste sería un objetivo a largo plazo. Desde la neurociencia educativa se debería empezar estudiando cómo los sistemas cognitivos se construyen sobre los sensoriales a lo largo del desarrollo. Aquí me centraré en el lenguaje. Pequeñas diferencias individuales iniciales en una función sensorial, por ejemplo la auditiva, podrían ser el origen de notables diferencias individuales en el desarrollo lingüístico. La neurociencia podría proporcionar una comprensión detallada de los mecanismos causales del desarrollo que vinculan la audición, el desarrollo fonológico y el desarrollo de la alfabetización. Este tipo de investigación neurocientífica básica podría orientar al campo de la educación y la pedagogía explorando los efectos que sobre estos mecanismos ejercen diferentes contextos pedagógicos y de aprendizaje

Neuroscience has the potential to transform education because it provides novel methods for understanding human learning and cognitive development. It therefore offers deeper understanding of causal mechanisms in learning and an empirical approach to evaluating the efficacy of different pedagogies. However, this will be a long-term enterprise and there will be few immediate pay-offs. Here I set out one possible framework for linking basic research in neuroscience to pedagogical questions in education. I suggest that the developing field of educational neuroscience must first study how sensory systems build cognitive systems over developmental time. I focus on one cognitive system, language, the efficient functioning of which is critical for reading acquisition. Small initial differences in sensory function, for example auditory function, have the potential to cause large differences in linguistic performance over the learning trajectory. The tools offered by neuroscience can enable better understanding of the causal developmental mechanisms linking audition, phonological development and literacy development, in fine-grained detail. Following this basic research, neuroscience can then inform education and pedagogy by exploring the effects on these neural mechanisms of different learning contexts and pedagogies

Diagnosis and treatment of mitochondrial myopathies.

Mitochondrial disorders are a heterogeneous group of disorders resulting from primary dysfunction of the respiratory chain. Muscle tissue is highly metabolically active, and therefore myopathy is a common element of the clinical presentation of these disorders, although this may be overshadowed by central neurological features. This review is aimed at a general medical and neurologist readership and provides a clinical approach to the recognition, investigation, and treatment of mitochondrial myopathies. Emphasis is placed on practical management considerations while including some recent updates in the field.

Audiometric screening of a population with intellectual disability.

OBJECTIVE: Evaluation of pure-tone audiometry (PTA) in hearing screening of a population with mild to profound intellectual disability (ID). DESIGN: PTA was performed at six frequencies at the screening level 20 dB HL. Referral criteria were threshold levels ≥ 25 dB HL at two or more frequencies for one ear or both. STUDY SAMPLE: 1478 participants aged 7-91 years were included. RESULTS: 1470 (99.5%) people cooperated in screening of which 1325 (90%) could be tested on both ears at all six frequencies. A majority, 987 (66.8%), performed ordinary PTA, 234 (15.8%) conditioned play audiometry, and 249 (16.9%) behavioural observation audiometry. Six hundred and sixty-nine (45%) passed and 809 (55%) failed according to referral criteria. Of those failing, 441 (54.5%) accepted referral to clinical evaluation. CONCLUSIONS: PTA with slight modifications is applicable for screening of a population with mild to profound intellectual disability. The most challenging and time-consuming activity is to introduce the test procedure in a way that reduces anxiety and establishes trust.

Donepezil in the treatment of musical hallucinations.

Musical hallucinations (MH) typically occur among elderly individuals and are associated with hearing impairment. The authors describe a patient with features of typical MH who was successfully treated with donepezil, a cholinesterase inhibitor, as a combination therapy and who has not shown any subsequent cognitive decline for approximately 5 years. The efficacy of donepezil in this patient indicates that age-dependent dysfunction of cholinergic neurons might be related to the development of MH.

Hearing voices: explanations and implications.

Integrating information on voice hearing from multiple disciplines and perspectives, we review current explanatory models and their implications for intervention strategies. Far from always signifying a mental illness, voice hearing may result from other causes, including drug side effects, brain lesions, and culturally-sanctioned phenomena. Accordingly, a wide range of assessment, intervention, and self-management strategies are available and appropriate. We conclude that by offering a diversity of treatment options, eliciting patients' causal theories, and incorporating these into an individualized treatment strategy, clinicians are likely to help clients control the distressing aspects of the voices, minimize stigma and discrimination, and make meaning of the experience.

A spatial hearing deficit in early-blind humans.

An important issue in neuroscience is the effect of visual loss on the remaining senses. Two opposing views have been advanced. On the one hand, visual loss may lead to compensatory plasticity and sharpening of the remaining senses. On the other hand, early blindness may also prevent remaining sensory modalities from a full development. In the case of sound localization, it has been reported recently that, under certain conditions, early-blind humans can localize sounds better than sighted controls. However, these studies were confined to a single sound source in the horizontal plane. This study compares sound localization of early-blind and sighted subjects in both the horizontal and vertical domain, whereas background noise was added to test more complex hearing conditions. The data show that for high signal-to-noise (S/N) ratios, localization by blind and sighted subjects is similar for both azimuth and elevation. At decreasing S/N ratios, the accuracy of the elevation response components deteriorated earlier than the accuracy of the azimuth component in both subject groups. However, although azimuth performance was identical for the two groups, elevation accuracy deteriorated much earlier in the blind subject group. These results indicate that auditory hypercompensation in early-blind humans does not extend to the frontal target domain, where the potential benefit of vision is maximal. Moreover, the results demonstrate for the first time that in this domain the human auditory system may require vision to optimally calibrate the elevation-related spectral pinna cues. Sensitivity to azimuth-encoding binaural difference cues, however, may be adequately calibrated in the absence of vision.

[Acoustic evoked potentials in patients with vocal problems in relation to their hearing in wide frequency range]. / Slukhovye vyzvannye potentsialy u bol'nykh s narusheniiami golosa v zavisimosti ot sostoianiia slukha v rashirennom diapazone chastot.

The function of different compartments of the acoustic analyser was assessed by the findings at tonal audiometry in standard and extended range of frequencies (10, 12, 14 and 16 kHz) as well as by characteristics of acoustic evoked potentials. A total of 62 patients with chronic vocal dysfunction (CVD) and 20 subjects with normal hearing and voice were examined. CVD patients were found to have: normal hearing both in standard and extended range of frequencies (25.8%); normal hearing in standard but defective one in extended range of frequencies (51.6%); defective hearing sensitivity to tones both in standard (4, 6 and 8 kHz) and extended frequency range (22.58%). CVD patients with abnormal hearing in the extended frequency range exhibited affection of the brain stem and cortical compartments of the acoustic analyser. Acoustic evoked potentials were especially abnormal in patients with high hearing thresholds (17.4 +/- 1.6; 25.8 +/- 1.9, 29.7 +/- 2.1 dB) in standard frequency range (4, 6 and 8 kHz), respectively. In such patients the disease ran a protracted course with frequent relapses. These findings can help in making decision on the treatment policy, occupational fitness expertise and selection of patients with vocal professions.

Tinnitus treatment by transcutaneous nerve stimulation (TNS).

Twenty-six patients were treated with transcutaneous nervous stimulation (TNS) for tinnitus. Except for 3 normal hearing patients, all had cochlear hearing losses. Tinnitus disappeared in none, but diminished in 7 cases against 3 in 24 nontreated controls. In the controls there were no reliefs in low-frequency tinnitus cases. One of these 7, who reported benefit initially, used the TNS system for several months. It seems that TNS is not as good as expected, but probably in cases where the tinnitus frequency is low and it disappears with TNS totally, the patients may use it.

Reversal of visual loss with hyperbaric oxygen treatment in a patient with Susac syndrome.

PURPOSE: The purpose of the study is to report on a 34-year-old woman with Susac syndrome who presented on two separate occasions with visual acuity loss from a recurrent branch retinal artery occlusion and underwent hyperbaric oxygen treatment with favorable outcome. METHODS: Visual acuity was 20/400 in the left eye and count fingers in the right eye after separate occlusive events. The patient underwent hyperbaric oxygen treatment on each occasion of visual acuity loss. The patient subsequently was diagnosed with Susac syndrome (microangiopathy of the retina, brain, and middle ear). The authors present visual fields, photographs, angiograms, and ancillary tests documenting diagnosis and course of treatment. RESULTS: On each occasion, visual acuity improved to 20/25 during and was maintained after hyperbaric oxygen treatment. Visual fields showed improvement immediately after treatment. CONCLUSION: This is the first report of hyperbaric oxygen treatment for Susac syndrome. Dramatic post-treatment visual field and acuity changes suggest benefit of treatment. Hyperbaric oxygen treatment can be considered a treatment option for visual complications of this syndrome. Susac syndrome should be included in the differential diagnosis of recurrent branch retinal artery occlusion.

Transient impairment in P50 auditory sensory gating induced by a cold-pressor test.

Diminished gating of the auditory evoked response to repeated stimuli is a psychophysiological defect associated with schizophrenia and several other psychiatric illnesses. The P50 wave of the auditory evoked response to the second of paired stimuli is decreased in most normal subjects, whereas many psychotic subjects show significantly less decrement. The aim of this experiment was to test whether the cold-pressor test, which causes transient distress and pain accompanied by increased sympathetic activity, also causes a transient impairment in P50 auditory sensory gating in normal control subjects. Ten normal control subjects with normal gating of the P50 response immersed their hands in an ice water bath for 2 min. This cold-pressor test diminished P50 auditory gating in nine of these subjects, although the degree of impairment was highly variable among subjects. The impairment in gating was transient, with partial resolution by 30 min. The cold-pressor test was subjectively viewed as painful and also caused blood pressure to increase. Thus, a transient stressor can impair P50 auditory gating in some subjects.

The use of intraoperative electrocochleography in Meniére's surgery.

Intra-operative electrocochleography was undertaken during surgery for Meniére's disease. It was found that the electrocochleogram (ECoG) provided a stable measure which accurately reflected changes within the inner ear during surgery. During salt osmosis of the round window, a rapid change in the summating potential versus action potential ratio (SP/AP) occurred which showed when the endolymphatic hydrops (ELH) had been altered. During a modified cochleostomy procedure, the ECoG showed when the cochlear duct had been ruptured. Forty ears were monitored during endolymphatic sac surgery. Twenty-five of these ears showed stable ECochG which did not alter at any time during the procedure; however, 8 of these ears showed normal SP/AP ratios during the surgery despite having been abnormal in the week prior to surgery. The SP/AP ratio was reduced in 8 ears, increased in 3 ears and showed other changes which were probably due to unstable electrode positioning in 4 ears. It was concluded that endolymphatic sac or duct surgery altered the inner ear physiology in a significant number of ears affected by endolymphatic hydrops.

Low frequency hearing threshold determination in newborns, infants and mentally retarded children by middle latency responses.

Middle latency (10-50 ms) responses (MLR) evoked by tone-pips (1,000 Hz 500 Hz) and early (0-10 ms) auditory evoked potentials (EAEP) evoked by chicks were recorded on 68 newborn babies (premature or at term), infants and children, some with central nervous system or psychiatric disorders, who had normal or impaired hearing. MLR were obtained either during sleep, chloral-hydrate sedation or ketamine anesthesia. Thresholds estimated from MLR and EAEP were compared to those from subsequent psychoacoustic pure tone testing. We confirm that MLR provide good threshold estimates for hearing in the low frequency range, whereas click evoked EAEP are good threshold indicators only for high frequencies.

Reflexo do músculo do estapédio alterado em portadores de epilepsia com audiçäo normal / Abnormal acoustic stapedius reflex in epilepitc patients with normal hearing

Os autores estudando pacientes portadores de epilepsia, sem qualquer evidência de disfunçäo do tronco do encéfalo, observaram o "alargamento" do reflexo estapediano em 47,6% dos casos. Discutem o possível mecanismo pelo qual esta alteraçäo pode ser produzida e enfatizam a importância deste achado no diagnóstico de disfunçäo audiológica central, uma vez que a literatura admite que esta alteraçäo é característica de disfnunçäo a nível do tronco cerebral

[The cervico-cranial syndrome in the practice of the otorhinolaryngologist]. / Das zervikokraniale Syndrom in der Praxis des HNO-Arztes.

The craniocervical syndrome is an entity whose symptoms: vertigo, cephalea, tinnitus, facial pain, otalgia, dysphagia, pain of the carotid artery are thought to be caused by cervical factors. In the majority of cases the cranio-cervical syndrome is caused by a spondylarthrogenic segmental dysfunction whose pathophysiology is explained. In the pathogenesis lesions of the joints of the skull which may be responsible for pain and dysfunction in the segmental areas are of great importance. The neurology of the joints of the skull, as well as the pathological mechanisms of spondylarthrogenic disturbances, responsible for the different kinds of dysfunction of the equilibrium and for cephalea are discussed. The pathophysiological basis of manual diagnosis is explained; also the radiological findings of the upper cervical vertebral column are principally discussed. A short review of therapeutic recommendations is given.

The incidence and significance of the Tullio phenomenon in man.

The purpose of this study was to investigate the incidence and significance of the Tullio phenomenon in a group of human subjects. The subjects included 40 patients with complaints of auditory or vestibular symptoms. Ten otologically normal subjects were included in the study as a control group. All subjects underwent routine audiologic evaluation as well as electronystagmogram (ENG) testing. All subjects were then tested for the presence of the Tullio phenomenon by the method described. The results of this study showed that of the 40 subjects with known auditory or vestibular disorders, 90% (36) demonstrated nystagmus in response to high-intensity sound stimulation. All patients in the otologically normal control group demonstrated the presence of the Tullio phenomenon. No specific correlations were made between the presence of the Tullio phenomenon and specific audiologic or ENG findings. Studies on the effects of sound on the vestibular system are reviewed and lend support to the finding that the Tullio phenomenon may be a normal physiologic response in man under certain test conditions.

The cross-check principle in pediatric audiometry.

We discuss a method of pediatric audiologic assessment that employs the "cross-check principle". That is, the results of a single test are cross-checked by an independent test measure. Particularly useful in pediatric evaluations as cross-checks of behavioral test results are impedance audiometry and brain-stem-evoked response audiometry (BSER). We present five cases highlighting the value of the cross-check principle in pediatric audiologic evaluation.

Feasibility studies of evoked response audiometry in the mentally subnormal.

Evoked response audiometry was attempted on a group of seventy-seven unsedated severly subnormal patients up to the age of twenty-two years. Data of some clinical value were obtained in fifty-seven cases. It is suggested that sedation need only be used if the initial attempt at E.R.A. is unsuccessful. Over twenty per cent of the subjects appeared to have significant hearing loss.

Auditory similarities associated with genetic and experimental acoustic deprivation.

Susceptibility to audiogenic seizures has been produced in otherwise non-susceptible mice by acoustic stress and by conductive hearing loss. Both procedures temporarily elevate the absolute threshold of the auditory evoked potential (AEP) and are maximally effective during a circumscribed period of early development. In the genetically SUSCEPTIBLE DBA/2J mouse, AEP thresholds indicated that its auditory system is functionally less mature during this early period than that of the nonsusceptible C57BL/6Jmouse. It was proposed that innate susceptibility found in the DBA/2J mouse results from auditory disuse supersensitivity during a critical developmental period, in support of Saunders' hypothesis for acoustically primed mice. The increased peak-to-peak AEP amplitudes, however, were not believed to be causally related to the audiogenic seizures.