Series en disnea. Parte 3. Mecanismos, copia eferente o descarga corolaria / Series on Dyspnea. Part 3. Mechanisms, efferent copy or corollary discharge

Todas las teorías sobre los mecanismos de generación de disnea tuvieron defensores y detractores e, interesantemente, con el desarrollo de sofisticadas técnicas neurofisiológicas y de imágenes funcionales ha sido posible jerarquizar cada uno de ellos. Todas han sobrevivido al paso del tiempo y ninguna puede explicar por sí sola la disnea en todas las situaciones clínicas, lo cual habla de la naturaleza compleja y multifactorial del fenómeno. El concepto de inadecuación tensión y longitud halló en las últimas décadas un sustento con nuevas evidencias a su favor. En particular, con el hallazgo de las vías involucradas y con la aplicación de conocimientos neurofisiológicos, la teoría de la inadecuación tensión y longitud se vería refinada con la descarga corolaria o copia eferente. Esta descarga corolaria o copia eferente es un atributo básico del sistema nervioso, que se encuentra en el reino animal, desde los invertebrados a los primates y en la especie humana. Este artículo está dedicado a la historia de la copia eferente y su incorporación como hipótesis para explicar la disnea, la más aceptada en la actualidad.

All the theories about the mechanisms of generation of dyspnea had defenders and detractors and, interestingly, with the development of sophisticated neurophysiological techniques and functional imaging, it has been possible to rank each one of them. All have survived the passage of time and none can singularly explain dyspnea in all clini cal situations, showing the complex and multifactorial nature of the phenomenon. The concept of length-tension inappropriateness has found support in recent decades with new evidence in its favor. Specially with the discovery of the pathways involved and with the application of neurophysiological knowledge, the length-tension inappropriate ness theory would be refined with the corollary discharge or efferent copy. This corol lary discharge or efferent copy is a basic attribute of the nervous system found in the animal kingdom, from invertebrates to primates and in the human species. This article is dedicated to the history of the efferent copy and its incorporation as a hypothesis to explain dyspnea, which is currently the most accepted one.

The Relationship between Contralateral Suppression of Transient Evoked Otoacoustic Emission and Unmasking of Speech Evoked Auditory Brainstem Response

Abstract Introduction Several studies have shown that efferent pathways of the auditory system improve perception of speech-in-noise. But, the majority of investigations assessing the role of efferent pathways on speech perception have used contralateral suppression of otoacoustic emissions as a measure of efferent activity. By studying the effect of efferent activity on the speech-evoked auditory brainstem response (ABR), some more light could be shed on the effect of efferent pathways on the encoding of speech in the auditory pathway. Objectives To investigate the relationship between contralateral suppression of transient evoked otoacoustic emission (CSTEOAE) and unmasking of speech ABR. Methods A total of 23 young adults participated in the study. The CSTEOAE was measured using linear clicks at 60 dB peSPL and white noise at 60 dB sound pressure level (SPL). The speech ABR was recorded using the syllable /da/ at 80 dB SPL in quiet, ipsilateral noise, and binaural noise conditions. In the ipsilateral noise condition, white noise was presented to the test ear at 60 dB SPL, and, in the binaural noise condition, two separate white noises were presented to both ears. Results The F0 amplitude of speech ABR was higher in quiet condition; however, the mean amplitude of F0 was not significantly different across conditions. Correlation analysis showed a significant positive correlation between the CSTEOAE and the magnitude of unmasking of F0 amplitude of speech ABR. Conclusions The findings of the present study suggests that the efferent pathways are involved in speech-in-noise processing.

Hiperacusia en trastornos del espectro autista: una revisión de la literatura / Hyperacusis in autism spectrum disorders: a review of the literature

Resumen La hiperacusia se define como la intolerancia a ciertos sonidos cotidianos que causa angustia y discapacidad significativas en las actividades sociales, ocupacionales, recreativas y otras actividades cotidianas. Los sonidos pueden percibirse como incómodamente fuertes, desagradables, atemorizantes o dolorosos. Se encuentra presente en aproximadamente un 3% población general, y aumenta significativamente en trastornos del espectro autista (TEA), alcanzando entre un 15% a 40%. Los mecanismos fisiopatológicos no son del todo claros, pero se ha propuesto, una alteración en el funcionamiento de mecanismos reflejos y de regulación, tanto a nivel de la vía auditiva periférica, como central, incluyendo estructuras no relacionadas directamente con la vía auditiva. El siguiente texto tiene como objetivo analizar la relación entre hiperacusia y TEA, enfatizando en la frecuencia en que se presentan como comorbilidades, en los posibles mecanismos fisiopatológicos, y en actualizaciones en el abordaje diagnóstico y terapéutico. Se realiza una revisión bibliográfica cualitativa en Pubmed con artículos entre los años 2008-2020 utilizando los términos: "hyperacusis autism", "sistema olivococlear", arrojando 39 artículos, de los cuales se seleccionaron en base a la temática de cada uno, evaluada por los autores. A pesar de una significativa relación entre hiperacusia y TEA, los mecanismos fisiopatológicos de ambas patologías siguen siendo un misterio. Existen estudios que sugieren pruebas de screening no invasivas que relacionan ambas patologías, pero debido a los sesgos de selección, todavía no son factibles de usar en forma universal. El abordaje terapéutico ha sido poco explorado, y no se dispone de fármacos que hayan demostrado su efectividad, por el contrario, algunos de ellos empeoran la sintomatología. Se recomienda al tratante, seguir un camino largo, en conjunto con el paciente, donde las terapias no farmacológicas como la terapia cognitivo conductual han mostrado tener buenos resultados.

Abstract Hyperacusis is defined as intolerance to certain sounds that causes significant distress and disability in social, occupational, recreational and other activities. Sounds can be perceived as uncomfortably loud, unpleasant, frightening, or painful. It is present in approximately 3% of the general population, and increases significantly in autism spectrum disorders (ASD), between 15% and 40%. The pathophysiological mechanisms are not entirely clear, but an alteration in the functioning of reflex and regulatory mechanisms has been proposed, both at the peripheral and central auditory pathways, including structures not directly related to the auditory pathway. The therapeutic approach has been little explored as there are no drugs that have demonstrated their effectiveness, on the contrary, some of them worsen the symptoms. The practitioner is recommended to follow a long path, in conjunction with the patient, where non-pharmacological therapies such as cognitive behavioral therapy have been shown to have good results. The following text shows a review of the literature with articles referring to the subject between the years 2008-2019.

Reliability of Contralateral Suppression in Evoked Distortion Product Otoacoustic Emissions

Abstract Introduction Distortion product otoacoustic emissions (DPOAE) and their suppression may be considered useful in monitoring cochlear function and the efferent auditory pathway inhibitory effect. Nonetheless, the establishment of reliable parameters of response variations is of great importance. Objectives To verify the replicability of test and retest in the research of the inhibitory effect of the efferent pathway using contralateral suppressing stimulus during DPOAE recording for clinical applicability. Methods Cross-sectional study with 48 volunteers, aged 18 to 30 years, with normal audiometric thresholds. The procedures included were audiometric and immittance measures to overrule any conductive or sensorineural conditions and DPOAE recordings without and with contralateral suppression with a 60 dBHL white noise. Distortion product otoacoustic emissions amplitudes were analyzed and compared in both conditions with Wilcoxon test, and the Spearman correlation test was used to assess test-retest reliability. Results The comparative analysis showed differences between amplitudes in test and retest conditions only in 1,500 Hz for DPOAE measures with all other tested frequencies showing no differences, and no difference was observed in all recorded frequencies in the test and retest comparison for DPOAE suppression. The degree of correlation between test and retest of DPOAE amplitude was good at 6,000 Hz and strong (r > 0.880) at the other frequencies. For DPOAE with suppression, all frequencies presented strong correlation between test and retest: 1,500 Hz (r = 0.880), 2,000 Hz (r = 0.882), 3,000 Hz (r = 0.940), and 6,000 Hz (r = 0.957). Conclusions The study found good replicability in contralateral suppression of DPOAE with potential clinical applicability, and we recommend conducting the test from 2000Hz to higher frequencies for more reliable results.

Efeito inibitório da via auditiva eferente na síndrome de Turner / Efferent Auditory Pathways Inhibition in Turner syndrome

RESUMO Objetivo investigar o efeito inibitório da via auditiva eferente na síndrome de Turner e relacionar com o perfil citogenético. Método estudo descritivo transversal com grupo de comparação. Amostra: Grupo estudo formado por 40 pacientes com síndrome de Turner (17,6 anos); e Grupo controle constituído por 54 indivíduos (18,9 anos), do sexo feminino sem síndrome. Os indivíduos selecionados foram submetidos à pesquisa do efeito inibitório da via auditiva eferente. Resultados A média do Efeito inibitório da via auditiva eferente no grupo estudo na orelha direita foi 0,4 dB e no grupo comparação foi de 1,9 dB, entretanto na orelha esquerda a média do efeito inibitório da via auditiva eferente foi 1,4 dB no grupo estudo e 0,8 dB no grupo comparação. O efeito inibitório da via auditiva eferente foi presente em 14 indivíduos com monossomia e em 15 com outras alterações citogenéticas. Conclusão No grupo estudo o valor do efeito inibitório da via auditiva eferente foi significantemente maior na orelha esquerda e significativamente menor que o grupo controle na direita. Não houve diferença significativa no efeito inibitório da via auditiva eferente entre os tipos de cariótipo.

ABSTRACT Purpose The goal of this study is to investigate the efferent auditory pathways inhibition in Turner's syndrome and to relate it to the cytogenetic profile. Methods This is a cross-sectional study with a comparison group. A sample with 94 participants divided into two groups: The study group was a sample of 40 patients diagnosed with Turner's syndrome (17.6 years of age). The control group was composed of 54 volunteers (18.9 years of age), female, without syndrome. The selected individuals were submitted to efferent auditory pathways inhibition research. Results The mean of the inhibitory effect of the efferent auditory pathway in the study group in the right ear was 0.4 dB and in the comparison group it was 1.9 dB, however in the left ear the mean of the inhibitory effect of the efferent auditory pathway was 1.4 dB in the study group and 0.8 dB in the comparison group. The inhibitory effect of the efferent auditory pathway was present in 14 individuals with monosomy and in 15 with other cytogenetic alterations. Conclusions In the study group, the efferent auditory pathways inhibition value was significantly higher in the left ear and significantly lower than the control group in the right ear. There was no significant difference in efferent auditory pathways inhibition of right ear and left ear between the karyotype types.

Advances in morphological and functional studies on the paraventricular thalamic nucleus / 解剖学报

Paraventricular thalamic nucleus (PVT) is an essential component of the midline thalamus, which has been regarded as a transmit relay nucleus and an integrated center in multiple behaviors including wakefulness, food intake, addiction, reward and fear memory. PVT is predominantly populated with glutaminergic excitatory neurons expressing vesicular glutamate transporter-2 (VGluT2) but without GABAergic inhibitory neurons. Therefore, based on the paradox of its multiplexed roles in different behaviors and its comparatively simplex excitatory nature, more specific subclassification of excitatory PVT neurons is required in studies in this field. In the present review, morphological and electrophysiological characteristics, efferent and afferent connections, and morphological and functional distinctions in anterior subregion and posterior subregion of PVT are summarized. In addition, neural connections and neurochemical properties are used as subclassification criteria in PVT neurons. This review might explain the integrated role of PVT in different behaviors, which would be helpful for further studies on the PVT.

Reflejo olivococlear contralateral y su relación con ansiedad y calidad de vida en pacientes con tinnitus

Resumen Introducción: La presencia de tinnitus se asocia a un incremento del nivel de ansiedad y empeoramiento de la calidad de vida, sin embargo, aún no existe claridad de si el sistema eferente auditivo podría influir en estas relaciones. Objetivo: Determinar si las amplitudes de las emisiones otoacústicas por producto de distorsión (EOAPD) y el efecto supresor del reflejo olivococlear gatillado con ruido contralateral (ROC) se asocian al grado del impacto psicoemocional y nivel de ansiedad en pacientes con tinnitus. Material y Método: Se evaluaron las amplitudes de EOAPD y magnitud del ROC para cada oído de manera independiente en una cohorte de 32 sujetos tinnitus y 26 controles, cuyos valores fueron correlacionados con State-Trait Anxiety Inventory (STAI) y Tinnitus Handicap Inventory (THI). Resultados: Los pacientes con tinnitus tuvieron una correlación significativa entre la magnitud del ROC del oído izquierdo y los puntajes en las pruebas de STAI y THI. Conclusión: Una mayor carga de ansiedad y peor calidad de vida en sujetos con tinnitus puede estar asociada con un empeoramiento del efecto supresor del ROC de la vía eferente auditiva.

Abstract Introduction: Tinnitus is associated with an increase in the degree of anxiety and with worse quality of life. However, whether there are relations between the function of the auditory efferent system and anxiety and tinnitus distress levels is not known. Aim: To determine possible associations between the distortion product otoacoustic emission (DPOAE) amplitudes and the suppressing effect of the olivo-cochlear reflex (OCR) with anxiety and psycho-emotional impact in tinnitus. Material and Method: DPOAE amplitudes and OCR strength were evaluated for each ear independently in a cohort of 32 tinnitus and 26 controls, whose values were correlated with the State-Trait Anxiety Inventory (STAI) and Tinnitus Handicap Inventory (THI). Results: A significant correlation of STAI and THI scales with the OCR strength measured in the left ear was found in subjects with tinnitus. Conclusion: A higher anxiety load and worse quality of life in subjects with tinnitus may be associated with an impaired olivocochlear reflex suppressing effect.

Efeito inibitório da via eferente auditiva no transtorno de processamento auditivo central / Auditory efferent inhibitory effect in central auditory processing disorder

RESUMO Objetivo verificar e comparar a ocorrência e magnitude do efeito inibitório da via auditiva eferente em crianças e adolescentes com processamento auditivo normal e alterado, identificando um valor de corte para uso na prática clínica. Métodos estudo prospectivo, com amostra composta por 30 crianças de 7 a 14 anos, sendo 15 com avaliação de processamento auditivo normal (grupo controle) e 15 com processamento auditivo alterado (grupo estudo). Ambos os grupos foram submetidos à anamnese e avaliados por meio dos testes de emissões otoacústicas evocadas por estímulos transientes na ausência e presença de ruído contralateral, avaliação audiológica básica e de processamento auditivo. Resultados houve menor ocorrência do efeito inibitório da via eferente no grupo estudo (p-valor=0,038). Os valores médios obtidos no grupo controle foram 0,71 na orelha direita e 0,87 na orelha esquerda e no grupo estudo, 0,55 na orelha direita e 0,41 na orelha esquerda. Os grupos controle e estudo diferiram de modo significativo na orelha esquerda. Conclusão houve redução do efeito inibitório da via eferente em crianças e adolescentes com transtorno de processamento auditivo, sugerindo alteração funcional do sistema eferente olivococlear medial. O valor que separou as crianças com e sem alteração do sistema eferente foi de 0,55 dB na prática clínica, com 70% de sensibilidade e 66,7% de especificidade.

ABSTRACT Purpose Verify and compare the occurrence and magnitude of the inhibitory effect of the efferent auditory pathway in children and adolescents with normal and auditory processing disorder, identifying a cutoff value to use in clinical settings. Methods A prospective study, with a total sample of 30 children aged 7 to 14 years, half with normal auditory processing assessment (Control Group) and the other half with auditory processing disorder (Study Group). Both groups were submitted to anamnesis and evaluated using the otoacoustic emissions tests evoked by transient stimuli in the absence and presence of contralateral noise, basic audiological evaluation and auditory processing. Results The study group presented a lower occurrence of the inhibitory effect of the efferent pathway when compared to the control group (p value=0.038). The mean values ​​obtained for the control group were 0.71 in the right ear and 0.87 in the left ear and for the study group, 0.55 in the right ear and 0.41 in the left ear. The two groups showed a statistically significant difference for the left ear. Conclusion There was a reduction in the inhibitory effect of the efferent pathway in children and adolescents with auditory processing disorder, suggesting a functional change in the medial olivocochlear efferent system. In this study, the cutoff value of 0.55 dB separated children with and without alteration of the efferent system with 70% sensitivity and 66.7% specificity.

Subthalamic Nucleus: Neuroanatomical Review

Discovered in 1865 by Jules Bernard Luys, the subthalamic nucleus is a set of small nuclei located in the diencephalon, inferior to the thalamus and superior to the substantia nigra, that can be visualized in a posterior coronal section. Histologically, it consists of neurons compactly distributed and filled with a large number of blood vessels and sparse myelinated fibers. This review presents an analysis of this anatomical region, considering what is most recent in the literature. Subthalamic neurons are excitatory and use glutamate as the neurotransmitter. In healthy individuals, these neurons are inhibited by nerve cells located in the side globus pallidus. However, if the fibers that make up the afferent circuit are damaged, the neurons become highly excitable, thus causing motor disturbances that can be classified as hyperkinetic, for example ballism and chorea, or hypokinetic, for example Parkinson disease (PD). The advent of deep brain stimulation has given the subthalamic nucleus great visibility. Studies reveal that the stimulation of this nucleus improves themotor symptoms of PD.

Experiences and opportunities for efferent treatment of COVID-19 convalescent plasma / Монголын Анагаах Ухаан

@#According to international medical organizations, the use of efferent therapy that COVID-19 convalescent plasma has shown some results. </br> Convalescent plasma that contains antibodies to severe acute respiratory syndrome coronavirus 2 or SARS-CoV-2. This is being studied for administration to patients with COVID-19. Use of convalescent plasma has been studied in outbreak of other respiratory infections, including the 2003 SARS-CoV-1, the 2009-2010 H1N1 influenza virus, and the 2012 MERS-CoV. </br> Although promising, convalescent plasma has not yet been shown to be safety and efficacy of COVID-19 convalescent plasma in clinical trials. </br> Plasmapheresis and membrane plasmapheresis of efferent therapy has been used in clinical toxicology since 1995, in Mongolia.

Short Term Test-Retest Reliability of Contralateral Inhibition of Distortion Product Otoacoustic Emissions

BACKGROUND AND OBJECTIVES: Strength of medial olivocochlear reflex can be measured reliably using contralateral inhibition of distortion product otoacoustic emissions (DPOAEs) when its fine structure is considered. However, measurement of fine structure of DPOAE is difficult with clinical equipment. Thus, this study investigated the clinically relevant test-retest reliability of contralateral inhibition of DPOAEs. SUBJECTS AND METHODS: Twenty-six young adults with normal hearing sensitivity participated. DPOAEs were recorded at 27 discrete f2 frequencies between 800 Hz and 8,000 Hz at frequency resolution of 8 points per octave with and without contralateral white noise presented at 50 dB SPL. To check for short term inter-session reliability, contralateral inhibition of DPOAEs were recorded in three sessions, two recording sessions on first day separated by 30 minutes and third time after one week of the first session. Within each session, DPOAEs were recorded twice in single probe-fit condition to test for intra-session reliability. RESULTS: Cronbach’s alpha was calculated having poor reliability (α≤ 0.7) of contralateral inhibition of DPOAEs in both intra-session and inter-session conditions for most of the tested frequencies. 95% confidence intervals of contralateral inhibition magnitude also showed large variability. CONCLUSIONS: The current results showed that though DPOAE amplitudes were highly reliable across sessions, amount of inhibition of DPOAEs was not reliable when DPOAEs were measured at discrete frequencies. These findings are concurrent with the literature.

Conductas de riesgo auditivo y acción del mecanismo de protección coclear en adolescentes / Auditory risk behaviors and the action of cochlear protection mechanism in adolescent

La exposición a ruido no ocupacional y a la música a alto nivel sonoro, constituye un creciente factor de riesgo de pérdida auditiva en adolescentes. Estudios internacionales postulan que una función importante del Sistema Eferente Medial (SEM) es proteger el oído interno frente al ruido mediante un mecanismo reflejo y que puede ser evaluado a través de la Supresión Contralateral (SC) de las otoemisiones acústicas transitorias (TEOAEs). El mecanismo subyacente de este fenómeno no se conoce en su totalidad y los antecedentes sobre el tema son escasos. En esta investigación se analizó la relación entre la Exposición General a Música (EGM), el estado de la función auditiva y el mecanismo de protección coclear. Participaron 91 adolescentes con edades entre 14 y 15 años. Se evaluaron dos dimensiones (a) Psicosocial: se examinó la EGM con un cuestionario de actividades extraescolares y (b) auditiva o sea el funcionamiento del SEM mediante SC de las TEOAEs y los perfiles audiométricos con audiometrías. Los resultados mostraron que la SC no influyó estadísticamente en los perfiles audiométricos y categorías de exposición. Sin embargo, los resultados de la SC se orientan hacia la menor magnitud de efecto supresor, disminución en la respuesta total en relación al descenso de los umbrales auditivos y en relación con las categorías alta y baja de EGM. Es necesario promover trabajos destinados al comportamiento de riesgo auditivo conjuntamente con el mecanismo protector del SEM. De esta manera se podrá contribuir en la identificación temprana de la sensibilidad auditiva en adolescentes expuestos a ruido no ocupacional.

Non-occupational exposure to noise, such as loud music sound level is an increasing risk factor for hearing loss in adolescents. International studies propose that an important function of the medial efferent system (MES) is protect the inner ear against noise by a reflex mechanism and can be evaluated through Contralateral Suppression (CS) of transient otoacoustic emissions (TEOAEs) to analyzing the presence or absence of suppressive effect. The absence of suppressive effect is considered a possible alteration of the MES and the role it exerts on the regulation of the outer hair cells. The underlying mechanism of this phenomenon is not known totality and the background about this topic are limited. However, researches suggests that MES would have an important role in protection against acoustic overstimulation under the hypothesis that a hearing with the presence of suppressive effect would tend to be more protected against exposure to high noise levels while ears with no effect suppressor may be more vulnerable to noise exposure. In this research the relationship between the General Exposure to Music (MGE), the state of hearing function and cochlear protection mechanism were analyzed in 91 adolescents with 14/15 years old, with male predominance, of two technical schools of the city of Córdoba (Argentina). Were evaluated the following dimensions: (a) Psychosocial: MGE through an Out of School Activities Questionnaire to know in detail the participation in five recreational activities to finally analyze the MGE and (b) Audiological: assessment of audiometric profiles, as a subjective method, by audiometry in the conventional frequency ranges (250-8000) Hz and an extended high frequency audiometry (8000-16000) Hz; function of MES assessment, objective method, through CS of TEOAEs to determine the presence or absence of suppressive effect. The study CS of TEOAEs consisted of two steps: Step 1, application of TEOAEs of an ear in form ipsilateral without acoustic stimulation in the contralateral ear (CAS) and Step 2, application of TEOAEs in the ear ipsilateral while applying CAS. Was considered presence of suppressive effect when there was a reduction in the response after the CAS that is to say when the difference of values obtained in the total response with and without CAS was positive. At the same time, was considered absence of suppressive effect in cases of maintained or increased the response after the CAS, obtaining a value of zero or negative. The results of the research showed that in the group with presence of suppressive effect the most of ears is among moderate and high categories of MGE with a lower average magnitude of suppressive effect and a decreased amplitude of the total response in the high category of MGE than the media category. Regarding audiometry the ears with presence of suppressive effect showed higher magnitude in the group of normal hearing thresholds compared with the group of descended hearing thresholds. The results related to CS of the TEOAEs statistically did not influence in the audiometric profiles and the exposure categories. However the results of the CS were oriented towards the smaller magnitude of suppressive effect, decreased total response related with the descended hearing thresholds and high and low categories of MGE. It is necessary to promote and intensify researches in relation to the auditory risk behaviors together with the protection mechanism of MES. In this way, more researches can contribute to the early identification of hearing sensitivity in adolescents exposed to non-occupational noise. It is important to implement a Psycho-Auditory Screening to collaborate in the prevention and promotion of hearing health.

Functional Significance of Medial Olivocochlear System Morphology in the Mouse Cochlea

OBJECTIVES: Baso-apical gradients exist in various cochlear structures including medial olivocochlear (MOC) efferent system. This study investigated the cochlear regional differentials in the function and morphology of the MOC system, and addressed the functional implications of regional MOC efferent terminals (ETs) in the mouse cochlea. METHODS: In CBA/J mice, MOC reflex (MOCR) was assessed based on the distortion product otoacoustic emission in the absence and presence of contralateral acoustic stimulation. High, middle, and low frequencies were grouped according to a mouse place-frequency map. Cochlear whole mounts were immunostained for ETs with anti-α-synuclein and examined using confocal laser scanning microscopy. The diameters of ETs and the number of ETs per outer hair cell were measured from the z-stack images of the basal, middle and apical regions, respectively. RESULTS: The middle cochlear region expressed large, clustered MOC ETs with strong MOCR, the base expressed small, less clustered ETs with strong MOCR, and the apex expressed large, but less clustered ETs with weak MOCR. CONCLUSION: The mouse cochlea demonstrated regional differentials in the function and morphology of the MOC system. Strong MOCR along with superior MOC morphology in the middle region may contribute to ‘signal detection in noise,’ the primary efferent function, in the best hearing frequencies. Strong MOCR in spite of inferior MOC morphology in the base may reflect the importance of ‘protection from noise trauma’ in the high frequencies.

The Hyperactivity of Efferent Auditory System in Patients with Schizophrenia: A Transient Evoked Otoacoustic Emissions Study

OBJECTIVE: Electrophysiological studies, which are mostly focused on afferent pathway, have proven that auditory processing deficits exist in patients with schizophrenia. Nevertheless, reports on the suppressive effect of efferent auditory pathway on cochlear outer hair cells among schizophrenia patients are limited. The present, case-control, study examined the contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) in patients with schizophrenia. METHODS: Participants were twenty-three healthy controls and sixteen schizophrenia patients with normal hearing, middle ear and cochlear outer hair cells function. Absolute non-linear and linear TEOAEs were measured in both ears by delivering clicks stimuli at 80 dB SPL and 60 dB SPL respectively. Subsequently, contralateral suppression was determined by subtracting the absolute TEOAEs response obtained at 60 dBpe SPL during the absence and presence of contralateral white noise delivered at 65 dB HL. No attention tasks were conducted during measurements. RESULTS: We found no significant difference in absolute TEOAEs responses at 80 dB SPL, in either diagnosis or ear groups (p>0.05). However, the overall contralateral suppression was significantly larger in schizophrenia patients (p<0.05). Specifically, patients with schizophrenia demonstrated significantly increased right ear contralateral suppression compared to healthy control (p<0.05). CONCLUSION: The present findings suggest increased inhibitory effect of efferent auditory pathway especially on the right cochlear outer hair cells. Further studies to investigate increased suppressive effects are crucial to expand the current understanding of auditory hallucination mechanisms in schizophrenia patients.

Lateralidade da atividade do sistema olivococlear medial eferente: estudo preliminar / Laterality of activity of medial olivocochlear efferent system: preliminary study

RESUMO: Objetivo: avaliar a diferença na supressão das emissões otoacústicas entre as orelhas direita e esquerda. Métodos: participaram da pesquisa 36 indivíduos, sendo 18 destros e 18 canhotos, todos sem queixa auditiva e com audição dentro dos padrões de normalidade. A coleta de dados foi realizada por meio das emissões otoacústicas transientes e pela supressão das emissões otoacústicas. A análise da presença/ausência do efeito de supressão foi realizada baseada no valor obtido em response. Resultados: não houve diferença entre a orelha direita e esquerda para os valores de response das emissões otoacústicas com ruído contralateral para os indivíduos destros e canhotos. No gênero masculino houve diferença entre a orelha direita e esquerda para os valores de response das emissões otoacústicas com ruído contralateral. Conclusão: a avaliação realizada por meio da supressão das emissões otoacústicas não evidenciou diferenças entre as orelhas direita e esquerda nos grupos estudados.

ABSTRACT: Purpose: to evaluate the difference in the suppression of otoacoustic emissions between the right and left ears Methods: participated in this study 36 individuals, being 18 right-handed and left-handed 18, all without hearing complaints and hearing within normal limits. Data collection was performed by: transient otoacoustic emissions and suppression of the otoacoustic emissions. The analysis of the presence / absence of the suppression effect was made based on the value obtained in response. Results: there was no difference between the right and left ears for the response values of otoacoustic emissions with contralateral noise for right and left handed individuals. In the male, there was a difference between the right and left ears for the response values of otoacoustic emissions with contralateral noise. Conclusion: the evaluation through the suppression of otoacoustic emissions showed no differences between the right and left ears in the groups studied.

Sistema olivococlear medial e genotoxicidade em escolares de região fumicultora / Medial olivocochlear system and genotoxicity in students of the tobacco-producing region

OBJETIVO: avaliar a associação entre a função do sistema olivococlear medial e biomarcadores genotóxicos em escolares residentes de região fumicultora. MÉTODOS: trata-se de um estudo observacional, prospectivo e transversal. O grupo estudo foi composto por 21 escolares normo-ouvintes residentes de região fumicultora e o grupo controle por 25 escolares normo-ouvintes que não residiam na zona rural. O sistema olivococlear medial foi avaliado por meio da supressão das Emissões otoacústicas produto de distorção, e os biomarcadores genotóxicos foram: ensaio cometa, teste de micronúcleos e ensaio fluorimétrico de quantificação de DNA. Os dados obtidos foram submetidos à análise estatística. RESULTADOS: ao comparar a ocorrência do efeito de supressão das emissões entre os grupos, não foi detectada associação significante. Tanto no ensaio cometa como no ensaio fluorimétrico de quantificação de DNA a média do grupo estudo mostrou-se significantemente mais elevada que a do grupo controle. No teste de micronúcleos, verificou-se diferença significante quanto ao somatório de células alteradas e à frequência de células binucleadas, sendo a média do grupo estudo mais elevada que a do grupo controle. Já referente à frequência de células com micronúcleo, não se observou diferença significante entre os grupos. Não foi detectada associação entre ocorrência do efeito de supressão e os resultados dos biomarcadores genotóxicos. CONCLUSÃO: o grupo estudo não apresentou alterações no sistema olivococlear medial, evidenciado pela presença de supressão das emissões, porém apresentou índices de dano significantemente mais elevados dos biomarcadores genotóxicos. Entretanto, não se verificou associação entre supressão das emissões e genotoxicidade. .

PURPOSE: to evaluate the association between the function of the medial olivocochlear system and the biomarkers of genotoxicity in resident students from the tobacco-producing region. METHODS: the study group was composed by 21 normal-hearing students from the tobacco-producing region and the control group by 25 normal-hearing students who did not live in the countryside. The medial olivocochlear system was assessed by the distortion of product otoacoustic emissions and genotoxic biomarkers, such as: comet assay, micronucleus test and fluorimetric assay for the quantification of DNA. The data were subjected to statistical analysis. RESULTS: by comparing the occurrence of suppression of emissions between the groups, no significant association was detected. Considering the comet assay and the fluorimetric assay for quantitation of DNA, the mean of the study group was considerate significantly higher than the mean of the control group. In the micronucleus test, it was found a significant difference in the sum of abnormal cells and in the frequency of binucleated cells, with the mean of the study group higher than the one found in the control group. And, in relation to the frequency of cells with micronucleus, it showed no significant difference between both groups. No association was found between the occurrence of suppression and the results of genotoxicity biomarkers. CONCLUSION: the study group had no alteration in medial olivocochlear system, which was evidenced by the presence of emissions suppression, but it presented injury rates considerate significantly higher in relation to the genotoxic biomarkers. However, there was no association between suppression of emissions and genotoxicity. .

Unilateral cryptorchidism induces morphological changes of testes and hyperplasia of Sertoli cells in a dog / 한국실험동물학회지

Cryptorchidism is one of the most common genital defects in dogs. This study investigated the effects of abdominal cryptorchidism on morphology, cell proliferation, and Sertoli cell condition in a dog with spontaneous unilateral cryptorchidism. Elective orchidectomy was performed on the abdominal right testis and the scrotal left testis. Significant reductions in numbers of spermatogonia, spermatocytes, and spermatids were observed in hematoxylin and eosin stained sections of the cryptorchid testis. The size of the epididymal duct was smaller than that of the control testis. Based on Ki67 immunohistochemistry, the proliferative activity of spermatogonia and spermatocytes was significantly decreased in the cryptorchid testis. However, proliferative activity was increased in the epididymal duct. Based on GATA-4 immunohistochemistry, Sertoli cells were relatively resistant to cryptorchidism, and the proliferative activity of Sertoli cells was markedly increased in the cryptorchid testis than in the control testis. These results suggest that spontaneous unilateral cryptorchidism causes morphological defects in spermatogonia and spermatocytes in the testis and changes the size of the efferent ductule of the epididymis. In addition, spontaneous unilateral cryptorchidism increases proliferative activity of Sertoli cells, which may be a predisposing factor for Sertoli cell cancer in cryptorchid testes.

Desde la corteza auditiva a la cóclea: progresos en el sistema eferente auditivo / From auditory cortex to cochlea: progress in the auditory efferent system

El sistema eferente auditivo está constituido por el sistema olivococlear y por vías descendentes que provienen de la corteza auditiva y se dirigen a la cóclea. El sistema olivococlear se divide en una porción medial y una lateral, con neuronas que inervan a las células ciliadas externas y a fibras del nervio auditivo respectivamente. El principal neurotransmisor de las sinapsis olivococleares es acetilcolina, y tanto las células ciliadas externas como las fibras del nervio auditivo poseen receptores para esta molécula. El sistema eferente córtico-coclear se origina en la capa V y VI de la corteza auditiva y proyecta a los colículos inferiores y complejo olivar superior, donde a través del sistema olivococlear se conecta con el órgano receptor auditivo. En este artículo se revisan importantes hallazgos obtenidos en los últimos años que involucran (i) nuevos neurotransmisores y receptores del sistema eferente auditivo; (ii) vías descendentes de la corteza auditiva y su rol fisiológico sobre las respuestas cocleares y (iii) rol del sistema eferente auditivo en patologías audiológicas y neuropsiquiátricas.

The auditory efferent system is composed by the olivocochlear fibers and descending projections that originate in the auditory cortex and end in the cochlea. The olivocochlear system is divided into a medial and lateral division, with fibers directed to the outer hair cells and to the auditory nerve fibers respectively. It is known that acetylcholine is the main neurotransmitter of the olivocochlear synapses and that outer hair cells and auditory nerve fibers have receptors to this molecule. The cortico-cochlear efferent system originates in layers V and VI of the auditory cortex. These descending projections are directed to the inferior colliculus and superior olivary complex, a site in which the olivocochlear fibers emerge and connect the brain with the cochlear receptor. In this article recent discoveries obtained in the last years are reviewed: (i) new neurotransmitters and receptors of the olivocochlear system; (ii) anatomy and physiology of descending pathways from the auditory cortex to the cochlea and, (iii) clinical role of auditory efferents in audiological and neuropsychiatric pathologies.

O papel do sistema olivococlear medial em crianças portadoras de TDAH / Role of the medial olivocochlear system among children with ADHD

Crianças portadoras de Transtorno do Déficit de Atenção/Hiperatividade (TDAH) apresentam como um de seus principais sintomas a dificuldade de atenção. Na audição, a Atenção Seletiva que se caracteriza por ser a capacidade de compreender a fala em ambientes ruidosos, pode ser avaliada de várias formas, salientando-se o funcionamento do Sistema Eferente Olivococlear Medial. Este sistema pode ser avaliado pelo exame de emissões otoacústicas (EOA). OBJETIVO: Este trabalho teve por objetivo verificar a ocorrência do efeito de supressão de EOA, caracterizado pela diminuição da amplitude de resposta das emissões otoacústicas evocadas por estímulo transiente (EOAT) em resposta a apresentação de ruído contralateral, em crianças com TDAH (grupo estudo) e normais (grupo controle). Forma de Estudo: Estudo caso-controle. MATERIAL E MÉTODO: Foi realizado um estudo com 20 crianças alocadas em dois grupos de 10 crianças, pareadas por sexo e idade. Foi realizado o exame de EOAET sem e com ruído em ambos os grupos. RESULTADOS: Não houve diferença nas respostas das EOAET sem e com ruído, entre os grupos estudados. CONCLUSÕES: Pôde-se concluir que não há diferenças no funcionamento do Sistema Eferente Olivococlear Medial nas crianças com transtorno do déficit de atenção/hiperatividade em relação às crianças normais.

Attention deficit hyperactivity disorder (ADHD) patients show, as one of the main symptoms, an attentional impairment. Selective attention in the hearing process is the ability to understand speech in a noisy environment, which can be evaluated by several methods. One of the main approaches is the functioning of the Medial Olivocochlear Efferent System, which can be accessed by Transient-Evoked Otoacoustic Emissions (TOAE). OBJECTIVE:This study aimed at evaluating the suppression effect of contralateral noise on TOAE in ADHD (study group) and normal subjects (control group). Study Design: Case-control study. MATERIAL AND METHODS: A study with 20 children distributed in two, age- and gender-matched groups. RESULTS: No differences were found in TOAE responses between the two groups, with and without noise. CONCLUSIONS: We conclude that there were no functional differences in the Medial Olivocochlear Efferent System in the two groups analyzed.

Ocorrência e efeito de supressão das Emissões Otoacústicas em adultos normo-ouvintes com zumbido e hiperacusia / Occurrence and suppression effect of Otoacoustic Emissions in normal hearing adults with tinnitus and hyperacusis

A associação entre zumbido e hiperacusia é frequente na literatura. OBJETIVOS: Verificar a ocorrência e o efeito de supressão das emissões otoacústicas transientes (EOATs), a existência de associação entre graus de zumbido e de hiperacusia, entre efeito supressor das EOATs e lateralidade, graus de zumbido e de hiperacusia, em adultos normo-ouvintes com queixas de zumbido e hiperacusia. MATERIAIS E MÉTODOS: Foram incluídos, nesta forma de estudo transversal, 25 indivíduos normo-ouvintes com queixas de zumbido e hiperacusia. Utilizou-se o Tinnitus Handicap Inventory (THI) para classificação do grau do zumbido e o Loudness Discomfort Level (LDL) para o da hiperacusia. RESULTADOS: A ocorrência das EOATs variou de 33 por cento a 88 por cento. Houve 63,7 por cento de presença de efeito de supressão na orelha direita e 81,7 por cento na orelha esquerda. Não ocorreu correlação significativa entre os graus de zumbido e os graus de hiperacusia em ambas as orelhas e não houve associação significativa entre efeito de supressão das EOATs e lateralidade, grau de zumbido e de hiperacusia. CONCLUSÃO: A ocorrência de EOATs foi inferior à encontrada em adultos normo-ouvintes. Obteve-se maior percentual de presença do efeito de supressão das EOATs em ambas as orelhas. Não houve associação entre as variáveis analisadas.

The association between tinnitus and hyperacusis is common according to the literature. AIM: To verify the occurrence and the suppression effect of transient otoacoustic emissions (TEOAE), the existence of association between tinnitus degrees and hyperacusis degrees, and between the suppressive effect of TEOAE and laterality, tinnitus and hyperacusis degrees in normal hearing adults with complaints of tinnitus and hyperacusis. MATERIALS AND METHODS: 25 normal hearing subjects with complaints of hyperacusis and tinnitus were studied in this cross-sectional study. The Tinnitus Handicap Inventory (THI) was used for the classification of tinnitus degrees, and the Loudness Discomfort Level (LDL) for the hyperacusis classification. RESULTS: The occurrence of TEOAE ranged from 33 to 88 percent. We observed the presence of TEOAE suppression effect on 63.7 percent in the right ear and 81.7 percent in the left ear. There was no significant correlation between the degrees of tinnitus and hyperacusis in both ears. No statistically significant associations between the TEOAE suppression effect and laterality, tinnitus degrees and hyperacusis degrees were found. CONCLUSION: The occurrence of TEOAE was lower than that found in normal hearing adults. A higher percentage of the presence of TEOAE suppression effect has been found in both ears. No association between the variables was observed.