Horizontal vestibulo-ocular reflex dynamics in acute vestibular neuritis and viral labyrinthitis: evidence of otolith-canal interaction.

OBJECTIVE: To evaluate the dynamic properties of the horizontal vestibulo-ocular reflex (h-VOR) in the acute stage of two common labyrinthine diseases that provoke severe attacks of vertigo with spontaneous nystagmus: vestibular neuritis (vestibular loss alone) and viral labyrinthitis (cochleovestibular loss). MATERIAL AND METHODS: Sixty-three patients were investigated: 42 were diagnosed with vestibular neuritis and 21 with viral labyrinthitis. The h-VOR function was evaluated by conventional caloric and impulsive testing. A simplified model of vestibular function was used to analyze the vestibulo-ocular response to rotational stimulation. RESULTS: The results showed a significant difference in h-VOR characteristics between the two pathologies. Patients with vestibular neuritis exhibited a strong horizontal semicircular canal deficit, but no h-VOR asymmetry between the two rotational directions. In contrast, patients with viral labyrinthitis demonstrated moderate canal paresis and a marked h-VOR deficit in rotation toward the affected ear. CONCLUSION: These findings support the hypothesis that the h-VOR dynamic asymmetry that occurs after an acute unilateral inner ear lesion is not due to canal dysfunction alone, but involves complex adaptive changes in the central VOR that may implicate the otolith system. Based on histopathologic and clinical differences in the two pathologies reported in the literature, we postulate that this otolith-canal interaction is mainly linked to the loss of saccular function.

Should Koos grade I vestibular schwannomas be treated early with gamma knife surgery? A subgroup analysis in a series of 190 consecutive patients.

INTRODUCTION: Gamma knife surgery (GKS) for vestibular schwannomas (VS) has a long-term clinical and scientific track record. After a period of de-escalation of dose prescription, results show a high rate of tumor control with improvement of clinical outcome (less than 1% facial palsy, 50-70% hearing preservation). Régis et al. (J Neurosurg 2013;119 Suppl.:105-11) suggested recently that proactive GKS management in intracanalicular tumors is better than a « wait and see » strategy when hearing is still useful at the time of diagnosis. MATERIALS AND METHODS: Based on these previous findings, we prospectively analyzed 190 vestibular schwannomas (VS), treated with GKS as first intention over a period of 4 years (2010-2014). We concentrated on patient, tumor and dosimetric characteristics. Special attention was given on the dose to the cochlea and its impact in maintaining serviceable hearing. RESULTS: The mean follow-up period was 1.3years (range 0.6-3.6). Preoperative serviceable hearing was present in 63.11% patients. The mean maximal diameter was 15.1mm (range 5-29.5). The size and volume of the tumor corresponded to Koos grade I, II, III and IV in 15.9%, 34.8%, 45.4% and 3.8% of the cases, respectively. The mean target volume was 1.24cm(3) (0.017-7.8). The mean prescription isodose volume was 1.6 cc (0.032-8.5). The mean marginal dose was 12Gy (11-12). The mean maximal dose received by the cochlea in patients with GR class 1 and 2 was 4.1Gy (1.5-7.6). Our preliminary neuroradiological follow-up shows 97% tumor control, with 45% shrinkage. Patients presenting with GR class 1 and class 2 at baseline retained serviceable hearing in 85% of cases. Among the patients with a follow-up of at least one year, those with Koos I tumors had the highest probability to maintain identical level of hearing after GKS. CONCLUSION: Our preliminary data suggest that Koos I patients should be treated early with GKS, before tumor growth and/or hearing deterioration, as they have the highest probability of hearing preservation.

Combined approaches in large vestibular schwannomas: surgical and radiosurgical perspective

Purpose: The management of vestibular schwanommas (VS) is challenging, with microsurgery remaining the main treatment option. Planned subtotal resection is now being increasingly considered to reduce the risk of neurological deficits following complete resection. The residual part of the tumor can then be treated with Gamma Knife surgery (GKS) to achieve long-term growth control. Methods: This case series of 11 patients documents early results with planned subtotal resection followed by GKS in Lausanne University Hospital, between July 2010 and March 2012. We analyzed clinical symptoms and signs for all cases, as well as MRI and audiograms. Results: Mean age in this series was 50.3 years (range 24.1-73.4). Two patients (18.2%) had a stereotactic fractionated radiotherapy, which had failed to ensure tumor control, before the microsurgical intervention. The lesions were solid in 9 cases (81.8%), and mixed (solid and cystic) in 2 patients (18.2%). Presurgical tumor volume was of a mean of 18.5 cm3 (range 9.7-34.9 cm3). The mean duration between microsurgery and GKS was 10.5 months (range 4-22.8). The mean tumor volume at the time of GKS treatment was 4.9 cm3 (range 0.5- 12.8). A mean number of 20.7 isocenters was used (range 8-31). Nine patients received 12 Gy and 2 patients with 11 Gy at the periphery (at the 50% prescription isodose). We did not have any major complications in our series. Postoperative status showed no facial nerve deficits. Four patients with useful pre-operative hearing underwent surgery aiming to preserve the cochlear nerve function. Of these patients, the patient who had Gardner-Robertson (GR) class 1 before surgery, remained in GR class 1. Two patients improved after surgery, one changing from GR 5 to GR 3 and the other with slight improvement, remaining in the same GR 3 class. Mean follow-up after surgery was 15.4 months (range 4-31.2). One patient, who presented with secondary trigeminal neuralgia before surgery, had transitory facial hypoesthesia following surgery. No other neurological deficits were encountered. Following GKS, the patients had a mean follow-up of 5.33 months (range 1-13). No new neurological deficits were encountered. Conclusions: Our data suggest that planned subtotal resection followed by GKS has an excellent clinical outcome with respect to preservation of cranial nerves, and other neurological functions, and a good possibility of recovery of many of the pre-operative cranial nerve dysfunctions

The effect of virtual reality on visual vertigo symptoms in patients with peripheral vestibular dysfunction: a pilot study.

Individuals with vestibular dysfunction may experience visual vertigo (VV), in which symptoms are provoked or exacerbated by excessive or disorientating visual stimuli (e.g. supermarkets). VV can significantly improve when customized vestibular rehabilitation exercises are combined with exposure to optokinetic stimuli. Virtual reality (VR), which immerses patients in realistic, visually challenging environments, has also been suggested as an adjunct to VR to improve VV symptoms. This pilot study compared the responses of sixteen patients with unilateral peripheral vestibular disorder randomly allocated to a VR regime incorporating exposure to a static (Group S) or dynamic (Group D) VR environment. Participants practiced vestibular exercises, twice weekly for four weeks, inside a static (Group S) or dynamic (Group D) virtual crowded square environment, presented in an immersive projection theatre (IPT), and received a vestibular exercise program to practice on days not attending clinic. A third Group D1 completed both the static and dynamic VR training. Treatment response was assessed with the Dynamic Gait Index and questionnaires concerning symptom triggers and psychological state. At final assessment, significant betweengroup differences were noted between Groups D (p = 0.001) and D1 (p = 0.03) compared to Group S for VV symptoms with the former two showing a significant 59.2% and 25.8% improvement respectively compared to 1.6% for the latter. Depression scores improved only for Group S (p = 0.01) while a trend towards significance was noted for Group D regarding anxiety scores (p = 0.07). Conclusion: Exposure to dynamic VR environments should be considered as a useful adjunct to vestibular rehabilitation programs for patients with peripheral vestibular disorders and VV symptoms.

The effect of virtual reality on visual vertigo symptoms in patients with peripheral vestibular dysfunction: a pilot study

Individuals with vestibular dysfunction may experience visual vertigo (VV), in which symptoms are provoked or exacerbated by excessive or disorientating visual stimuli (e.g. supermarkets). VV can significantly improve when customized vestibular rehabilitation exercises are combined with exposure to optokinetic stimuli. Virtual reality (VR), which immerses patients in realistic, visually challenging environments, has also been suggested as an adjunct to VR to improve VV symptoms. This pilot study compared the responses of sixteen patients with unilateral peripheral vestibular disorder randomly allocated to a VR regime incorporating exposure to a static (Group S) or dynamic (Group D) VR environment. Participants practiced vestibular exercises, twice weekly for four weeks, inside a static (Group S) or dynamic (Group D) virtual crowded square environment, presented in an immersive projection theatre (IPT), and received a vestibular exercise program to practice on days not attending clinic. A third Group D1 completed both the static and dynamic VR training. Treatment response was assessed with the Dynamic Gait Index and questionnaires concerning symptom triggers and psychological state. At final assessment, significant betweengroup differences were noted between Groups D (p = 0.001) and D1 (p = 0.03) compared to Group S for VV symptoms with the former two showing a significant 59.2% and 25.8% improvement respectively compared to 1.6% for the latter. Depression scores improved only for Group S (p = 0.01) while a trend towards significance was noted for Group D regarding anxiety scores (p = 0.07). Conclusion: Exposure to dynamic VR environments should be considered as a useful adjunct to vestibular rehabilitation programs for patients with peripheral vestibular disorders and VV symptoms.

Anterior inferior cerebellar artery aneurysms mimicking vestibular schwannomas.

BACKGROUND AND PURPOSE: Unruptured anterior inferior cerebellar artery (AICA) aneurysms are rare but potentially lethal cerebellopontine angle (CPA) lesions that may be misdiagnosed as vestibular schwannomas when they present with vestibulo-cochlear symptoms. METHODS: We report two cases of unruptured but symptomatic AICA aneurysms initially referred to us as atypical vestibular schwannomas requiring surgery. Two discriminant MR features are described. RESULTS: One patient refused treatment. The other was successfully treated by coil occlusion. CONCLUSIONS: Caution is advised before suspecting a CPA mass to be a purely extra-canalicular schwannoma, given its extreme rarity. Deafness and cerebellar ischemia may be prevented if AICA aneurysms are correctly identified preoperatively. In the absence of specific arterial imaging, two MR features may distinguish them from vestibular schwannomas: (1) the absence of internal auditory canal enlargement and (2) the "blurry dot sign," representing blood flow artefacts on pre- and postcontrast studies.

Modern Gamma Knife radiosurgery of vestibular schwannomas: treatment concept, volumetric tumor response, and functional results.

The objective of the present study was longitudinal evaluation of the volumetric tumor response and functional results after Gamma Knife radiosurgery of vestibular schwannomas, performed according to the modern standards of treatment. From October 2003 to September 2007, 133 consecutive patients with vestibular schwannomas were treated according to the concept of robotic Gamma Knife microradiosurgery, which is based on precise irradiation of the lesion, sparing adjacent structures, and delivery of the high radiation energy to the target. Multiple small-sized isocenters located within the border of the neoplasm were applied. The mean marginal dose was 11.5 Gy (range, 11-12 Gy). In total, 126 cases with a minimum posttreatment follow-up of 2 years (range, 2-7 years; median, 4 years) were analyzed. Temporary enlargement was noted in 25 % of tumors at 6 months after radiosurgery. At 3 years of follow-up, tumor shrinkage, stabilization, and increase in volume were marked in 73 %, 23 %, and 4 % of cases, respectively. All progressing lesions spontaneously stabilized later on and did not require additional management. In 3 % of patients, transitory impairment of the facial nerve function was marked; however, neither its permanent dysfunction nor trigeminal neuropathy attributed to radiosurgery was noted. Impairment of hearing compared to its pretreatment level was revealed in 4 %, 12 %, 13 %, and 16 % of patients at 6 months, 1 year, 2 years, and 3 years after radiosurgery, respectively, and this trend was statistically significant (P = 0.0042). Overall, 77 % of patients with serviceable hearing before treatment preserved it 3 years thereafter. In conclusion, modern Gamma Knife radiosurgery provides effective and safe management of vestibular schwannomas. Nevertheless, possible temporary tumor enlargement, delay of its growth arrest, transient dysfunction of the cranial nerves, and gradual deterioration of hearing after irradiation should be always taken into consideration.

Capacidad de trabajo en equipo "multidisciplinar" : actividad sobre la fisiología y la valoración del dolor en un entorno multidisciplinar y biopsicosocial para estudiantes de ciencias de la salud

La importancia del tratamiento de una situación tan compleja como el dolor hace en ocasiones insuficientes los conocimientos incluidos en los planes de estudio de las titulaciones de ciencias de la salud. Por otro lado, existe un gran desconocimiento entre los alumnos de estas carreras sanitarias sobre cual es el papel que desempeñan las otras profesiones sanitarias lo que puede dificultar la posibilidad de trabajar en el futuro de una manera multidisciplinar. Para poder dar solución a estos problemas, la Facultad de Enfermería de la Universidad de Lleida ha puesto en práctica una actividad piloto en la que participan alumnos de enfermería y fisioterapia. La actividad tiene como finalidad el ampliar y unificar los conocimientos de la fisiología y valoración del dolor de una manera multidisciplinar. Lo favorable de los resultados sugiere la necesidad de incorporar este tipo de actividades a otras asignaturas, a la vez que se evidencia la necesidad de incorporar otras carreras sanitarias a dicha actividad.

Role of CYP2E1-mediated metabolism in the acute and vestibular toxicities of nineteen nitriles in the mouse

Allylnitrile, cis-crotononitrile, and 3,3 -iminodipropionitrile are known to cause vestibular toxicity in rodents, and evidence is available indicating that cis-2-pentenenitrile shares this effect. We evaluated nineteen nitriles for vestibular toxicity in wild type (129S1) and CYP2E1-null mice, including all the above, several neurotoxic nitriles, and structurally similar nitriles. A new acute toxicity test protocol was developed to facilitate evaluation of the vestibular toxicity by a specific behavioral test battery at doses up to sub-lethal levels while using a limited number of animals. A mean number of 8.5±0.3 animals per nitrile, strain and sex was necessary to obtain evidence of vestibular toxicity and optionally an estimation of the lethal dose. For several but not all nitriles, lethal doses significantly increased in CYP2E1-null mice. The protocol revealed the vestibular toxicity of five nitriles, including previously identified ototoxic compounds and one nitrile (trans-crotononitrile) known to have a different profile of neurotoxic effects in the rat. In all five cases, both sexes were affected and no decrease in susceptibility was apparent in CYP2E1-null mice respect to 129S1 mice. Fourteen nitriles caused no vestibular toxicity, including six nitriles tested in CYP2E1-null mice at doses significantly larger than the maximal doses that can be tested in wild type animals. We conclude that only a subset of low molecular weight nitriles is toxic to the vestibular system, that species-dependent differences exist in this vestibular toxicity, and that CYP2E1-mediated metabolism is not involved in this effect of nitriles although it has a role in the acute lethality of some of these compounds

Fisiología bucal infantil: función y crecimiento de la cavidad oral del lactante

Todas las funciones que se realizan en la cavidad oral (respiración, succión, deglución, masticación y fonación), estimulan el crecimiento y desarrollo del tercio inferior de la cara. Por ello, el tipo de lactancia, así como los hábitos orales disfuncionales, pueden influir sobre la morfología definitiva de los maxilares y de la oclusión dentaria.

Control of hair cell excitability by vestibular primary sensory neurons.

In the rat utricle, synaptic contacts between hair cells and the nerve fibers arising from the vestibular primary neurons form during the first week after birth. During that period, the sodium-based excitability that characterizes neonate utricle sensory cells is switched off. To investigate whether the establishment of synaptic contacts was responsible for the modulation of the hair cell excitability, we used an organotypic culture of rat utricle in which the setting of synapses was prevented. Under this condition, the voltage-gated sodium current and the underlying action potentials persisted in a large proportion of nonafferented hair cells. We then studied whether impairment of nerve terminals in the utricle of adult rats may also affect hair cell excitability. We induced selective and transient damages of afferent terminals using glutamate excitotoxicity in vivo. The efficiency of the excitotoxic injury was attested by selective swellings of the terminals and underlying altered vestibular behavior. Under this condition, the sodium-based excitability transiently recovered in hair cells. These results indicate that the modulation of hair cell excitability depends on the state of the afferent terminals. In adult utricle hair cells, this property may be essential to set the conditions required for restoration of the sensory network after damage. This is achieved via re-expression of a biological process that occurs during synaptogenesis.

La coordinación entre profesores de fisiología y toxicología: un caso práctico en la facultad de farmacia de la Universidad de Barcelona

El aprendizaje es un proceso continuo que no debería finalizar una vez aprobada una determinada asignatura. En cualquier estudio universitario hay muchas materias que, para su comprensión, requieren de conocimientos adquiridos previamente en otras. En los estudios de Farmacia del plan 2002, los profesores de toxicología habían constatado que los estudiantes de dicha asignatura no recordaban conceptos básicos cursados en asignaturas de semestres anteriores. La asignatura de toxicología necesita para su comprensión conocimientos de, entre otras materias, fisiología y fisiopatología. Por esta razón se planteó la necesidad de hacer una actuación conjunta entre los profesores de Fisiología y Toxicología. Los objetivos de este proyecto fueron: a) Identificación de los contenidos fisiológicos y fisiopatológicos que los alumnos deben conocer para el seguimiento de la asignatura de toxicología. b) Unificación terminológica. c) Realización de un conjunto de preguntas básicas sobre estos contenidos. d) Detección, a través de estas preguntas, de los temas o grupos de temas con porcentajes más altos de respuestas incorrectas. e) Detectar los temas de fisiología y fisiopatología en los que hay que hacer más hincapié para favorecer el seguimiento de toxicología. En esta comunicación se describe la experiencia y los resultados obtenidos.

La coordinación entre profesores de fisiología y toxicología: un caso práctico en la facultad de farmacia de la Universidad de Barcelona

El aprendizaje es un proceso continuo que no debería finalizar una vez aprobada una determinada asignatura. En cualquier estudio universitario hay muchas materias que, para su comprensión, requieren de conocimientos adquiridos previamente en otras. En los estudios de Farmacia del plan 2002, los profesores de toxicología habían constatado que los estudiantes de dicha asignatura no recordaban conceptos básicos cursados en asignaturas de semestres anteriores. La asignatura de toxicología necesita para su comprensión conocimientos de, entre otras materias, fisiología y fisiopatología. Por esta razón se planteó la necesidad de hacer una actuación conjunta entre los profesores de Fisiología y Toxicología. Los objetivos de este proyecto fueron: a) Identificación de los contenidos fisiológicos y fisiopatológicos que los alumnos deben conocer para el seguimiento de la asignatura de toxicología. b) Unificación terminológica. c) Realización de un conjunto de preguntas básicas sobre estos contenidos. d) Detección, a través de estas preguntas, de los temas o grupos de temas con porcentajes más altos de respuestas incorrectas. e) Detectar los temas de fisiología y fisiopatología en los que hay que hacer más hincapié para favorecer el seguimiento de toxicología. En esta comunicación se describe la experiencia y los resultados obtenidos.

Actividades de aprendizaje y evaluación a través del Campus Virtual. Experiencia en Fisiología y Fisiopatología I del Grado de Farmacia

[spa] Nuestro objetivo consiste en fomentar, entre alumnos internos del Departamento de Fisiología, el autoaprendizaje, el trabajo autónomo y en equipo, espíritu crítico y habilidad para buscar y analizar información. A la vez se pretende iniciar a estos alumnos en los sistemas de transferencia de resultados de la investigación básica a la investigación aplicada. Para ello a los alumnos se les proporciona materiales que contienen información sobre las materias objeto de aprendizaje y enlaces a diferentes sitios webs de interés relacionados con el tema. En ellos se promueve la exposición de trabajos y la participación en jornadas especializadas. El uso de estos materiales bajo supervisión del profesorado, ha permitido la mejora del conocimiento en Fisiología y la creación de equipos especializados en diferentes aspectos de la Fisiología. Además, la transferencia de información entre alumnos, ha propiciado que puedan adquirir una visión clara y amplia sobre qué es un trabajo de investigación básica o un trabajo de investigación aplicada, así como la importancia del trabajo en equipo, lo que ha posibilitado que pudieran diseñar pequeños experimentos y estudiar su aplicabilidad. Al final del periodo de formación, los alumnos demostraron haber adquirido las competencias genéricas CG1, CG3, CG5, CG6, CG11, CG13 y CG15 incluidas en la ficha Verifica para el Grado en Farmacia, así como las competencias específicas para el módulo 5 (Medicina y Farmacología) CEM5.8, CEM5.9 y CEM5.11, concluyendo así que la aplicación de métodos de enseñanza basados en el autoaprendizaje (bajo supervisión de equipos docentes) constituye una excelente herramienta para la promoción de la adquisición de competencias generales y específicas en el Grado en Farmacia.