Rafael Garcia-Tapia

Cerebral auditory plasticity and cochlear implants.

Previous animal research and clinical experiences in humans suggest the existence of an auditory critical period in language acquisition. We review the literature and present the changes within the cochlear nuclei in bilaterally deafferentated adult non-human primates. We also present and analyse the results of 98 prelingually deaf children and teenagers who underwent a cochlear implantation at the University of Navarra. Patients received a Nucleus 22 or 24 multichannel cochlear implant (CI). They were grouped in five categories according to their age at surgery. Performance is compared with a control group of 58 postlinguals. Only early-implanted prelingual children (before 6 years of age) achieved a complete open-set speech recognition, even with better performance than postlinguals. These results clearly demonstrate the existence of a period of high neural auditory plasticity within the first 6 years of life. The introduction of auditory stimulation with a CI can not restore the loss of neural plasticity out of this period. Prelingual children under 6 years of age should receive a CI as soon as there is a reliable diagnosis of bilateral sensorineural hearing loss.

Dizziness: relating the severity of vertigo to the degree of handicap by measuring vestibular impairment.

OBJECTIVE: We sought to correlate the severity of vertigo and handicap in patients with vestibular pathology according to measures of impairment. STUDY DESIGN AND SETTING: We conducted a prospective assessment of patients with dizziness by means of caloric, rotatory test, and computerized dynamic posturography to estimate impairment. Handicap and severity of vertigo were determined with specific questionnaires (Dizziness Handicap Inventory and UCLA-DQ). RESULTS: A fair relationship were found between severity of dizziness and vestibular handicap. When impairment was taken into consideration, values were still fair and only moderate for a group of patients with an abnormal caloric test as the only pathologic finding. The composite score from the sensory organization test portion of the computerized dynamic posturography is fairly correlated to severity of vertigo and handicap in the whole population of patients, but no correlation was found when they were assigned to groups of vestibular impairment. CONCLUSION: To assess vestibular impairment, the results from several tests must be taken into account. However, vestibular handicap is not solely explained with measurements of impairment and/or severity.

Intratympanic gentamicin for intractable Meniere's disease.

Objective The study aimed to analyze the results of the intratympanic injection of gentamicin as a treatment option for patients with unilateral Menieres disease who were refractory to medical treatment.

Factor Analysis and Correlation Between Dizziness Handicap Inventory and Dizziness Characteristics and Impact on Quality of Life Scales

In order to assess the different dimensions of disability and handicap analyzed in the Dizziness Handicap Inventory (DHI) and Dizziness Characteristics and Impact on Quality of Life (UCLA-DQ) questionnaires a factor analysis study was done. The instruments used were the corresponding transculturally adapted versions of the originals into Spanish. The study included 337 patients with dizziness, independent of location and etiology, who were able to respond to all the items in the questionnaires given before vestibular testing. Factor analysis was used to determine the structure of both scales; a principal components analysis with orthogonal rotation (Varimax) was conducted on data collected from the patients. A three-factor solution was obtained in the DHI and a two-factor solution for the UCLA-DQ. The factors obtained from the DHI were related to vestibular handicap, vestibular disability and visuo-vestibular disability; the factors from the UCLA-DQ were related to frequency and severity of dizziness. There was no coincidence between the items in each of the factor obtained in the DHI questionnaire and the items in the subscales provided in the original version. The main relation between factors was found between vestibular handicap and frequency. The DHI and UCLA-DQ questionnaires are multidimensional questionnaires for the assessment of the impact of dizziness and provide a model for vestibular disability and handicap.In order to assess the different dimensions of disability and handicap analyzed in the Dizziness Handicap Inventory (DHI) and Dizziness Characteristics and Impact on Quality of Life (UCLA-DQ) questionnaires a factor analysis study was done. The instruments used were the corresponding transculturally adapted versions of the originals into Spanish. The study included 337 patients with dizziness, independent of location and etiology, who were able to respond to all the items in the questionnaires given before vestibular testing. Factor analysis was used to determine the structure of both scales; a principal components analysis with orthogonal rotation (Varimax) was conducted on data collected from the patients. A three-factor solution was obtained in the DHI and a two-factor solution for the UCLA-DQ. The factors obtained from the DHI were related to vestibular handicap, vestibular disability and visuo-vestibular disability; the factors from the UCLA-DQ were related to frequency and severity of dizziness. There was no coincidence between the items in each of the factor obtained in the DHI questionnaire and the items in the subscales provided in the original version. The main relation between factors was found between vestibular handicap and frequency. The DHI and UCLA-DQ questionnaires are multidimensional questionnaires for the assessment of the impact of dizziness and provide a model for vestibular disability and handicap.

Benign Paroxysmal Positional Vertigo in Patients With Ménière's Disease Treated With Intratympanic Gentamycin

Objectives To analyze the incidence and characteristics of benign paroxysmal positional vertigo (BPPV) in patients with Ménières disease who did not respond to medical treatment and to whom intratympanic gentamycin treatment was proposed.

Cochlear implantation in radical cavities of mastoidectomy

In recent years, cochlear implants have been found to be effective in the treatment of bilateral profound hearing loss. Their use has been extended progressively to different populations, including prelingually and postlingually deaf children and adults as well as patients with associated handicaps. Cochlear implants have also been used in patients with anatomic variations of the cochlea and the middle ear, such as cochlear ossification, congenital malformations of the ear, and previous middle ear surgery.

Development of speech in 2-year-old children with cochlear implant

Auditory deprivation in children causes important adverse effects in speech development, acquisition of knowledge, and the affective area. The use of multichannel cochlear implants permits to restore the auditory capacity and therefore affects directly the children’s language and speech development. The aim of this study is to evaluate the speech development in a group of children treated with early cochlear implantation.

Influence of canal paresis and compensation on gain and time constant of nystagmus slow-phase velocity to yaw-axis rotation.

In order to assess the influence of canal paresis and compensation on the yaw-axis rotatory chair test parameters gain and time constant, a study was conducted in 435 patients diagnosed with unilateral peripheral vestibulopathy. Patients were grouped according to the amount of canal paresis found in the caloric test and by the result of a bedside examination of the vestibulo-ocular reflex (VOR). The time constant of the VOR diminishes as canal paresis increases and, when using a high-velocity sinusoidal test, there is a similar reduction in gain. Mean time constant was reduced when rotations were to the side of the lesion (ipsilesional) and to the normal (contralesional) and differences between both rotations were found for 21-80% canal paresis. Ipsilesional gain was significantly less than contralesional gain, which had a normal result independent of the amount of canal paresis; differences between them were significant when canal paresis was > 41%. Spontaneous nystagmus significantly influenced the appearance of asymmetries in gain and time constant in the tests performed while, with high-velocity sinusoidal rotation, gain was found to be significantly different for ipsilesional and contralesional rotations in non-acute symptomatic patients.In order to assess the influence of canal paresis and compensation on the yaw-axis rotatory chair test parameters gain and time constant, a study was conducted in 435 patients diagnosed with unilateral peripheral vestibulopathy. Patients were grouped according to the amount of canal paresis found in the caloric test and by the result of a bedside examination of the vestibulo-ocular reflex (VOR). The time constant of the VOR diminishes as canal paresis increases and, when using a high-velocity sinusoidal test, there is a similar reduction in gain. Mean time constant was reduced when rotations were to the side of the lesion (ipsilesional) and to the normal (contralesional) and differences between both rotations were found for 21-80%, canal paresis. Ipsilesional gain was significantly less than contralesional gain, which had a normal result independent of the amount of canal paresis; differences between them were significant when canal paresis was > 41%. Spontaneous nystagmus significantly influenced the appearance of asymmetries in gain and time constant in the tests performed while, with high-velocity sinusoidal rotation, gain was found to be significantly different for ipsilesional and contralesional rotations in non-acute symptomatic patients.

Results of vestibular autorotation testing at the end of intratympanic gentamicin treatment for Ménière's disease

Objective--The vestibular autorotation test (VAT) examines the ocular response to voluntary horizontal and vertical head movements at frequencies for which the vestibular system is the main source for eye stabilization. The purpose of this study was to analyse the VAT results in patients with disabling Méniéres disease and to evaluate the change in VAT values once treatment with intratympanic gentamicin had terminated and clinical signs of vestibular hypofunction could be observed. Material and methods--The 30 study subjects were patients diagnosed with definitive unilateral Méniéres disease that could not be controlled with medication. The vestibulo-ocular reflexes of each patient were evaluated by means of the VAT before the first injection of gentamicin and after the last injection. Results--The pattern of abnormalities found in this population conformed to the selection criteria and the findings reflected a severe disabling process, with major modifications in the vestibulo-ocular reflex. At the end of treatment there was a reduction in the peak frequency of head oscillation. Furthermore, we commonly found that, in the horizontal VAT, gain and phase were reduced while in the vertical VAT some subjects registered a normal response. The phase in the horizontal and vertical VATs was most significantly reduced for oscillation frequencies of 2-3.7 Hz. Conclusion--This study provides further evidence that effective control of vertigo in patients with Méniéres disease can be achieved by administering intratympanic gentamicin.