The present paper reports about a 16-year-old male with neurofibromatosis type 2 (NF-2) of the Wishart type with bilateral deafness who had undergone cochlear implantation after resection of the ...acoustic neuroma (AN) of the same side. Neural response telemetry (NRT) recordings are essential in those patients during cochlear implantation where no stapedial reflexes can be electrically elicited due to the resection of the AN. In the present case, amplitude growth function and a type II pattern of the NRT waveforms could be well established. The comparison of the N(1) response intra-operatively and after 2 years showed a decline in latency by 50% and an increase in absolute amplitude by 10 times at the same current level of electrical stimulation. This improved auditory nerve transduction suggested a change to a 'faster' encoding strategy to improve speech understanding. The change from SPEAK to ACE 18 months after the operation led to an increase in the open-set sentence recognition test from 52 to 88%. Thus, NRT recordings monitor the intra-operative success of electrode placement and help to assess the integrity of the auditory pathway. Moreover, they can reliably be used in programming the speech processor postoperatively as objective tool. In patients with NF-2, the restoration of hearing can be successfully achieved in several ways. The indications for hearing implants (auditory brain stem and cochlear implants) should be carefully considered with respect to the remaining, functional integrity of the auditory nerve and the technical possibilities to monitor the success of these procedures.
Zusammenfassung
Die seitengetrennte Diagnostik aller Gleichgewichtsrezeptoren ist heute reproduzierbar und mit hoher Spezifizität möglich. Die Messung von vestibulär evozierten myogenen Potenzialen ...ist für die Sakkulusfunktion gut etabliert. Für die isolierte Utrikulusfunktionsprüfung stehen Screeningtests zur Verfügung, die ohne großen apparativen Aufwand durchgeführt werden können und Hinweise auf einen Teilausfall der Otolithenorgane geben können. Neben der Prüfung der Bogengangsfunktion mittels Kalorik und Kopfimpulstest gehört die Otolithendiagnostik zu einer vollständigen modernen Gleichgewichtstestung. Otolithenfunktionsstörungen können erfolgreich mithilfe von Neurofeedbackverfahren therapiert werden.
The inferior colliculus (IC) in vivo is reportedly subject to a noise-induced decrease of GABA-related inhibitory synaptic transmission accompanied by an amplitude increase of auditory evoked ...responses, a widening of tuning curves and a higher neuronal discharge rate at suprathreshold levels. However, other in vivo experiments which demonstrated constant neuronal auditory thresholds or unchanged spontaneous activity in the IC after noise exposure did not confirm those findings. Perhaps this can be the result of complex noise-induced interactions between different central auditory structures.
It was, therefore, the aim of the present study to investigate the effects of noise exposure on the spontaneous electrical activity of single neurons in a slice preparation of the isolated mouse IC.
Normal hearing mice were exposed to noise (10
kHz center frequency at 115
dB SPL for 3
h) at the age of 21 days under anesthesia (Ketamin/Rompun 10:1). After one week, auditory brainstem response (ABR) recordings and extracellular single-unit recordings from spontaneously active neurons within the IC slice were performed in noise-exposed and in normal hearing control mice.
Noise-exposed animals showed a significant ABR threshold shift in the whole tested frequency range and a significant lower neuronal spontaneous activity in all investigated isofrequency laminae compared to controls. In both groups, the firing rate of 80% of IC neurons (approximately) increased significantly during the application of the GABA
A receptor antagonist Bicucullin (10
μM).
The present findings demonstrate a noise-related modulation of spontaneous activity in the IC, which possibly contribute to the generation of noise-induced tinnitus and hearing loss.
Zusammenfassung
Im vorliegenden Beitrag werden in einer retrospektiven Analyse von 94 berufsgenossenschaftlich Versicherten aus den Jahren 2005–2008 die stationären Behandlungsverläufe und das ...therapeutische Outcome posttraumatischer Gleichgewichtsstörungen beschrieben. In 59% der Fälle bestand eine einzelne Gleichgewichtsstörung, bei den übrigen Patienten fanden sich ≥2 parallel oder sequenziell. Neben primären, d. h. sofort aufgetretenen, Schädigungen mit guter Prognose fanden sich bei 35% sekundäre, d. h. später, im Intervall aufgetretene/bemerkte Störungen mit schlechterer Prognose. Entscheidend für die Heilverfahrenssteuerung ist nach unseren Daten eine Verkürzung der Zeitabschnitte bis zur Vorstellung der Versicherten in einer spezialisierten Einrichtung zur Abklärung. Hierin liegt mit Blick auf die Steuerung des Heilverfahrens derzeit das größte Problem, da Gleichgewichtsstörungen mit ihren scheinbar unspezifischen Patientenangaben fehlgedeutet werden können (Übersehen der „yellow flags“). Die HNO-Klinik des ukb (Unfallkrankenhaus Berlin) bietet für diese Patienten seit kurzem eine spezialisierte Gleichgewichtstherapie an, die sowohl eine hochspezialisierte Abklärung als auch Therapieoptionen umfasst.
Postural control in otolith disorders Basta, Dietmar; Todt, Ingo; Scherer, Hans ...
Human movement science,
04/2005, Letnik:
24, Številka:
2
Journal Article
Recenzirano
It was the aim of the present paper to investigate the influence of otolith disorders on human postural control by different methods. The 33 patients of our study had undergone a minor head injury ...and suffered subsequently from an utricular or sacculo-utricular disorder as evidenced by vestibular evoked myogenic potential recordings and eccentric rotation recordings of the otolith-ocular responses. Postural control was assessed by performing stance/gait tests (standard balance deficit test, SBDT) and by evaluating trunk sway (using angular velocity sensors). Moreover, classical tests of the posterior column of the spinal tract (Romberg/Unterberger) and the dynamic posturography (sensory organization test, SOT) were included. It could be shown that SBDT tasks with reduced proprioceptive and visual cues (e.g. standing on foam, eyes closed) are most sensitive for an otolith disorder. The patients showed an increased trunk sway in the pitch plane (i.e. linear motion as adequate utricular stimulus) and an increase in sway velocities (i.e. tilting movements as adequate saccular stimulus) compared to controls. The SOT was most sensitive for combined (sacculo-utricular) otolith disorders (78%) while vestibulospinal tests are not enough sensitive. In essence, otolith disorders evidently impair human postural control and have been possibly underestimated as a source of posttraumatic postural imbalance as yet.
The gap junctional network of the inner ear plays an important role in cochlear ionic homoeostasis. Mutations of connexin 26 can induce different types of hearing loss and even deafness. Therefore, ...it is hypothesized that gap junctions of the human vestibular organ are functionally impaired by mutations of connexin 26. In a prospective, nonrandomized study, the functional status of the semicircular canals and the otolith organs was assessed in one homozygous and six heterozygous carriers of connexin 26 mutations. Five out of seven patients (71.4%) had pathological vestibular evoked myogenic potentials, indicating a loss of saccular function. The utricular function (as tested by subjective haptic vertical) and the function of the semicircular canals (as tested by recording the vestibuloocular reflex) were largely normal. Thus, connexin 26 mutations can be associated with saccular defects of the vestibular receptors.
Background: Breast cancer is the most common cancer in women. While mammography is the standard for early detection in women older than 50 years of age, there is no standard for younger women. The ...aim of this prospective pilot study was to assess liquid crystal contact thermography, using the Braster device, as a means for the early detection of breast cancer. The device is intended to be used as a complementary tool to standard of care (sonography, mammography, etc). Patients and Methods: A total of 274 consecutive women presenting at Polish breast centers for prophylactic breast examination were enrolled to receive thermography; 19 were excluded for errors in thermographic image acquisition. The women were divided according to age (n = 135, <50 years; n = 120, ≥50 years). A control population was included (n = 40, <50 years; n = 23, ≥50 years). The primary endpoint, stratified by age group, was the C-statistic for discrimination between breast cancer and noncancer. Results: In women with abnormal breast ultrasound (n = 95, <50 years; n = 87, ≥50 years), the C-statistic was 0.85 and 0.75, respectively (P = .20), for discrimination between breast cancer and noncancer. Sensitivity did not differ (P = .79) between the younger (82%) and older women (78%), while specificity was lower in the older women (60% vs 87%, P = .025). The false-positive rate was similar in women with normal and abnormal breast ultrasound. Positive thermographic result in women with Breast Imaging Reporting and Data System (BIRADS) 4A on ultrasound increased the probability of breast cancer by over 2-fold. Conversely, a negative thermographic result decreased the probability of cancer more than 3-fold. Breast size and structure did not affect the thermography performance. No adverse events were observed. Conclusions: Thermography performed well in women <50 years of age, while its specificity in women ≥50 years was inadequate. These promising findings suggest that the Braster device deserves further investigation as a supporting tool for the early detection of breast cancer in women younger than 50 years of age.
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