Marc Bloching

Comparing the habituation of late auditory evoked potentials to loud and soft sound

The objective fitting of hearing aids and cochlear implants remains a challenge. In particular, the determination of whether sound is perceived as too loud or comfortable represents an unsolved problem in noncooperative patients. In a first step of an ongoing study, we assess the feasibility of habituation correlates in late auditory evoked potentials (LAEPs) to discriminate between a soft sound (SS) of 50 dB SPL and a loud sound (LS) of 100 dB SPL. We applied a new sweep-to-sweep time-scale coherence measure to analyse the habituation in LAEPs, i.e., relative changes within sweep sequences. From the comparison between both stimulation levels, a total discrimination of responses to SS and LS in the individual normal hearing subject was possible. As just relative changes in SS and LS sweep sequences were considered, purely exogenously driven morphological alternations in the responses such as intensity related amplitude and latency changes were excluded from the analysis. It is concluded that the proposed method allows for the reliable detection of auditory habituation and differentiation of SS from LS. The proposed scheme might provide an electrophysiological measurement and signal processing framework for the objective detection of the most comfortable loudness level and can be used in further, more clinically oriented studies.

Detection of human utricular otoconia degeneration in vital specimen and implications for benign paroxysmal positional vertigo

Otoconia are assumed to be involved in inner ear disorders such as benign paroxysmal positional vertigo (BPPV). Up to now, the distinct structure and morphology of intact and degenerate human utricular otoconia has been only poorly investigated on vital specimen. In this study, human otoconia were obtained from the utricle in five patients undergoing translabyrinthine vestibular schwannoma surgery. Specimens were examined by environmental scanning electron microscopy. Intact and degenerate otoconia as well as fracture particles of otoconia and bone were analyzed by energy dispersive X-ray microanalysis (EDX) and powder X-ray diffraction (XRD). Intact otoconia reveal a uniform size showing characteristic symmetry properties. Degenerative changes can be observed at several stages with gradual minor and major changes in their morphology including fragment formation. EDX analyses reveal the characteristic chemical composition also for otoconia remnants. XRD shows that intact and degenerate otoconia as well as remnants consist of the calcite modification. In conclusion, electron microscopy serves as a standard method for morphological investigations of otoconia. Human utricular otoconia show a uniform outer morphology corresponding to a calcite-based nanocomposite. Morphological changes provide further evidence for degeneration of utricular otoconia in humans, which might be a preconditioning factor causing BPPV. In case of uncertain origin, particles can be clearly assigned to otoconial origin using EDX and XRD analyses.

Sclerotherapy of cervical cysts with Picibanil (OK-432)

The effectiveness of intralesional sclerotherapy of lymphangiomas and ranulas with OK-432 (Picibanil) has been proved in several clinical studies. The aim of our study was to review the effectiveness of sclerotherapy of benign cervical cysts with Picibanil as an alternative method to surgical excision. Between March 2002 and March 2006, a prospective observational study was carried out to assess the effects of Picibanil on cervical cysts. Between 2002 and 2006 we treated 14 patients having cervical cysts through intralesional application of Picibanil with a dose of 0.01xa0mg/ml. So far we used Picibanil with 13 patients achieving a high success rate. In eight cases we observed, both clinically and ultrasonographically, a nearly complete regression, and a complete regression of the cysts in three cases. In two cases the cysts atrophied. In these cases only residual findings could be observed. In one case we extirpated the remaining cyst. If there is no clear reaction of the cyst to the treatment, an excision is indicated 6xa0weeks after the injections to gain meaningful histological examination. No significant complication after sclerotherapy with Picibanil was observed. According to our results the application of OK-432 (Picibanil) is a safe and effective primary method for sclerotherapy of benign cervical cysts which can replace surgical extirpation in special cases. However, the risk of malign diseases has to be excluded before the commencement of the Picibanil treatment.

Horizontal VOR function shows frequency dynamics in vestibular schwannoma.

AbstractnThe objective of this retrospective study was to investigate the horizontal vestibulo-ocular reflex (hVOR) pathway with caloric test (low-frequency hVOR) and video head impulse test (vHIT) (high-frequency hVOR) in patients with sporadic vestibular schwannoma (69 patients, 27–86xa0years, mean age 58.1xa0years) and to compare both test methods in terms of their sensitivity and specificity to detect a retrocochlear lesion. Test results with a unilateral weakness (UWCaloric)xa0>25xa0% (caloric test) or a Mean-GainvHITxa0<0.79/asymmetry ratio of Gain (AR-GainvHIT)xa0>8.5xa0% and accompanied refixation saccades (vHIT) were considered abnormal. The overall sensitivity of the caloric test was 72xa0%. The evaluation of AR-GainvHIT detected more abnormal cases than did Mean-GainvHIT (44 vs. 36xa0%). In up to 4xa0%, a normal caloric test result was related to an abnormal vHIT. There was only a moderate correlation of UWCaloric and AR-GainvHIT (rxa0=xa00.54, pxa0<xa00.05) with a linear regression line intercept/slope of 32.2/0.9 (pxa0<xa00.05). Receiver operating characteristics curve analysis exhibited at a UWCaloric of 50xa0% a vHIT sensitivity/specificity/positive predictive value/negative predictive value of 0.45/0.9/0.94/0.42. Vestibular testing at varying frequencies provides deeper insights into hVOR function and is helpful in detecting a cerebello-pontine lesion. Whereas caloric test yields a high sensitivity for nerve dysfunction, vHIT test reveals a remaining function of hVOR in the high-frequency range.

Video-Kopfimpulstest oder thermische Prüfung?

ZusammenfassungDer Video-Kopfimpulstest (vKIT) ist eine neue vestibuläre Testmethode, die hinsichtlich ihrer Wertigkeit für die klinische Diagnostik in der HNO-Heilkunde derzeit wenig untersucht ist. Wie bisher mit der thermischen Prüfung kann auch mit dem vKIT der horizontale vestibulookuläre Reflex (hVOR) seitengetrennt getestet werden. In der vorliegenden Studie wurden thermische Prüfung und vKIT bei 46xa0Patienten mit einem Vestibularisschwanomm verglichen. Die Ergebnisse zeigen, dass die thermische Prüfung eine höhere Sensitivität als der vKIT (72% versus 41%) aufweist und beide Testverfahren nur in geringem Maß korrelieren. Die Tumorgröße und das Hörvermögen korrelieren mit Auffälligkeiten in der thermischen Prüfung, jedoch nicht beim vKIT. Da thermische Prüfung und vKIT den hVOR im nieder- bzw. hochfrequenten Arbeitsbereich testen, sind sie als komplementäre Verfahren zu betrachten und gleichermaßen in Diagnostik und Therapieplanung von Bedeutung.AbstractThe video head impulse test (vHIT) is a new method for investigating vestibular function that is currently poorly studied in terms of its value for clinical diagnosis in otolaryngology. Both the caloric irrigation and vHIT serve to evaluate the horizontal vestibulo-ocular reflex. In the present study, caloric irrigation and vHIT were compared in 46xa0patients with vestibular schwannoma. Caloric irrigation exhibits a higher sensitivity than vHIT (72% versus 41%) and both tests show only a moderate correlation. Tumor size and hearing level was significantly correlated with caloric abnormalities but not with vHIT findings. Since caloric irrigation and vHIT measure the hVOR in low and high frequency ranges, respectively, these tests have to be considered complementary and are valuable in both diagnostics and therapeutic decisions.

Rezeptorfunktion der Bogengänge

The perception and conversion of motion stimuli by the vestibular receptors, unimpaired postural control and intact visual acuity are essential for spatial orientation. Disturbances in these three sensory systems can manifest as vertigo, dizziness or imbalance. The integrity of peripheral receptor function, especially of the three semicircular canals, plays a superficial role. They are sensitive to acceleration stimuli, which they transmit via reflexes to the eye muscles. The stabilization of a visual target is via vestibulo-ocular reflexes, which have a very short latency and thus ensure a permanently stable image on the retina. Modern lateral-specific testing procedures are available to diagnose the receptor function of the peripheral vestibular system. The function of the semicircular canals can be analyzed using a head impulse test (HIT) and, more recently, by means of video-HIT as well as on the basis of a caloric test. Using these techniques, all three semicircular canals can be assessed in a side- and receptor-specific manner.ZusammenfassungDie Aufnahme und Umwandlung von Bewegungsreizen durch die vestibulären Rezeptoren, eine ungestörte posturale Kontrolle sowie ein intakter Visus sind die Voraussetzung für eine Orientierung im Raum. Störungen dieser drei reizaufnehmenden Sinnessysteme werden als „Schwindel“ oder „Gleichgewichtsstörungen“ reflektiert. Die Integrität peripherer Rezeptoren, insbesondere der 3xa0Bogengänge, spielt dabei eine vordergründige Rolle. Sie reagieren auf Beschleunigungsreize und leiten diese über reflektorische Verbindungen zu den Augenmuskeln weiter. Die Stabilisierung eines Blickziels erfolgt dabei über vestibulookuläre Reflexe, die eine sehr kurze Latenzzeit aufweisen und so permanent ein stabiles Abbild auf der Retina gewährleisten. Für die Diagnostik der Rezeptorfunktion des peripher-vestibulären Systems stehen unterschiedliche Testverfahren zur Verfügung. Neben der thermischen Prüfung wird in letzter Zeit der Kopfimpulstest (KIT) zur Rezeptorfunktionsanalyse der Bogengänge genutzt. Damit lassen sich alle 3xa0Bogengänge seiten- und rezeptorspezifisch beurteilen.AbstractThe perception and conversion of motion stimuli by the vestibular receptors, unimpaired postural control and intact visual acuity are essential for spatial orientation. Disturbances in these three sensory systems can manifest as “vertigo”, “dizziness” or “imbalance”. The integrity of peripheral receptor function, especially of the three semicircular canals, plays a superficial role. They are sensitive to acceleration stimuli, which they transmit via reflexes to the eye muscles. The stabilization of a visual target is via vestibulo-ocular reflexes, which have a very short latency and thus ensure a permanently stable image on the retina. Modern lateral-specific testing procedures are available to diagnose the receptor function of the peripheral vestibular system. The function of the semicircular canals can be analyzed using a head impulse test (HIT) and, more recently, by means of video-HIT as well as on the basis of a caloric test. Using these techniques, all three semicircular canals can be assessed in a side- and receptor-specific manner.

Cystic fibrosis: ultrastructural changes of nasal mucosa

Cystic fibrosis (CF) is an inherited multisystemic disorder that results in a generalized dysfunction of exocrine glands. Besides chronic obstructive pulmonary diseases, chronic sinusitis, nasal polyposis and hypertrophy of the inferior turbinates with nasal airway obstruction are typical signs. Tissue samples of the inferior turbinates and nasal polyps were taken during nasal surgery from 21 children, ranging from 3 to 16xa0years of age. Light- and electron microscopical examination were carried out. Furthermore, specimens of nasal mucosa of patients without chronic inflammation as controls and specimens of duodenal mucosa of patients with CF were investigated. Under a thick layer of respiratory epithelium with a high proportion of goblet cells, the seromucous glands display abnormal morphological structures with wide mucous cells and cystic dilatation. The glandular cells show inhomogeneous glandular droplets in the supranuclear cell portion. The nucleus contains dispersed chromatin as a sign of increased activity and the structures of the Golgi apparatus are clearly detectable. Apart from investigations concerning nasal polyps in CF, studies on the different morphological changes of nasal mucosa at the electron microscopic level are rare. This histological study focuses on various morphological changes of nasal glands at the ultrastructural level in correlation with typical symptoms in CF. In addition, a comparison with electron microscopic findings of CF-enteropathies is proposed. These findings could help to bring information concerning new morphological aspects in the pathophysiology of patients with CF.

[Receptor function of the semicircular canals: Part 1: anatomy, physiology, diagnosis and normal findings].

The perception and conversion of motion stimuli by the vestibular receptors, unimpaired postural control and intact visual acuity are essential for spatial orientation. Disturbances in these three sensory systems can manifest as vertigo, dizziness or imbalance. The integrity of peripheral receptor function, especially of the three semicircular canals, plays a superficial role. They are sensitive to acceleration stimuli, which they transmit via reflexes to the eye muscles. The stabilization of a visual target is via vestibulo-ocular reflexes, which have a very short latency and thus ensure a permanently stable image on the retina. Modern lateral-specific testing procedures are available to diagnose the receptor function of the peripheral vestibular system. The function of the semicircular canals can be analyzed using a head impulse test (HIT) and, more recently, by means of video-HIT as well as on the basis of a caloric test. Using these techniques, all three semicircular canals can be assessed in a side- and receptor-specific manner.ZusammenfassungDie Aufnahme und Umwandlung von Bewegungsreizen durch die vestibulären Rezeptoren, eine ungestörte posturale Kontrolle sowie ein intakter Visus sind die Voraussetzung für eine Orientierung im Raum. Störungen dieser drei reizaufnehmenden Sinnessysteme werden als „Schwindel“ oder „Gleichgewichtsstörungen“ reflektiert. Die Integrität peripherer Rezeptoren, insbesondere der 3xa0Bogengänge, spielt dabei eine vordergründige Rolle. Sie reagieren auf Beschleunigungsreize und leiten diese über reflektorische Verbindungen zu den Augenmuskeln weiter. Die Stabilisierung eines Blickziels erfolgt dabei über vestibulookuläre Reflexe, die eine sehr kurze Latenzzeit aufweisen und so permanent ein stabiles Abbild auf der Retina gewährleisten. Für die Diagnostik der Rezeptorfunktion des peripher-vestibulären Systems stehen unterschiedliche Testverfahren zur Verfügung. Neben der thermischen Prüfung wird in letzter Zeit der Kopfimpulstest (KIT) zur Rezeptorfunktionsanalyse der Bogengänge genutzt. Damit lassen sich alle 3xa0Bogengänge seiten- und rezeptorspezifisch beurteilen.AbstractThe perception and conversion of motion stimuli by the vestibular receptors, unimpaired postural control and intact visual acuity are essential for spatial orientation. Disturbances in these three sensory systems can manifest as “vertigo”, “dizziness” or “imbalance”. The integrity of peripheral receptor function, especially of the three semicircular canals, plays a superficial role. They are sensitive to acceleration stimuli, which they transmit via reflexes to the eye muscles. The stabilization of a visual target is via vestibulo-ocular reflexes, which have a very short latency and thus ensure a permanently stable image on the retina. Modern lateral-specific testing procedures are available to diagnose the receptor function of the peripheral vestibular system. The function of the semicircular canals can be analyzed using a head impulse test (HIT) and, more recently, by means of video-HIT as well as on the basis of a caloric test. Using these techniques, all three semicircular canals can be assessed in a side- and receptor-specific manner.

On the single sweep processing of auditory brainstem responses: Click vs. chirp stimulations and active vs. passive electrodes

We have recently shown that click evoked auditory brainstem responses (ABRs) single sweeps can efficiently be processed by a hybrid novelty detection system. This approach allowed for the objective detection of hearing thresholds in a fraction of time of conventional schemes, making it appropriate for the efficient implementation of newborn hearing screening procedures.

[Video head impulse test or caloric irrigation?. Contemporary diagnostic tests for vestibular schwannoma].

ZusammenfassungDer Video-Kopfimpulstest (vKIT) ist eine neue vestibuläre Testmethode, die hinsichtlich ihrer Wertigkeit für die klinische Diagnostik in der HNO-Heilkunde derzeit wenig untersucht ist. Wie bisher mit der thermischen Prüfung kann auch mit dem vKIT der horizontale vestibulookuläre Reflex (hVOR) seitengetrennt getestet werden. In der vorliegenden Studie wurden thermische Prüfung und vKIT bei 46xa0Patienten mit einem Vestibularisschwanomm verglichen. Die Ergebnisse zeigen, dass die thermische Prüfung eine höhere Sensitivität als der vKIT (72% versus 41%) aufweist und beide Testverfahren nur in geringem Maß korrelieren. Die Tumorgröße und das Hörvermögen korrelieren mit Auffälligkeiten in der thermischen Prüfung, jedoch nicht beim vKIT. Da thermische Prüfung und vKIT den hVOR im nieder- bzw. hochfrequenten Arbeitsbereich testen, sind sie als komplementäre Verfahren zu betrachten und gleichermaßen in Diagnostik und Therapieplanung von Bedeutung.AbstractThe video head impulse test (vHIT) is a new method for investigating vestibular function that is currently poorly studied in terms of its value for clinical diagnosis in otolaryngology. Both the caloric irrigation and vHIT serve to evaluate the horizontal vestibulo-ocular reflex. In the present study, caloric irrigation and vHIT were compared in 46xa0patients with vestibular schwannoma. Caloric irrigation exhibits a higher sensitivity than vHIT (72% versus 41%) and both tests show only a moderate correlation. Tumor size and hearing level was significantly correlated with caloric abnormalities but not with vHIT findings. Since caloric irrigation and vHIT measure the hVOR in low and high frequency ranges, respectively, these tests have to be considered complementary and are valuable in both diagnostics and therapeutic decisions.