Hans Scherer

The strong connection between sensory and cognitive performance in old age: not due to sensory acuity reductions operating during cognitive assessment.

Cognitive aging research has documented a strong increase in the covariation between sensory and cognitive functioning with advancing age. In part, this finding may reflect sensory acuity reductions operating during cognitive assessment. To examine this possibility, the authors administered cognitive tasks used in prior studies (e.g., Lindenberger & Baltes, 1994) to middle-aged adults under age-simulation conditions of reduced visual acuity, auditory acuity, or both. Visual acuity was lowered through partial occlusion filters, and auditory acuity through headphone-shaped noise protectors. Acuity manipulations reduced visual acuity and auditory acuity in the speech range to values reaching or approximating old-age acuity levels, respectively, but did not lower cognitive performance relative to control conditions. Results speak against assessment-related sensory acuity accounts of the age-related increase in the connection between sensory and cognitive functioning and underscore the need to explore alternative explanations, including a focus on general aspects of brain aging.

Management of posttraumatic vertigo

OBJECTIVE: To evaluate patients after blunt trauma of the head, neck, and craniocervical junction (without fractures) with vertigo and to report the results of treatment after extensive diagnostics. STUDY DESIGN: Prospective study of consecutive new cases with vertigo after trauma at different periods of onset. During 2000–2002, 63 patients were examined and treated. SETTING: Regional trauma medical center for the greater Berlin Area, tertiary referral unit. RESULTS: The primary disorders included labyrinthine concussion (18), rupture of the round window membrane (6), and cervicogenic vertigo (12). The secondary disorders included otolith disorders (5), delayed endolymphatic hydrops (12), and canalolithiasis (9). The patients were free of vertigo symptoms (except cervicogenic and otolith disorder) after treatment, which consisted of habituation training, medical and surgical therapy options. The follow-up was 1 year. CONCLUSION: Posttraumatic vertigo can be treated with a high success rate once the underlying disorder has been identified. The extent of the neurotological test battery determines the precision and quality of diagnostics. Surgical measures should be an integral part of treatment modalities if conservative treatment is not effective. SIGNIFICANCE: Minor trauma of the head, neck, and craniocervical junction can have major impact on the vestibular system at different sites. Patients need to be carefully diagnosed, even if the onset of vertigo occurs a few weeks or months after the initial trauma.

The anti-motion sickness mechanism of ginger. A comparative study with placebo and dimenhydrinate.

A controlled, double-blind study was carried out to determine whether nystagmus response to optokinetic or vestibular stimuli might be altered by some agent contained in powdered ginger root (Zingiber officinale). For comparative purposes, the test subjects were examined after medication with ginger root, placebo and with dimenhydrinate. Eye movements were recorded using standard ENG equipment and evaluation was performed by automatic nystagmus analysis. It could be demonstrated that the effect of ginger root did not differ from that found at baseline, or with placebo, i.e. it had no influence on the experimentally induced nystagmus. Dimenhydrinate, on the other hand, was found to cause a reduction in the nystagmus response to caloric, rotatory and optokinetic stimuli. From the present study it can be concluded that neither the vestibular nor the oculomotor system, both of which are of decisive importance in the occurrence of motion sickness, are influenced by ginger. A CNS mechanism, which is characteristic of the conventional anti-motion sickness drugs, can thus be excluded as regards ginger root. It is more likely that any reduction of motion-sickness symptoms derives from the influence of the ginger root agents on the gastric system.

The dynamic contributions of the otolith organs to human ocular torsion

We measured human ocular torsion (OT) monocularly (using video) and binocularly (using search coils) while sinusoidally accelerating (0.7 g) five human subjects along an earth-horizontal axis at five frequencies (0.35, 0.4, 0.5, 0.75, and 1.0 Hz). The compensatory nature of OT was investigated by changing the relative orientation of the dynamic (linear acceleration) and static (gravitational) cues. Four subject orientations were investigated: (1) Y-upright — acceleration along the interaural (y) axis while upright; (2) Y-supine — acceleration along the y-axis while supine; (3) Z-RED — acceleration along the dorsoventral (z) axis with right ear down; (4) Z-supine — acceleration along the z-axis while supine. Linear acceleration in the Y-upright, Y-supine and Z-RED orientations elicited conjugate OT. The smaller response in the Z-supine orientation appeared disconjugate. The amplitude of the response decreased and the phase lag increased with increasing frequency for each orientation. This frequency dependence does not match the frequency response of the regular or irregular afferent otolith neurons; therefore the response dynamics cannot be explained by simple peripheral mechanisms. The Y-upright responses were larger than the Y-supine responses (P<0.05). This difference indicates that OT must be more complicated than a simple low-pass filtered response to interaural shear force, since the dynamic shear force along the interaural axis was identical in these two orientations. The Y-supine responses were, in turn, larger than the Z-RED responses (P<0.01). Interestingly, the vector sum of the Y-supine responses plus Z-RED responses was not significantly different (P=0.99) from the Y-upright responses. This suggests that, in this frequency range, the conjugate OT response during Y-upright stimulation might be composed of two components: (1) a response to shear force along the y-axis (as in Y-supine stimulation), and (2) a response to roll tilt of gravitoinertial force (as in Z-RED stimulation).

Measuring Three Dimensions of Eye Movement in Dynamic Situations by Means of Videooculography

A primary function of the vestibular system is the stabilisation of the eye during head movement. Consequently, evaluation of reflex eye movements represents an essential means to both clinical diagnosis and researching of the vestibular function. Movements in the eye can be resolved into three orthogonal components, i.e. horizontal, vertical and torsional. As an improvement on most current techniques, which provide only measurement of the horizontal and vertical components, videooculography (VOG) facilitates non-invasive measurement of all three of the defined components. To date, only the scleral coil technique, which involves the semi-invasive placement of coil rings onto the bulbi, yields a continuous measure of eye torsion. Employment of suitable solid-state devices permit the integration of a compact, high resolution video recording system. In the basic configuration, eye movements can be observed and simultaneously recorded for later analysis or documentation. The video images of the eye are obtained by means of a miniaturised CCD video sensor mounted on a light-occluding mask. Image processing of the acquired video images determines horizontal and vertical coordinates of eye position online. Ocular torsion, as reflected by the rotation of the natural iris, is measured for each video frame. The VOG algorithm has been implemented on a PC based workstation, which permits online observation, recording and evaluation of eye movements. In addition, the technique has found clinical application as a portable eye-movement observation and recording system, allowing bedside examination and recording of transient symptoms. Preliminary results from various studies, including the objective evaluation of positional nystagmus (BPPN), are presented.

Ocular Counterrolling in Response to Asymmetric Radial Acceleration

The fact that the labyrinths are positioned at approx. 3.5 cm from the head-centric axis leads to the generation of systematic radial acceleratory, or centrifugal, forces during physiological head rotations. Under physiological conditions, the forces exerted on the right and left maculae are generally assumed to be equal and opposite. In the present test, however, the subject was displaced eccentrically during constant angular velocity so that one labyrinth was aligned concentrically with the rotatory axis, whilst the other was exposed to the radial acceleration component generated by the chair rotation. In comparison with previous testing based on subjective setting of the visual vertical, three-dimensional eye movements were recorded in order to obtain an objective measure of the otolith-ocular response mechanisms in the brainstem. The results obtained from normal subjects demonstrate a predominant ocular counterroll (OCR) response to this asymmetric, or unilateral application of linear acceleration. The direction of the OCR response proved to be independent of direction of rotation. The findings demonstrate a symmetrical response magnitude for stimulation of the left and right maculae. In comparison with the OCR response to head-tilt, which can be described as critically damped, the time course of the present response appeared to be underdamped.

Die Lasertonsillotomie bei der Tonsillenhyperplasie des Kleinkindes

ZusammenfassungDie Teilresektion der hyperplastischen Tonsille, die Tonsillotomie, wird in Deutschland zur Behandlung der frühkindlichen Obstruktion des Isthmus faucium allgemein abgelehnt. Das muss überdacht werden. Die Ergebnisse aus dem Universitätsklinikum Benjamin Franklin (n=637), einer HNO-Belegabteilung und einer operativ ausgerichteten HNO-Praxis (n=189) zeigen, dass die in der Literatur zu findenden Angaben über schwere Spätkomplikationen mit Vernarbungen der Tonsillenkrypten und Häufungen von Peritonsillarabszessen als Folge einer Tonsillotomie nicht weiter aufrechterhalten werden können. Im Nachbeobachtungszeitraum trat keine dieser Komplikationen auf.Die Tonsillotomie ist eine adäquate Behandlung der Tonsillenhyperplasie im frühen Kindesalter und führt zu sehr guter Besserung der präoperativen Beschwerden (Schnarchen, Atmungsbehinderung, Schluckbeschwerden, Gedeihstörungen). Voraussetzung für einen langfristigen Erfolg ist dabei die konsequente Beschränkung dieses Eingriffs auf die Diagnose der Tonsillenhyperplasie.AbstractTonsillotomy, the partial resection of hyperplastic tonsils, is generally rejected in Germany as a treatment option for obstructions of the isthmus faucium in early childhood. We think this approach merits consideration. The favorable results obtained with tonsillotomy in the University Hospital Benjamin Franklin (n=637), a private clinic, and an ENT practice with surgical facilities (n=189) showed that there is no justification for adhering to literature reports of severe late complications with scarred tonsillar crypts and peritonsillar abscesses. No patient has developed any of these complications thus far.Following tonsillotomy, preoperative complaints (snoring, respiratory obstruction, dysphagia, and failure to grow) decreased considerably. Thus, tonsillotomy proved to be a suitable modality for treating tonsillar hyperplasia in early childhood.The prerequisite for long-term success is strict limitation of this intervention to the diagnosis of tonsillar hyperplasia.

Experimental studies on the suitability of the erbium laser for stapedotomy in an animal model

Animal experiments in mature guinea pigs were devised to determine whether and to what extent inner ear damage can be caused by in vivo use of the erbium laser for stapedotomy. The present study examined the laser effect in connection with perforation of the basal convolution of the cochlea and subsequent application in the opened cochlea. Acoustic evoked potentials as compound action potentials (CAP) were recorded for changes in inner ear function. Findings demonstrated that five applications of the erbium:YSGG (yttrium-scandium-gallium-garnet) laser (energy, 85 mJ/pulse; energy density, 36 J/cm2) were needed to create a footplate perforation of 500–600 μm and did not lead to CAP alteration in any animal (n = 20). An increase of the repetition rate from 1 to 5 Hz likewise caused no CAP alteration (n = 17). Application of high total energies in the open cochlea (n = 5) to determine the safety of the laser system for stapedotomy revealed that a 10-fold increase in the total energy required for adequate perforation led to irreversible CAP alterations and no CAP could be recorded at a 15-fold increase in total energy. In contrast, a 5-fold maximum increase in total energy caused no CAP alterations. These results demonstrate the safety of the Er:YSGG laser comparable to that of the CO2 laser for stapedotomy, supporting its utility as an alternative method for surgery.

Effects of continuous-wave laser systems on stapes footplate

The aim of the present study was to clarify which of the presently available continuous‐wave laser systems are best suited for application in stapes surgery.

Impact of laser eustachian tuboplasty on middle ear ventilation, hearing, and tinnitus in chronic tube dysfunction.

Objectives: Long-term Eustachian tube dysfunction (ETD) predisposes to various secondary middle ear diseases. Most surgical and prosthetical interventions on the Eustachian tube itself have proven to be ineffective, whereas middle ear surgeries treat the sequelae of ETD without major influence on the underlying tubal pathology. The purpose of our study was to evaluate the outcome of laser Eustachian tuboplasty (LETP) on tubal function and associated otological symptoms in topically anesthetized ETD patients with intact or perforated eardrums. Design: In a prospective clinical investigation, outpatient LETP was carried out in 31 subjects with therapy-refractory chronic ETD. The study population comprised two groups: 16 patients with mesotympanic eardrum perforations diagnosed with noninflammatory chronic otitis media (COM) and 15 patients with intact eardrums including otitis media with effusion, adhesion processes, and dysfunctional pressure equalization. Clinical examination and data acquisition were performed 2 wks before LETP as well as 8 wks and 1 yr postoperatively. On COM patients, LETP was done at 10-wk intervals before the scheduled tympanoplasty. Assessment of clinical effectiveness was based on transnasal videoendoscopy, ear microscopy, tubal function tests (Valsalva maneuver and passive tubal opening), audio- and tympanometric measurements, and visual analog scales. Tansnasal, fiber-guided laser surgery was performed in contact mode using a semiconductor diode laser (&lgr; = 830 nm, 4 W). We hypothesized that regulated laser ablation of hyperplastic mucosa at the epipharyngeal dorsal circumference of the tubal ostium could be effective in improving the associated symptoms such as dysfunctional pressure equalization, aural fullness, conductive hearing loss, and tinnitus. Results: LETP resulted in persistent volume reduction of the posterior tubal circumference in all patients. Objective parameters revealed significant improvement of tubal function tests and middle ear ventilation in 62% of subjects after 8 wks (66% after 1 yr). Significant long-term reduction of conductive hearing loss was achieved in both patient groups. Besides, tinnitus loudness was significantly reduced in COM subjects after tympanoplasty. Visual analog scales showed very low values for intraoperative pain and discomfort and high scores for long-term overall patient satisfaction as well as improvement of the symptoms such as dysfunctional pressure equalization and aural fullness. Subjects with post-LETP Valsalva feasibility marked higher values for satisfaction and symptom improvement than patients without successful Valsalva maneuver. COM subjects scored higher in hearing improvement and satisfaction after LETP and successful tympanoplasty than patients with intact eardrums. Conclusions: Outpatient LETP seems to be a suitable, safe, easily applicable, and well-tolerated treatment option before (revision) tympanoplasties and in all investigated diseases developing from long-lasting pathologic middle ear ventilation. Minimally invasive shaping of the hyperplastic nasopharyngeal Eustachian tube under topical anesthesia seems to be effective in improving tubal function as well as the associated symptoms such as dysfunctional pressure equalization, aural fullness, and conductive hearing loss in otherwise therapy-refractory chronic ETD.