Towards single-trial classification of invasively recorded auditory evoked potentials in cochlear implant users.

Objective.One promising approach towards further improving cochlear implants (CI) is to use brain signals controlling the device in order to close the auditory loop. Initial electroencephalography (EEG) studies have already shown promising results. However, they are based on noninvasive measurements, whereas implanted electrodes are expected to be more convenient in terms of everyday-life usability. If additional measurement electrodes were implanted during CI surgery, then invasive recordings should be possible. Furthermore, implantation will provide better signal quality, higher robustness to artefacts, and thus enhanced classification accuracy.Approach.In an initial project, three additional epidural electrodes were temporarily implanted during the surgical procedure. After surgery, different auditory evoked potentials (AEPs) were recorded both invasively (epidural) and using surface electrodes, with invasively recorded signals demonstrated as being markedly superior. In this present analysis, cortical evoked response audiometry (CERA) signals recorded in seven patients were used for single-trial classification of sounds with different intensities. For classification purposes, we used shrinkage-regularized linear discriminant analysis (sLDA). Clinical speech perception scores were also investigated.Main results.Analysis of CERA data from different subjects showed single-trial classification accuracies of up to 99.2% for perceived vs. non-perceived sounds. Accuracies of up to 89.1% were achieved in classification of sounds perceived at different intensities. Highest classification accuracies were achieved by means of epidural recordings. Required loudness differences seemed to correspond to speech perception in noise.Significance.The proposed epidural recording approach showed good classification accuracy into sound perceived and not perceived when the best-performing electrodes were selected. Classifying different levels of sound stimulation accurately proved more challenging. At present, the methods explored in this study would not be sufficiently reliable to allow automated closed-loop control of CI parameters. However, our findings are an important initial contribution towards improving applicability of closed auditory loops and for next-generation automatic fitting approaches.

Epidural recordings in cochlear implant users.

OBJECTIVE: In the long term it is desirable for CI users to control their device via brain signals. A possible strategy is the use of auditory evoked potentials (AEPs). Several studies have shown the suitability of auditory paradigms for such an approach. However, these investigations are based on non-invasive recordings. When thinking about everyday life applications, it would be more convenient to use implanted electrodes for signal acquisition. Ideally, the electrodes would be directly integrated into the CI. Further it is to be expected that invasively recorded signals have higher signal quality and are less affected by artifacts. APPROACH: In this project we investigated the feasibility of implanting epidural electrodes temporarily during CI surgery and the possibility to record AEPs in the course of several days after implantation. Intraoperatively, auditory brainstem responses were recorded, whereas various kinds of AEPs were recorded postoperatively. After a few days the epidural electrodes were removed. MAIN RESULTS: Data sets of ten subjects were obtained. Invasively recorded potentials were compared subjectively and objectively to clinical standard recordings using surface electrodes. Especially the cortical evoked response audiometry depicted clearer N1 waves for the epidural electrodes which were also visible at lower stimulation intensities compared to scalp electrodes. Furthermore the signal was less disturbed by artifacts. The objective quality measure (based on data sets of six patients) showed a significant better signal quality for the epidural compared to the scalp recordings. SIGNIFICANCE: Altogether the approach revealed to be feasible and well tolerated by the patients. The epidural recordings showed a clearly better signal quality than the scalp recordings with AEPs being clearer recognizable. The results of the present study suggest that including epidural recording electrodes in future CI systems will improve the everyday life applicability of auditory closed loop systems for CI subjects.

[Implementation of a SharePoint-based quality-assured document control system to achieve optimized patient safety]. / Implementierung eines SharePoint-basierten qualitätsgesicherten Dokumentenlenkungssystems zur Erreichung einer optimierten Patientensicherheit.

BACKGROUND: Where the facts relating to a patient's case are not unambiguously laid out, this constitutes a risk for the patient. A requirement, therefore, in the many documents necessitated by a given therapy is to achieve unambiguity, thus avoiding risks and enhancing the safety of treatment. The aim of this study was to arrive at this unambiguity using a systematic approach. MATERIALS AND METHODS: During the course of a project, all clinically relevant documents generated by the department were converted from an uncontrolled form stored within the department's IT system to a SharePoint-based, controlled form. To this end, a means of systematization was developed that reflects the organizational realities of the department. RESULTS: The relevant documents are now available only in a controlled form using a SharePoint system. Access to these documents was successfully achieved for all employees. Any change to the documents is now logged. CONCLUSION: The project can be viewed as exemplary in nature, since its outcome represents a multidimensional contribution to patient safety that can be regarded as an important milestone in a given department's clinical culture. It may also be beneficial as a model for other equally motivated departments as well as being useful from an interdisciplinary perspective.

[Certification of a University Department of Otolaryngology according to DIN EN ISO 9001:2008]. / Zertifizierung einer Universitäts-Hals-Nasen-Ohren-Klinik nach DIN EN ISO 9001:2008.

INTRODUCTION: Quality management (QM) is a control tool for the implementation of a wide range of organizational measures aimed at achieving process orientation and process optimization. The organizational framework for these measures can be structured to fulfill the requirements of certification to the DIN EN ISO 9001 standard. The objective was to implement this tool within a university otorhinolaryngology department. MATERIAL AND METHOD: After drawing up a project plan, the measures required to fulfill the audit requirements were put into practice by a QM core team, which included employees from four areas: healthcare, research, nursing and teaching. RESULTS: The measures carried out resulted in the achievement of certification, provided that annual surveillance audits are performed. DISCUSSION: The attainment of the certificate requires continuous fulfillment of the required standards. Future requirements, such as the demands placed on knowledge management, necessitate further appropriate measures.

[Evidence and Evidence Gaps in the Treatment of Eustachian Tube Dysfunction and Otitis Media]. / Evidenz und Evidenzlücken zur Behandlung der gestörten Mittelohrbelüftung sowie der Otitis media.

Evidence-based medicine is an approach to medical treatment intended to optimise patient-oriented decision-making on the basis of empirically proven effectiveness. For this purpose, a classification system has been established to categorise studies - and hence therapy options - in respect of associated evidence according to defined criteria. The Eustachian tube connects the nasopharynx with the middle ear cavity. Its key function is to ensure middle ear ventilation. Compromised ventilation results in inflammatory middle ear disorders. Numerous evidence-based therapy options are available for the treatment of impaired middle ear ventilation and otitis media, the main therapeutic approach being antibiotic treatment. More recent procedures such as balloon dilation of the Eustachian tube have also shown initial success but must undergo further evaluation with regard to evidence. There is, as yet, no evidence for some of the other long-established procedures.Owing to a multitude of variables, the classification of evidence levels for various treatment approaches calls for highly diversified assessment. Numerous evidence-based studies are therefore necessary in order to evaluate the evidence pertaining to existing and future therapy solutions for impaired middle ear ventilation and otitis media. If this need is addressed, a wealth of implications can be expected for therapeutic approaches in the years to come.

[The Marketing of Healthcare Services in ENT-Clinics]. / Marketing von Gesundheitsleistungen in Hals-, Nasen-, Ohrenkliniken.

OBJECTIVE: The provision of healthcare services in Germany is based on fundamental principles of solidarity and is highly regulated. The question arises which conditions exist for marketing for healthcare services in ENT-clinics in Germany. MATERIAL AND METHODS: The marketing options will be elicited using environmentally analytical considerations. RESULTS: The objectives can be achieved using measures derived from external instruments (service policy, pricing policy, distribution policy or communications policy) or from an internal instrument (human resources policy). The policy environment is particularly influenced by the regulatory framework, which particularly restricts the scope for both the pricing and communications policies. All measures must, however, reflect ethical frameworks, which are regarded as the fundamental premise underlying healthcare services and may be at odds with economic factors. Scope for flexibility in pricing exists only within the secondary healthcare market, and even there only to a limited extent. The significance of price in the marketing of healthcare services is thus very low. If marketing activities are to succeed, a market analysis must be carried out exploring the relevant factors for each individual provider. However, the essential precondition for the marketing of healthcare services is trust. CONCLUSIONS: The marketing of healthcare services differs from that of business management-oriented enterprises in other branches of economy. In the future the importance of marketing activities will increase.

[Group phenomena in medical decisions--an analysis among residents of a department of otolaryngology]. / Gruppenphänomene in ärztlichen Entscheidungen--Eine Analyse unter Assistenzärzten einer HNO-Klinik.

OBJECTIVE: Group phenomena concern the behaviour of particular groups which differs from that of individuals. One relevant phenomenon is the 'risky shift', which describes the observation of groups making riskier decisions than individuals. These phenomena have not been investigated for German physicians as yet. MATERIAL AND METHODS: In a prospective study, participating ENT residents received a questionnaire with a description of 12 clinical borderline cases. The participants were asked to answer these individually using a 10-point analogous scale from 1 (no indication for surgery/treatment) to 10 (indication for surgery/treatment). In the afternoon, the questions were again -provided and discussed within the group. RESULTS: For the morning round, the median of the answers had values between 3 and 9 (average: 6.25). After group discussion in the afternoon, the medians averaged 4 with values between the minimum '1' and the maximum '10'. Regarding statistics, these changes in response behaviour were partially significant (p<0.05). Furthermore, a trend towards more extreme -decisions was observed. CONCLUSIONS: This study shows, that group discussions influence the outcome of the decision-making process in medical residents. Therefore, one should always be aware of this kind of phenomenon when making medical decisions within a group. However, group discussions must still be encouraged and remain fundamental for clinical routine.

Pulmonary Metastases of a Uterine Smooth Muscle Tumour with Undefined Malignancy Potential.

Smooth muscle neoplasms with atypical proliferative behaviour, but without clear histopathological malignancy represent a diagnostic and therapeutic challenge, as distinction from a sarcoma can be difficult and no guaranteed treatment recommendations are available due to the rarity of these changes. In the event of uncertain primary histology, even metastases cannot be assessed as malignancy criteria, but may contribute to the clarification of the histology. Similarities with other smooth muscle proliferations, such as lymphangioleiomyomatosis, are striking. The diagnostic difficulties and treatment options are explained based on the example of a 59-year-old patient, in whom a retroperitoneal mass and pulmonary lesion of such a tumour occurred 4 years after a hysterectomy. Even though the genesis and histological diagnostics have not been conclusively clarified, slow growth and a low recurrence rate for post-menopausal patients allow for a wait-and-see approach, whereby the option for anti-hormonal treatment exists in the event of positive evidence of hormone receptors.

Taste sensation following cochlear implantation surgery.

OBJECTIVES: The chorda tympani nerve (CTN) is at risk of damage during cochlear implantation, especially during posterior tympanotomy. The aim of this study was, therefore, to elicit the risk of taste disorders following cochlear implantation surgery involving a mastoidectomy and a posterior tympanotomy approach. METHOD: Twenty-six patients underwent a taste test before, 3 days after, and 6 weeks after cochlear implantation surgery. The taste sensations - sweet, sour, salt and bitter - were determined. Patients' self-ratings of taste function were also obtained. In addition, the surgeons provided information concerning the intraoperative status of the CTN. RESULTS: In total, 19.2% (5 of 26) of the patients had postoperative taste dysfunction, as measured either subjectively or objectively or both. One of these five individuals had taste disturbance as assessed by both subjective and objective measures; in another, it was merely reported subjectively. Three patients were subjectively asymptomatic but the postoperative taste test revealed a dysfunction. Sixteen percent of the patients in whom the CTN was reported to be preserved intraoperatively had a postoperative taste dysfunction. Although the CTN was rerouted in five patients, only two of them (40%) had transient gustatory dysfunction. In two of those patients with postoperative taste dysfunction, the CTN was not intraoperatively exposed (being protected by bone) despite these individuals' experiencing postoperative taste problems. The recovery rate was 100% at 6 weeks after surgery. CONCLUSION: Our study indicates that cochlear implantation entails only a minimal risk of taste dysfunction and that this is chiefly a transient problem.

[The role of CT in the diagnosis of peritonsillar abscesses after Punctio Sicca]. / Stellenwert der Computertomografie in der Peritonsillarabszessdiagnostik nach Punctio sicca.

BACKGROUND: Peritonsillar abscesses are considered to be complications of a peritonsillar inflammation and are a frequently occurring condition. Often, to confirm the presence of an abscess and to locate it following a dry-tap aspirate, computed tomography (CT) is performed. No validated data has been published to date concerning the role of CT in the diagnosis of peritonsillar abscesses. MATERIAL AND METHODS: In a retrospective analysis, the records of patients presenting at a German university hospital with a suspected peritonsillar abscess between 2006 and 2011 were evaluated. A particular focus was placed on the diagnostic procedure for patients with dry tap. The CT images were evaluated by 2 neuroradiologists. RESULTS: 310 patients with a suspected peritonsillar abscess from the period 2006­2011 were evaluated. In 51 cases (31 male and 20 female patients; 16.5 %), a dry tap was found to have occurred. Of these, in 42 patients (82.3 %) a CT scan was performed to rule out or locate an abscess. In 36 patients (85.7 %), an abscess was verified by CT imaging. CONCLUSION: Where there are clinical grounds for suspecting a peritonsillar abscess, and where a dry tap occurs, our data indicate that performing a CT scan to verify and locate an abscess is an effective diagnostic procedure. However, greater attention should be paid to additional diagnostic methods.

[Laryngology in the late 19th century: using the treatment of Frederick III as an example]. / Laryngologie im ausgehenden 19. Jahrhundert: Das Beispiel der Behandlung Friedrich III.

INTRODUCTION: In 1887, the future Emperor Frederick III developed a laryngeal carcinoma. The long history of this case, from his incipient hoarseness in January 1887 to his death in June 1888, is documented in detail owing to the prominent position of this patient and provides insights into laryngology in the late 19th century. MATERIALS AND METHODS: The team of attending German physicians led by the English physician Dr. Mackenzie wrote reports about the treatment of Frederick III and the circumstances surrounding it, which were published in 1888 by the Imperial Printing House ("Reichsdruckerei"). These reports were analyzed with regard to the assumptions underlying treatment at the time as well as the diagnostic and therapeutic techniques used. RESULTS: The passages cited from these records provide a historical perspective shedding light on the premises underlying treatment and the procedures adopted for diseases of the larynx in the late 19th century. DISCUSSION: The analysis of this illustrative example reveals the similarities and differences between laryngology in the 19th century and that of today. Many of the techniques and assumptions developed back then can still be regarded as the foundation for modern treatment options. Other procedures, however, are now obsolete.

[Current status of outpatient surgery in German ENT clinics. Exemplary analysis of a university hospital]. / Aktueller Stellenwert der ambulanten Chirurgie in deutschen HNO-Kliniken. Exemplarische Analyse einer Universitätsklinik.

AIM: German ENT clinics currently do not attach great importance to outpatient surgical procedures. However, up-to-date data on the proportion of outpatient surgeries are not yet available. MATERIALS AND METHODS: In a retrospective study, outpatient surgical procedures using anesthesia or sedation at a German ENT clinic were analyzed as an illustrative case study. RESULTS: In 2010, the proportion of outpatient surgeries performed under anesthesia or sedation in relation to the total number of surgeries performed under anesthesia or sedation was no more than 3.1%. Although a broad range of surgeries was offered, mainly adenoidectomies were carried out. DISCUSSION: In view of the increasingly limited financial resources in the German health care system and considering the situation in international health care systems, the significance of outpatient surgical procedures in ENT clinics is expected to increase in the future. Future-oriented clinic organization should therefore include sufficient capacity for outpatient surgeries. The basic requirement is realistic cost reimbursement by the insurers.

Validity of cochlear microphonics at high sound pressure levels as an important clinical aspect.

INTRODUCTION: Cochlear microphonics are electrical stimulus responses of the inner ear, generated by mechanical displacement of the hair cells caused by acoustic stimulation. As cochlear microphonics are often used in the diagnosis of hearing impairment and deafness, in preliminary investigations it was seen that obliteration or ossification have no effect on the extent to which cochlear microphonics can be recorded at high sound pressure levels. As artifacts at high sound pressure levels suggested, measurements were subsequently conducted using temporal bone specimens. METHODS: In a test setup equivalent to that for electrocochleography, a needle electrode was placed on the cochlear promontory and used to record potentials following application of an acoustic stimulus. RESULTS: Curves comparable to cochlear microphonics were registrable down to a threshold of 80 dB HL. Additional measurements conducted on damp cloths yielded comparable findings. CONCLUSIONS: Registration of cochlear microphonics at high sound pressure levels does not serve as an indicator of hair cell function, but should instead be regarded as artifacts. The possible sources are discussed.

[Wearing of motorcycle helmets and occurrence of auricular hematomas: a connection?]. / Tragen von Motorradhelmen und Inzidenz von Othämatomen: Ein Zusammenhang?

INTRODUCTION: In addition to trauma, risk factors for the formation of auricular hematomas include the influence of tangential shearing forces upon the auricle. Thus far, no data are available concerning the impact of these forces as caused by the putting on and removal of motorcycle helmets. MATERIAL AND METHODS: In a retrospective observational study, all patients presenting with auricular hematoma and auricular seroma at a German Department of Otolaryngology between January 2005 and March 2011 were analyzed as to a possible connection with the wearing of motorcycle helmets. RESULTS: The proportion of auricular hematoma and seroma patients who were helmet-wearing users of motorcycles, motor scooters or mopeds was 41%. However, none of these patients indicated having put on a protective helmet prior to the occurrence of the hematoma. DISCUSSION: According to our findings, the wearing of motorcycle helmets, with the possible associated influence of tangential shearing forces when putting on or removing the helmet is - despite isolated cases having been described - not a cause of the acute formation of auricular hematomas or seromas. However, the proportion of motorcycle/motor scooter/moped users among patients with these conditions appears to be higher than that for the population as a whole. It may be, therefore, that this does have chronic effects on the auricle.

Preliminary results of the new individual made magnet-based nasal septal button.

The surgical care of large nasal septal defects is often not feasible. As an alternative method, these defects may be closed by nasal septal buttons. Although these buttons should be replaced on a regular basis for cleaning purposes, this procedure is usually painful and causes discomfort to the patient. Moreover, it could cause the nasal septal defects to become enlarged. In a retrospective observational study we analyzed a new method, which combines the advantages of an individually made nasal septal button with a magnet-based technique. After casts of the nasal septal defects were taken under general anaesthesia and magnet-based nasal septal buttons were custom-made, patients were fitted with these devices. The results were evaluated using a questionnaire developed specifically for this purpose. All patients reported that the replacement procedure was being less uncomfortable. The insertion or removal of the magnet-based nasal septal button was not reported as causing particular discomfort in these patients. A precise, tight fit was documented in all cases. The general characteristics of nasal septal buttons are, however, also present in this procedure. Individually made magnet-based nasal septal buttons are practicable and a less uncomfortable alternative method in the treatment of large inoperable nasal septal defects.

[The implementation of risk management in a department of otolaryngology]. / Implementierung eines Risikomanagements in einer Hals-, Nasen-, Ohrenklinik.

The reasons for introducing risk management in hospitals are manifold. Not only legal but also ethical and moral aspects are of great importance.The implementation of risk management in a German department of otolaryngology is presented. Although various instruments were introduced, the main emphasis was placed on the establishment of a risk management team with the aim of prospectively and retrospectively addressing critical situations in hospital operation management and also with the goal of achieving a change of attitude towards mistakes, complications and damages in the clinic.Many aspects of the in-house processes were critically analyzed and optimization strategies were developed such as the introduction of checklists for preoperative patient identification. Furthermore the implemented CIRS has been well accepted.A meaningful objectivity of the results seems difficult. A main reason is that the index "reduction of damage and medical malpractice" is too small to make a conclusive statistical analysis. However, implementation of risk management is advisable for every ENT clinic.

Diffusion-weighted MRI in the diagnosis of cholesteatomas.

OBJECTIVE: The diagnosis of a cholesteatoma can be difficult in cases with an intact tympanic membrane. The aim of our study was to examine whether diffusion-weighted MRI can confirm the diagnosis of a cholesteatoma. STUDY DESIGN: A preoperative diffusion-weighted MRI (echo-planar imaging) scan of the temporal bone was performed in 31 patients with clinically suspected cholesteatoma. The diagnosis was confirmed by pathohistological examination in 18 cases, while the majority of the remaining patients showed chronic otitis media without cholesteatoma. RESULTS: In 3 out of 18 patients with histologically confirmed cholesteatoma, diffusion-weighted imaging produced a hyperintense signal. Another 4 of the 18 cases had a questionable positive result. No increased signal was observed in 11 of these 18 patients. Of 12 patients without a cholesteatoma, 2 showed a positive signal while a questionable hyperintense signal was observed in 5 patients. CONCLUSIONS: According to our present findings, diffusion-weighted MRI (echo-planar imaging) can--with a low sensitivity and specificity--be helpful in individual cases in provisionally diagnosing a cholesteatoma in association with standard MRI and high-resolution CT, even though the lack of a hyperintense signal in diffusion-weighted MRI does not exclude a cholesteatoma.

[Tuberculous Otitis media - a rare differential diagnosis in Germany]. / Tuberkulöse Otitis media -Eine seltene Differenzialdiagnose in Deutschland.

A 28-year-old female patient with a migrant background presented for surgery with a suspected cholesteatoma in the left ear. The patient reported having had an aural discharge for several months; otoscopic examination revealed a runny ear, and discrete granulation tissue was seen. Pure-tone audiometry showed conduction hearing loss of 30-40 dB across all frequencies in the left ear; high-resolution computed tomography of the temporal bone revealed that the mastoid and tympanic cavity were completely obscured. The intraoperative finding showed a caseous space-occupying mass that completely filled the tympanic cavity. The suspected diagnosis of tuberculosis was corroborated by pathohistological, microbiological and molecular biological tests. Tuberculostatic therapy was initiated at a different location. Although tuberculosis of the middle ear is a rare condition in Germany, it should nevertheless be considered when making a differential diagnosis, especially in high-risk patients where cholesteatoma is suspected on clinical and radiological evidence or in patients with a chronic middle ear process.