[Objective audiometry and clinical application]. / Objektive Audiometrie und klinische Anwendung.

Subjective and objective hearing tests are used for evaluation of hearing impairments. Objective methods include impedance measurement with tympanometry and stapedius reflex measurement, otoacoustic emissions (OAE), and auditory evoked potentials (AEP). Combined with statistical analysis, the introduction of auditory steady state responses (ASSR) has enabled objective hearing tests in newborn hearing screening and automated hearing threshold assessment. The type and degree of hearing loss can be determined using the abovementioned methods. Precise interpretation of the test results is helpful to distinguish an auditory synaptopathy/neuropathy from classical sensorineural hearing loss.

[Electrocochleography using Transtympanic, Ear Drum and Ear Canal Electrode in Diagnosis of Morbus Menière]. / Elektrokochleografie mit Trommelfell-, Gehörgangs- und transtympanaler Elektrode bei V.a. Morbus Menière.

OBJECTIVE: Aim of this study was to explore the clinical value of non-invasive recordings of electrocochleography in comparison to the use of invasive electrodes for the diagnosis of endolymphatic hydrops in patients with suspicious Morbus Menière. MATERIAL AND METHODS: 15 patients with clinical suspicion of Morbus Menière underwent electrocochleography with transtympanic needle-electrode as well as tympanic membrane electrode. 10 patients received electrocochleography with transtympanic needle-electrode and ear canal electrode. A control group of 12 healthy adults was evaluated using tympanic membrane electrode. The negative electrode was placed on the ipsilateral mastoid, the ground electrode in the middle of the forehead. For stimulation broadband click stimulus as well as long tone bursts of 1, 2 and 4 kHz were applied. In addition the impedance of the electrode was registered. RESULTS: While transtympanic electrocochleography gave reliable results in 100% of these cases, extratympanic recordings often manifested poor wave morphology. The electrocochleographic measures following stimulation with 1 and 2 kHz long tone bursts were the best measures to identify endolymphatic hydrops. This was the case with transtympanic as well as with tympanic membrane electrodes. There was no correlation between impedance and wave morphology. CONCLUSIONS: For the evaluation of Morbus Menière non-invasive electrocochleography showed good results using a tympanic canal electrode with 1 and 2 kHz tone bursts. Yet in unclear cases transtympanic electrocochleography should be preferred.

[Auditory evoked potentials: basics and clinical applications]. / Akustisch evozierte Potenziale: Grundlagen und klinische Anwendung.

Auditory evoked potentials (AEPs) are elicited at various levels of the auditory system following acoustic stimulation. Electrocochleography is a technique for recording AEPs of the inner ear. The recording is performed by means of a needle electrode placed on the promontory or non-invasive with tympanic membrane or ear canal electrodes. Clinically, electrocochleography is used for the diagnosis of auditory neuropathy spectrum disorder (ANSD) and endolymphatic hydrops. According to their latencies, AEPs of the central auditory pathway are subdivided into early, middle and late (cortical) AEPs. These AEPs are recorded via surface scalp electrodes. Normally, the larger EEG masks AEPs. For unmasking the AEP, several techniques are applied. Early AEPs or auditory brainstem responses (ABR) are the most widely used AEPs for functional evaluation of the auditory pathway. In contrast to otoacoustic emissions, early AEPs can detect ANSD. Thus, they are more suitable for hearing screening in newborns. For this purpose automated procedures are implemented.

[Evaluation of the Freiburg monosyllabic speech test in background noise]. / Evaluation des Freiburger Einsilbertests im Störschall.

BACKGROUND: The Freiburg speech test has been the gold standard in speech audiometry in Germany for many years. Previously, however, this test had not been evaluated in assessing the effectiveness of a hearing aid in background noise. Furthermore, the validity of particular word lists used in the test has been questioned repeatedly in the past, due to a suspected higher variation within these lists as compared to the other word list used. PATIENTS AND METHODS: In this prospective study, two groups of subjects [normal hearing control subjects and patients with SNHL (sensorineural hearing loss) that had been fitted with hearing aid] were examined. In a first group, 113 control subjects with normal age- and gender-related pure tone thresholds were assessed by means of the Freiburg monosyllabic test under free-field conditions at 65 dB. The second group comprised 104 patients that had been fitted with hearing aids at least 3 months previously to treat their SNHL. Members of the SNHL group were assessed by means of the Freiburg monosyllabic test both with and without hearing aids, and in the presence or absence of background noise (CCITT-noise; 65/60 dB signal-noise ratio, in accordance with the Comité Consultatif International Téléphonique et Télégraphique), under free-field conditions at 65 dB. RESULTS: The first (control) group exhibited no gender-related differences in the Freiburg test results. In a few instances, inter-individual variability of responses was observed, although the reasons for this remain to be clarified. Within the second (patient) group, the Freiburg test results under the four different measurement conditions differed significantly from each other (p>0.05). This group exhibited a high degree of inter-individual variability between responses. In light of this, no significant differences in outcome could be assigned to the different word lists employed in the Freiburg speech test. CONCLUSION: The Freiburg monosyllabic test is able to assess the extent of hearing loss, as well as the effectiveness of a fitted hearing aid, in the presence or absence of background-noise (CCITT-noise). The present study could not evidence statistically significant differences in outcome when using the different word lists in this test battery.

[New ways to combat eating disorders-evaluation of an internet-based self-help program in bulimia nervosa]. / Neue Wege bei der Behandlung von Bulimia nervosa.

CONTENT: Results of the German part of a European multicenter study on the effectiveness and practicability of an internet-based self-help program (SHG self-help guide) in bulimia nervosa (BN). METHOD: The internet-based program SHG builds on the principles of cognitive behavioral therapy (CBT) and comprises seven cumulative therapeutic steps. Twenty-two women with BN made use of the program over a period of six months. The patients were supported by three evaluation interviews and a once-weekly email contact with a female psychologist. During the interview, data on general psychopathology, specific eating disorder complaints and symptoms of depression were collected. RESULTS: The examination showed definite effects both in terms of a reduction in eating disorder-specific behavior and a statistically and clinically relevant improvement in the symptoms of depression. CONCLUSION: After working with the SHG, the patient sample studied here registered improvements in eating disorder and depressive symptoms. The design of the study, however, made it impossible to assess effectiveness. Practicability and usefulness were positively assessed by the patients. Thanks to its considerable flexibility in terms of time and place, the method could well be a valuable supplementary building block in the treatment of bulimia nervosa.

[Effects and cost-effectiveness analysis of inpatient treatment for somatoform disorders]. / Wirksamkeit und Kosten-Nutzen-Effekte der stationären Therapie somatoformer Störungen.

Patients with somatoform disorders represent an expensive problem group of the healthcare system characterized by inappropriately high medical costs. This paper describes a controlled inpatient treatment study using a cognitive-behavioral approach. The aim of this treatment program was to improve the patients' symptomatology and their psychosocial functioning, as well as reducing unnecessary medical costs. We treated 172 patients with somatoform disorders (DSM-IV) and compared them with 262 patients of a waiting control list. An additional control group consisted of 123 patients with other mental disorders. Direct and indirect illness-related costs for the two-year periods before and after treatment were re-calculated using objective data provided by the health insurance companies. The results show a marked improvement in the areas of bodily complaints, health anxieties, dysfunctional beliefs towards body and health, depression and psychosocial impairments. The medical costs in the post-treatment period decreased by 1,098 euro (-36.7 %) for inpatient and 382 euro (-24.5 %) for outpatient treatments. Indirect costs due to days lost from work were 6,702 euro (-35.3 %) lower than during the two-years before treatment. The treatment costs had amortized after 21.5 months. We identified a subgroup of high-utilizing somatoform patients for which per patient savings of 32,174 euro (-63.9 %) were found. These results confirm that the cognitive-behavioral approach is effective in improving complaints as well as reducing the health-economical burden of somatoform disorders.

Objective detection of the amplitude modulation following response (AMFR).

The amplitude modulation following response (AMFR) has been shown to be a promising tool for objective frequency-specific assessment of hearing thresholds children. AMFR represented in the frequency domain by a single spectral line. This simplifies the objective statistical detection in comparison other responses with a more complex waveform. The aim of the present study is to compare the performance of four known tests (phase coherence (PC), new Hotelling T2 (HT2*), modified PC (PC*), magnitude-squared coherence (MSC)) on the basis of a large sample (n=1484) of AMFR recordings (stimulus level of 30 dB nHL in normally-hearing subjects, and 30 dB SL in hearing-impaired subjects) to find the test best suited for AMFR detection. The decision was made on the basis of the detection rates as well as of the ROC curves. Based on the large data pool, MSC and PC* show equal performance and a small but consistent advantage in objective detection of AMFR over HT2* and PC.

Efficient stimuli for recording of the amplitude modulation following response.

Amplitude modulation following response (AMFR) is a promising tool for objective frequency-specific assessment of hearing thresholds in children. The stimulus generally used for AMFR recording (one amplitude-modulated carrier) activates only a small part of the basilar membrane. Therefore, the response amplitude is small. Combined frequency and amplitude modulation is not significantly more effective. A new stimulus is proposed that is composed of several carriers. All carriers are modulated with the same modulation frequency. The signal to noise ratio of the response to the multiple-carrier stimulus is significantly increased compared with the usual one-carrier stimulus. Therefore, response detection near threshold is expected to be improved. AMFR also seems to be well suited to newborn hearing screening. Simultaneous recording of six responses (three AMFRs from each ear) to 1-, 2-, and 4-kHz multiple-carrier stimuli of a 40 dB HL stimulus level is demonstrated in normally-hearing adults. Verification in babies will be necessary.

Objective detection of transiently evoked otoacoustic emissions.

Newborn hearing screening with transiently evoked otoacoustic emissions (TEOAE) is a well-established method. A screening device must be equipped with a test procedure for objective TEOAE detection. The statistical tests implemented in the commercially available screening devices are the correlation, an estimation of the signal-to-noise ratio and a binominal test. The aim of the present study is to compare the TEOAE detection performance of these tests with that of several other tests in the time and frequency domains (variance ratio F(SP) and its modification F(SP)*, Friedman test, modified q-sample uniform scores test). The comparison was based on a data sample of 420 TEOAE. The frequency range examined was 1.5-4.0 kHz. As a new feature, two frequency sub-ranges (1.5-2.5 kHz, 2.5-4.0 kHz) were tested separately. The modified variance ratio F(SP)* was the most powerful test, whereas the tests implemented in the known screening devices showed the lowest detection performance.

Objective detection of auditory brainstem potentials: comparison of statistical tests in the time and frequency domains.

Newborn hearing screening with auditory brainstem potentials (ABR) requires objective ABR detection by a statistical test procedure with high performance. Statistical testing can be performed in the time or frequency domain. The aim of the present study was to compare the performance of three tests in the time domain (Friedman test, variance ratio F(SP), Cochran's Q-test) with that of a test in the frequency domain (modified q-sample uniform scores test) that, in a former investigation, was shown to be the best test in the frequency domain. To compare the performance of the four tests, the test power was calculated and receiver operating characteristics (ROCs) were constructed from the probability density functions estimated using Monte Carlo simulations. In addition, a comparison on the basis of real near-threshold ABR data was carried out. The modified q-sample uniform scores test appeared to be the most powerful one. Some aspects of practical application are discussed.

Objective response detection in the frequency domain: comparison of several q-sample tests.

The objective assessment of the hearing threshold requires a suitable statistical test for response detection. For checking the q spectral lines of an auditory-evoked potential spectrum in the frequency domain, a q-sample test seems to be more favourable compared to q applications of a one-sample test. The response detection performance of three q-sample tests (q-sample analogue of Watsons U2 test, q-sample uniform scores test and a modified q-sample uniform scores test) has been checked by extensive Monte Carlo simulations. To compare the performance of the three test statistics, sensitivity was calculated and receiver-operating characteristics were constructed from the probability density functions estimated by the Monte Carlo simulations. In addition, a comparison on the basis of real near-threshold auditory brainstem response data was carried out. The modified q-sample uniform scores test appeared to be the most powerful test. Some aspects of the practical application of this test are discussed in this paper.

The clinical value of human pancreas-specific protein procarboxypeptidase B as an indicator of necrosis in acute pancreatitis: comparison to CRP and LDH.

Early assessment of severity in acute pancreatitis (AP) has a major impact on further treatment. Previous studies have shown that human pancreas-specific protein (hPASP)/procarboxypeptidase B (PCPB) is a new diagnostic and prognostic marker in AP. In the present study we focused on the prognostic properties of this parameter and analyzed the clinical value of hPASP in discriminating edematous from necrotizing AP. The results were compared to those for C-reactive protein (CRP) and lactate dehydrogenase (LDH). A total of 70 patients was enrolled in this prospective study. Based on contrast-enhanced computed tomography or intraoperative results, 39 patients (27 male, 12 female; median age, 42 years; median Ranson score, 6) suffered from necrotizing pancreatitis (NP) and 31 patients (12 male, 19 female; median age, 57; median Ranson score, 1.5) from acute interstitial-edematous pancreatitis (AIP). Serum concentrations of hPASP/PCPB, CRP, and LDH were measured at 24-h intervals over 14 days after admission by a radioimmunoassay (upper normal value, 60 ng/ ml), a lasernephelometric assay (upper normal value, 4 mg/L), and an enzymekinetic method (upper normal value, 240 U/L), respectively. During the overall observation period concentrations of hPASP/PCPB, CRP, and LDH were significantly higher in patients with NP compared to those with AIP. Based on receiver operating characteristics, the best cutoff levels for predicting NP were >200 ng/ml for hPASP/PCPB, >140 mg/L for CRP, and >290 U/L for LDH. Discrimination between AIP and NP was best on day 3 for both hPASP/PCPB (sensitivity, 91%; specificity, 64%; accuracy, 79%) and CRP (sensitivity, 83%; specificity, 84%; accuracy, 83%) and on day 5 of AP for LDH (sensitivity, 88%; specificity, 100%; accuracy, 91%). The overall accuracy in differentiating AIP from NP within the first 4 days after onset of symptoms was 74% for hPASP/PCPB, 75% for CRP, and 76% for LDH. None of the parameters correlated with the extent of necrosis or the etiology of AP. hPASP/PCPB provides good discrimination between AIP and NP at an early stage of the disease, with results comparable to those for CRP and LDH. Although hPASP/PCPB is both disease specific and predictive for necrosis, the clinical use of this test in its present form is limited due to drawbacks in terms of test performance and cost factors.

Objective detection of auditory evoked potentials. Comparison of several statistical tests in the frequency domain on the basis of near-threshold ABR data.

A fully objective electric response audiometry (ERA) requires an objective response detection by an appropriate statistical test. The Rayleigh test, Watson's U2 test, Kuiper's test and Hodges-Ajne's test check the phase angle distribution of a Fourier harmonics. The modified Rayleigh test uses, in addition to the phase angles, the amplitude information in the form of the ranks of the spectral amplitudes, whereas magnitude-squared coherence (MSC) uses the spectral amplitudes themselves. The signal detection performance of these six tests was judged on the basis of a sample of near-threshold click-evoked ABR. MSC was found to be the best suited test out of the six tests investigated, but the performance differences to the modified Rayleigh test (and even to the unmodified Rayleigh test), and to Watson's test as well were only slight. Hodges-Ajne's test and Kuiper's test have the lowest sensitivity and the mean time required for response detection is longest for Hodges-Ajne's test.

The speaker's formant in male voices.

Spectral analysis of vowels during connected speech can be performed using the spectral intensity distribution within critical bands corresponding to a natural scale on the basilar membrane. Normalization of the spectra provides the opportunity to make objective comparisons independent from the recording level. An increasing envelope peak between 3,150 and 3,700 Hz has been confirmed statistically for a combination of seven vowels in three groups of male speakers with hoarse, normal, and professional voices. Each vowel is also analyzed individually. The local energy maximum is called "the speaker's formant" and can be found in the region of the fourth formant. The steepness of the spectral slope (i.e. the rate of decline) becomes less pronounced when the sonority or the intensity of the voice increases. The speaker's formant is connected with the sonorous quality of the voice. It increases gradually and is approximately 10 dB higher in professional male voices than in normal male voices at neutral loudness (60 dB at 0.3 min). The peak intensity becomes stronger (30 dB above normal voices) when the overall speaking loudness is increased to 80 dB. Shouting increases the spectral energy of the adjacent critical bands but not the speaker's formant itself.

Objective detection of auditory evoked potentials. Comparison of several statistical tests in the frequency domain by means of Monte Carlo simulations.

Fully objective assessment of the hearing threshold by auditory evoked potentials requires an objective detection of these responses by means of suitable statistical tests. The Rayleigh test, Watson's U2 test, Kuiper's test and Hodges-Ajne's test check the phase angle distribution of a Fourier harmonics in a sample of stimulus-related EEG epochs. The modified Rayleigh test includes, in addition to the phase angles, the amplitude information in the form of ranks of the spectral amplitudes. To compare the signal detection performance of these tests, estimates of the probability density functions were calculated by means of extensive Monte Carlo simulations. From the probability density functions, the sensitivity of the tests was calculated and receiver operating characteristics (ROC) were constructed. The modified Rayleigh test appeared to be the most powerful test, followed by the Rayleigh test and Watson's U2 test. The application of Kuiper's test and Hodges-Ajne's test as well is not to be recommended for AEP detection.