Josef Schlittenlacher

• PhD
• Lecturer at University College London

Objective: Exploring applications of automatic speech recognition and text-to-speech technologies in hearing assessment and evaluations of hearing aids. Design: Review protocol was registered at the INPLASY database and was performed following the PRISMA scoping review guidelines. A search in ten databases was conducted in January 2023 and updat...

The irrelevant speech effect (ISE) depends on psychoacoustic features such as the perceived fluctuation of the sound. Thus, it seems likely that a hearing loss may also affect the amount of the ISE. The present experiment studied the ISE in 30 listeners with normal hearing and 30 listeners with self-reported hearing loss in four different backgroun...

This study aimed to assess the validity of a high-frequency audiometry tool based on Bayesian learning to provide a reliable, repeatable, automatic, and fast test to clinics. The study involved 85 people (138 ears) who had their high-frequency thresholds measured with three tests: standard audiometry (SA), alternative forced choice (AFC)-based algo...

The diagnosis of noise-induced hearing loss (NIHL) is based on three requirements: a history of exposure to noise with the potential to cause hearing loss; the absence of known causes of hearing loss other than noise exposure; and the presence of certain features in the audiogram. All current methods for diagnosing NIHL have involved examination of...

An intense low-frequency tone can affect the perception of amplitude modulation (AM) applied to a high-frequency carrier. Here, thresholds for detecting AM of a 3000-Hz carrier were measured in the presence of a 50-Hz pure tone at 91 dB SPL. When the carrier was presented at 20 dB sensation level (SL), the thresholds were higher than in the absence...

Goal: Advances in computational models of biological systems and artificial neural networks enable rapid virtual prototyping of neuroprosthetics, accelerating innovation in the field. Here, we present an end-to-end computational model for predicting speech perception with cochlear implants (CI), the most widely-used neuroprosthetic. Methods: The...

Current clinical strategies to assess benefits from hearing aids (HAs) are based on self-reported questionnaires and speech-in-noise (SIN) tests; which require behavioural cooperation. Instead, objective measures based on Auditory Brainstem Responses (ABRs) to speech stimuli would not require the individuals’ cooperation. Here, we re-analysed an ex...

When developing new vehicles that are to be operated in existing background noise, such as electric vertical take-off and landing aircraft (eVTOLs) in cities, a sound design goal should be to minimize the loudness in the given background noise. Rotorcraft sounds are characterised by their pulses, and the choice of rotor size and number allows to va...

Continuous magnitude estimation and continuous cross-modality matching with line length can efficiently track the momentary loudness of time-varying sounds in behavioural experiments. These methods are known to be prone to systematic biases but may be checked for consistency using their counterpart, magnitude production. Thus, in Experiment 1, we p...

No PDF available ABSTRACT A major problem of remote or online hearing tests is the calibration of the equipment and control of the acoustic environment: For example, an audiogram requires calibrated headphones with a wide dynamic range and a silent room. Instead, a notched-noise test alleviates these problems and gives valuable information about au...

Text-to-speech (TTS) offers the opportunity to compensate for a hearing loss at the source rather than correcting for it at the receiving end. This removes limitations such as time constraints for algorithms that amplify a sound individually and can lead to higher speech quality for hearing-impaired listeners. We propose an algorithm that restores...

Time-efficient hearing tests are important in both clinical practice and research studies. This particularly applies to notched-noise tests, which are rarely done in clinical practice because of the time required. Auditory-filter shapes derived from notched-noise data may be useful for diagnosis of the cause of hearing loss and for fitting of heari...

The “time-varying loudness” (TVL) model of Glasberg and Moore calculates “instantaneous loudness” every 1 ms, and this is used to generate predictions of short-term loudness, the loudness of a short segment of sound, such as a word in a sentence, and of long-term loudness, the loudness of a longer segment of sound, such as a whole sentence. The cal...

Time-efficient hearing tests are important in both clinical practice and research studies. Bayesian active learning (BAL) methods were first proposed in the 1990s. We developed BAL methods for measuring the audiogram, conducting notched-noise tests, determination of the edge frequency of a dead region (fe), and estimating equal-loudness contours. T...

The “time-varying loudness (TVL)” model calculates “instantaneous loudness” every 1 ms, and this is used to generate predictions of short-term loudness, the loudness of a short segment of sound such as a word in a sentence, and of long-term loudness, the loudness of a longer segment of sound, such as a whole sentence. The calculation of instantaneo...

The irrelevant sound effect (ISE) denotes the fact that short-term memory is disrupted while being exposed to sound. The ISE is largest for speech. The presented study investigated the underlying acoustic properties that cause the ISE. Stimuli contained changes in either the spectral content only, the envelope only, or both. For this purpose two ex...

The present paper introduces a deep neural network (DNN) for predicting the instantaneous loudness of a sound from its time waveform. The DNN was trained using the output of a more complex model, called the Cambridge loudness model. While a modern PC can perform a few hundred loudness computations per second using the Cambridge loudness model, it c...

Bayesian active learning, machine learning, auditory filter, notched noise, tests for clinical practice

This article describes a Bayesian active-learning procedure for estimating the edge frequency, fe, of a dead region, that is, a region in the cochlea with no or very few functioning inner hair cells or neurons. The method is based on the psychophysical tuning curve (PTC) but estimates the shape of the PTC from the parameters of a hearing model, nam...

Two methods for estimating audiograms quickly and accurately using Bayesian active learning were developed and evaluated. Both methods provided an estimate of threshold as a continuous function of frequency. For one method, six successive tones with decreasing levels were presented on each trial and the task was to count the number of tones heard....

This paper describes some experimental tests and modifications to a model of loudness for time-varying sounds incorporating the concept of binaural inhibition. Experiment 1 examined the loudness of a 100% sinusoidally amplitude-modulated 1000-Hz sinusoidal carrier as a function of the interaural modulation phase difference (IMPD). The IMPD of the t...

Listeners can judge the overall loudness of time-varying sounds quite easily, i.e., assign a single value that represents the loudness of the entire sound. This holds even if the duration is long and the judgment includes memory effects. Different metrics for calculating overall loudness have been developed. They agree that overall loudness is high...

The loudness model of Moore et al. (2016) was developed from a model for time-varying sounds (Glasberg and Moore, 2002) but incorporates the concept of binaural inhibition; a sound at one ear can reduce the internal response to a sound at the other ear (Moore and Glasberg, 2007). It is important to consider the stage of processing at which binaural...

The aim was to test a model of loudness for binaurally presented time-varying sounds (Moore et al., Trends in Hearing, in press). A 1000-Hz sinusoidal carrier was 100% sinusoidally amplitude modulated. The effect on its loudness of varying the interaural modulation phase difference (the IMPD) was assessed. The IMPD of the test sound was 90° or 180°...

The presence and edge frequency, fe, of a dead region in the cochlea can be diagnosed using psychophysical tuning curves (PTCs). When the signal frequency, fs, falls in a dead region, the tip of the PTC lies close to fe, rather than close to fs. However, measurement of PTCs is time consuming, limiting their application in clinical practice. We have...

Although many studies have explored the relation between reaction time (RT) and loudness, including effects of intensity, frequency, and binaural summation, comparable work on spectral summation is rare. However, most real-world sounds are not pure tones and typically have bandwidths covering several critical bands. Since comparing to a 1-kHz pure...

A prominent feature of the auditory system is that neurons show tuning to audio frequency; each neuron has a characteristic frequency (CF) to which it is most sensitive. Furthermore, there is an orderly mapping of CF to position, which is called tonotopic organization and which is observed at many levels of the auditory system. In a previous study...

A prominent feature of the auditory system is that neurons show tuning to audio frequency; each neuron has a characteristic frequency (CF) to which it is most sensitive. Furthermore, there is an orderly mapping of CF to position, which is called tonotopic organization and which is observed at many levels of the auditory system. In a previous study...

This article describes a model of loudness for time-varying sounds that incorporates the concept of binaural inhibition, namely, that the signal applied to one ear can reduce the internal response to a signal at the other ear. For each ear, the model includes the following: a filter to allow for the effects of transfer of sound through the outer an...

Although many studies have explored the relation between reaction time (RT) and loudness, including effects of intensity, frequency, and binaural summation, comparable work on spectral summation is rare. However, most real-world sounds are not pure tones and typically have bandwidths covering several critical bands. Since comparing to a 1-kHz pure...

The loudness recruitment associated with cochlear hearing loss increases the perceived amount of amplitude modulation (AM), called “fluctuation strength.” For normal-hearing (NH) subjects, fluctuation strength “saturates” when the AM depth is high. If such saturation occurs for hearing-impaired (HI) subjects, they may show poorer AM depth discrimin...

The loudness recruitment associated with cochlear hearing loss increases the perceived amount of amplitude modulation (AM), called "fluctuation strength." For normal-hearing (NH) subjects, fluctuation strength "saturates" when the AM depth is high. If such saturation occurs for hearing-impaired (HI) subjects, they may show poorer AM depth discrimin...

A journal article about this work will follow. Conference abstract: Fluctuations in the envelopes of sounds, including speech, convey important information. Discrimination of amplitude modulation (AM) depth provides one measure of the ability to process AM. The loudness recruitment associated with cochlear hearing loss increases the perceived amoun...

Although auditory simple reaction time (RT) is usually defined as the time elapsing between the onset of a stimulus and a recorded reaction, a sound cannot be specified by a single point in time. Therefore, the present work investigates how the period of time immediately after onset affects RT. By varying the stimulus duration between 10 and 500 ms...

There are two competing national standards for the calculation of loudness of steady sounds, DIN 45631 and ANSI S3.4. Their different concepts of critical bands lead to different predictions for broadband sounds. As that discrepancy is neither constant nor linear but highly frequency-dependent, the present study investigates spectral loudness summa...

In order to yield equal loudness, different studies using scaling or matching methods have found binaural level differences between monaural and diotic presentations ranging from less than 2 dB to as much as 10 dB. In the present study, a reaction time methodology was employed to measure the binaural level difference producing equal reaction time (...

The various methods used to measure the subjective intensity of sound, i.e., loudness, are reviewed, among them axiomatic approaches, intramodal and cross-modality matching, direct and indirect estimation, and simple reaction time. Subsequently, the merit of using molecular psychophysics to the study of loudness is discussed. As an example, the bi...

Applying a performance-based approach to fire protection design emphasizes the safe performance of a building as a whole rather than meeting detailed code requirements. To this effect, fire safety engineers make use of computer models and simulations to describe the expected spread of fire and smoke, and the safety evacuation. Since the protection...

Triadic comparisons have been proposed as an indirect method for identifying perceptual structures, i. e., the hierarchy of auditory attributes emerging from a given set of sounds. Compared to alternative methods it has the advantage that it disconnects the identification of auditory sensations from their labeling. While the technique has been appl...

Electric or hybrid vehicles are very quiet at low speeds, which represents a very good opportunity to reduce traffic noise annoyance in cities. On the other hand, this may be very hazardous for vulnerable pedestrians (e.g. visually impaired people). The aim of the eV ADER project is to propose solutions in order to add warning sounds to such cars,...

Increasing customer demand and softer motors which do not mask the sound of gear units any longer have increased interest in the perceived quality of gear sounds. In the present study, listeners were asked to rate more than 50 sounds recorded from industrial gear units with respect to 16 auditory attributes. These included common psychoacoustic des...

Future vehicles will exchange much information through a wireless network in order to efficiently maintain their inner model of the environment. Before they can believe received pieces of information, they must evaluate their reliability. Trust is a mechanism to estimate this reliability based on the sender. It depends on friendship-like relations...

Current loudness standards disagree in the evaluation of broadband sounds. For example, ANSI S3.4-2007 predicts pink noise to result in greater loudness than other standards do, e.g. DIN 45631, and - more importantly - overestimates loudness compared to actual experimental results. For this reason, an extension of ANSI S3.4-2007 is proposed that co...

Although their basic concept is similar, the current standards for the calculation of loudness, ANSI S3.4-2007 and DIN 45631 (1991), produce significantly different results for many kinds of sounds. While their values for pure tones can be explained by the equal loudness contours of their times, they also show huge discrepancies for broadband sound...

Vehicles will exchange much information in the future in order to efficiently maintain their inner model of the environment. Before they can belief received pieces of information, they must evaluate their reliability. Trust is a mechanism to estimate this reliability based on the sender. As cars often drive the same route, they meet each other agai...