Tactile Sensibility of Single‐Tooth Implants and Natural Teeth Under Local Anesthesia of the Natural Antagonistic Teeth

Introduction and Aim: The term osseoperception describes the capability of developing a subtle tactile sensibility over dental implants. The present clinical study aims at clarifying the question of how far tactile sensibility is to be attributed to the periodontium of the natural opposing tooth of the implant. Material and Method: Thirty‐two subjects with single‐tooth implants with natural opposing teeth were included in this clinical, single‐blind, split‐mouth study. The natural antagonistic tooth of the implant and the corresponding natural contralateral tooth were anesthetized with a locally infiltrated articaine anesthetic. In a computer‐assisted and randomized way, copper foils of varying thickness (0–100 µm) were placed interocclusally between the single‐tooth implant and the natural opposing tooth, and between the contralateral pair of natural opposing teeth in order to investigate the active tactile sensibility according to the psychophysical method of constant stimuli and evaluate it statistically by the Weibull distribution. Results: The average tactile sensibility of the implants with anesthetized antagonists at the 50% value calculated by means of the Weibull distribution was 20 ± 11 µm with a support area (90%–10% value) of 77 ± 89 µm. For the pair of natural teeth, the tactile sensibility at the 50% value was 16 ± 9 µm with a support area of 48.4 ± 93 µm. This resulted in an average intraindividual difference of 3.5 ± 7 µm at the 50% value and 29 ± 93 µm in the support area. The statistical calculations demonstrated an equivalent tactile sensibility (50% value) of the single‐tooth implant and the contralateral natural control tooth with the natural antagonists being anesthetized in each case (double t‐test, equivalence limit ± 8 µm, P < 0.01, power >80%). Conclusion: Apparently, the active tactile sensibility of single‐tooth implants with natural opposing teeth is not only to be attributed to the periodontium of the opposing tooth but also to a perception over the implant itself. This could support the hypothesis according to which the implant may have a tactile sensibility of its own.     

Outcomes in adults implanted with the FLEXsoft electrode

Conclusion. Achieving deep insertions, as well as good speech perception results, the FLEX^soft electrode array allows for some preservation in subjects with measurable low frequency hearing, even after a period of time. This opens the door for future research in electrode design, hearing preservation research and drug delivery systems. Objectives. The FLEX^soft electrode is designed to be atraumatic to the structures of the cochlea during deep insertion of a cochlear implant electrode. This paper reports on the surgical and functional outcomes in implantations with the FLEX^soft electrode array. Patients and methods. Twenty-three adult subjects received a FLEX^soft electrode array and were assessed on speech perception tests (monosyllables, sentences in quiet and in noise), a subjective questionnaire (Nijmegen Cochlear Implant Questionnaire) and a pure-tone audiogram. Results at 1, 3, 6 and 12 months post first fitting were compared to scores from the preoperative interval. Results. Surgery was uneventful in all cases, the surgical handling was satisfactory and correct position of the electrode was achieved in all cases. Hearing could be preserved (as determined by the audiogram) in half of the subjects who had measurable audiograms preoperatively at the 1 month test interval, and in a quarter of subjects after 12 months of device use, despite deep insertion of the electrode. Speech perception scores showed significant improvement over time, as did quality of life scores, and were comparable to results with the standard electrode array as used in the COMBI 40+ and PULSARCI¹⁰⁰.     

Dynamic Systems (Complexity) theory as a new conceptual model for researching PBL in dental education

Although problem‐based learning (PBL) was introduced into dental education some 20 years ago, there have been relatively few well‐designed studies carried out to clarify whether, how or why it works in a dental context. This paper introduces the Dynamic Systems (Complexity) theory as a new and potentially productive theoretical framework for researching PBL in dental education. This framework emphasises the importance of emergent self‐organisation, perception and brain plasticity in learning. In this paper, a brief overview of the history of PBL in dentistry is presented and then the fundamentals of a Dynamic Systems Approach (DSA) are explained, drawing on two recently published papers advocating the DSA in medical education and teacher education. We focus on three key points related to this new approach: emergent self‐organisation rather than simple construction of knowledge; the notion that perception drives the learning process; and the brain as the substrate of all learning. The paper also suggests how the DSA can help us move forward, both in terms of the future application of PBL in dental education and also in relation to posing new types of research questions.     

Music enjoyment with cochlear implantation

Since the advent of cochlear implant (CI) surgery in the 1960s, there have been remarkable technological and surgical advances enabling excellent speech perception in quiet with many CI users able to use the telephone. However, many CI users struggle with music perception, particularly with the pitch-based and melodic elements of music. Yet remarkably, despite poor music perception, many CI users enjoy listening to music based on self-report questionnaires, and prospective studies have suggested a disassociation between music perception and enjoyment. Music enjoyment is arguably a more functional measure of one’s listening experience, and thus enhancing one’s listening experience is a worthy goal. Recent studies have shown that re-engineering music to reduce its complexity may enhance enjoyment in CI users and also delineate differences in musical preferences from normal hearing listeners.     

Effect of deep insertion of the cochlear implant electrode array on pitch estimation and speech perception

Conclusion. Deeply inserted electrodes offer the possibility that apical stimulation may improve speech performances. Therefore, deep insertion is reasonable and should be performed in patients with profound or total hearing loss. Objectives. To evaluate the importance of insertion depth beyond 25 mm in a group of cochlear implant patients with deeply inserted electrodes up to 32 mm. Patients and methods. In the first part of the study patients were asked to perform a pitch estimation for channels across the whole length of the electrode array. We evaluated whether pitch discrimination was possible along the whole cochlea and especially in its apical part. Then, the audiological performances of 10 patients were tested in 5 conditions, in which we artificially varied the insertion depth in each patient by activating and deactivating channels. The patients were tested immediately in the new condition to avoid adaptation. Results. The results showed that activating the electrodes in the uppermost region of the cochlea improves speech perception significantly. Furthermore it could be demonstrated that the pitch perceived in the cochlea with electrical stimulation decreases with increasing insertion depth along the whole length of deeply inserted electrode arrays.     

A Clinical Test for the Assessment of Binaural Speech Perception in Noise

The present paper describes a clinical test for the assessment of speech perception in noise. The test was designed to separate the effects of several relevant monaural and binaural cues. Results show that the performance of individual hearing-impaired listeners deviates significantly from normal for at least 2 of the following aspects: (1) perception of speech in steady-state noise; (2) relative binaural advantage due to directional cues; (3) relative advantage due to masker fluctuations. In contrast, both the hearing loss for reverberated speech and the relative binaural advantage due to interaural signal decorrelation, caused by reverberation, were essentially normal for almost all hearing impaired.     

Using response time to speech as a measure for listening effort

Abstract

Objective: Speech signals that do not differ in intelligibility might differ in listening effort. This study aimed to investigate the effect of background noise on response time to intelligible speech. Design: We added various amounts of stationary noise to spoken digit triplets and measured the influence of noise on the response time for both an identification and an arithmetic task: Task 1 ‘identify the final digit in a triplet’, and Task 2 ‘calculate the sum of the initial and the final digits in a triplet.’ Study sample: Twelve normal-hearing participants with a mean age of 30.6 years (range: 28–44 years). Results: Response time increased with lower (i.e. worse) signal to noise ratios for both tasks, even for signal to noise ratios with almost maximum intelligibility (close to 100%). The response time during the arithmetic task was more affected by the noise than during the identification task, but the arithmetic task demonstrated higher variance. Conclusions: The response time to digit triplets reduces significantly for increasing signal to noise ratios, even where speech intelligibility is optimal. These differences in response time might be related to listening effort and as such might be used to evaluate hearing-aid signal processing at positive SNRs.