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Common otology viva topics
Published in Joseph Manjaly, Peter Kullar, Advanced ENT Training, 2019
Terms you may be asked to define:Acoustic gain: The difference in output from the aid compared with input. For example, a tone presented at 50 dB and output at 80 dB would have an acoustic gain of 30 dB.Distortion: The altered reproduction of sound by a hearing aid.Occlusion effect: Occurs when an object fills the outer portion of the EAC. This causes the subject to perceive the sound of their own voice as ‘hollow’ or ‘booming’. It is thought to be caused by bone conduction as sounds vibrate back towards the TM from the medial portion of the occlusive object. The effect can increase the sound pressure of low-pressure sounds (typically below 500 Hz) by up to 20 dB. The effect can be reduced by increasing the size of vents and/or the use of hollow tips/domes.Saturation sound pressure level: The maximum amount of sound pressure (power) that the aid can produce.
Hearing Aids
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
One unwanted consequence of a hearing aid can be an occlusion effect, in which the aid wearer’s own voice is excessively amplified by bone-conducted sound. For many hearing aid fittings, vent selection is a careful juggle between choosing a vent that is big enough to avoid an unacceptable occlusion effect, but not so big that it causes feedback oscillations or limits the ability to achieve sufficient low-frequency gain and maximum output. For patients with mild or moderate hearing loss, the choice will often be an extremely open fitting comprising a BTE connected to thin tubing, or a wire connection for an ITE style, terminating in a preformed, flexible, perforated, dome-shaped canal fitting.
Neurological Examination of Malingering
Published in Alan R. Hirsch, Neurological Malingering, 2018
Jose L. Henao, Khurram A. Janjua, Alan R. Hirsch
The Chimani–Moos test applies the same concepts as Weber’s tuning fork test. When the tuning fork is placed on the vertex of the head the patient has the ability to hear the noise (conduction) in the good ear, which causes lateralization. Normal patients would be able to hear conduction even if the clinician’s fingers occludes both ears. So, in the second part of the examination the good ear is occluded. The examination is repeated and the patient is asked where they hear the noise. The malingering patients will state they cannot hear the noise since their good ear is occluded; however, the occlusion effect causes patients with an occluded ear to hear bone conduction with increased intensity due to the reduction of ambient noise. So, this effect can provide clues about patients malingering hearing loss (Sethi, Pearson, and Bajaj, 2017).
Does person-centred care improve outcomes for musicians fitted with hearing protectors?
Published in International Journal of Audiology, 2020
Siobhan McGinnity, Elizabeth Francis Beach, Robert Cowan, Johannes Mulder, Dominic Power, Caitlin Barr
The typical path for a musician to obtain MHP is through an appointment with an audiologist. There are, however, no accepted guidelines as to how an audiologist should assess the need for, and/or proceed with fitting a MHP. As the audiologist is an integral part of customising the MHP for their client, their treatment may also impact the musician’s overall experience with their protectors. For instance, occlusion, a deleterious echo of one’s own voice or instrument heard loudly in the ears or head (Pirzanski 2006) is a commonly reported problem with MHP. The occlusion effect is often reported by brass/woodwind instrumentalists, but it can be reduced through various techniques including the use of tightly fitting plugs extending beyond the second bend of the ear canal (Pirzanski 2006; Beach and O’Brien 2017). Furthermore, with proper training by an audiologist, the insertion depth of hearing protectors can be greatly improved, resulting in more consistent sound attenuation – a benefit sustained over time (Toivonen et al. 2002; Tsukada and Sakakibara 2008). With the lack of recommended guidelines, however, previous research indicates that both audiologists and manufacturers differ greatly in how they proceed with the creation and prescription of hearing protectors, suggesting examples of optimal care such as those described above, may not be industry-wide (McGinnity et al. 2018). It is therefore important to explore the impact that audiological care related to MHP has on outcomes, to see if satisfaction and usage can be improved from the outset.
Caring for musicians’ ears: insights from audiologists and manufacturers reveal need for evidence-based guidelines
Published in International Journal of Audiology, 2018
Siobhan McGinnity, Elizabeth Francis Beach, Johannes Mulder, Robert Cowan
Audiologists most frequently reported difficulty fitting MHP for musicians who played instruments that involve vocalisation, either directly or as a by-product of playing, i.e. voice, brass and wind. It is well recognised that players of these instruments are more likely to nominate the occlusion effect as a negative aspect of wearing earplugs than musicians playing other instruments. For these players, the intensity of the occlusion effect is directly linked to the canal length and seal of the musicians’ earplug (Killion 2012). Earplugs with a shallow fit provide greater room for amplification of internalised low-frequency sounds, often interpreted as over-powering and intolerable to the musician. This has been demonstrated to lead to earplug rejection (Laitinen and Poulsen 2008). However, it has also been documented that the occlusion effect can be managed (at least in part) with insertion of the earplug beyond the second bend of the ear canal (Killion 2012; Lee 2011; Pirzanski 2006). It is concerning then, that although most manufacturers recommended a long canal length in our survey, almost half of audiologists routinely ordered medium-sized canal lengths. As a result, the likelihood of musicians experiencing the occlusion effect is increased, as is their risk of rejecting their hearing protectors.
Occlusion and coupling effects with different earmold designs – all a matter of opening the ear canal?
Published in International Journal of Audiology, 2023
Florian Denk, Thomas Hieke, Malte Roberz, Hendrik Husstedt
The Step-Vent earmold includes a shortening of the vent by removal of material at the medial lower part of the earmold, such that the vent is largely increased to the residual ear canal diameter in this region (c.f. Figure 2). This decreases the acoustic mass of the vent and leads to a desired larger opening of the ear canal (see also Table 1). In comparison to the Standard earmold with equivalent vent diameter, in the present data the Step-Vent showed an increase in feedback path and reduced bass response that were in line with the change in acoustic mass (Figures 3–5). However, in spite of the larger ventilation of the ear canal, the subjective occlusion effect with the vented Step-Vent earmold was approx. 1.5 rating points larger than appropriate for its acoustic mass (Figure 4). This is probably due to the fact that in the Step-Vent design, the sealing zone is effectively moved outwards. In consequence, a larger area of the cartilaginous part of the ear canal walls is exposed to the residual ear canal volume. More sound flux generated by bone-conducted parts of the own voice is thus directed into the residual ear canal volume, leading to higher low-frequency levels and thus a higher subjective occlusion effect. This interpretation is generally consistent with previous studies reporting a higher occlusion effect for shallower inserted earmolds/earplugs (Blau et al. 2008; Carillo, Doutres, and Sgard 2020; Stenfelt and Reinfeldt 2007). In the present data, the occlusion effect with the Step-Vent design was higher than observed with a standard earmold of equal diameter, i.e. higher acoustic mass. In conclusion, according to our data a Step-Vent is not helpful, but even detrimental in reducing the occlusion effect – while coupling performance is reduced according to the reduction of acoustic mass of the vent, the occlusion effect is not reduced or even increased due to the altered sealing zone.