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Beating Patterns of Mammalian Spermatozoa
Published in Claude Gagnon, Controls of Sperm Motility, 2020
Stroboscopic illumination is admirably suited to applications where the object being recorded is actively moving. Because the duration of each flash is extremely short (on the order of 20 to 40 μsec), very sharp images of rapidly moving specimens such as beating flagella can be obtained. Short exposure times are also a special advantage when recording flagellar movements of mammalian spermatozoa that are liable to damage by heat. Thus, this method of illumination has been employed in cinemicrography13 and in videomicrography9,10,17,32 in order to give good definition.
The Professional Voice
Published in John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford, Head & Neck Surgery Plastic Surgery, 2018
Declan Costello, Meredydd Harries
Stroboscopic examination can be performed either with a rigid endoscope (70 degree or 90 degree) or with a chip-tip (distal-chip) flexible endoscope. The details of stroboscopy are discussed in Chapter 61, Assessment and examination of the larynx, but it is worth bearing in mind the biomechanics of examination in each situation. Rigid endoscopy requires the patient’s neck to be slightly extended, and for the tongue to be protruded. The endoscope can then be advanced over the tongue and the vocal folds can be examined. Needless to say, this is a very ‘unphysiological’ position in which to be phonating. In general, it is only possible to elicit an ‘ee’ vowel in this position. By contrast, with the chip-tip endoscope passed through the nose, the performer can sing and speak almost as normal. A wide variety of vocal gestures can be performed, including those specific gestures that are causing the performance problems. This is particularly helpful when muscle tension is believed to be a feature. On the other hand, the images achieved with the distal-chip flexible endoscopes are not quite as good as the rigid views. Different vocal problems may call for different examination techniques, or sometimes both.
Case 25
Published in Simon Lloyd, Manohar Bance, Jayesh Doshi, ENT Medicine and Surgery, 2018
Simon Lloyd, Manohar Bance, Jayesh Doshi
This is a method of imaging movements of the vocal folds that allows identification of subtle abnormalities of the vocal fold that would otherwise be very difficult to visualise. The vocal folds vibrate when talking but the waves produced in the fold during this process are too rapid to see with the naked eye. Stroboscopy uses a light (the strobe), delivered via a rigid or flexible endoscope, that flashes at a slightly slower speed than the mucosal wave of the vocal fold. This gives the illusion that vocal fold motion is slowed down and makes it much easier to assess vocal fold mobility and the presence of vocal fold pathology.
Diagnostic vocal fold injection as an intervention for secondary muscle tension dysphonia
Published in Hearing, Balance and Communication, 2021
Christopher D. Dwyer, Thomas L. Carroll
A 68 year-old male presented to our academic voice centre with complaints of gradually progressive and worsening vocal fatigue and a rough, strained quality to his voice. He was assessed concurrently by a fellowship trained laryngologist and voice-specialised speech-language pathologist. He works as a university physics professor, requiring high vocal demands with several hours of lectures in a large auditorium daily. His voice is usually best during his morning lectures, but by the afternoon he finds himself straining to speak. His voice becomes raspy and difficult to project, and he develops throat discomfort that persists into the evening. He has never had difficulties with his voice in the past and was easily able to meet these vocal demands over the past 3 decades of teaching. He denies heartburn or regurgitation, swallowing or breathing difficulties, but admits to throat clearing and a globus sensation with increased voice use. Palpation of the peri-laryngeal structures revealed a tense tongue base and contracted thyrohyoid space with tenderness to palpation. Perceptually, his voice was notable for roughness and strain. Flexible laryngoscopy demonstrated moderate supraglottic hyper-function during phonation, as demonstrated below in Figure 1. Vocal fold motion was symmetric without notable laryngeal lesions, erythema or edoema. Findings of note on stroboscopy included increased amplitude, vibration asymmetry and a short, but complete phase closure pattern. A diagnosis of secondary MTD from vocal fold atrophy was established.
The effect of stroboscopic vision on performance in a football specific assessment
Published in Science and Medicine in Football, 2021
Adam Beavan, Lars Hanke, Jan Spielmann, Sabrina Skorski, Jan Mayer, Tim Meyer, Job Fransen
This study aims to investigate how restricted visual feedback impacts the performance on a football-specific skill assessment that requires a more complex and reactive perception-action coupling. Importantly, the new skills assessment task aims to expand on Fransen et al. (2017) work by controlling for the velocity of the delivered ball equally for both skilled and less-skilled players. This will remove the reported error effect caused by a larger magnitude of ball displacement for skilled players while under intermittent moments of occluded vision (Fransen et al. 2017) to better observe the Specificity of Practice hypothesis. It is hypothesised that athletes will incur worse performances under stroboscopic vision compared to a full vision condition. It is further hypothesised that such decrements in performance will be more pronounced in more skilled players compared to the lesser-skilled players.
Intermittent Vision and Goal-Directed Movement: A Review
Published in Journal of Motor Behavior, 2021
Digby Elliott, Simon J. Bennett
We found that MOT performance when wearing the Nike eyewear was not influenced by strobe frequency. However, MOT performance did deteriorate in the other two stroboscopic vision conditions as a function of strobe frequency. Interestingly, at the lowest strobe frequency there was an increase in probe reaction time in all vision condition, thus indicating an increased attentional demand irrespective of the way in which stroboscopic vision was experienced. In Experiment 2, we conducted a learning study in which participants practiced a novel precision-aiming task (i.e., multiple object avoidance - MOA) in different vision conditions (Normal Vision, Nike Vapor Strobe, PLATO visual occlusion). We found that participants in the PLATO visual occlusion group exhibited worse performance during practice and at post-test than the Vapor Strobe and normal vision groups. In fact, the PLATO group performed at a similar level in the post-test as a control group that didn’t receive any treatment during the practice phase. Conversely, the Vapor Strobe group demonstrated greater success, longer movement time and reduced end-point error than the normal vision and PLATO groups (see Figure 5).