Depth-kymography is the 3D display of the human vocal fold vibrations by measuring their vertical and horizontal movements simultaneously, using a specially designed 3D endoscope. This 3D imaging method and the scientific term "Depth-Kymography" were introduced by Dr. Nibu A George, Prof. Frits de Mul and Prof. Harm Schutte. [1] [2] from the University Medical Center Groningen, The Netherlands in 2007. The term "Depth-Kymography" is included in the current medical terminology.
Human vocal folds vibrate in a very complex manner. During phonation vocal folds move in both horizontal and vertical directions. The imaging of vocal fold vibrations is achieved by inserting an endoscope through the mouth. The vocal folds are viewed from the top. Hence, with a normal endoscope, only the horizontal movements of the vocal folds are visible. Endoscopes used for the visualization of larynxes are commonly known as Laryngoscopes. With a specially designed 3D laryngoscope, movement of the vocal folds in the horizontal and the vertical directions can be simultaneously measured and displayed with horizontal and vertical displacements, forming the two orthogonal planes with time as the third dimension. Using this method, researchers were also able to measure the mucosal wave propagation. Depth-kymography has great potential in the investigation of voice disorders and in phonosurgical applications. It is the next generation of the popular videokymography. [3]
The term phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology and speech production in general. Phoneticians in other subfields, such as linguistic phonetics, call this process voicing, and use the term phonation to refer to any oscillatory state of any part of the larynx that modifies the airstream, of which voicing is just one example. Voiceless and supra-glottal phonations are included under this definition.
In humans, vocal cords, also known as vocal folds or voice reeds, are folds of tissue in the throat that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speech or singing, the folds are controlled via the recurrent laryngeal branch of the vagus nerve. They are composed of twin infoldings of mucous membrane stretched horizontally, from back to front, across the larynx. They vibrate, modulating the flow of air being expelled from the lungs during phonation.
The human voice consists of sound made by a human being using the vocal tract, including talking, singing, laughing, crying, screaming, shouting, humming or yelling. The human voice frequency is specifically a part of human sound production in which the vocal folds are the primary sound source.
The pupil is a black hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil. The term "pupil" was coined by Gerard of Cremona.
A view camera is a large-format camera in which the lens forms an inverted image on a ground glass screen directly at the plane of the film. The image is viewed and then the glass screen is removed and the film inserted in its place, and thus the film is exposed to exactly the same image as was seen on the screen.
Reinke's edema is the swelling of the vocal cords due to fluid (edema) collected within the Reinke's space. First identified by the German anatomist Friedrich B. Reinke in 1895, the Reinke's space is a gelatinous layer of the vocal cord located underneath the outer cells of the vocal cord. When a person speaks, the Reinke's space vibrates to allow for sound to be produced (phonation). The Reinke's space is sometimes referred to as the superficial lamina propria.
In biology, binocular vision is a type of vision in which an animal has two eyes capable of facing the same direction to perceive a single three-dimensional image of its surroundings. Neurological researcher Manfred Fahle has stated six specific advantages of having two eyes rather than just one:
Stereoscopy is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word stereoscopy derives from Greek στερεός (stereos) 'firm, solid', and σκοπέω (skopeō) 'to look, to see'. Any stereoscopic image is called a stereogram. Originally, stereogram referred to a pair of stereo images which could be viewed using a stereoscope.
Scanning laser ophthalmoscopy (SLO) is a method of examination of the eye. It uses the technique of confocal laser scanning microscopy for diagnostic imaging of the retina or cornea of the human eye.
A hoarse voice, also known as dysphonia or hoarseness, is when the voice involuntarily sounds breathy, raspy, or strained, or is softer in volume or lower in pitch. A hoarse voice, can be associated with a feeling of unease or scratchiness in the throat. Hoarseness is often a symptom of problems in the vocal folds of the larynx. It may be caused by laryngitis, which in turn may be caused by an upper respiratory infection, a cold, or allergies. Cheering at sporting events, speaking loudly in noisy situations, talking for too long without resting one's voice, singing loudly, or speaking with a voice that's too high or too low can also cause temporary hoarseness. A number of other causes for losing one's voice exist, and treatment is generally by resting the voice and treating the underlying cause. If the cause is misuse or overuse of the voice, drinking plenty of water may alleviate the problems.
Throat singing refers to several vocal practices found in different cultures around the world. The most distinctive feature of such vocal practices is to be associated to some type of guttural voice, that contrasts with the most common types of voices employed in singing, which are usually represented by chest (modal) and head registers. Also, throat singing is often described as producing the sensation of more than one pitch at a time, i.e., the listener perceives two or more distinct musical notes, while the singer is producing a single vocalization.
Vocal pedagogy is the study of the art and science of voice instruction. It is used in the teaching of singing and assists in defining what singing is, how singing works, and how proper singing technique is accomplished.
The cricothyroid joint is a joint connecting the cricoid cartilage and the thyroid cartilage. It plays a key role in adjusting human voice pitch by changing the tension of the vocal cords. This tension is controlled mostly by the endolaryngeal vocalis and the extralaryngeal cricothyroid muscles which change vocal fold tension by narrowing the cricothyroid space created by rotation and gliding movements in horizontal and vertical direction allowed for by the cricothyroid articulation.
A dose-volume histogram (DVH) is a histogram relating radiation dose to tissue volume in radiation therapy planning. DVHs are most commonly used as a plan evaluation tool and to compare doses from different plans or to structures. DVHs were introduced by Michael Goitein and Verhey in 1979. DVH summarizes 3D dose distributions in a graphical 2D format. In modern radiation therapy, 3D dose distributions are typically created in a computerized treatment planning system (TPS) based on a 3D reconstruction of a CT scan. The "volume" referred to in DVH analysis is a target of radiation treatment, a healthy organ nearby a target, or an arbitrary structure.
Videokymography is a high-speed medical imaging method to visualize the human vocal fold vibration dynamics. It was invented by Jan G. Švec under the guidance of Harm K. Schutte.
Conjugate eye movement refers to motor coordination of the eyes that allows for bilateral fixation on a single object. A conjugate eye movement is a movement of both eyes in the same direction to maintain binocular gaze. This is in contrast to vergence eye movement, where binocular gaze is maintained by moving eyes in opposite directions, such as going “cross eyed” to view an object moving towards the face. Conjugate eye movements can be in any direction, and can accompany both saccadic eye movements and smooth pursuit eye movements.
Cyclovergence is the simultaneous occurring cyclorotation of both eyes which is performed in opposite directions to obtain or maintain single binocular vision.
Endoscopic laser cordectomy, also known as Kashima operation, is an endoscopic laser surgical procedure performed for treating the respiratory difficulty caused as a result of bilateral abductor vocal fold paralysis. Bilateral vocal fold paralysis is basically a result of abnormal nerve input to the laryngeal muscles, resulting in weak or total loss of movement of the laryngeal muscles. Most commonly associated nerve is the vagus nerve or in some cases its distal branch, the recurrent laryngeal nerve. Paralysis of the vocal fold may also result from mechanical breakdown of the cricoarytenoid joint. It was first described in by Kashima in 1989.
Arytenoid adduction is a surgical procedure used to treat vocal cord paralysis. A suture is used to emulate the action of the lateral cricoarytenoid muscle and position the paralyzed vocal cord closer to the midline. This allows the two vocal cords to meet and can improve speaking and swallowing ability for affected patients. Arytenoid adduction is often performed in conjunction with medialization thyroplasty.
Videostroboscopy is a high-speed medical imaging method used to visualize the dynamics of human vocal fold vibration.