Dysphonia: Difficulty and/or pain in PHONATION or speaking.Voice Disorders: Pathological processes that affect voice production, usually involving VOCAL CORDS and the LARYNGEAL MUCOSA. Voice disorders can be caused by organic (anatomical), or functional (emotional or psychological) factors leading to DYSPHONIA; APHONIA; and defects in VOICE QUALITY, loudness, and pitch.Voice Quality: That component of SPEECH which gives the primary distinction to a given speaker's VOICE when pitch and loudness are excluded. It involves both phonatory and resonatory characteristics. Some of the descriptions of voice quality are harshness, breathiness and nasality.Vocal Cord Paralysis: Congenital or acquired paralysis of one or both VOCAL CORDS. This condition is caused by defects in the CENTRAL NERVOUS SYSTEM, the VAGUS NERVE and branches of LARYNGEAL NERVES. Common symptoms are VOICE DISORDERS including HOARSENESS or APHONIA.Recurrent Laryngeal Nerve: Branches of the vagus (tenth cranial) nerve. The recurrent laryngeal nerves originate more caudally than the superior laryngeal nerves and follow different paths on the right and left sides. They carry efferents to all muscles of the larynx except the cricothyroid and carry sensory and autonomic fibers to the laryngeal, pharyngeal, tracheal, and cardiac regions.Vocal Cords: A pair of cone-shaped elastic mucous membrane projecting from the laryngeal wall and forming a narrow slit between them. Each contains a thickened free edge (vocal ligament) extending from the THYROID CARTILAGE to the ARYTENOID CARTILAGE, and a VOCAL MUSCLE that shortens or relaxes the vocal cord to control sound production.Laryngeal Diseases: Pathological processes involving any part of the LARYNX which coordinates many functions such as voice production, breathing, swallowing, and coughing.Laryngoscopy: Examination, therapy or surgery of the interior of the larynx performed with a specially designed endoscope.Laryngeal Muscles: The striated muscle groups which move the LARYNX as a whole or its parts, such as altering tension of the VOCAL CORDS, or size of the slit (RIMA GLOTTIDIS).Aphonia: Complete loss of phonation due to organic disease of the larynx or to nonorganic (i.e., psychogenic) causes.Voice Training: A variety of techniques used to help individuals utilize their voice for various purposes and with minimal use of muscle energy.Voice: The sounds produced by humans by the passage of air through the LARYNX and over the VOCAL CORDS, and then modified by the resonance organs, the NASOPHARYNX, and the MOUTH.Larynx: A tubular organ of VOICE production. It is located in the anterior neck, superior to the TRACHEA and inferior to the tongue and HYOID BONE.Betamethasone Valerate: The 17-valerate derivative of BETAMETHASONE. It has substantial topical anti-inflammatory activity and relatively low systemic anti-inflammatory activity.Vocal Cord Dysfunction: A disorder characterized by an intermittent abnormal VOCAL CORDS movement toward the midline during inspiration or expiration resulting in upper AIRWAY OBSTRUCTION.Stroboscopy: The observation of successive phases of MOVEMENT by use of a flashing light.Speech Production Measurement: Measurement of parameters of the speech product such as vocal tone, loudness, pitch, voice quality, articulation, resonance, phonation, phonetic structure and prosody.Phonation: The process of producing vocal sounds by means of VOCAL CORDS vibrating in an expiratory blast of air.Neuromuscular Agents: Drugs used for their actions on skeletal muscle. Included are agents that act directly on skeletal muscle, those that alter neuromuscular transmission (NEUROMUSCULAR BLOCKING AGENTS), and drugs that act centrally as skeletal muscle relaxants (MUSCLE RELAXANTS, CENTRAL). Drugs used in the treatment of movement disorders are ANTI-DYSKINESIA AGENTS.Spasm: An involuntary contraction of a muscle or group of muscles. Spasms may involve SKELETAL MUSCLE or SMOOTH MUSCLE.Laryngoplasty: Restoration, reconstruction, or improvement of a defective or damaged LARYNX.Hoarseness: An unnaturally deep or rough quality of voice.Laryngeal Nerves: Branches of the VAGUS NERVE. The superior laryngeal nerves originate near the nodose ganglion and separate into external branches, which supply motor fibers to the cricothyroid muscles, and internal branches, which carry sensory fibers. The RECURRENT LARYNGEAL NERVE originates more caudally and carries efferents to all muscles of the larynx except the cricothyroid. The laryngeal nerves and their various branches also carry sensory and autonomic fibers to the laryngeal, pharyngeal, tracheal, and cardiac regions.Speech Therapy: Treatment for individuals with speech defects and disorders that involves counseling and use of various exercises and aids to help the development of new speech habits.Recurrent Laryngeal Nerve Injuries: Traumatic injuries to the RECURRENT LARYNGEAL NERVE that may result in vocal cord dysfunction.Botulinum Toxins, Type A: A serotype of botulinum toxins that has specificity for cleavage of SYNAPTOSOMAL-ASSOCIATED PROTEIN 25.Arytenoid Cartilage: One of a pair of small pyramidal cartilages that articulate with the lamina of the CRICOID CARTILAGE. The corresponding VOCAL LIGAMENT and several muscles are attached to it.Glottis: The vocal apparatus of the larynx, situated in the middle section of the larynx. Glottis consists of the VOCAL FOLDS and an opening (rima glottidis) between the folds.Deglutition Disorders: Difficulty in SWALLOWING which may result from neuromuscular disorder or mechanical obstruction. Dysphagia is classified into two distinct types: oropharyngeal dysphagia due to malfunction of the PHARYNX and UPPER ESOPHAGEAL SPHINCTER; and esophageal dysphagia due to malfunction of the ESOPHAGUS.Meige Syndrome: A syndrome characterized by orofacial DYSTONIA; including BLEPHAROSPASM; forceful jaw opening; lip retraction; platysma muscle spasm; and tongue protrusion. It primarily affects older adults, with an incidence peak in the seventh decade of life. (From Adams et al., Principles of Neurology, 6th ed, p108)Speech Acoustics: The acoustic aspects of speech in terms of frequency, intensity, and time.