Multimedia Encyclopedia

Delayed swallow reflex

Refers to when a person’s automatic swallow reflex—which normally kicks in when liquid or chewed food in the mouth reaches the base of the tongue—is delayed. Individuals with normal swallowing rarely notice or think about the action of their swallow reflex, but on occasion the reflex may startle a person and draw more attention to itself: for example, when a person sucks on a hard candy that inadvertently goes a little too far back in the mouth and—gulp!—it is involuntarily swallowed.

If a person’s swallow reflex is delayed, then food material may slip back to the base of the tongue and, before the swallow happens, drop down to fill the vallecula or even the pyriform sinuses. A delayed swallow reflex is of particular concern when swallowing liquids because, given their low viscosity, thin liquids can easily flow downward into the larynx and trachea (aspiration). Compare this disorder with absent swallow reflex.

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Di-indolemethane (DIM)

Di-indolemethane (DIM) is a phytochemical derived from cruciferous vegetables such as cabbage, broccoli, Brussels sprouts, cauliflower, collards, and kale. Promotes estrogen metabolism to a form that has been shown to be anti-proliferative. Used in treating recurrent respiratory papillomatosis (RRP).

See also: indole-3-carbinol (I3C).

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Diagnostic model

Diagnostic model refers to the codified tools and sequence used during diagnosis of a disorder. In the realm of voice disorders in particular, different clinics may use different models for diagnosis. For purposes of discussion, at our practice we distinguish somewhat artificially between the traditional diagnostic model, the technology-driven or reductionistic diagnostic model, and what we prefer: the integrative diagnostic model.

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Diet Modification for Dysphagia

Diet modification for dysphagia are suggested dietary changes, particularly regarding food consistencies, directed at improving a patient’s ability to swallow and at avoiding aspiration. For example, an individual who is struggling with aspiration might be advised to avoid thin liquids and use thicker or carbonated liquids instead. Or this individual might be advised to avoid composite foods, since his or her swallowing deficiency could make it harder to “stay organized” with several consistencies in the mouth at once.

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Differential Diagnosis

Differential diagnosis refers to the short list of possible diagnoses based upon the findings of the initial consultation. Sometimes the diagnosis can be narrowed down to only one possibility; in other cases, additional tests are done to distinguish between competing diagnoses. Sometimes the most likely diagnosis of those in the differential diagnosis becomes the working diagnosis and trial treatment for this leading diagnosis is begun.

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Dilatation (Dilation)

Dilatation, or dilation, is to stretch an opening to a larger size. When an individual has stenosis of the laryngeal airway or the trachea, a dilation procedure is one option for treatment. The two primary methods of dilation in these cases are to use either a balloon expansion device or successively larger tapered laryngeal dilators. With tracheal stenosis, a balloon expansion device might be used more often, but for high tracheal stenosis, the tapered laryngeal dilators can also be very effective.

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Diplophonia

Diplophonia is double pitch phonation. Often seen with vocal cord paralysis, and in submucosal disorders such as epidermoid cyst and glottic sulcus. Except for a type of luffing diplophonia that may be functionally produced, diplophonia tends to be a pathologic vocal phenomenon.

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Disorder of vocal loudness perception

A lack of awareness or perception of one’s personal vocal “volume level” to the point that it is creating difficulty in one’s life. If asked to place oneself on a personal loudness scale from 1 to 7, most individuals can do so with reasonable accurateness. Occasionally, however, an individual (with normal hearing ability) lacks this kind of self-insight, and such an individual could be said to have a disorder of vocal loudness perception.

At one end of this spectrum was a patient who was an operatic tenor. He had a powerful, almost head-rattling voice even in close quarters in a quiet room, and he was aware that others thought him loud, but he clearly could not “relate” to this. When coaxed and coached repeatedly to use a moderate voice to read a passage out loud, he quite sincerely (and loudly!) said, “Oh, I could never do that! That’s whispering!” At the other end of the spectrum, there was a 30-something woman with a voice one had to strain to hear. When she was coaxed and coached to read the same passage with a moderately loud voice, her utterly sincere but almost whispered reply? “Oh, I couldn’t talk like that. That’s yelling.”

Vocal loudness can vary between individuals considerably and still be accepted as “within normal limits.” Yet the two individuals described above were considered to have a disorder of vocal loudness perception because their inappropriate vocal loudness was exceptional enough to cause life difficulty. The man had considerable vocal cord injury, and the young woman was struggling at her job, with customers who were occasionally angry about the impossibility of hearing her. The approach was the same with both of these individuals: both were asked to retrain their “set point” for personal vocal loudness by recruiting other people (and their ears) to the re-training task.

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Dysphagia

Abnormal swallowing, or inability to swallow. Dysphagia can result from such diverse causes as surgery on the larynx or neck, stroke, the aging process, tumor, injury to the neck, or radiation, among other things.

Treatment for Dysphagia (Swallowing therapy):

This therapy is typically provided by a speech-language pathologist (and, more informally and adjunctively, by other healthcare professionals). General areas of teaching might include: choosing wisely which food types and consistencies to eat; swallowing maneuvers such as tucking the chin, double swallow, effortful swallow, head turning, and supraglottic swallow; and direct exercises for the tongue, pharynx, palate, and larynx.

Diet modification:

These are suggested dietary changes, particularly regarding food consistencies, directed at improving a patient’s ability to swallow and at avoiding aspiration. For example, an individual who is struggling with aspiration might be advised to avoid thin liquids and use thicker or carbonated liquids instead. Or this individual might be advised to avoid composite foods, since his or her swallowing deficiency could make it harder to “stay organized” with several consistencies in the mouth at once.

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Dysphonia

Abnormal production of vocal sound; more commonly used as a synonym for hoarseness. Dysphonia may be the result of injury to the mucosa of the vocal cords; or it may be neurogenic, the result of a benign or malignant tumor; or it may be nonorganic.

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Dystonia

A benign neurological disorder in which twisting and repetitive or sustained but unwanted muscle contraction occurs in a body part. It can affect a specific muscle (focal dystonia), a region of the body (regional dystonia), or even the body as a whole (generalized dystonia).

Common focal dystonias include laryngeal (spasmodic dysphonia or respiratory dystonia); ocular (blepharospasm); neck or cervical (torticollis and related neck disorders); and limb dystonia (writer’s cramp). Treatment for focal dystonias is most commonly via Botox™ injection into affected muscles, and occasionally by selective denervation. More regional and generalized dystonias may respond to a variety of systemic medications such as clonazepam and others.

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Dystonic tremor of the voice or larynx

A tremor that sometimes accompanies laryngeal dystonia and its effects on voice function (spasmodic dysphonia), breathing function (respiratory dystonia), or both. This dystonic tremor is heard as a “wavering” in the voice (if the person has spasmodic dysphonia) or in the sound of inhaled or exhaled air (if the person has respiratory dystonia), or it can be detected in both the voice and the sound of inhaled or exhaled air (if the person has both spasmodic dysphonia and respiratory dystonia). A patient who exhibits this kind of tremor in tandem with spasmodic dysphonia, for example, may be described by the examining clinician as having “spasmodic dysphonia with a small/moderate/large/overwhelming tremor component.” Dystonic tremor can also appear in other parts of the body (e.g., as head or limb movements) when a person’s dystonia affects those parts, but our focus here is on dystonia of the larynx.

Voice-affecting dystonic tremor might sometimes be mistaken for the tremor induced by a different neurological disorder, essential voice tremor. If one knows what to listen for, however, it is usually possible to distinguish dystonic tremor from the tremor induced by essential voice tremor. Most obviously, dystonic tremor is almost always accompanied by other manifestations of dystonia, such as phonatory arrests, dropouts to a whisper, or squeezedowns. Dystonic tremor may worsen under specific circumstances—with stress, fatigue, or during telephone use, for example. Dystonic tremor is often (though not always) more pronounced in the patient’s chest register voice than falsetto register voice—sometimes dramatically so—and this difference might be heard when the patient is asked to sustain a single sung note as steadily as possible. Finally, dystonic tremor’s amplitude can vary from cycle to cycle; to use singers’ parlance, it is as though a couple of cycles of “wild” vibrato are followed by a few cycles of merely wide vibrato, followed by a second or two of much more stable voice. In the occasional case, however, a patient’s tremor is so overwhelming and these distinctive qualities of dystonic tremor so subtle that the clinician proceeds initially with a working, rather than settled, diagnosis.

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