The Study of Laryngeal Muscle Activity in Normal Human Subjects and in Patients With Laryngeal Dystonia Using Multiple Fine‐Wire Electromyography

Abstract

The normal human larynx performs numerous complex tasks with nearly complete reliability. These tasks require precise timing of movements that are effected by the laryngeal muscles. The most specific method to examine these muscles is by electromyography. Although many studies on laryngeal electromyography have been reported using multichannel recordings, none has provided a detailed analysis of each laryngeal muscle's role during a variety of common tasks and the spectrum of normative values. Simultaneous eight-channel, fine-wire electromyographic recordings were made in 11 human subjects. The timing patterns of the laryngeal muscles during the coordinated efforts for phonation and other common glottic functions were examined. In addition, normative values for latencies and amplitudes of response were determined. During simple phonation, a "set pattern" for the thyroarytenoid, lateral cricoarytenoid , and interarytenoid muscles was found. The thyroarytenoid and lateral cricoarytenoid muscles demonstrated a burst at onset preceding phonation and then decreased activity, whereas the interarytenoid sustained glottic position during phonation. The coordination of the laryngeal muscles was similarly determined for connected speech, respiration, Valsalva maneuver, cough, throat-clear task, and swallow. These patterns of response, the latencies for activities, and the amplitudes of response in normal subjects provided the basis to examine the abnormal laryngeal function in a group of 59 patients with four clinical varieties of laryngeal dystonia (adductor, tremor, abductor, and mixed). The findings include abnormal patterns of response, increased latencies, and increased amplitudes of recruitment in many tasks including nonphonatory tasks. Although specific distinctions were noted in each group, the responses were remarkably similar, indicating that all clinical varieties of laryngeal dystonia should be classified as mixed dystonia with a clinical preponderance for one or more types of behavior.

The Distribution and Severity of Tremor in Speech Structures of Persons with Vocal Tremor

“…Specifically, tremor activity was noted in the cricothyroid in 23 of 31 participants (74%) (Ardran et al, 1966;Finnegan et al, 2003;Hillel, 2001;Koda & Ludlow, 1992;Tomoda et al, 1987), the thyroarytenoid muscles in 71 of 110 participants (65%) (Finnegan et al, 2003;Hillel, 2001;Klotz et al, 2004;Koda & Ludlow, 1992;Tomoda et al, 1987), the posterior cricoarytenoid in nine of 16 participants (56%) (Hillel, 2001;Koda & Ludlow, 1992), the lateral cricoarytenoid in 36 of 67 participants (54%) (Hillel, 2001;Klotz et al, 2004), and the interarytenoid in eight of 49 participants (16%) (Hillel, 2001;Klotz et al, 2004). Ardran, Kinsbourne, and Rushworth (1966) recorded EMG from the cricothyroid muscle of a single participant with severe vocal tremor.…”

“…Hillel (2001) recorded EMG from the thyroarytenoid muscle and two other intrinsic laryngeal muscles (cricothyroid in 12 participants, posterior cricoarytenoid in 11 participants, lateral cricoarytenoid in 7 participants, and interarytenoid in 7 participants) during phonation and connected speech in 20 participants with tremor spasmodic dysphonia. Tremor spasmodic dysphonia was defined as a variant of adductor spasmodic dysphonia in which tremor was the primary characteristic with concurrent strain and/or vocal breaks.…”

“…Vocal tremor is often associated with head or limb tremor (Massey & Paulson, 1985). It can also occur concurrently with another disorder (e.g., spasmodic dysphonia) (Hillel, 2001;Klotz, Maronian, Waugh, Shahinfar, Robinson, & Hillel, 2004), or as a component of other disorders (e.g., Parkinson's disease, supranuclear palsy, or amyotrophic lateral sclerosis (Lundy, Roy, Xue, Casiano, & Jassir, 2002)). "Essential tremor is a postural tremor that is accentuated by voluntary movement (Elble & Koller, 1990, p. 55)," which generally disappears when the individual is completely at rest, such as during sleep.…”

“…However, studies describing the distribution of tremor are limited. Several studies have examined tremor in muscles of the larynx (Ardran et al, 1966;Brown & Simonson, 1963;Finnegan, Luschei, Barkmeier, & Hoffman, 2003;Hachinski et al, 1975;Hillel, 2001;Klotz et al, 2004;Koda & Ludlow, 1992;Massey & Paulson, 1985;Tomoda, Shibasaki, Kuroda, & Shin, 1987), respiratory system (Ardran et al, 1966;Hachinski et al, 1975;Lebrun, Devreux, Rousseau, & Darimont, 1982;Massey & Paulson, 1985;Tomoda et al, 1987), or articulatory region (Ardran et al, 1966;Brown & Simonson, 1963;Hachinski et al, 1975;Koller, Glatt, Biary, & Rubino, 1987;Lebrun et al, 1982; and most authors agree that patients with vocal tremor experience muscle contractions in multiple muscles. Sulica and Louis (2010) demonstrated that individuals with essential voice tremor have multiple structures affected by tremor, including the palate, base of tongue, pharyngeal walls, supraglottis, and true vocal folds.…”

Active and Passive Properties of Canine Abduction/Adduction Laryngeal Muscles

“…TA, LCA, and IA are all adductors, whereas PCA is the sole abductor of the vocal folds. [1][2][3][4] Models of vocal fold posturing require information on the geometry and structure of the laryngeal cartilages and joints, origin and insertion of laryngeal muscles, and response to neural excitation. In particular, a dynamic (time-dependent) model of posturing depends on the active and passive properties of the aforementioned muscles including contraction times, forceelongation relations, and force-velocity relations.…”