Thyroarytenoid Muscle Responses to Air Pressure Stimulation of the Laryngeal Mucosa in Humans

2003 ◽  
Vol 112 (10) ◽  
pp. 834-840 ◽  
Author(s):  
Priyanka Bhabu ◽  
Christopher Poletto ◽  
Steven Bielamowicz ◽  
Eric Mann ◽  
Christy L. Ludlow

Others have observed glottic adduction in response to air puff stimuli and suggested that this is a reliable indicator of laryngeal sensation. We undertook to determine whether the same thresholds are found if one uses either thyroarytenoid (TA) muscle responses or subjects' reports of laryngeal sensation. We also studied the characteristics of TA responses to unilateral air pressure stimulation of the mucosa overlying the arytenoid cartilages. Ten normal volunteers provided button press responses to air pressure stimuli during bilateral TA electromyography. Similar thresholds were determined by reports of sensation as by electromyographic responses (p < .0005). The early TA responses occurred either around 80 ms or around 125 ms after onset of the air puff, with equal frequency on the ipsilateral and contralateral sides. The TA muscle responses to air pressure stimulation differ in physiological characteristics from the laryngeal adductor reflex that occurs in response to electrical stimulation of the superior laryngeal nerve.

2005 ◽  
Vol 114 (4) ◽  
pp. 264-270 ◽  
Author(s):  
Pamela Reed Kearney ◽  
Eric A. Mann ◽  
Christopher J. Poletto ◽  
Christy L. Ludlow

Repeated stimulation of the laryngeal mucosa occurs during speech. Single stimuli, however, can elicit the laryngeal adductor response (LAR). Our hypothesis was that the LAR to repeated rapid air pressure stimuli is centrally suppressed in humans. Hookedwire electrodes were inserted into the thyroarytenoid and cricothyroid muscles on both sides and into the posterior cricoarytenoid muscle on one side. Pairs of air puff stimuli were presented to the mucosa over the arytenoids at pressure levels three times threshold with interstimulus intervals from 250 to 5,000 ms. Bilateral thyroarytenoid responses occurred at around 150 ms to more than 70% of the initial stimuli. With repeated presentation at intervals of 2 seconds or less, the percent occurrence decreased to less than 40% and response amplitudes were reduced by 50%. Central suppression of adductor responses to repeated air puff stimuli may allow speakers to produce voice without eliciting reflexive spasms that could disrupt speech.


1992 ◽  
Vol 101 (2) ◽  
pp. 127-134 ◽  
Author(s):  
Christy L. Ludlow ◽  
Frederick Van Pelt ◽  
Junji Koda

To characterize human thyroarytenoid and cricothyroid muscle responses to stimulation of the internal (sensory) and external (motor) branches of the superior laryngeal nerve (SLN), three awake subjects were studied at rest and during muscle activation with stimulation at different current levels. When only the external branch was stimulated, direct cricothyroid muscle responses were obtained without responses in either thyroarytenoid muscle. When only the internal branch was stimulated, no cricothyroid responses were obtained, but two late thyroarytenoid responses occurred (R1 and R2). The R1 response was usually ipsilateral and had a mean onset latency of 18 milliseconds, while the R2 response was bilateral and occurred between 66 and 70 milliseconds. Both responses tended to decrease in latency and increase in amplitude with increased stimulation level. The similarity of Rl to the adductor response and R2 to other late responses is discussed.


1987 ◽  
Vol 97 (1) ◽  
pp. 28-38 ◽  
Author(s):  
George S. Goding ◽  
Mark A. Richardson ◽  
Ronald E. Trachy

The laryngeal chemoreflex (LCR) was investigated in 21 piglets (ages 6 to 80 days old) with the use of physiologic and histologic techniques. The central projection of the superior laryngeal nerve (SLN) was determined in 14 animals by use of horseradish peroxidase-wheat germ agglutinin. Ipsilateral labeling of the solitary tract nucleus was seen. The caudal extent of the labeling varied with age. Sensory labeling of the nucleus ambiguus was present bilaterally in three younger animals and unilaterally in older piglets. Bilateral labeling of the nucleus dorsomedialis was seen in all ages. Apneic and cardiovascular response to water stimulation of laryngeal mucosa and the laryngeal adductor reflex (LAR) were examined in 16 piglets. Blunting of the apneic and cardiovascular response was seen after sacrifice of a single SLN. Hypoxia did not significantly affect the LAR or apnea duration in animals with only one intact SLN. A contralateral LAR was found in younger animals. Relevance to the LCR is also discussed.


1997 ◽  
Vol 106 (7) ◽  
pp. 594-598 ◽  
Author(s):  
Sina Nasri ◽  
Joel A. Sercarz ◽  
Pouneh Beizai ◽  
Young-Mo Kim ◽  
Ming Ye ◽  
...  

The neuroanatomy of the larynx was explored in seven dogs to assess whether there is motor innervation to the thyroarytenoid (TA) muscle from the external division of the superior laryngeal nerve (ExSLN). In 3 animals, such innervation was identified. Electrical stimulation of microelectrodes applied to the ExSLN resulted in contraction of the TA muscle, indicating that this nerve is motor in function. This was confirmed by electromyographic recordings from the TA muscle. Videolaryngostroboscopy revealed improvement in vocal fold vibration following stimulation of the ExSLN compared to without it. Previously, the TA muscle was thought to be innervated solely by the recurrent laryngeal nerve. This additional pathway from the ExSLN to the TA muscle may have important clinical implications in the treatment of neurologic laryngeal disorders such as adductor spasmodic dysphonia.


2000 ◽  
Vol 83 (3) ◽  
pp. 1264-1272 ◽  
Author(s):  
Julie M. Barkmeier ◽  
Steve Bielamowicz ◽  
Naoya Takeda ◽  
Christy L. Ludlow

Laryngeal sensori-motor closure reflexes are important for the protection of the airway and prevent the entry of foreign substances into the trachea and lungs. The purpose of this study was to determine how such reflexes might be modulated during volitional swallowing in awake humans, when persons are at risk of entry of food or liquids into the airway. The frequency and the amplitude of laryngeal adductor responses evoked by electrical stimulation of the internal branch of the superior laryngeal nerve (ISLN) were studied during different phases of volitional swallowing. Subjects swallowed water on command while electrical stimuli were presented to the ISLN at various intervals from 500 ms to 5 s following the command. Laryngeal adductor responses to unilateral ISLN stimulation were recorded bilaterally in the thyroarytenoid muscles using hooked wire electrodes. Early ipsilateral R1 responses occurred at 17 ms, and later bilateral R2 began around 65 ms. The muscle responses to stimuli occurring during expiration without swallowing were quantified as control trials. Responses to stimulation presented before swallowing, during the swallow, within 3 s after swallowing, and between 3 and 5 s after a swallow were measured. The frequency and amplitude of three responses (ipsilateral R1 and bilateral R2) relative to the control responses were compared across the different phases relative to the occurrence of swallowing. Results demonstrated that a reduction occurred in both the frequency and amplitude of the later bilateral R2 laryngeal responses to electrical stimulation for up to 3 s after swallowing ( P= 0.005). The amplitude and frequency of ipsilateral R1 laryngeal responses, however, did not show a significant main effect following the swallow ( P = 0.28), although there was a significant time by measure interaction ( P = 0.006) related to reduced R1 response amplitude up to 3 s after swallowing ( P = 0.021). Therefore, the more rapid and shorter unilateral R1 responses continued to provide some, albeit reduced, laryngeal protective functions after swallowing, whereas the later bilateral R2 responses were suppressed both in occurrence and amplitude for up to 3 s after swallowing. The results suggest that R2 laryngeal adductor responses are suppressed following swallowing when residues may remain in the laryngeal vestibule putting persons at increased risk for the entry of foreign substances into the airway.


2002 ◽  
Vol 93 (5) ◽  
pp. 1622-1629 ◽  
Author(s):  
Richard D. Andreatta ◽  
Eric A. Mann ◽  
Christopher J. Poletto ◽  
Christy L. Ludlow

Laryngeal adductor responses (LAR) close the airway in response to stimulation of peripheral afferents in the superior laryngeal nerve. Although both mucosal afferents and proprioceptive receptors are present in the larynx, their relative contribution for reflex elicitation is unknown. Our purpose was to determine which receptor types are of importance in eliciting the LAR. A servomotor with displacement feedback was used to deliver punctate displacements to the body of the arytenoid cartilage and overlying mucosa on each side of the larynx in eight anesthetized cats. The same displacements were delivered both before and after surgical excision of the overlying mucosa. With the mucosa intact, early short-latency component R1 LAR responses recorded from the thyroarytenoid muscles were frequent (ipsilateral > 92%, contralateral > 95%). After the mucosa was removed, the LAR became infrequent (<3%) and was reduced in amplitude in both the ipsilateral and contralateral thyroarytenoid muscle recording sites ( P < 0.0005). These findings demonstrate that mucosal mechanoreceptors and not proprioceptive afferents contribute to the elicitation of LAR responses in the cat.


2017 ◽  
Vol 26 (3) ◽  
pp. 729-736 ◽  
Author(s):  
Asako Kaneoka ◽  
Jessica M. Pisegna ◽  
Gintas P. Krisciunas ◽  
Takaharu Nito ◽  
Michael P. LaValley ◽  
...  

Purpose Clinicians often test laryngeal sensation by touching the laryngeal mucosa with the tip of a flexible laryngoscope. However, the pressure applied to the larynx by using this touch method is unknown, and the expected responses elicited by this method are uncertain. The variability in pressure delivered by clinicians using the touch method was investigated, and the subject responses to the touches were also reported. Methods A fiberoptic pressure sensor passed through the working channel of a laryngoscope, with its tip positioned at the distal port of the channel. Two examiners each tested 8 healthy adults. Each examiner touched the mucosa covering the left arytenoid 3 times. The sensor recorded the pressure exerted by each touch. An investigator noted subject responses to the touches. From the recorded videos, the absence or presence of the laryngeal adductor reflex in response to touch was judged. Results Pressure values obtained for 46 of the 48 possible samples ranged from 17.9 mmHg to the measurement ceiling of 350.0 mmHg. The most frequently observed response was positive subject report followed by the laryngeal adductor reflex. Conclusion Pressure applied to the larynx by using the touch method was highly variable, indicating potential diagnostic inaccuracy in determining laryngeal sensory function.


2011 ◽  
Vol 120 (11) ◽  
pp. 755-760 ◽  
Author(s):  
Qi-Jian Sun ◽  
Jia Min Chum ◽  
Tara G. Bautista ◽  
Paul M. Pilowsky ◽  
Robert G. Berkowitz

Objectives: Electromyographic studies of the laryngeal adductor reflex, glottal closure occurring in response to laryngeal stimulation, have demonstrated an early ipsilateral response (R1) and a late bilateral response (R2). To better define the physiologic properties of these responses, we recorded responses from expiratory laryngeal motoneurons (ELMs) in rats during stimulation of the superior laryngeal nerve (SLN). Methods: Single unit extracellular recordings were obtained from 5 ELMs, identified by their antidromic responses to recurrent laryngeal nerve stimulation and postinspiratory firing pattern, in 4 Sprague-Dawley rats. Results: Unilateral stimulation of the SLN (at 20 Hz) stopped both phrenic nerve inspiratory activity and ELM postinspiratory activity. However, the ELMs displayed robust tonic firing, consisting of non-respiratory burst activity and single action potentials. The single action potentials were identified as short-latency ones (5 to 10 ms) activated by ipsilateral SLN stimulation, with an occurrence rate of 90%, and long-latency ones (20 to 50 ms) activated by bilateral SLN stimulation, with occurrence rates of 47% on the ipsilateral side and 58% on the contralateral side. Conclusions: The R1 response appears to be the result of the short-latency action potentials, orthodromically activated by ipsilateral stimulation of the SLN. The R2 response is likely to be a result of the long-latency action potentials that can be recorded from ELMs on both sides.


2004 ◽  
Vol 16 (2) ◽  
pp. E8 ◽  
Author(s):  
Karl F. Kothbauer ◽  
Klaus Novak

Object Intraoperative neurophysiological recording techniques have found increasing use in neurosurgical practice. The development of new recording techniques feasible while the patient receives a general anesthetic have improved their practical use in a similar way to the use of digital recording, documentation, and video technology. This review intends to provide an update on the techniques used and their validity. Methods Two principal methods are used for intraoperative neurophysiological testing during tethered cord release. Mapping identifies functional neural structures, namely nerve roots, and monitoring provides continuous information on the functional integrity of motor and sensory pathways as well as reflex circuitry. Mapping is performed mostly by using direct electrical stimulation of a structure within the surgical field and recording at a distant site, usually a muscle. Sensory mapping can also be performed with peripheral stimulation and recording within the surgical site. Monitoring of the motor system is achieved with motor evoked potentials. These are evoked by transcranial electrical stimulation and recorded from limb muscles and the external anal sphincter. The presence or absence of muscle responses are the parameters monitored. Sensory potentials evoked by tibial or pudendal nerve stimulation and recorded from the dorsal columns via an epidurally inserted electrode and/or from the scalp as cortical responses are used to access the integrity of sensory pathways. Amplitudes and latencies of these responses are then interpreted. The bulbocavernosus reflex, with stimulation of the pudendal nerve and recording of muscle responses in the external anal sphincter, is used for continuous monitoring of the reflex circuitry. Presence or absence of this response is the pertinent parameter that is monitored. Conclusions Intraoperative neurophysiology provides a wide and reliable set of techniques for intraoperative identification of neural structures and continuous monitoring of their functional integrity.


1988 ◽  
Vol 64 (4) ◽  
pp. 1337-1345 ◽  
Author(s):  
J. S. Jodkowski ◽  
A. J. Berger

The purpose of this study is to analyze the reflex effects of laryngeal afferent activation on respiratory patterns in anesthetized, vagotomized, paralyzed, ventilated cats. We recorded simultaneously from the phrenic nerve, T10 internal intercostal nerve, and single bulbospinal expiratory neurons of the caudal ventral respiratory group (VRG). Laryngeal afferents were activated by electrical stimulation of the superior laryngeal nerve (SLN) or by cold-water infusion into the larynx. Both types of stimuli caused inhibition of phrenic activity and facilitation of internal intercostal nerve activity, indicating expiratory effort. The activity of 46 bulbospinal expiratory cells was depressed during SLN electrical stimulation, and 13 of them were completely inhibited. In 44 of 56 neurons tested, mean firing frequency (FFmean) was decreased in response to cold-water infusion and 8 others responded with increased FFmean; in the remaining 4 neurons, FFmean was unchanged. Possible reasons for different neuronal responses to SLN electrical stimulation and water infusion are discussed. We conclude that bulbospinal expiratory neurons of VRG were not the source of the reflex motoneuronal expiratory-like activity produced by SLN stimulation. Other, not yet identified inputs to spinal expiratory motoneurons are activated during this experimental condition.


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