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Upper esophageal sphincter mechanical states analysis: a novel methodology to describe UES relaxation and opening.

Omari TI, Wiklendt L, Dinning P, Costa M, Rommel N, Cock C - Front Syst Neurosci (2015)

Bottom Line: Our results indicated that eight different mechanical states were almost always seen during healthy swallowing and some of these calculated changes in muscle function were consistent with the known neurally dependent phasic discharge patterns of cricopharyngeus muscle activity during swallowing.Clearly defined changes in the mechanical states were observed in motor neuron disease when compared to age matched healthy controls.Our data indicate that mechanical state predictions were simple to apply and revealed patterns consistent with the known neural inputs activating the different muscles during swallowing.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Physiology, School of Medicine, Flinders University Adelaide, SA, Australia ; Department of Gastroenterology and Hepatology, Flinders Medical Centre and School of Medicine, Flinders University Adelaide, SA, Australia.

ABSTRACT
The swallowing muscles that influence upper esophageal sphincter (UES) opening are centrally controlled and modulated by sensory information. Activation of neural inputs to these muscles, the intrinsic cricopharyngeus muscle and extrinsic suprahyoid muscles, results in their contraction or relaxation, which changes the diameter of the lumen, alters the intraluminal pressure and ultimately inhibits or promotes flow of content. This relationship that exists between the changes in diameter and concurrent changes in intraluminal pressure has been used previously to calculate the "mechanical states" of the muscle; that is when the muscles are passively or actively, relaxing or contracting. Diseases that alter the neural pathways to these muscles can result in weakening the muscle contractility and/or decreasing the muscle compliance, all of which can cause dysphagia. Detecting these changes in the mechanical state of the muscle is difficult and as the current interpretation of UES motility is based largely upon pressure measurement (manometry), subtle changes in the muscle function during swallow can be missed. We hypothesized that quantification of mechanical states of the UES and the pressure-diameter properties that define them, would allow objective characterization of the mechanisms that govern the timing and extent of UES opening during swallowing. To achieve this we initially analyzed swallows captured by simultaneous videofluoroscopy and UES pressure with impedance recording. From these data we demonstrated that intraluminal impedance measurements could be used to determine changes in the internal diameter of the lumen when compared to videofluoroscopy. Then using a database of pressure-impedance studies, recorded from young and aged healthy controls and patients with motor neuron disease, we calculated the UES mechanical states in relation to a standardized swallowed bolus volume, normal aging and dysphagia pathology. Our results indicated that eight different mechanical states were almost always seen during healthy swallowing and some of these calculated changes in muscle function were consistent with the known neurally dependent phasic discharge patterns of cricopharyngeus muscle activity during swallowing. Clearly defined changes in the mechanical states were observed in motor neuron disease when compared to age matched healthy controls. Our data indicate that mechanical state predictions were simple to apply and revealed patterns consistent with the known neural inputs activating the different muscles during swallowing.

No MeSH data available.


Related in: MedlinePlus

An example of a 10 ml liquid swallow showing the temporal correlation of luminal diameter and intraluminal admittance at the level of the reference impedance segment (RIS). (A) Sequential images from swallow onset (laryngeal elevation) showing barium passing through the RIS. Dotted lines chart the trajectory of movement of the tracheal air column (TAC, white line) and the RIS (yellow dotted line). Note decoupling of the TAC and proximal margin of the RIS at time points 0.72 and 1.16 s after swallow onset. (B) Diameter of the barium contrast column and admittance measured at the level of RIS over time from swallow onset. Individual diameter curves are shown for locations D1–D3 (per Figure 3) as well as the mean diameter. (C) Time correlation of diameter and admittance with colors indicating whether samples correspond to when the lumen was increasing (yellow) or decreasing (blue) in diameter.
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Figure 4: An example of a 10 ml liquid swallow showing the temporal correlation of luminal diameter and intraluminal admittance at the level of the reference impedance segment (RIS). (A) Sequential images from swallow onset (laryngeal elevation) showing barium passing through the RIS. Dotted lines chart the trajectory of movement of the tracheal air column (TAC, white line) and the RIS (yellow dotted line). Note decoupling of the TAC and proximal margin of the RIS at time points 0.72 and 1.16 s after swallow onset. (B) Diameter of the barium contrast column and admittance measured at the level of RIS over time from swallow onset. Individual diameter curves are shown for locations D1–D3 (per Figure 3) as well as the mean diameter. (C) Time correlation of diameter and admittance with colors indicating whether samples correspond to when the lumen was increasing (yellow) or decreasing (blue) in diameter.

Mentions: Sequential diameter measurements were performed until all of the barium had passed through the reference impedance segment (Figure 4A). The catheter electrode rings produced a discernible radiological shadow. Therefore, even though the lumen contained contrast and there was the inevitable decoupling of the axial positions of the tracheal air column and the reference segment due to further superior laryngeal movement, we were still able to accurately measure the diameters at very precise locations along the pressure-impedance catheter at all times (Figure 4A). All measurements were calibrated for magnification by using the known distance between visible adjacent electrodes. Diameters were expressed net of the width of the indwelling catheter (~3 mm) such that the lumen fully closed on the catheter was defined as having a diameter of 0 mm (rather than 3 mm). The three separate diameter measurements (D1–D3 Figure 3B) taken over consecutive video frames were averaged for each time point to produce a single value of diameter for the reference segment over time. The diameter dataset was then smoothed by resampling from 25 to 40 Hz using a piece-wise cubic Hermite interpolation method. The corresponding midpoint pressure data and impedance data for the reference segment were then exported from the acquisition system in comma-separated value text-file format. These data were smoothed by interpolation to match the diameter dataset as previously described.


Upper esophageal sphincter mechanical states analysis: a novel methodology to describe UES relaxation and opening.

Omari TI, Wiklendt L, Dinning P, Costa M, Rommel N, Cock C - Front Syst Neurosci (2015)

An example of a 10 ml liquid swallow showing the temporal correlation of luminal diameter and intraluminal admittance at the level of the reference impedance segment (RIS). (A) Sequential images from swallow onset (laryngeal elevation) showing barium passing through the RIS. Dotted lines chart the trajectory of movement of the tracheal air column (TAC, white line) and the RIS (yellow dotted line). Note decoupling of the TAC and proximal margin of the RIS at time points 0.72 and 1.16 s after swallow onset. (B) Diameter of the barium contrast column and admittance measured at the level of RIS over time from swallow onset. Individual diameter curves are shown for locations D1–D3 (per Figure 3) as well as the mean diameter. (C) Time correlation of diameter and admittance with colors indicating whether samples correspond to when the lumen was increasing (yellow) or decreasing (blue) in diameter.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4285690&req=5

Figure 4: An example of a 10 ml liquid swallow showing the temporal correlation of luminal diameter and intraluminal admittance at the level of the reference impedance segment (RIS). (A) Sequential images from swallow onset (laryngeal elevation) showing barium passing through the RIS. Dotted lines chart the trajectory of movement of the tracheal air column (TAC, white line) and the RIS (yellow dotted line). Note decoupling of the TAC and proximal margin of the RIS at time points 0.72 and 1.16 s after swallow onset. (B) Diameter of the barium contrast column and admittance measured at the level of RIS over time from swallow onset. Individual diameter curves are shown for locations D1–D3 (per Figure 3) as well as the mean diameter. (C) Time correlation of diameter and admittance with colors indicating whether samples correspond to when the lumen was increasing (yellow) or decreasing (blue) in diameter.
Mentions: Sequential diameter measurements were performed until all of the barium had passed through the reference impedance segment (Figure 4A). The catheter electrode rings produced a discernible radiological shadow. Therefore, even though the lumen contained contrast and there was the inevitable decoupling of the axial positions of the tracheal air column and the reference segment due to further superior laryngeal movement, we were still able to accurately measure the diameters at very precise locations along the pressure-impedance catheter at all times (Figure 4A). All measurements were calibrated for magnification by using the known distance between visible adjacent electrodes. Diameters were expressed net of the width of the indwelling catheter (~3 mm) such that the lumen fully closed on the catheter was defined as having a diameter of 0 mm (rather than 3 mm). The three separate diameter measurements (D1–D3 Figure 3B) taken over consecutive video frames were averaged for each time point to produce a single value of diameter for the reference segment over time. The diameter dataset was then smoothed by resampling from 25 to 40 Hz using a piece-wise cubic Hermite interpolation method. The corresponding midpoint pressure data and impedance data for the reference segment were then exported from the acquisition system in comma-separated value text-file format. These data were smoothed by interpolation to match the diameter dataset as previously described.

Bottom Line: Our results indicated that eight different mechanical states were almost always seen during healthy swallowing and some of these calculated changes in muscle function were consistent with the known neurally dependent phasic discharge patterns of cricopharyngeus muscle activity during swallowing.Clearly defined changes in the mechanical states were observed in motor neuron disease when compared to age matched healthy controls.Our data indicate that mechanical state predictions were simple to apply and revealed patterns consistent with the known neural inputs activating the different muscles during swallowing.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Physiology, School of Medicine, Flinders University Adelaide, SA, Australia ; Department of Gastroenterology and Hepatology, Flinders Medical Centre and School of Medicine, Flinders University Adelaide, SA, Australia.

ABSTRACT
The swallowing muscles that influence upper esophageal sphincter (UES) opening are centrally controlled and modulated by sensory information. Activation of neural inputs to these muscles, the intrinsic cricopharyngeus muscle and extrinsic suprahyoid muscles, results in their contraction or relaxation, which changes the diameter of the lumen, alters the intraluminal pressure and ultimately inhibits or promotes flow of content. This relationship that exists between the changes in diameter and concurrent changes in intraluminal pressure has been used previously to calculate the "mechanical states" of the muscle; that is when the muscles are passively or actively, relaxing or contracting. Diseases that alter the neural pathways to these muscles can result in weakening the muscle contractility and/or decreasing the muscle compliance, all of which can cause dysphagia. Detecting these changes in the mechanical state of the muscle is difficult and as the current interpretation of UES motility is based largely upon pressure measurement (manometry), subtle changes in the muscle function during swallow can be missed. We hypothesized that quantification of mechanical states of the UES and the pressure-diameter properties that define them, would allow objective characterization of the mechanisms that govern the timing and extent of UES opening during swallowing. To achieve this we initially analyzed swallows captured by simultaneous videofluoroscopy and UES pressure with impedance recording. From these data we demonstrated that intraluminal impedance measurements could be used to determine changes in the internal diameter of the lumen when compared to videofluoroscopy. Then using a database of pressure-impedance studies, recorded from young and aged healthy controls and patients with motor neuron disease, we calculated the UES mechanical states in relation to a standardized swallowed bolus volume, normal aging and dysphagia pathology. Our results indicated that eight different mechanical states were almost always seen during healthy swallowing and some of these calculated changes in muscle function were consistent with the known neurally dependent phasic discharge patterns of cricopharyngeus muscle activity during swallowing. Clearly defined changes in the mechanical states were observed in motor neuron disease when compared to age matched healthy controls. Our data indicate that mechanical state predictions were simple to apply and revealed patterns consistent with the known neural inputs activating the different muscles during swallowing.

No MeSH data available.


Related in: MedlinePlus