Dysphagia: Research Trends and Resources http://www.asha.org/Publications/leader/2012/120424/Research-Trends-and-Resources--Dysphagia.htm Clinicians often recommend the chin-down posture for patients with neurogenic dysphagia to prevent tracheal aspiration. But is it effective? According to researchers in Spain, the indication for chin-down posture should be evaluated by videofluoroscopic examination. In a study in Neurogastroenterology & Motility (DOI: 10.1111/j.1365-2982.2011.01869.x), the researchers used videofluoroscopy ... Research in Brief
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Research in Brief  |   April 01, 2012
Dysphagia: Research Trends and Resources
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Swallowing, Dysphagia & Feeding Disorders / Research in Brief
Research in Brief   |   April 01, 2012
Dysphagia: Research Trends and Resources
The ASHA Leader, April 2012, Vol. 17, 16-17. doi:10.1044/leader.RIB.17052012.16
The ASHA Leader, April 2012, Vol. 17, 16-17. doi:10.1044/leader.RIB.17052012.16
Does Chin-Down Swallowing Prevent Aspiration?
Clinicians often recommend the chin-down posture for patients with neurogenic dysphagia to prevent tracheal aspiration. But is it effective? According to researchers in Spain, the indication for chin-down posture should be evaluated by videofluoroscopic examination.
In a study in Neurogastroenterology & Motility (DOI: 10.1111/j.1365-2982.2011.01869.x), the researchers used videofluoroscopy to assess the effectiveness of the posture to prevent aspiration in patients with neurogenic dysphagia secondary to stroke or traumatic brain injury (TBI). In a randomized, alternating, cross-over study—with and without the chin-down posture—they examined 47 patients with a videofluoroscopic diagnosis of aspiration (31 stroke, 16 TBI) and 25 controls without aspiration (14 stroke, 11 TBI).
During the chin-down posture, 55% of patients avoided aspiration (40% preswallow aspiration and 60% aspiration during swallow). The percentage was similar for both groups (58% stroke and 50% TBI). Fifty-one percent of patients had silent aspiration; of these, 48% persisted with aspiration while in the chin-down posture. The researchers found a statistically significant relationship between the existence of pharyngeal residue, cricopharyngeal dysfunction, pharyngeal delay time, and bolus volume with the persistence of aspiration. The chin-down posture did not change swallow biomechanics in patients without aspiration.
Only half the patients with acquired brain injury avoided aspiration while keeping their chin down; 48% of silent aspirators continued to aspirate during the maneuver. Several videofluoroscopic parameters were related to inefficiency of the maneuver. Researchers conclude, therefore, that the indication for chin-down posture should be evaluated by videofluoroscopic examination.
Surface Electromyography for Swallowing Disorders?
The application of surface electromyography (sEMG) to speech and swallowing shows potential as a clinical and research tool when used correctly, according to a Journal of Speech, Language, and Hearing Research literature review in press (DOI: 10.1044/1092-4388(2011/11-0214).
The authors discuss the theory behind recording sEMG for speech and swallowing systems and discuss several factors known to affect the content of the sEMG signal, including signal degradation, placement of sensors with regard to neuromuscular junctions, and cross-talk—the detection of signals from more than one muscle at a time.
Finally, the authors present practical guidelines for sEMG recording and analysis, focusing on special considerations within the context of the speech and swallowing anatomy. Speech and swallowing muscles are often small, with overlapping fibers, making it difficult to isolate the activity of single muscles of speech. But the authors suggest that as long as the recording limitations are understood prior to interpreting data, sEMG can provide a valuable tool to help understand and assess speech and swallowing physiology.
The authors identified unique challenges in applying sEMG to the speech and swallowing musculature, due to the small size of the muscles in relation to the sEMG detection volume and the current lack of knowledge about neuromuscular junction locations. Therefore, the results suggest sEMG is best suited to noninvasive clinical studies for which detection of specific, isolated muscle activities is not necessary.
Predicting Pneumonia in Older Adults
Elderly patients living in nursing homes who aspirate saliva detected by videoendoscopy (VE) are at significant risk for both pneumonia and body weight loss, according to a Japanese study that appeared in the Journal of Oral Rehabilitation (DOI: 10.1111/j.1365-2842.2011.02286.x).
Researchers wanted to examine the dysphagic signs identified by VE that could predict the incidence of pneumonia and body weight loss. They evaluated 148 subjects (85.1 ± 8.0 years, male/female: 43/105) at six nursing care facilities in Japan for their feeding and swallowing movements by clinical and VE examinations during the consumption of a regular meal. The VE examination items included existence/absence of pharyngeal residue, laryngeal penetration, and aspiration of food and saliva. The patients then received three months of individualized feeding treatment based on the results of the clinical/VE examination at baseline.
The researchers examined pneumonia incidence as the primary outcome. In patients without pneumonia, they measured body weight change as a secondary outcome. Even with feeding treatment, 12 (8.1%) of the 148 patients developed pneumonia during the three-month follow-up period. Signs of silent aspiration of saliva or aspiration of saliva detected by VE examination were a significant risk factor for both pneumonia and a body weight loss of 3% or more.
Dysphagia Assessments Via Telepractice
A clinical swallowing examination via telepractice can provide valid, reliable outcomes comparable to clinical decisions made in a face-to-face environment, according to an article in Dysphagia (DOI: 10.1007/s00455-011-9390-9).
To assess the validity of conducting telepractice clinical dysphagia assessments, researchers assessed 40 individuals with dysphagia using a face-to-face speech-language pathologist and an SLP at a remote location via an Internet-based videoconferencing system. An assistant at the patient’s site helped facilitate the assessment.
The two SLPs showed clinically acceptable levels of agreement on most parameters. Exact agreement between the two SLPs’ ratings for the oral, oromotor, and laryngeal function tasks ranged from 75% to 100%. Exact agreement relating to food and fluid trials ranged from 79% to 100%. Exact agreement related to aspiration risk and clinical management ranged between 79% and 100%.
Chewing Rates Vary With Age and Food Consistency
Variable factors in children’s and adults’ food chewing—chewing rate, chewing sequence duration, and estimated number of chewing cycles—appear to follow distinct developmental trajectories, and are consistency-dependent in children as young as 7 years old, according to a Journal of Speech, Language, and Hearing Research paper in press (DOI: 10.1044/1092-4388(2011/10-0236).
Researchers used small—approximately 2 mm—reflective markers to pinpoint subjects’ facial landmarks, and three-dimensional motion-capture cameras to record jaw movements. Data were collected from 60 participants (48 children, 12 adults) across five age ranges (beginners, 7 months, 12 months, 35 months, and adults). Each age group included 12 participants who were presented with food items in three consistencies: puréed, semi-solid, and solid. Because the ability to manage different consistencies is a learned behavior, participants received consistencies with which they had approximately two weeks of experience. Researchers collected data on a total of 528 chewing sequences, noting age effects and consistency effects for each group.
The results suggest both age- and consistency-related changes in chewing rate, sequence duration, and estimated number of chewing cycles, with consistency differences affecting masticatory timing in children as young as 7 months of age. Chewing rate varied as a function of age and consistency, and chewing sequence duration was shorter for adults than children regardless of consistency type. Additionally, the results from the estimated number of chewing cycles measure suggest that chewing effectiveness increased with age, but this measure was also dependent on consistency type.
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April 2012
Volume 17, Issue 5