Michael E. Groher

Methodology for detecting swallowing sounds

The use of cervical auscultation in the evaluation of the pharyngeal swallow may become a part of the clinical evaluation of dysphagic patients. Though its use is based on subjective evaluation, an acoustic analysis of swallowing sounds might establish more objective criteria in the detection of swallowing disorders. The present study sought to investigate three aspects of the methodology for detecting swallowing sounds: (1) the type of acoustic detector unit suited to an acoustic analysis of the pharyngeal swallow, (2) the type of adhesive suited for the attachement of the detector, and (3) the optimal site for sound detection of the pharyngeal swallow. An accelerometer with double-sided paper tape was selected as the appropriate detector unit because of its wide range of frequency response and small attenuation level. Using this detector unit, swallowing sounds and noise associated with simulated laryngeal elevation and the carotid pulse were acquired at 24 sites on the neck in 14 normal subjects; these signals were acoustically analyzed. The determination of the optimal site for detecting swallowing sounds was based on the signal-to-noise ratio. The site over the lateral border of the trachea immediately inferior to the cricoid cartilage is the optimal site for detection of swallowing sounds because this site showed the greatest signal-to-noise ratio with the smallest variance. The site over the center of the cricoid cartilage and the midpoint between the site over the center of the cricoid cartilage and the site immediately superior to the jugular notch were also considered to be the most appropriate sites.

Functional Benefits of Dysphagia Therapy Using Adjunctive sEMG Biofeedback

This article describes a retrospective analysis of functional outcome, time in therapy, and cost per unit of functional change in patients who received therapy for pharyngeal dysphagia. Twenty-five patients presenting dysphagia following stroke and 20 patients with dysphagia following treatment for head/neck cancer completed a systematic therapy program supplemented with surface electromyographic (sEMG) biofeedback. Eighty-seven percent (39/45) of all patients increased their functional oral intake of food/liquid including 92% of stroke patients and 80% of head/neck cancer patients. Patients with dysphagia following stroke demonstrated greater improvement than those in the head/neck cancer group. Patients in the stroke group completed more therapy sessions thus increasing the total cost of therapy, but they made more functional progress resulting in lower costs per unit of functional change than patients in the head/neck cancer group. Limitations of this study are described in reference to implications for future clinical research on the efficacy of this therapy approach.

Development and dissemination of an aspiration risk reduction diet

Patients with oropharyngeal swallowing disorders secondary to neurologic impairments benefit from diets that minimize the risk of aspiration. An aspiration risk reduction diet was developed from our hospitals regular menu cycle. Examples of the diets preparation, dissemination, and use in a 600-bed acute medical/surgical teaching hospital are discussed.

Symmetry and reproducibility of swallowing sounds

Cervical auscultation is being used more frequently in the clinical assessment of dysphagic patients. The present study was designed to assess symmetry and the reproducibility of swallowing sounds detected simultaneously from bilateral cervical sites. Symmetry of the swallowing sounds acquired using our method was verified because no significant differences were found for any parameters in both time and frequency domain analyses between swallowing sounds detected bilaterally. This result supports the use of a “unilateral” site for the detection of swallowing sounds. The reproducibility of swallowing sounds was assessed by a coefficient of variation. Results of this analysis suggest that one should evaluate the acoustic characteristics of swallowing sounds from repeated swallows rather than from one swallow.

Reinstituting oral feeding in tube-fed adult patients with dysphagia.

Feeding tubes are valuable assets in the rehabilitation of adult patients with dysphagia. Feeding tubes may be placed in response to perceived risks of airway compromise or insufficient nutrient intake. However, not all patients require long-term enteral feeding. With intensive dysphagia therapy, many patients will experience resolving deficits or improvement in swallowing ability. These patients require an appropriate strategy to transition from tube to oral feeding. This article reviews some of the basic characteristics of dysphagia and identifies specific swallowing difficulties in 2 groups of patients who often benefit from temporary enteral feeding: stroke survivors and patients treated for head and neck cancer. Specific suggestions are offered for clinical strategies to reinstitute oral feeding in these groups of tube-fed patients.

Basic Concepts of Surface Electromyographic Biofeedback in the Treatment of Dysphagia: A Tutorial

Surface electromyographic (sEMG) biofeedback has been used to enhance behavioral treatment interventions in a variety of movement disorders involving the head and neck musculature. These include, b...

The Detection of Aspiration and Videofluoroscopy

The use of videofluoroscopy to study the upper aerodigestive tract is considered to be the most useful examination for documenting the oropharyngeal swallow sequence in those patients suspected of having dysphagia [1]. It use has been popularized by speech/language pathologists. Working together with the radiologist, studies are designed to have both a diagnostic and treatment focus in the care of those with oropharyngeal impairments of both speech and swallow. When videorecorded images of the swallow sequence are played in slow motion, the clinician seeks not only to document irregularities of function, but to predict from dysfunction which set of swallowing treatment strategies should be employed. Documentation of aspiration and the physiologic abnormalities responsible for its presence has become a focal point of the analysis, largely because of the failure of the clinical examination to correctly identify the presence or absence of aspiration. Interestingly, there are few data to support the validity of the procedure as it impacts the care/outcome of those suspected of oropharyngeal swallowing impairment. Questions also remain regarding test protocol and interpretation. For instance, what type and amount of testing stimuli are best suited for this examination? If a patient has a safe or efficient swallow on a 5 cc bolus, is this predictive of a safe and efficient swallow on a 20 cc bolus? Are successive swallows testing different aspects of swallow vs. single swallows? How many swallows are sufficient in a single examination to be predictive of

Speech-language pathology and dysphagia: A brief historical perspective

In the past decade, speech-language pathologists have taken a leading role in the management of services for patients with oropharyngeal dysphagia. This article presents the historical perspective of this role, the rationale for assuming the responsibility, and suggests directions for continued involvement.

Ethical Dilemmas in Providing Nutrition

The decisions involved in the institution of artificial feeding in patients with chronic and/or terminal illness are difficult. They are more complex when one is deciding if nutrition and hydration are to be withdrawn. In both instances the decision must be based on a combination of factors: the patients right to self-determination; documented medical evidence demonstrating the need for artificial feeding, combined with a risk/benefit analysis if alternative alimentation is recommended; and an appreciation of prior legal decisions as they relate to the implementation of alternative forms of nutrients to sustain life.

Determination of the risks and benefits of oral feeding

The dysphagia team is often faced with the dilemma of whether or not to let patients with known aspiration feed orally. The criteria that assist professionals in their final decisions may be more anecdotal than empirical. Undoubtedly, the decision-making process that is activated in determinations of oral vs. non-oral feeding will vary among institutions and by patient presentation. For some dysphagia teams, the presence of tracheal penetration of swallowed contents is sufficient indication to preclude oral feeding. For others, some amounts of aspiration are acceptable.