11 Assessment of Swallowing: Clinical Assessment and Diagnostic Procedures

Dysphagia screening assessments efficiently identify at-risk patients and appropriately prioritize high-risk patients. Screening assessments provide information identifying whether a patient is dysphagic or not. This is different from a diagnostic swallow assessment such as videofluoroscopy (VF; modified barium swallow) that provides information regarding physiology of the patient’s dysphagia. Screening may consist of observations of patients while eating, observing signs of dysphagia (coughing, food left in the mouth, rejection of food, aspirated food being coughed out of a tracheostomy tube), or review of medical notes.1 Patients often experience psychological and social stresses due to their dysphagia impacting on their quality of life. Standardized patient questionnaires have been developed, for example, SWAL-QOL. SWAL-QOL is a standardized 93-item questionnaire used both in clinical and research settings for measuring dysphagia outcome for 10 quality-of-life concepts, quality of care, and patient satisfaction.¹

Bedside/Office

The bedside/office assessment of dysphagia is a familiar process within the role of the speech language pathologist (SLP). Typically bedside/office swallowing assessment involves gathering preparatory information regarding patients’ case history and symptoms and should identify medical diagnosis, medical and swallowing history nutritional status, tube feeding, and patient’s awareness of swallowing difficulties. Respiratory function during swallowing is important to note.¹ Bedside/office assessment should consider oromotor function and anatomy, oral sensation and sensitivity, dentition, and oral health.

Oromotor assessment determines age-appropriate oral reflexes and the presence or absence of the gag reflex. In general practice when introducing food and fluid boluses the following sequence is used in the author’s practice:

•Teaspoon (5 mL) syrup consistency fluid

•Sip syrup-consistency fluid

•Teaspoon normal fluid

•Sip normal fluid, larger bolus normal fluid

•Sip custard-consistency fluid

•Teaspoon pudding/puree (e.g., sieved kiwi fruit)

•Fork-mashable consistency (e.g., mashed vegetables)

•Soft diet (e.g., banana or soft cake)

•Normal food (e.g., biscuit)

Observations are made of swallowing behaviors and can be monitored by cervical auscultation (CA, described later), palpation of oral and laryngeal movements for example laryngeal elevation, and forward movement of the hyoid by placing fingertips at these locations on the patient’s neck.

Successful oral phase of swallow should demonstrate no oral residue in the mouth or around teeth, adequate lip seal to prevent oral escape, and one or two swallows to clear each bolus. The oral phase of swallow should complete as the swallow reflex is triggered. Late-onset swallow may present as a patient with a clear mouth but incomplete or no laryngeal elevation.

Pharyngeal phase of swallow requires complete clearance of the bolus with one swallow. Observations of multiple swallows, struggle to clear the bolus, altered respiratory patterns, and head or postural changes during swallowing are made. Most importantly, coughing/choking before or after swallowing and “wet” voice are important indicators of airway penetration or true aspiration.

During assessment, different consistencies are trialed along with modified swallowing techniques such as supraglottic swallow or Mendelsohn maneuver to determine the safest consistencies and swallowing techniques for the patient to avoid the complications of dysphagia. Clear reporting and communicating with the patient, staff, and carers is of utmost importance.

Cervical Auscultation

CA is experiencing a renewed interest as an addition to the bedside/office swallowing assessment. CA provides audible cues that can enable reliable classification of swallowing problems when incorporated in a comprehensive bedside/office swallowing assessment and is used as such by the author. CA is a controversial technique with a relatively small evidence base. CA requires a stethoscope or microphone to be placed on the thyroid cartilage (lamina) while the patient swallows. Cervical swallowing sounds, “clicks,” are associated with the opening of the pharyngotympanic tube and “clunks” are associated with the opening of the upper esophageal sphincter (UES). The “click” and “clunk” are the most reliable sounds described.1,2 In patients with swallowing difficulties, these sounds may be weaker, absent, or out of sequence.

Videofluoroscopy

VF or “modified barium swallow” is often viewed as the “gold standard” of dysphagia assessment. VF is proficient in imaging swallowing physiology and enables accurate measurement of the sequence and timing of swallowing events, opening of the UES, and identification of physiological causes for aspiration.

VF is useful to determine management and therapeutic strategies and monitor progress of therapy. VF is limited in being able to identify the quantity of material aspirated and the completeness of bolus clearance from the oral and pharyngeal cavities. VF is normally performed by an SLP and radiologist.

During VF, patients are positioned in the lateral view initially to gain best view of aspiration that may occur. Anterior–posterior (AP) view is used later in the assessment to view symmetry of anatomy and function. The patient is seated as upright as possible.

Many clinical settings have facilities to assess patients sitting, standing, or reclined in bed. A specialized chair for VF is used with a radio-transparent back support to allow fluoroscopy imaging in the seated AP position. VF field of view should include the lips to the posterior pharyngeal wall, larynx, and upper and mid-esophagus. In the author’s practice, the SLP requests the radiologist routinely to view one or more boluses traveling down the esophagus to identify any indications of esophageal problems that may require further investigation by the appropriate clinician.

Bedside or office assessment is normally completed in the author’s practice before VF, enabling appropriate planning of bolus consistencies and volumes presented during VF. Clinical judgment is needed to determine modifications to the procedure if the patient appears unable to protect their airway.

During VF assessment, it is essential to keep fluoroscopy time to minimum (< 3 minutes). The fluoroscopy images are observed on a monitor during the procedure and in some cases stills are taken. The assessment is recorded for further review. It is noninvasive and can accommodate patients of all ages in most feeding positions.

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is recognized as an emerging tool in the assessment of dysphagia.³ MRI is able to visualize soft tissues and individual muscles in detail and complements other assessments, for example, VF or fiberoptic endoscopic examination of swallowing (FEES; described later). The extent of movement of oropharyngeal structures during swallowing can be seen in detail, particularly in patients with soft-tissue deficits or abnormalities, following oropharyngeal surgery to detect soft-tissue gaps or assessing esophageal stricture in laryngectomy patients.

MRI assessment of swallowing has been studied with the patient reclined and the patient sitting in open MRI. Images are taken in the sagittal, coronal, and axial planes providing additional detail without moving the patient. Information achieved through MRI is applicable to surgery planning to minimize impact on function, therapy planning, and evaluation. Limitations include lost information between each picture, altered anatomy in reclined position, and patients with implants or inappropriate dental material.

Electromyography

Electromyography (EMG) provides measurements of the timing and amplitude of contractions of selected muscles involved in the swallowing process. Surface electrodes are used to measure muscles usually in the floor of the mouth and muscles involved in laryngeal elevation. Electrical energy is created by muscle activity. It is therefore possible to measure when the electrical activity occurs and how much. When the muscle(s) begin to contract in the sequence of swallowing, the extent of muscle contraction can be appreciated.⁴

Surface EMG is a simple, reliable, and noninvasive evaluation of some swallowing parameters with low level of discomfort during the assessment. Normative data for the timing of swallowing events can be used for the evaluation of dysphagia symptoms, for comparison in preoperative and postoperative stages, and in EMG monitoring before, during, or after treatment.

Electroglottography

Electroglottography (EGG), sometimes referred to as a “laryngograph,” tracks closure of vocal folds by measuring electrical resistance between two electrodes placed on the thyroid lamina.⁵ EGG allows measurement of time variations of degree of contact between the vibrating vocal folds during phonation. EGG can be altered to measure larynx elevation to determine onset and completion of pharyngeal swallow and biofeedback on distance and duration of laryngeal elevation during swallowing, for example, when patients are trying to improve swallow function. EGG signal is composed of a high-frequency component related to vocal fold vibration (voice) and a low-frequency component related to slow movement of the larynx (swallowing). For analysis of swallowing, the system filters high frequencies leaving the low-frequency component for swallowing measurement.⁶

Manometry (Pharyngeal)

Pharyngeal manometry evaluates pharyngeal and UES pressures occurring during swallowing. Pharyngeal and upper sphincter manometry detects insufficient relaxation of the UES and coordination between the contractions of the pharynx in relation to the relaxation of the UES. Swallowing is a very rapid activity (< 1 second onset to completion). In VF alone, it can be difficult to determine the degree of pharyngeal impairment, sequence of pressure changes, or cause of residue in a patient with dysphagia. For example, is residue in pyriform sinuses the result of weak pharyngeal contraction and/or reduced UES opening?7

Pharyngeal manometry is performed by passing a small manometric catheter containing one or more pressure sensors via the nose to the level of the base of the tongue, the cricopharyngeal sphincter, and/or the cervical esophagus. Pressures are measured locally while swallowing different consistencies and volumes. Pharyngeal manometry is usually combined with VF (manofluorography) or FEES to determine physiology causing pressure changes measured during the test. For example, if decreased UES relaxation/opening is suspected, the SLP may choose to use the Mendelsohn maneuver compensatory technique or the Shaker exercise.⁸ However, if weak pharyngeal contraction is identified, the SLP can use effortful swallow.⁹ Manometry is also useful in patients following total laryngectomy where the normal pressures in swallowing are disrupted by surgery and reconstruction.

Scintigraphy

Scintigraphy is a nuclear medicine test that enables the measurement of swallow clearance and oropharyngeal function. The main advantage of scintigraphy is the ability to accurately quantify the amount of radionuclide in any structure (e.g., aspirated into lungs) and timing of bolus transit.¹⁰ Patients swallow a measured bolus containing a radionuclide. During the swallow, the bolus transit is imaged and recorded by a gamma camera and computer. Results of scintigraphy demonstrate presence and quantity of aspirated bolus and residue and also the esophageal effects of dysphagia, particularly gastroesophageal reflux disease. Scintigraphy does not, however, enable assessment of physiology of the mouth and pharynx; therefore, it is not possible to diagnose dysfunction causing the dysphagia. The test is most useful when combined with VF to enable diagnosis of the causes of the dysphagia.¹¹

Videoendoscopy (FEES, FEES/ST)

FEES allows indirect visualization of the soft palate, base of the tongue, oropharynx, hypopharynx, larynx, and subglottis. FEES enables the assessment and observation of anatomy, secretions, and function before and after swallowing. It can be performed during bedside/office assessment and can incorporate Laryngeal Sensory Testing (LST) or FEES with Sensory Testing (FEES/ST) (described later) and is complementary to other assessments. Normally, FEES is performed by the otolaryngologist and the SLP trained in nasendoscopy. FEES is used in the author’s practice to assess in detail patients with pharyngeal-stage swallowing difficulties, for example, posttransoral laser resection of laryngeal and hypopharyngeal carcinomas, at day 2 postsurgery. It is repeatable, does not involve radiation, and can include using any foods the patient finds difficult in addition to the assessment protocol.¹²

During FEES, a nasendoscope is passed into the patient’s nose to the level of the soft palate or just over the velum. When assessing the laryngopharyngeal structures and function, the position of the scope tip is normally positioned just beyond the tip of the velum.

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