27.Assessment of eating and swallowing function using Medical Devices

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Explanation

Learning goals

1) To understand the significance and points to note for swallowing evaluation using medical devices besides VF and VE

2) To understand the methods of swallowing evaluation using medical devices that are widely employed in clinical practice and the features of those methods

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Explanation

There are other methods besides videofluoroscopy and videoendoscopy that use medical devices to evaluate swallowing function. They are used as auxiliary methods with videofluoroscopy and videoendoscopy.

Most of the medical devices used are less expensive than an endoscope or X-ray machine, they don't require special skills to use, and they allow for measurements to be made easily in a short period of time.

They provide numeric results, and these numeric results allow for a comparison with the results of healthy individuals or a comparison of the results obtained before and after intervention.

The results can be referenced when creating a training plan, evaluating the results of training, or using feedback to motivate patients to put effort into training.

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Explanation

The results tend to be influenced by factors such as sex and age, and we must consider this when selecting the control group. For example, the results of a female patient should not be compared with results of a healthy man.

These measurements require cooperation from patients, so they may not reflect the actual abilities of patients who can't sufficiently cooperate.

Two or three measurements should be performed for each test to confirm reliability of the results. If the results show large variation for individual patients, they may not have executed the instructed action during one of the repetitions.

The results merely show someone's maximum ability to perform a certain function. In other words, a poor result doesn't always indicate dysphagia. For example, even if patients have lower tongue pressure than the average healthy person, they may be able to eat normal food as long as they have the necessary capacity to do so. However, this result may suggest a reduced reserve capacity.

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Explanation

The term "reserve capacity" refers to the difference between the maximum ability to execute a function and the necessary capacity to execute normal activities of daily living. A reduced reserve capacity prevents someone from functioning in situations that require abilities beyond what they use for their normal activities. For example, a reduced reserve capacity of occlusal force would mean someone is unable to chew a tough piece of meat, even if they have no problems eating their normal diet.

People with a reduced reserve capacity are at risk of having difficulties for eating regular diet if something happens to further reduce their abilities (Figure).

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Explanation

Tongue pressure is the pressure exerted by the tongue pushing on the roof of the mouth. Weak tongue pressure makes bolus formation and transport more difficult, and it may also affect swallowing pressure.

A proper measurement can't be made if the patient doesn't understand instructions, can't execute the instructed tongue movement, can't insert the probe, or can't hold the probe.

Tongue pressure < 30 kPa measured using the JMS tongue pressure measuring instrument® (manufactured by GC Corporation) is one criterion for deterioration of oral function.

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Explanation

The slide shows how to measure tongue pressure using the JMS tongue pressure measuring instrument®.

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Explanation

Two of the suprahyoid muscles, the mylohyoid muscle and the digastric muscle, lift the hyoid bone during swallowing. A third, the geniohyoid muscle, moves the hyoid bone forward.2 All of these are muscles that open the mouth, so the function of the suprahyoid muscles can be evaluated by measuring mouth-opening force. A proper measurement cannot be made if the patient doesn't understand instructions or can't execute the instructed movements. Measurement of mouth-opening force is contraindicated in patients with temporomandibular joint disorders because they may experience temporomandibular joint dislocation or pain during the procedure.

In one study that used mouth-opening force to screen for aspiration, cutoff values were ≤ 3.2 kg (57% sensitivity, 93% specificity) in men and ≤ 4 kg in women (79% sensitivity, 52% sensitivity).3

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Explanation

Here we see how to measure mouth-opening force using the Mouth-opening Force Trainer®.

  1. Have cap of Mouth opening Force Trainer KT2016 on the examinee's head.
  2. Place jaw cup on the jaw as the examinee close the mouth and fix the cup with the belt.
  3. The examinees opens their mouth as wide as possible.
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Explanation

We consider occlusal force when determining whether someone can tear and crush food. When occlusal force decreases, not only the person's risk of swallowing food without chewing and choking may increase, but their intake of vegetables, vitamins A, C, and B6, folic acid, and dietary fiber may also decrease.4

Proper measurement can't be done if the patient doesn't understand instructions, can't execute the instructed action, or doesn't have opposing teeth. Measurement is also contraindicated in patients who experience pain when they clench their teeth.

Occlusal force < 200 N measured using the Dental Prescale® system is one criterion for deterioration of oral function.1)

In Dental Prescale II® , it is proposed that the criterion for deterioration of oral function should be less than 500 N without a pressure filter and less than 350 N with a pressure filter.5)

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Explanation

Here we see how to measure occlusal force using the Dental Prescale® system.

  1. Insert the measurement device into the mouth.
  2. Bite 3 seconds the device.
  3. Scan the device and measure the mastication force by bite force analyzer.
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Explanation

Mastication requires tearing, crushing, and grinding abilities as well as the ability to mix saliva with the food to form a bolus that is easy to swallow. However, because it's difficult to evaluate each of these abilities individually, it is common to evaluate mastication by observing tearing and crushing abilities using food such as gelatin gummies or peanuts. Special chewing gum, its color changes as mixed with saliva, is also be used for evaluating mastication.

We should avoid evaluating mastication in patients who can't follow instructions or have no opposing teeth because they may leave the food in their mouth without chewing or swallow it without chewing.

A glucose concentration < 100 mg/dL measured using the masticatory function testing system is one criterion for deterioration of oral function.1

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Explanation

Here we see an evaluation of masticatory function using the Gluco Sensor GS-II®.

  1. The examinees chew 2g of 2 gummy jelly (chewing specimen) for 20 seconds.
  2. Gargle with 10ml of water and spit out gummi and water onto mesh to filter.
  3. Measure glucose concentration of filtered solution by Gluco Sensor GS-II.
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References

  1. Japanese Society of Gerodontology Academic Committee: Deterioration of Oral Function in the Elderly. The Position Paper from Japanese Society of Gerodontology in 2016, J J Gerodont 31(2), 81-99, 2016.
  2. William G. Pearson Jr, Susan E. Langmore, Ann C. Zumwalt: Evaluating the structural properties of suprahyoid muscles and their potential for moving the hyoid, Dysphagia 26(4), 345-351, 2011.
  3. Hara K, Tohara H, Wada S, Iida T, Ueda K, Ansai T: Jaw-opening force test to screen for Dysphagia: preliminary results, Arch Phys Med Rehabil 95(5), 867-874, 2014.
  4. Inomata C, Ikebe K, Kagawa R, et al: Significance of occlusal force for dietary fibre and vitamin intakes in independently living 70-year-old Japanese:from SONIC Study, J. Dent 42, 556-564, 2014.
  5. Yasuhiro H, Koichiro M, Kazunori I, et al: Relationship between two pressure-sensitive films for testing reduced occlusal force in diagnostic criteria for oral hypofunction, Gerodontology, Online ahead of print.
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