«Taste and Smell Examination Component Manual January 2013 TABLE OF CONTENTS Chapter Page 1 OVERVIEW OF TASTE AND SMELL COMPONENT 1.1 Background of ...»
Taste and Smell
TABLE OF CONTENTS
1 OVERVIEW OF TASTE AND SMELL COMPONENT
1.1 Background of Taste and Smell Perception
1.2 Basic Principles of Taste and Smell
1.2.1 The Sense of Smell
1.2.2 The Sense of Taste
1.3 Medical Disorders of the Chemosenses
1.3.1 Disorders of Smell
1.3.2 Disorders of Taste
1.4 Importance of Taste and Smell Data
1.4.1 Public Health Goals of the NHANES Study
1.5 Overview of the Taste and Smell Examination
2 EQUIPMENT AND SUPPLIES
2.3 Equipment Care and Maintenance
2.3.1 Start of Stand and Start of Session
2.3.2 Equipment Care and Maintenance between SP’s................ 2-8 2.3.3 End of Session
2.5 Setup Procedures
2.5.1 Porto-Dent II
2.6 Teardown Procedure
2.6.1 Porto-Dent II
3 Examination Protocol
3.1 Eligibility Criteria
3.2 Pre-Examination Procedures
5 Quality Control
5.1 Introduction to Quality Control
5.3 Monitoring Equipment and Equipment Repair
Appendix A EXAM FLOW
B TALKING POINTS
C REPORT OF FINDINGS
Figure 1-1 Maps of the nasal lining
2-1 Sensory Perception Light Box
2-2 Portable Lux Meter
2-3 Porto-Dent II Suction Machine (front view)
2-4 Porto-Dent II Suction Machine (back view)
2-5 Porto-Dent II Suction Machine – cabinet view
2-10 Gooseneck microphone stand with slip-on clip
2-11 Dry oral evacuation funnel
2-12 High-volume evacuation valve
2-13 Low-volume vacuum line plug
2-14 gLMS and dry erase marker
Vacuum line connector
2-18 2-19 Overflow shut-off mechanism
2-20 Canister lid alignment indicator markings
2-21 HVE with lever in the open position “Down”
2-22 Motor and canister assembly inside cabinet
3-1 General Labeled Magnitude Scale (gLMS)
3-2 The tongue tip taste test
Exhibit 4-1 Logon SP screen
4-2 ISIS screen characteristics
4-3 Screening questions
4-5 gLMS Introduction and Practice Screen
4-6 gLMS Light Standards Testing Screen
4-7 Tongue Tip Taste Test screen
4-10 Odor Identification screen – item 1
4-11 Odor Identification screen – item 2
4-12 Odor Identification screen – item 3
4-13 Odor Identification screen – item 4
4-14 Odor Identification screen – item 5
4-15 Odor Identification screen – item 6
4-16 Odor Identification screen – item 7
4-17 Odor Identification screen – item 8
4-18 Replicate Whole Mouth Taste Test “A”
4-19 Replicate Whole Mouth Taste Test “B”
4-20 SP’s understanding of the test screen
4-21 Component status screen – Complete
4-22 Component status screen – Partial
4-23 Component status screen – Not Done
4-24 Soft Edit Warning
4-25 Soft Edit Description of Taste
4-26 Soft Edit Label Preference
4-27 Hard Edit Exclusion Questions
4-28 Hard Edit Screening Questions
4-29 Hard Edit gLMS
5-1 Quality Control Checks
5-2 Start of Stand QC Checks
5-3 Start of Session QC Checks
5-4 Daily QC Checks
5-5 End of Session QC Checks
5-6 End of Stand QC Checks
5-7 Quality Control Checks – Not Done QC
1.1 Background of Taste and Smell Perception The vast majority of people with smell and taste disorders have problems with smell, not taste. Smell plays the most important role in appreciating flavors in eating. Common “tastes” such as chocolate, coffee, strawberry, apple, peach, pizza, steak sauce, and chicken actually reflect smellmediated sensations: odors from chewing food are released and propelled upwards towards the olfactory receptors via the posterior nasal pharynx. Taste buds, located mainly on the tongue surface, palate, and oropharynx, are primarily responsible for mediating sweet, sour, bitter, salty, and metallic sensations. The roles of the taste system include: (1) triggering digestive reflex systems that alter secretions of saliva, stomach acid, and pancreatic juices; (2) enhancing the feelings of pleasure and satiety when eating; and (3) enabling the determination of the quality of sampled foodstuffs and distinguishing nutrients, which usually taste “good” (e.g., sweet) from potential toxins, which usually taste “bad” (e.g., bitter). Although not usually appreciated, taste dysfunction can alter food choices and patterns of consumption, producing weight loss, malnutrition, and in some cases impaired immunity and even death. In someone who is hypertensive or diabetic, taste loss can lead to a dangerous tendency to overcompensate for the loss of a sense of taste by adding additional salt or sugar to the food.
The sense of smell is mediated by specialized smell receptor cells of the nasal cavity. These smell receptors, unlike the receptors of most sensory systems, are directly exposed to the outside environment, except for a thin protective layer of mucus, making them relatively susceptible to damage from such exogenous agents as viruses, bacteria, pollutants, and airborne toxins. A number of factors influence the function of smell in “normal” individuals. These include age, gender, and smoking habits, among others. Of these three, aging is by far the most important. Medical treatments and the use of medications and drugs have also been shown to profoundly affect the sense of smell.
1-1 22.214.171.124 Olfactory (Smell) System The olfactory system is able to recognize a great variety of odors or substances and discriminate subtle differences between chemicals. The primary olfactory receiving center of the brain is the “olfactory bulb.” After processing in the olfactory bulb, physiological signals for smell are delivered directly to the olfactory areas in the brain.
The nasal passages are complex, dynamic channels for breathing and smell detection. The inside of the nasal passages are covered with mucus membranes.2 The location of the smell receptors in the nasal passages is shown in Figure 1-1. This illustration shows maps of the nasal lining illustrated with plus (+) signs of the location where biopsy specimens contained olfactory epithelium or fasicles of the olfactory nerve indicate the location of olfactory mucosa smell receptors. The minus (-) signs indicate that no olfactory epithelium or nerve was found.
The numbers and the distribution of smell receptors in the nasal passages are known to vary within and between individuals. Factors such as chemical exposure, bacterial and viral infection, and head trauma may affect the distribution and it has been shown that the olfactory epithelium decreases with age.
1-2 1.2.2 The Sense of Taste Taste or gustation is one of the two main chemical senses. Humans detect taste with taste receptor cells. These are clustered in taste buds which are not visible to the naked eye. Most of them are buried in specialized structures called papillae on specific parts of the tongue. These papillae give the tongue its bumpy appearance. Most of the bumps are filiform papillae but there are other types of papillae. The papillae on the tongue have no taste function. Filiform papillae come in different shapes. In the cat, they are shaped like tiny spoons with sharp edges. They help the cat lap up liquids. The filiform papillae on our tongues do not have these sharp edges. Thus, if we try to lap fluids from a dish, we will find it to be a tiring task. The taste buds themselves are distributed in a line across the roof of the mouth and in papillae distributed in an oval on the surface of the tongue. Normally we have no subjective awareness of this distribution of taste buds.
Taste cells have a limited life span. After a few days they die and are replaced by new cells.
This constant renewal allows the taste system to recover from a variety of sources of damage and explains why our taste systems tend to remain robust even into old age.
126.96.36.199 Transduction and the Four Basic Tastes The first event in the sensation of taste is the contact between a substance to be tasted (the “tastant”) and a site on the microvillus that extends from the taste receptor cell. The signal that is generated by this contact is called a “transduction.” Transduction mechanisms are very different for different tastes. We can divide the transduction mechanisms into two groups: salty and sour acids versus bitter and sweet. Salts and sour acids are made up of charged particles; bitter and sweet stimuli have particular molecular shapes that fit complementary shapes on the microvilli of the taste cells.
There are four “basic tastes” (sweet, salty, bitter, and sour). Sweet is the taste of the sugars that are biologically useful to us (sucrose, fructose, and glucose); the sweet taste of mother’s milk may serve to produce suckling immediately after birth before an infant has had time to learn the consequences of ingesting milk. Salty is the taste of sodium, a mineral that must be available in relatively large quantities to maintain nerve and muscle function; loss of body sodium leads to a swift death. Bitter is the taste of many poisons. Sour is the taste of acid that in high enough concentrations can damage tissue.
1-3 When we consider the functions that taste performs, we can see how important that coding is. If taste mixtures behaved as do color mixtures, we would have a problem. For example, pure salt is not often found in nature. The ability to analyze a mixture to detect the presence of salt is critical to survival.
Similarly, poisonous plants contain components with a variety of tastes; if bitterness were to synthesize with those other tastes, we could not identify it and thus avoid the poison. The functions of the four tastes are well served by keeping them independent of one another.
Adaptation, a powerful phenomenon in taste also operates to maintain the separation of the four tastes. Perhaps one of the best demonstrations of taste adaptation is our own saliva. For example, if we rinse our mouths with distilled water and then taste a salt solution of the same salt content that saliva has, the solution tastes salty. But normally we are adapted to the same concentration of salt in our saliva so we do not taste it; we only taste saltiness from concentrations above that to which we are adapted.
188.8.131.52 Genetic Differences in the Ability to Taste
Part of the ability to detect bitter tastes is genetically determined. The best example of this is the ability to taste phenylthiocarbamide (PTC) which has been used for many years in taste studies. There is natural variation in the ability to taste PTC in the population – some people cannot taste it, some are average tasters, and some are extremely sensitive to it (“supertasters”). In modern taste testing studies, a chemical relative of PTC that was safer to test, 6-n-propylthiouracil (“PROP” or “PTU”) is used instead of PTC. Taste studies have shown that tasters may be more finicky eaters (they do not like bitter-tasting foods as much as nontasters) and there may be a relationship between taster status, obesity, and health.
Also, there is some research that links genetic variation in bitter taste preference to preferences for sweet and fat in foods.
1.3 Medical Disorders of the Chemosenses
Individuals with taste and smell impairments may be at increased risk of health and nutritional problems and also at risk of safety problems from fire and gas explosions. Many factors contribute to taste and smell impairments, such as medications/drugs, radiation therapy, unhealthy habits (cigarette smoking), head trauma, chronic sinusitis and rhinitis, and some toxic environmental exposures.
The most common causes of permanent smell loss are upper respiratory infections, head trauma or injury, and chronic rhinosinusitis. Although the data are limited, these causes account for the majority of patients who present to physicians with chemosensory problems. Other less common causes of smell loss include chronic alcoholism, epilepsy, and neurological disorders such as multiple sclerosis, Alzheimer’s disease, and Parkinson’s disease. There is some literature to suggest that smell testing of persons who may be at risk for Alzheimer’s disease may be a predictor of who later will be clinically diagnosed with that disease.
Exposure to a number of toxic chemicals can induce smell loss. Olfactory loss can occur as a result of exposure to air pollution and to chemical exposures in the workplace. In addition to directly damaging the smell receptors, some chemicals may produce damage indirectly by inducing upper respiratory inflammatory responses or infections that, in turn, cause damage. The best scientifically documented examples of smell loss due to chemical exposures in humans are for acrylates, methacrylates, and cadmium. It should be noted that tobacco smoke is known to have a high amount of cadmium.
1.3.2 Disorders of Taste
The most debilitating taste disorders are those in which there is a persistent, chronic bad taste in the mouth, such as a bitter, salty, or “metallic” taste. The causes of this fall into two broad categories: (1) cases where an abnormal substance actually gains access to the mouth, and (2) “taste phantoms” that occur when there is nothing in the mouth. Taste phantoms originate in the brain itself.