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Instrument Function assessed Substances used Protocol Advantages Disadvantages Brief or Cross-Cultural Smell Identification Test83 Identification Banana, chocolate, cinnamon*, gasoline, lemon, onion, paint thinner, pineapple, rose, soap, smoke, turpentine Derived from the UPSIT. Using microencapsulated odorants, subjects progress through 12-item multiple-choice test for 12 odors Requires less time, cost efficient
Can be self-administeredLess thorough evaluation Pocket Smell Test69 Identification Lemon, lilac, smoke Derived from the UPSIT. Using microencapsulated strips, subjects progress through 3-item multiple-choice test for 3 odors. Requires less time, cost efficient
Can be self-administeredLess thorough evaluation Q-Sticks84 Identification Cloves*, coffee, rose Using felt-tip pens with odorants, subjects progress through 3-item multiple-choice test for 3 odors. Can be self-administered Less thorough evaluation Quick Smell Identification Test85 Identification Chocolate, banana, smoke Using microencapsulated odorant strips, subjects progress through 3-item multiple-choice test for 3 odors. Can be self-administered Less thorough evaluation University of Pennsylvania Smell Identification Test86 Identification Banana, bubble gum, cedar, cheddar cheese, cherry, chocolate, cinnamon*, cloves*, coconut, dill pickle, fruit punch, gasoline, gingerbread, grape, grass, leather, lemon, lilac, lime, licorice, menthol*, mint, motor oil, natural gas, onion, orange, peach, peanut, pine, pineapple, pizza, root bear, rose, smoke, soap, strawberry, thinner, turpentine, watermelon, wintergreen* Using scratch and sniff scented strips, subjects progress through 40-item multiple-choice test for 40 odors. High sensitivity and reliability; extensive normative data
Can be self-administeredMore time intensive Snap & Sniff Threshold Test87 Threshold PEA, dilutions ranging from 10−2 (strongest) to 10−9 (weakest) volume/volume concentrations The kit contains 20 smell “wands.” Five contain no smell, while the other 15 contain PEA dilutions. Examiners plan the wand under subjects' noses and briefly present the dilution scent. A single staircase forced-choice paradigm is recommended. Time efficient, rapid assessment of general olfactory function
Newer test but recently validatedLess thorough evaluation – only evaluates detection threshold Alcohol Threshold Test88 Threshold Ethyl alcohol (10%, 25%, 50%, 70%, 96%) Examiners place 100 mL bottles with saline and with varying concentrations of ethyl alcohol under subjects' noses. The threshold scores of 1, 2, 3, 4, and 5 correspond to the weakest detectable alcohol concentrations of 10%, 25%, 50%, 70%, and 96%, respectively. The threshold score of 6 corresponds to participants not detecting 96% alcohol. Time efficient, rapid assessment of general olfactory function Less thorough evaluation
Requires clinician administrationSmell Threshold Test89 Threshold Polypropylene, PEA Examiners place 120 mL polypropylene squeeze bottles with mineral oil and varying concentrations of PEA in mineral oil under subjects' noses. The threshold is the mean of the last 4 of 7 staircase reversals. Less thorough evaluation
Requires clinician administration“Sniffin' Sticks”90 Identification, discrimination, threshold Apple, anise seed, banana, cinnamon*cloves*, coffee, fish, garlic*, lemon, licorice, orange, peppermint*, pineapple, rose, shoe leather, turpentine, n-butanol Using felt-tip pens with odorants, subjects progress through 16-item multiple-choice test of 16 odors for identification, triple forced choice for 16 pairs of odorants for discrimination, and the presentation of n-butanol in varying concentrations for threshold. Threshold was calculated as the mean of the last 4 of 7 staircase reversals. Enables testing of three smell domainsCan be self- or clinician-administered More time intensive Abbreviations: PEA, phenyl ethyl alcohol; UPSIT, University of Pennsylvania Smell Identification Test.
↵* Indicates potential olfaction and chemesthesis overlap.
Instrument Function assessed Substances used Protocol Advantages Disadvantages Whole mouth evaluation Taste sprays Identification Substances diluted in 100 mL distilled water: sweet (10g D-saccharose), sour (5g citric acid), salty (7.5g NaCl), bitter (0.025g quinine hydrochloride), and umami (4g MSU) Patients open mouth for spray application and close mouth as they identify flavor. Patients receive 1 point for each correctly identified taste. The score is graded 0 to 5. Indicates whether “suprathreshold” taste perception has been preserved, provides overall taste quality perception data, short time needed for testing, good reproducibility of results, long shelf life Examiners cannot test individual parts of the oral cavityRequires clinician administration “Sip and spit” tests Identification Patients imbibe flavors from cups or other vessels and then report on the detected flavor. Regional evaluation Taste strips Identification, threshold 20 taste-impregnated filter-paper strips presented in randomized order with taste qualities in increasing concentrations: sweet (0.4, 0.2, 0.1, 0.05 g/mL sucrose), sour (0.3, 0.165, 0.09, 0.05 g/mL citric acid), salty (0.25, 0.1, 0.04, 0.016 g/mL NaCl), bitter (0.006, 0.0024, 0.0009, 0.0004 g/mL quinine hydrochloride), and umami (0.25, 0.1, 0.04, 0.016 g/mL MSG) Patients identify the taste quality on a form. Patients receive 1 point for each correctly identified taste. The score is graded 0 to 20. An overall score ≤9 is considered hypogeusia. Allows examiners to test each side of the tongue independently, provides basic data on detection threshold and intensity of flavor, short time needed for testing, good reproducibility of results, long shelf life Certain areas of the tongue may be difficult to isolate or reach with strips or dropsRequires clinician administration Abbreviations: MSG, monosodium glutamate; MSU, monosodium urate; NaCl, sodium chloride.
Instrument Function assessed Substances used Protocol Advantages Disadvantages Stimuli lateralization108 Lateralization Benzaldehyde, eucalyptol Subjects were presented with two bottles, one for either nostril. Bottles are filled with chemicals dissolved in propylene glycol or propylene glycol alone. A 15 mL puff of air from each bottle is simultaneously administered into one nostril. Subjects report which nostril was presented with the stimuli. Simple administration, distinguishes olfactory function from chemesthesis Requires clinician administration, protocol requires ∼30 minutes per stimuli Odorant Detection Test110 Detection threshold, discrimination, identification, lateralization Camphor, diallyl sulfide, ethanol, eucalyptol, menthol, propranolol Using felt-tip pens with chemicals dissolved in propylene glycol, subjects progress through identification of the sensation quality and triple-forced-choice procedure for discrimination for the 6 chemicals. Threshold and lateralization were assessed with menthol. Threshold was calculated as the mean of the last 4 of 7 staircase reversals. Simple administration, similar protocol to Sniffin' Sticks Not validatedRequires clinician administration CO2 device111 Pain responsiveness CO2 stimuli with various durations (multiples of 50 ms) CO2 stimuli is provided through standard nasal cannula in 10 seconds intervals. With each interval, stimulus duration is increased by 50 ms until the subject pushes a button, indicating a painful sensation. Assesses “mass of a stimulus” rather than concentration Not validatedRequires clinician administration
