xRead - Olfactory Disorders (September 2023)

20426984, 2022, 4, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/alr.22929, Wiley Online Library on [04/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

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INTERNATIONAL CONSENSUS ON OLFACTION

Value judgments : Nuclear medicine studies provide interesting results and seem promising; however, there are fewer studies in comparison to MRI. Moreover, they require the use of radioisotopes, some of which are not routinely available. For a majority of clinical centers, the gold-standard MRI is probably more accessible and has less potential harm. Policy level :Option. Intervention : Currently, MRI remains the gold stan dard to evaluate patients with OD. Nuclear medicine tech niques can be considered in particular cases or when MRI is not accessible or feasible (contraindications to MRI). It is well established that patients have difficulty in assess ing the degree of their own OF. Self-ratings of smell function only rarely correlate well with quantitative mea sures of such function, with some patients believing they have severe loss when this is not the case and other patients being completely unaware of significant dysfunc tion until being tested. 49,312,316,549,564,697,1095–1099 Among variables that accentuate such discrepancies are older age and poorer cognition. 543 Clearly, reliable and valid tests are needed to accurately define a patient’s function, estab lish efficacy of medical or surgical interventions, aid in dif ferential diagnosis, and detect malingering. Unlike hear ing, balance, and vision testing, insistence on short olfac tory tests has been traditionally the clinical norm, in many cases sacrificing sensitivity for expediency. Types of olfactory tests employed clinically This review focuses solely on psychophysical tests, ie, tests that require a conscious response on the part of the patient and which relate private sensory experiences to antecedent physical stimulus properties. Papers that trans late or change extant tests to other languages/cultures without significant alterations are not included, nor are tests focused on hedonics. Studies earlier than the 20th century are not considered. Electrophysiological measures are not reviewed. Their use in clinic settings has been lim ited, given their current high cost, space requirements, and the need for trained personnel and relatively long test sessions. Moreover, they have yet to add insight into a patient’s chemosensory disturbance. For example, they often do not detect function in patients with demonstrated psychophysical OF. 1100 Imaging can be useful, although its C Use of validated quantitative smell tests

applications are beyond the scope of this section of the document. A large number of psychophysical olfactory tests have been introduced into the clinical literature and a num ber are well established, practical, and have a strong scientific basis. Based on test length, complexity, and administration time, they can be divided into “very brief tests” (ie, < 5-minute administration time; Table VIII.6), “moderately brief tests” (ie, 6–15 minutes of administra tion time; Table VIII.7), and “longer tests” ( > 15 minutes of administration time; Table VIII.8). Because administra tion time can be influenced by the time patients spend in making decisions and other factors, these categories are heuristic and overlap in many instances. Moreover, a num ber of tests are self-administered so that their administra tion times are less critical from a practice management perspective. Very brief tests are often used as simple screening tests that take only a few minutes to administer. They only sug gest dysfunction and, when positive, should be followed by longer, more reliable, definitive tests. In most cases, nor mative data, per se, are lacking for such tests, although cut off values for defining abnormality are commonly noted. Some longer tests can differentiate degrees of dysfunc tion, eg, anosmia, severe microsmia, moderate microsmia, mild microsmia, and normosmia, and have normative data based on age and sex. Short tests cannot make such fine distinctions. Decisions regarding which tests to use depend on the purpose of the intended test (eg, for brief screening, more definitive clinical conclusions, research). Odorant presentation procedures range from simple “scratch & sniff” microencapsulated odorant labels, sniff bottles, atomizers, squeeze bottles, injection devices, and odorized wands, pens, and strips of filter paper dipped in odorant solutions to sophisticated olfactometers, includ ing ones that automatically vary stimulus concentrations relative to patient responses. Both tests of baseline sensi tivity (eg, odor detection and recognition threshold tests, signal detection tests) and tests of suprathreshold function (eg, tests of odor identification, discrimination, memory, hedonics, and build-up of odor intensity as odorant concentration increases) have been described in detail in the clinical literature, with a number being commercially available. Each type of test has strengths and weaknesses. Moreover, as described below, some tests have been applied to, and in some cases specifically designed for, children (Table VIII.9). Concerns regarding sanitation suggest that some stimulus presentation procedures, most notably open sniff bottles, can be contaminated by succes sive uses by different patients, a consideration in the age of COVID-19.