xRead - Olfactory Disorders (September 2023)

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INTERNATIONAL CONSENSUS ON OLFACTION

TABLE IX-16 (Continued) Study

Year LOE Study design

Study groups

Clinical end point CCCRC olfactor test

Conclusions Compared with placebo,

Meltzer

1998 2

RCT

MixedAR(n = 121) MFNS Placebo

et al 1369

Mometasone group demonstrated significantly greater improvement in identification on CCRC beclomethasone drops demonstrated significant improvement in subgroup in patients with initial subjective olfactory impairment

Golding-wood et al 1370

1996 4

Case series

MixedAR(n = 25) Beclomethasone nasal drops

UPSIT R VAS

Compared with baseline, the

AR = allergic rhinitis; AZE = azelastine hydrochloride; CCCRC = Connecticut Chemosensory Clinical Research Center; FP = fluticasone propionate; LOE = level of evidence; MF = mometasone furoate; NS = nasal spray; OF = olfactory function; QOL = quality of life; RCT = randomized controlled trial; SS = Sniffin’ Sticks; SS-TDI = Sniffin’ Sticks threshold, discrimination, identification combination; UPSIT R = University of Pennsylvania Smell Identification Test; VAS = visual analog scale.

with posttraumatic anosmia (oral steroid pulse over 15 days) or PD (rasagiline). There is anecdotal data from a case report that olanzapine can mitigate parosmias and improve objective smell function in a patient with olfac tory reference syndrome. 1481 An aerobic exercise program stabilized the UPSIT R score over 8 weeks relative to no exercise, although regression to the mean may account for this result. 1482 The available evidence on OT is limited to neurode generative disease and is composed of two prospective cohort studies and one clinical trial. While these stud ies demonstrate improvement in subjective measures of olfaction following smell training, the data on objective measures are mixed. 246 One study of patients with PD tested OT of the test odors versus no training with same day and 1- to 2-month follow-up. Significant improve ment was noted in odor identification in the trained group versus nontrained PD group at both the same day and 1- to 2-month follow-up. 1483 Performance on other odor tasks or identification of nontrained odors were not assessed. A recent meta-analysis of smell train ing found no significant improvement in smell func tion caused by PD, although there was a trend towards improvement in odor discrimination. 1484 Smell train ing improved OF, which is associated with structural changes in the olfactory processing regions of the brain, in healthy individuals. 1485 While further high-level stud ies are needed, smell training may be recommended in a patient with OD related to intracranial disease, neurochemistry/neurotransmitter, and neurodegenerative

disease. Much of the available olfactory literature includes prospective cohort studies or retrospective case series that focus on OF as a diagnostic for neurodegenerative disease. Evidence for smell training and medical treatment for smell dysfunction in intracranial, neurochem istry/neurotransmitter, and patients with neurodegener ative diseases requires further study with double-blinded trials to determine their efficacy. In the interim, empiric smell training protocols appear to be safe and can be considered in the appropriate clinical text for subjective and objective improvement, while patients undergo the specific medical or surgical treatments available for their specific underlying intracranial etiology. Smell training therapy for OD in intracranial, neurotransmitter, and neurodegenerative disease Aggregate grade of evidence : C (Level 3: two studies). Benefit : Smell training may improve subjective and objective measures of olfaction in patients with neurode generative disease–caused smell loss. Harm : Very low. Very small risk of allergy to smells in training kit. Direct: Small up-front monetary costs associated with assembly of smell training kit and tests to assess progress. Indirect: Time required for procedure. Benefits-harm assessment : Benefit over harm, partic ularly in patients with PD. Value judgments : As part of a shared decision-making process with patients, it is reasonable to recommend smell