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

597

PATEL et al.

TABLE IX-29 (Continued) Study Year

LOE Study design

Study groups

Clinical end point SS-TDI Thresholds for other odors

Conclusions

TDI improved by 2.4 for OT vs –0.6 for controls Thresholds for all 4 odors improved and discrimination also improved in the OT group Significant difference in OT TDI vs controls Thresholds improved, but not discrimintion or identification scores 28% in the OT group met MCID vs 6% in controls

Haehner et al 1486

2013

3

Prospective cohort

70 patients with PD COT(n = 35) Controls (n = 35) for 12 weeks

Hummel et al 1539

2009

3

Prospective cohort

56 patients with PIOD(n = 35),

SS-TDI PEA odor thresholds

PTOD(n = 7), or IOD(n = 14)

COT(n = 40) Controls (n = 16) for 12 weeks

BAST-24 = Barcelona Smell Test-24; COT = classic olfactory training; EBRR = evidence-based review with recommendation; EOG = electro-olfactogram; IOD = idiopathic olfactory dysfunction; LOE = level of evidence; MCID = minimum clinically important difference; MRI = magnetic resonance imaging; NS = not significant; OBV = olfactory bulb volume; OD = olfactory dysfunction; OT = olfactory training; PEA = phenylethyl alcohol; PIOD = postinfectious olfactory dysfunction; PTOD = posttraumatic olfactory dysfunction; RCT = randomized controlled trial; SS-TDI = Sniffin’ Sticks threshold, discrimination, identification combination; TDI = threshold, discrimination, and identification; UPSIT R = University of Pennsylvania Smell Identification Test; UPSIT R -TC = Chinese version of the University of Pennsylvania Smell Identification Test; VAS = visual analog scale.

with a modest further improvement over the following 9 months for those who continued to train. Those in the short-term group maintained their benefit without further training. At the end of the study, 71% in the long-term group met MCID thresholds for TDI, versus 58% for the short-term training group and 37% in the control group. Adherence to therapy has been shown to be a challenge. 250 Fornazieri et al 1551 found an adherence rate of 88% after 3 months and 56% after 6 months. By making OT more con venient, Saatci et al 1546 demonstrated improved adherence with an OT ball (56% versus 30%) over 12 weeks. Overall, all 22 studies reported some improvement with OT. A wide variety of odors have been reported to be effec tive and are most effective with good adherence to therapy for a longer duration of time. The degree of recovery in all studies is modest, just meeting the threshold for an MCID difference. Only four studies had randomized controls, and blinding patients to therapy remains a challenge. OT for patients with OD Aggregate grade of evidence : B (Level 1: five studies; Level 2: eight studies; Level 3: nine studies). Benefit : Modest improvement in objective olfactory measures (UPSIT R score, TDI score, discrimination and identification) and subjective perception of olfaction. Harm : Low: Expense of odorants, inconvenience of dailyOT. Cost : Ranges from minimal to high. Minimal cost for household items to $40 USD for commercially available

kits. Individual essential oils can cost as low as $1 per bottle to upwards of $150. Benefits-harm assessment : Preponderance of bene fit over harm given low risk potential and established improvement in clinical trials. Expectations for recovery should be tempered. Value judgments : As an adjunctive therapy, OT can empower patients struggling with anosmia and provide some hope for olfactory recovery during a difficult adjust ment period. Value is high. Policy level : Recommendation. Intervention : OT is recommended in conjunction with other treatments for olfactory loss and should be started as soon as olfactory loss is identified. Further investigation into odorants (number and type), duration, and frequency is warranted. 3 Intranasal sodium citrate Sodium citrate, a solution licenced and used safely in other body cavities (eg, stomach and bladder) is known to buffer calcium ions (Ca 2 + ) and reduce mucosal Ca 2 + . Intranasally, sodium citrate is able to sequester calcium ions. This is thought to reduce free mucosal calcium with subsequent reduction in negative feedback and increasing sensitivity to odorants. Recent systematic reviews have highlighted sodium cit rate as a potential treatment modality in PIOD 374 and