Effects of olfactory training on posttraumatic olfactory dysfunction: a systematic review and meta-analysis.
Level 2 - randomized trial
Systematic review and meta-analysis of predominantly non-randomized or uncontrolled interventional studies
PubMed 33486898 · doi:10.1002/alr.22758
What was done
Authors conducted a systematic review across PubMed, Embase, Cochrane Library, and Web of Science to assess olfactory recovery after olfactory training in patients with posttraumatic olfactory dysfunction. From 812 screened abstracts, 13 full-text articles met criteria, and 6 were included in quantitative meta-analysis. Clinically significant improvement was defined as a threshold, discrimination, and identification (TDI) score improvement ≥6 or University of Pennsylvania Smell Identification Test (UPSIT) score improvement ≥4.
What was found
Across the 6 meta-analyzed studies, 36.31% (95% CI, 0.28 to 0.45) of posttraumatic patients achieved clinically significant improvement after olfactory training, with a pooled mean increase in TDI score of 4.61.
Why it matters
Posttraumatic smell loss has few evidence-based treatment options; this meta-analysis indicates that structured olfactory training yields clinically relevant recovery in over a third of patients.
Limits
The abstract does not report the total participant count. Most included studies lacked control groups, limiting the ability to differentiate training effects from spontaneous neural recovery. Subcomponent-specific outcomes were not resolved.
Cited by
- supports Smell training protocols involving repeated deliberate sniffing of specific odors can improve olfactory acuity and assist recovery after olfactory loss or injury.