Post-Stroke Olfactory Dysfunction: Network Mechanisms, Clinical Consequences, and Rehabilitation

Abstract

Stroke is the second leading cause of death after ischemic heart disease, accounting for 10% of all deaths worldwide. Stroke is also a major cause of long-term neurological disability, yet olfactory dysfunction remains an underrecognized consequence of cerebrovascular injury. Smell is rarely evaluated in stroke patients despite its central role in appetite, hedonia, hazard detection, memory, emotional processing, and quality of life. The olfactory system extends from the olfactory epithelium and olfactory bulb to primary olfactory cortex, limbic regions, orbitofrontal cortex, insula, thalamus, hippocampus, broader fronto-limbic networks and cerebellum. The broad anatomical organization of the olfactory system subjects it to frequent perturbation due to stroke or other lesions. Post-stroke olfactory deficits may result from direct injury to olfactory structures, disruption of higher-order olfactory networks, diaschisis, altered sniffing and sensorimotor control, or secondary degeneration. Clinically, these deficits are manifested as hyposmia, anosmia, impaired odor identification, discrimination and memory, altered odor pleasantness, reduced flavor perception, loss of appetite, or reduced odor-guided behavior. Current evidence indicates that olfactory dysfunction can persist into the chronic phase of stroke, although a single prevalence estimate cannot be established because populations, timing, testing methods, and reporting differ substantially across studies. This narrative review provides an overview of stroke-related olfactory dysfunction, emphasizing olfactory pathway anatomy, lesion-relevant mechanisms, clinical consequences, measurement limitations, rehabilitation approaches, and future research priorities. We argue that post-stroke olfactory dysfunction should be understood as a multidimensional network-based disorder rather than a simple binary loss of smell.

The authors' abstract, as published at the source. Brain Sciences, 2026 · DOI ↗