Neural Changes in Patients with Post-Traumatic Anosmia: Insights from Resting-State fMRI

Area of Science:

• Neuroscience
• Neuroimaging
• Olfactory Disorders

Background:

• Traumatic brain injury (TBI) frequently causes anosmia (loss of smell).
• Anosmia is a common consequence of severe head trauma.
• Investigating brain changes in anosmia is crucial for understanding TBI sequelae.

Purpose of the Study:

• To examine functional connectivity (FC) changes in patients with post-traumatic anosmia (PTA).
• To compare FC networks in PTA patients versus healthy controls (HCs) using resting-state fMRI (rs-fMRI).

Main Methods:

• Retrospective rs-fMRI study on 44 PTA patients and 43 HCs.
• Olfactory function assessed using the Sniffin' Sticks test.
• Seed-based Analysis (SBA) and Independent Component Analysis (ICA) were performed.

Main Results:

• PTA patients had significantly lower olfactory function (TDI scores) than HCs.
• SBA showed increased FC in anterior cingulate cortex, piriform, insular, and prefrontal areas in PTA patients.
• ICA revealed widespread increased FC in PTA patients, including frontal pole, cerebellum, putamen, and amygdala.
• Global brain network efficiency correlated with olfactory performance in PTA patients.

Conclusions:

• Neural deficits in post-traumatic anosmia extend beyond primary olfactory regions.
• SBA and ICA effectively characterize higher-order brain network alterations in PTA.
• rs-fMRI provides valuable insights into the neural underpinnings of olfactory dysfunction after head trauma.