Historically, it has been proposed that functional neurological symptoms occur more frequently on the left side of the body due to a distinct body representation and emotional processing of the right hemisphere, yet objective imaging data to support this are lacking. We aimed to investigate whether patients with acute left-sided symptoms (right hemisphere) suspected of having a minor stroke are more likely to show negative diffusion-weighted imaging (DWI) compared to those with right-sided symptoms.

Data are from the SpecTRA (Spectrometry for Transient Ischemic Attack Rapid Assessment) multicenter prospective cohort study conducted between 2013 and 2017. Patients with mild persistent unilateral hemiparesis and/or hemisensory symptoms (National Institute of Health Stroke Scale ≤ 3) and available DWI were included. The primary outcome was the proportion of patients with a negative DWI.

Of 1731 patients, 584 (30.8%) were included. Of these, 310 (53.1%) patients presented with left-sided symptoms and 274 (46.9%) with right-sided symptoms. Overall, 214 (36.6%) patients had a negative DWI, 126 (58.9%) with left-sided symptoms and 88 (41.1%) with right-sided symptoms: risk ratio (RR) 1.27 (95% CI = 1.02–1.57). Left-sided hemiparesis was associated with negative DWI (RR 1.42 [95% CI = 1.08–1.87]), while left-sided hemisensory symptoms were not (RR 1.11 [95% CI = 0.87–1.41]). There was no effect modification by age or sex on this association (Pinteraction 0.787 and 0.057, respectively).

Unilateral left-sided neurological symptoms were more frequently associated with negative DWI compared to right-sided symptoms in suspected minor stroke patients. This observation is exploratory, as the final diagnosis in DWI-negative cases was not established.