Uncinate seizures — MRCPsych Paper A MCQ

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ModerateNeuroanatomyUncinate seizuresMRCPsych Paper A

A 34-year-old man has recurrent focal seizures. Each begins with a brief unpleasant smell of burning rubber, followed by behavioural arrest and impaired awareness. Which brain region is most strongly implicated by this seizure semiology?

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Correct answer: C — Anterior mesial temporal region

Explanation lettering: E = shown as A · A = shown as B · B = shown as D · D = shown as E

C is correct. A stereotyped unpleasant olfactory aura followed by impaired awareness is characteristic of a focal temporal-lobe seizure and particularly implicates anterior mesial temporal structures, including the amygdala and adjacent olfactory cortex. Such episodes have traditionally been called uncinate seizures, although modern localisation should not imply that the anatomical uncus is invariably the sole symptomatogenic zone. The precentral hand area would produce focal motor phenomena affecting the contralateral hand. The cuneus is associated with visual symptoms, while pontine tegmental dysfunction produces brainstem signs rather than an isolated olfactory aura. The subcallosal cortex has limbic and olfactory connections but is not the best-supported localisation for this characteristic progression to impaired awareness.

Reference: Hirsch M et al. Ictal semiology in lateral temporal epilepsy: A systematic review and meta-analysis. Epileptic Disorders, 2026. https://pubmed.ncbi.nlm.nih.gov/41626773/