Peduncular hallucinosis

Peduncular hallucinosis is an uncommon neurological symptom characterized by vivid, well formed visual hallucinations.

Clinical presentation

The visual hallucinations are sterotyped, vivid and tend to not cause the patient significant distress. Additional symptoms include difficulty sleep at night with resultant hypersomnia during the day. Oculomotor abnormalities are also encountered .

Radiographic features

Causative lesions are typically in the rostral brainstem (especially cerebral peduncle as the name suggests) but may also be seen in the thalamus, pons and basal diencephalon . Essentially any lesion in this area can be causative, including ischemic (most common), hemorrhagic lesions, vascular malformations and tumors .

Although CT may give a clue as to the presence of an abnormality in the region, MRI is the modality of choice of assessing patients with suspected peduncular hallucinosis.