Peduncular hallucinosis is an uncommon neurological symptom characterised by vivid, well formed visual hallucinations.
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 1.
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 1. Essentially any lesion in this area can be causative, including ischaemic (most common), hemorrhagic lesions, vascular malformations and tumours 1-2.
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.
- 1. Talih FR. A probable case of peduncular hallucinosis secondary to a cerebral peduncular lesion successfully treated with an atypical antipsychotic. Innov Clin Neurosci. 2013;10 (5-6): 28-31. Free text at pubmed - Pubmed citation
- 2. Manford M, Andermann F. Complex visual hallucinations. Clinical and neurobiological insights. Brain. 1998;121 ( Pt 10) (10): 1819-40. doi:10.1093/brain/121.10.1819 - Pubmed citation