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Complex visual hallucinations. Clinical and neurobiological insights
Manford M, Andermann F.. Brain : a journal of neurology, 1998-10-01
Topic: Risk, prevention and care in population studies
Complex visual hallucinations may affect some normal individuals on going to sleep and are also seen in pathological states, often in association with a sleep disturbance. The content of these hallucinations is striking and relatively stereotyped, often involving animals and human figures in bright colours and dramatic settings. Conditions causing these hallucinations include narcolepsy-cataplexy syndrome, peduncular hallucinosis, treated idiopathic Parkinson's disease, Lewy body dementia without treatment, migraine coma, Charles Bonnet syndrome (visual hallucinations of the blind), schizophrenia, hallucinogen-induced states and epilepsy. We describe cases of hallucinosis due to several of these causes and expand on previous hypotheses to suggest three mechanisms underlying complex visual hallucinations. (i) Epileptic hallucinations are probably due to a direct irritative process acting on cortical centres integrating complex visual information. (ii) Visual pathway lesions cause defective visual input and may result in hallucinations from defective visual processing or an abnormal cortical release phenomenon. (iii) Brainstem lesions appear to affect ascending cholinergic and serotonergic pathways, and may also be implicated in Parkinson's disease. These brainstem abnormalities are often associated with disturbances of sleep. We discuss how these lesions, outside the primary visual system, may cause defective modulation of thalamocortical relationships leading to a release phenomenon. We suggest that perturbation of a distributed matrix may explain the production of similar, complex mental phenomena by relatively blunt insults at disparate sites.
Key findings
- (ii) Visual pathway lesions cause defective visual input and may result in hallucinations from defective visual processing or an abnormal cortical release phenomenon.
- These brainstem abnormalities are often associated with disturbances of sleep.
- We suggest that perturbation of a distributed matrix may explain the production of similar, complex mental phenomena by relatively blunt insults at disparate sites.
Why it matters
This paper proposes three mechanisms for complex visual hallucinations, including brainstem effects on cholinergic and serotonergic pathways that may also be involved in Parkinson's disease. It is a mechanistic discussion of hallucinations, not a study of treating, curing, or preventing Alzheimer's disease.
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Study details
- Evidence strengthLow
How this study scored 47/100
Published in a leading specialty journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Brain : a journal of neurology) |
| Journal's citation record | 4 / 4 | Brain: journal h-index 503 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 1998 — older than 20 years, still counted |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 6 / 7 | Cited 682 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 22.7 citations a year over 30 year(s) since 1998 |
| Impact for its field and year | 3 / 6 | Cited 5.7× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 4 other studies in this library |
| Still being cited | 2 / 4 | Cited 32 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Mark Manford: h-index 21 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Addenbrooke's Hospital: institution h-index 1,025 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 9798740) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 47 / 100 | — |
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Read the original
May need a subscription OpenAlex found no free copy of the full text (checked 6 Feb 1020), so the publisher may charge for it. The PubMed abstract is free.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Manford, M., & Andermann, F. (1998). Complex visual hallucinations. Clinical and neurobiological insights. Brain : a journal of neurology. https://doi.org/10.1093/brain/121.10.1819
Vancouver
Manford M, Andermann F. Complex visual hallucinations. Clinical and neurobiological insights. Brain : a journal of neurology. 1998. doi:10.1093/brain/121.10.1819. PMID: 9798740.
BibTeX
@article{manford1998-9798740,
author = {Manford, M. and Andermann, F.},
title = {{Complex visual hallucinations. Clinical and neurobiological insights}},
journal = {Brain : a journal of neurology},
year = {1998},
doi = {10.1093/brain/121.10.1819},
pmid = {9798740},
url = {https://doi.org/10.1093/brain/121.10.1819}
}
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