Peduncular hallucinosis
Peduncular hallucinosis | |
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Other names | Lhermitte's peduncular hallucinosis |
basilar migraine, basilar vascular hypoplasia, and following regional surgical or angiographic interventions.[1] |
Peduncular hallucinosis (PH) is a rare neurological phenomenon that causes vivid visual hallucinations that typically occur in dark environments and last for several minutes. Unlike some other kinds of hallucinations, the hallucinations that patients with PH experience are very realistic, and often involve people and environments that are familiar to the affected individuals. Because the content of the hallucinations is never exceptionally bizarre, patients can rarely distinguish between the hallucinations and reality.[2]
In 1922, the French
The accumulation of additional cases by Lhermitte and by others influenced academic medical debate about hallucinations and about behavioral neurology. Lhermitte provided a full account of his work in this area in his book "Les hallucinations: clinique et physiopathologie," which was published in Paris in 1951 by Doin publishing. Contemporary researchers, with access to new technologies in medical brain imaging, have confirmed the brain localization of these unusual hallucinations.
Signs and symptoms
The hallucinations are normally colorful, vivid images that occur during wakefulness, predominantly at night.
Cause
Peduncular hallucinosis is attributed to a range of various pathologies such as vascular and infectious midbrain, pontine and thalamic lesions, local subarachnoid
Lesions
The lesions that disturb brainstem reticular formation or thalamic targets seem to be the source behind peduncular hallucinosis.
The effect lesions on the brainstem have on the ascending reticular activating system (ARAS) has also been hypothesized. It was proposed that since the ARAS plays a role in consciousness and waking, the lesions of the brainstem common to peduncular hallucinosis may “disrupt ARAS impulses from the brainstem reticular formation” and, as a consequence, lead to the sleep disturbances characteristic of peduncular hallucinosis.[6] The use of drugs such as Olanzapine may help treat sleep disturbances as it has been found to “improve sleep continuity, sleep quality, and [to] increase slow wave sleep.”[6]
Correlation between other diseases
People diagnosed with Parkinson's disease, narcolepsy-cataplexy syndrome, delirium tremens, Lewy body dementia, and temporal lobe epilepsy are more prone to complex visual hallucinations such as peduncular hallucinosis.[1] Peduncular hallucinosis is more common in patients with a long duration of Parkinson's disease and also with a long treatment history, depression, and cognitive impairment.[4] Paranoid delusions are common in these patients even though the hallucinations can occur during clear sensorium.[4]
Differences from other visual hallucinations
Other visual hallucinations tend to stem from psychological disorders. Whereas a person with a psychological disorder thinks their hallucinations are real, people with peduncular hallucinosis normally know that the visual hallucinations they see are not real. Peduncular hallucinations are independent of
Diagnosis
Diagnosis can be made by multimodal approach such as by detailed history regarding sleep pattern, vividness of images, intact reality testing, and association of any brain pathology particularly brain stem areas, pons, and mid brain,[clarification needed] evidence of any tumor, parkinsonism, Lewy body dementia.[citation needed]
Treatment
Treatment of any kind of complex visual hallucination requires an understanding of the different pathologies in order to correctly diagnose and treat. If a person is taking a pro-hallucinogenic medication, the first step is to stop taking it. Sometimes improvement will occur spontaneously and
More invasive treatments include corrective surgery such as
History
The first documented case of peduncular hallucinosis was by French neurologist and neuropsychiatrist Jean Lhermitte, which described a 72-year-old woman’s visual hallucinations.
References
- ^ S2CID 12151224.
- S2CID 25990312.
- ^ a b c d Kumar, R., Wahi, J., Banerji, D., & Sharma, K. (1999). Peduncular Hallucinosis: An Unusual Sequel to Surgical Intervention in the Suprasellar Region. British Journal of Neurosurgery, 13(5), 500-503.
- ^ a b c Benke, T. (2006). Peduncular Hallucinosis - a Syndrome of Impaired Reality Monitoring. Journal of Neurology, 253(12), 1561-1571.
- ^ a b c FEINBERG W, M., & RAPCSAK S, Z. (1989). Peduncular Hallucinosis Following Paramedian Thalamic Infarction. Neurology, 39(11), 1535-1536.
- ^ a b c d Spiegel, D., Eastern Virginia Medical School Dept. of Psychiatry, interviewed by C. Byars, Oct. 12, 2009.
- ^ Howlett, D., Downie, A., Banerjee, A., Tonge, K., & Oakeley, H. (1994). MRI of an Unusual Case of Peduncular Hallucinosis (Lhermitte's Syndrome). Neuroradiology, 36(2), 121-122.
External links
- Lhermitte's Peduncular Hallucinosis: An historical perspective (broken link, Wayback archive version) Anthony H. Risser and Frank C. Powell: Lhermitte's Peduncular Hallucinosis - An historical perspective. Paper presented at the 45th Meeting of the American Academy of Neurology. New York, 1993.