James Dolbow, DO PGY-3 Neurology Resident Case Western Reserve University University Hospitals Cleveland Medical Center Cleveland, Ohio
Sean Duke, MD PGY-4 Neurology Resident Case Western Reserve University University Hospitals Cleveland Medical Center Cleveland, Ohio
Neel Fotedar, MD Staff Epileptologist Epilepsy Center, Neurological Institute University Hospitals Cleveland Medical Center Cleveland, Ohio Assistant Professor Department of Neurology Case Western Reserve University School of Medicine Cleveland, Ohio ORCID ID 0000-0003-0424-7767
Disclosures The authors report no financial relationships with any companies whose products are mentioned in this article, or with manufacturers of competing products.
Simple visual auras have a very high localizing value to the occipital lobe. The primary visual cortex (Brodmann area 17) is situated in the banks of calcarine fissure and activation of this region produces these simple hallucinations. If the hallucinations are consistently lateralized, the seizures are very likely to be coming from the contralateral occipital lobe.
Visual hallucinations in brain tumors
In general, a tumor anywhere along the optic path can produce visual hallucinations; however, the exact causal mechanism of the hallucinations is unknown. Moreover, tumors in different locations—namely the occipital lobes, temporal lobes, and frontal lobes—appear to produce visual hallucinations with substantially different characteristics.27-29 Further complicating the search for the mechanism of these hallucinations is the fact that tumors are epileptogenic. In addition, 36% to 48% of patients with brain tumors have mood symptoms (depression/mania), and 22% to 24% have psychotic symptoms (delusions/hallucinations); these symptoms are considerably location-dependent.30-32
Content and associated signs/symptoms. There are some grouped symptoms and/or hallucination characteristics associated with cerebral tumors in different lobes of the brain, though these symptoms are not specific. The visual hallucinations associated with brain tumors are typically confined to the field of vision that corresponds to the location of the tumor. Additionally, many such patients have a baseline visual field defect to some extent due to the tumor location.
In patients with occipital lobe tumors, visual hallucinations closely resemble those experienced in occipital lobe seizures, specifically bright flashes of light in colorful simple and complex shapes. Interestingly, those with occipital lobe tumors report xanthopsia, a form of chromatopsia in which objects in their field of view appear abnormally colored a yellowish shade.26,27
In patients with temporal lobe tumors, more complex visual hallucinations of people, objects, and events occurring around them are often accompanied by auditory hallucinations, olfactory hallucinations, and/or anosmia.28In those with frontal lobe tumors, similar complex visual hallucinations of people, objects, and events are seen, and olfactory hallucinations and/or anosmia are often experienced. However, these patients often have a lower likelihood of experiencing auditory hallucinations, and a higher likelihood of developing personality changes and depression than other psychotic symptoms. The visual hallucinations experienced in those with frontal lobe tumors are more likely to have violent content.29
Continue to: Visual hallucinations in migraine with aura
