Complex visual hallucinations as the sole manifestation of symptomatic temporo-occipital lobe epilepsy due to old intracerebral hemorrhage

A Narrative Review of Visual Hallucinations in Migraine and Epilepsy: Similarities and Differences in Children and Adolescents

Since the earliest descriptions of the simple visual hallucinations in migraine patients and in subjects suffering from occipital lobe epilepsy, several important issues have arisen in recognizing epileptic seizures of the occipital lobe, which often present with symptoms mimicking migraine. A detailed quantitative and qualitative clinical scrutiny of timing and characteristics of visual impairment can contribute to avoiding mistakes. Differential diagnosis, in children, might be challenging because of the partial clinical, therapeutic, and pathophysiological overlaps between the two diseases that often coexist. Ictal elementary visual hallucinations are defined by color, shape, size, location, movement, speed of appearance and duration, frequency, and associated symptoms and their progression. The evaluation of the distinctive clinical features of visual aura in migraine and visual hallucinations in occipital epilepsy could contribute to understanding the pathogenetic mechanisms of these two conditions. This paper aims to critically review the available scientific evidence on the main clinical criteria that address diagnosis, as well as similarities and differences in the pathophysiological mechanisms underlying the visual impairment in epilepsy and migraine.

[Dural arteriovenous fistula causing complex visual hallucinations without an anopsia]

We report the case of a 76-year-old woman who presented with recurrent episodes of complex visual hallucinations in her right visual field without an anopsia. The electroencephalogram showed sharp transients in the left parietotemporal region with phase reversals at T5 and P3. FLAIR MRI revealed hyperintense lesions in the left temporo-occipital lobe, located mainly in the left inferior temporal lobe. Cerebral angiography revealed an arteriovenous shunt from the left occipital artery to the left transverse sinus with cortical venous reflux. The complex visual hallucinations were resolved after transarterial embolization. We therefore hypothesize that this patient's complex visual hallucinations were caused by epileptic seizures or changes in cortical blood flow caused by the cortical venous reflux from the arteriovenous fistula. In general, epileptic hallucinations expand into the bilateral visual field. We reveal that in rare cases, complex visual hallucinations can also be limited to the unilateral visual field without an anopsia. Additionally, we reveal that a dural arteriovenous fistula can cause visual hallucinations without hemianopia.

Melatonin-Responsive Complex Nocturnal Visual Hallucinations

ABSTRACT

Complex nocturnal visual hallucinations are vivid, dramatic, intricate visual hallucinations occurring during sleep onset or awakenings at night, generally lasting for a few minutes at most and disappearing with increased levels of light. They may occur in a number of neurological conditions, as well as in normal individuals. The optimal treatment for this condition remains unclear. We describe three patients with complex nocturnal visual hallucinations in whom melatonin brought about a dramatic improvement in symptoms. Our report suggests that melatonin may be a safe, effective treatment for this rare but often distressing and anxiety-provoking condition.