Gustatory hallucinations: Description, Causes and Risk Factors:
Also known as gustatory phantasma and hallucination of taste. The term gustatory hallucination is indebted to the Latin noun gustus, which means taste. It is used to denote a taste sensation occurring in the absence of an appropriate tastant. Gustatory hallucinations tend to be enduring, unpleasant taste sensation qualified simply in terms of bitter, sour, sweet, disgusting, etc. However, they can also be described in more specific terms such as chloroform, charcoal, tobacco, rusty iron, blood, sperm, bile, garlic, grilled, peanuts, oysters, and mussels. Reports of pleasant taste sensation are rare. Most gustatory hallucinations are rare. Most gustatory hallucinations have occasionally been reported in association with contralateral epileptic seizures. Traditionally gustatory hallucinations have been distinguished from taste disorders that are not classified as hallucinations that are ageusia, hypogeusia, dysgeusia, hypergeusia, and taste agnosia.
Pathophysiologically, the mediation of gustatory hallucination is associated primarily with aberrant neuronal discharges in the primary gustatory areas, which are tentatively located in the temporal and/or parietal lobes. Theoretically, however, they can be mediated by any part of the taste delivery system. The anatomical correlates of this system are only partially known, but are believed to include the hippocampus, amygdala, peripheral taste nerves, and the tongues taste cells. In the latter case it has been suggested that tonic stimulation of the taste cells may play a part in their mediation. Etiologically, the centrally mediated type of gustatory hallucination is associated primarily with aura occurring in the context of paroxysmal neurological disorder such as epilepsy and migraine
These hallucinations, which are typically strange or unpleasant, are relatively common among individuals who have certain types of focal epilepsy, especially temporal lobe epilepsy (TLE). The regions of the brain responsible for gustatory hallucination in this case are the insula and the superior bank of the sylvian fissure.
Certain drugs, such as marijuana, ecstasy and LSD (lysergic acid diethylamide), blur the lines between consciousness and subconsciousness thereby causing hallucinations. Consuming a high content of alcohol can also lead to the same effect. The occurrence of hallucinations after taking these is common, and one of the withdrawal symptoms of these drugs might also include hallucinations.
Migraine sufferers can experience illusions or hallucinations of taste as gustatory aura symptoms.
Emotional disturbances were observed mainly when there was an involvement of the cingulate gyrus. When care was taken to avoid methodological errors in the interpretation of the clinical signs occurring after electrical stimulation, it became clear that gustatory hallucinations in man were related to the disorganization of the parietal and/or rolandic operculum. Electrically-induced temporal lobe seizures which included gustatory hallucinations as an ictal event probably spread to the opercular region by a functional reorganization of the connections within these epileptogenic areas.
The incidence of gustatory hallucination has not been well established, although temporal lobe epilepsy literature would suggest a figure far low than olfactory hallucinations.
Patients with gustatory hallucinations experience taste alterations
, a sensation of thirst, or excess salivation
. Other symptoms may include headaches.
The clinical assessment of gustatory hallucinations is notoriously difficult, due to their relative rarity, their susceptibility to suggestion, and confounding factors such as the prior - presence of food or drink in the oral cavity, smoking, the use of therapeutics or illicit substance, local medical conditions such as rhinitis and oral candidiasis, and general medical conditions such as influenza. In addition, their assessment is complicated by the close relation between the sense of smell and the sense of taste.
The detailed description of the experience is the critical diagnosis assessment. Additional tests for identifying mesial temporal lobe epilepsy may also be useful. These include interictal and ictal EEG, high resolution MRI with thin sections through the long axis of the temporal lobes, fluorodeoxyglucose PET, and neuropsychological testing. Each test may identify mesial temporal abnormality, which would support the diagnosis of epilepsy.
Treatment typically recommended only when the seizures progresses from a hallucination impaired awareness. In such situation, antiepileptic medications for focal seizures are the first-line treatment.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.