Chemosensory Disorders | Odd Smells and Tastes | Smell Disorders
Taste Disorders
| Burning Mouth Syndrome | Head Trauma

Chemosensory Disorders

At the Smell & Taste Treatment and Research Foundation we are devoted to testing patients with chemosensory disorders (dysfunction of smell or taste). The diagnostic evaluation includes a neurological examination, blood screening tests and a variety of smell and taste tests. We also assess how smell loss impacts upon psychological well-being, such as depression or social interaction and hence the quality of life.

Terminology describing the sense of smell and taste encompasses a whole new vocabulary. Listed below are some of the commonly used terms:

"Taste" or "Flavor" is defined as a combination of true taste, consistency, viscosity and smell. Approximately 90 percent of taste is smell. This is easily demonstrated by holding your nose and eating a chocolate bar. The taste of the chocolate will be similar to chalk. This demonstrates the phenomenon called olfactory synesthesia syndrome when you misperceive one sense as demonstrated by placing gentle pressure directly to your eyelids with eyes closed. You begin to see light spots before your eyes. These spots are actually caused by the pressure misperceived as light.

Similar is a combination of Cranial Nerve I (olfactory) and Cranial Nerve V (trigeminal) function. The trigeminal nerve is the nerve of the nose and face which detects pain or irritation. Trigeminal stimuli can be seen when a person begins crying while cutting an onion. The integration of the two nerves we interpret as smell.

The absent ability to smell is called anosmia. The most frequent cause for this is from head trauma secondary to automobile accidents.

A reduced ability to smell is hyposmia. We often see patients who present to our clinic with these complaints following an upper respiratory condition.

An increased ability to smell is called hyperosmia. For example, being able to identify the perfume that a person wore who sat in the chair before. Hyperosmia is seen in patients with cluster headaches, migraines and adrenal cortical insufficiency - Addison's Disease.

A hallucinated smell, phantosmia, implies olfactory system disruption which is often times seen in patients with seizures.

Dysosmia is a distorted smell seen in the presence of an odorant. Parosmia implies a smell system dysfunction, but still intact.Both definitions can be used interchangeably and are often times due to nasal polyps. A patient that exemplifies this is a woman who in the presence of the smell of coffee would smell flowers.

When an odor is normally perceived as hedonically pleasant and that same odor is perceived as unpleasant, this is called cacosmia. Symptoms also associated with this are headaches, dizziness, shortness of breath and anxiety.

Torquosmia is where a normally hedonically pleasant odor is perceived as chemical, burned or metallic

It is estimated that one-half of people over the age of 65 have a decreased ability to smell, as do 75 percent of those over 80 years old. Presbyosmia is the gradual decrease of olfactory ability with age.

Absent taste, ageusia, is often attributed to medications and surgical procedures. Antithyroid and antimetabolic agents along with radiation therapy, neoplasms and inflammatory diseases in the oral cavity can cause ageusia.

A hallucinated taste is called phantogeusia. This is described as an abnormal taste present in the mouth when nothing is there. One origin of this is seen in patients who have had dental fillings.

Metallic phantogeusia is a hallucinated taste of metal and has been seen as part of an aura or seizure in patients with temporal lobe epilepsy.

Many in the normal population experience a specific ageusia of one or more of the taste categories (salt, sweet, sour, bitter).

Hypergeusia is an increased ability to taste, while hypogeusia is a reduced ability to taste.

Windows are episodes in which those people who cannot smell or taste experience episodes of normal smell or taste lasting a second or two. This is called olfactory windows as it relates to smell andgustatory windows as it relates to taste.

Burning Mouth Syndrome (BMS) is more commonly seen in women than men. Patients complain of sensation as if their mouth and lips are on fire Diseases causing BMS include viral infection, salivary gland dysfunction, taste dysfunction, hematological disorders, central nervous system disorders, diabetes mellitus, and Sjogren's syndrome.


The treatment depends on the underlying origin for the problem. Treatment involves surgical intervention, use of medications such as vitamins, steroids, GABA modifiers, calcium channel blockers, antidepressants or anticonvulsants.

Origins of smell and taste problems include posttraumatic head injury, post viral infection, allergic rhinitis, polyps, neoplasms, nutritional and metabolic deficiencies, endocrine disorders, congenital/hereditary etiologies, medication, chemical pollutants, industrial dusts, surgery, and psychiatric disorders.

Most patients seen at our clinic are referred by their physician. Some are referred by attorneys whose clients have lost their smell or taste secondary to head trauma and are looking for diagnosis, treatment and compensation for their loss. We have even been asked to evaluate entire towns with exposure to toxic chemicals where entire communities are left without the sense of smell.

Some of the problems seen in association with chemosensory dysfunction are changes in appetite and diet, and the absent ability to detect gas leaks and spoiled foods. Due to the overwhelming effects the disorder can have on one's lifestyle, a high incidence of mood disorders also co-exist. Therefore , it is important to seek out help to identify, assess, treat, and manage chemosensory disorders.

General treatment approaches that can be implemented immediately for the safety of the chemosensory dysfunction patient include use of a gas detector, smoke detector, food taster, smell buddy, group therapy, and to check dates on all foods.

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Sensa Weight Loss System & Weight Loss Study:

For questions or information regarding the Sensa Weight Loss System please visit Please free free to call us toll free at (866) 514-2554.

Over the course of 25 years, Sensa creator Dr. Alan Hirsch has conducted ongoing research on the effects of smell and taste on eating habits, ultimately leading him to spearhead one of the largest studies ever conducted on weight loss. Over a 6 month period, 1,436 women and men sprinkled scented, flavorless "Tastant" crystals on everything they ate. Participants were instructed not to change their existing diet or exercise program.

The 1,436 people in the treatment group who completed the program lost an average of 30.5 pounds - nearly 15% of their total body weight. Those in the control group lost only 2 pounds, on average.

This was followed by a double-blind, placebo-controlled study conducted by an independent laboratory, in which participants lost 27.5 pounds and about 14% of their body mass, on average. Participants were instructed not to change their existing diet or exercise program. Those in the control group gained half a pound, on average.

Click here to view the 1,436-person clinical study
Click here to view the Double-Blind 3rd-party study

Foundation & Research Questions:

For questions regarding the Smell & Taste Treatment and Research Foundation or on the disorders discussed please feel free to write, phone, fax or email us. Please do not call the foundation directly for questions or information on Sensa.

To reach the Foundation call: (312) 938-1047 

e-mail address:

Postal address (Foundation only)
Smell & Taste Treatment and Research Foundation, Ltd. 
845 North Michigan Avenue, Suite 990W   
Chicago, IL.  60611    


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